efin 941 March 1900 u F» An Examination of some THEORIIES i? Summary Studies were conducted by the Department of Home Economics in which tenderness data on two muscles cooked under four conditions were obtained on 91 steers. These steers were produced and fed under controlled conditions. All cattle were graded was especially outstanding in bottom round a to one-third grade by the area supervisor of the USDA cooked very well-done (212°F. + 25 minut Meat Grading Branch for the Texas-Oklahoma area. moist heat. Thus the bottom: round steaks be Percent ether extract, a chemical measure of marbling, very well-done tended to have tender muscle __ was obtained on the trimmed ribeye from the 9-10-11 and tender connective tissue. ’ rib cut. Scores for crumbliness of muscle fibers the amount of tiny, hard, dry particles which= the meat crumble on pressure by the teeth.f characteristic was not prominent in loin stea Scores for softness were highest in steaks c” rare (142°F.) by dry heat. Apparently their moisture content was at least partly responsi the impression of softness. * Two types of methods were used for tenderness testing: shear force values as the objective method and panel scores for three components of tenderness as the subjective method. The three components Y were connective tissue, crumbliness of muscle fibers Shear rerre Varaes rharrarea rhar lerh srea and softness. The theories relating tenderness to eame reagher as rheY were eeekea rhereUQhlY- a carcass grade and fatness, to connective tissue and ever, cooking bY "1055? hedi did "er Seem re muscle fibers, and to the conditions of cooking have them. Apparently by the time a steak temperat been examined in the light of the findings from 176°F. was reached, toughening had already this study. place and no tendering of loin steaks occur Carcass grade and marbling were not consist- . higher rerhPerareres~ Shear reree Values er . ently nor closely related to measures for tenderness reeha sreaks braised VerY Welhaehe iharraree} of connective tissue or of muscle fibers. Carcass rheY Were mesh mere rehaer rhah lerh sreaks Y grade and marbling were not as good bases for in the same way. Shear force values were deciding between moist and dry heat methods of similar for loin and bottom round steaks cooke; cooking as was formerly supposed. (142°F.) and gave little or no indication of the Connective tissue was much more tender in loin ehre er rhe rea9h eehherhve rrssae reuha '1' than in bottom round steaks. In bottom round steaks lea9es- Frem rhe aara Presehrear shear rerre V, it was quite tough in rare (142°F.) became somewhat dPPedfed i0 be le$$ The" Perreer as a "lease more tender when cooked either well-done (176°F.) total tenderness of meat from all cuts. _ by dry heat or medium-rare (185°F.) by moist heat; Th f. d. . d. t ‘h f H‘ ‘w c‘ and became still more tender when cooked very well- _ ese m mgs m ‘w e a ese .0 done (212°F. for 25 minutes) by moist heat. Results lom and 1391mm r°und_c_l° not respond all!“ of these tests show that the moisture in the moist- same fsmdnmns or ‘smlfmg’ Much addmm‘ heat method appeared to have been needed to obtain search '5 heeded r° explum h°w rehder meal m, high meat temperatures and not to furnish water for aereerea herere weklns, Whar haPleehs re rhe re the chemical change of collagen into gelatin, as had "e55 er mear as rr reeks aha Whar rauses rhes been thought previously, ferences in tenderness. Contents $Ummary... ........................ ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, a 2 Softness Related to Cut > Introduction ,,,,,, ,,,, ,,,,, ____________________________ H 3 and Condition of Cooking _________________________ Some Theories about Tenderness ,,,,,,,,,,,,,,,,,,,,,,, _, 3 Tenderness Characterized by v Experimental Conditions ....................... 6 Shear Force Value ,,,,,,,,,,,,,,,,, .......................... Tenderness Characterized by Scores Shear Force Value Related for Connective Tissue.......... .............................. _. 8 to Carcass Grade. ......................................... . Connective Tissue Related to Carcass Grade .. .. 9 Shear Force Value Related r‘ Connective Tissue Related to to Ether Extract Percentage of Ether Extract ...... .................... .. 9 Shear Force Value Related . Connective Tissue Related to to Cut and Condition of Cooking Cut and Condition of Cooking... .................. .. 9 Relation of Shear Force Relation of Results to Older Theories .............. ._ 11 Values to Panel Scores .................................. Tenderness Characterized by Scores Discussion ,,,,,,,,,,,,,,,,,,,,,,, I for Crumbliness of Muscle Fibers , ,,,,,,,,,,,,,,,,,,,,,, ._ 14 Grades . Crumbliness Related to Cut Marbling , , a ,,,, __________________________________ __ ‘ end Condition of Cooking...... ............... _. . 15 Conditions of Cooking .............................. __ Tenderness Characterized by References . ,. _____________________ __ 5<0te$ for Softness . ................................ .. . 16 Acknowledgment .. . COVER: Loin steak from USDA Prime Carcass has more fat and more abundant marbling than loin steak from USDA Stand- ard (Iarrass. examination of some DERNESS Is ONE OF THE MOST IMPORTANT cteristics of beef from a consumer’s view- ' . Yet the causes 0f tenderness or toughness oorly understood, and no visible character- ‘is known which is thoroughly reliable as an v ator of tenderness in beef. I There are many theories about selection of t for tenderness and the best methods of cook- ito retain or to develop tenderness. While ~ theories have seemed logical to many peo- iithey were seldom based on adequate knowl- . A thoroughly reliable indicator of tender- in the feedlot or in the meat market is not Y, n, but research is in progress to improve . situation. me Theories about Tenderness - Connective tissue was thought to be the prin- . lcause of natural toughness in meat. This resulted in the division of the meaty cuts of jcarcass into the so-called “tender cuts” with f- connective tissue (such as rib and loin) and L “less tender cuts” with much connective tis- v (such as bottom round). ‘ “Marbling” is the term used to indicate the ence of flecks or streaks of fat within mus- . Marbling has been regarded as an import- ; indicator of tenderness for the following rea- a fat deposited in the cells was supposed to _nd them and make them more tender; fat . supposed to spread apart the strands of con- " ive tissue between the muscle fibers and be- n the muscle bundles, making the meat more der. Marbling is an important factor in de- w ining USDA carcass grade; Figure 1 gives trations of marbling. _ USDA carcass grades were supposed to be n indicators of natural tenderness in beef (Bu- ; of Human Nutrition and Home Economics, 2; United States ‘Department of Agriculture, 1; National Livestock and Meat Board, Meat nual). However, grading is designed, primar- , to group carcasses according to certain char- lvia Cover, professor, and Robert L. Hostetler, instruc- r, Department of Home Econmics, Texas Agricultural wperiment Station. Theories about Beef Tenderness By using new methods SYLVIA COVER and ROBERT L. HOSTETLER* acteristics as a means of facilitating their trans- fer through commercial channels. Three factors are used to determine USDA carcass grade: con- formation, quality and finish (United States De- partment of Agriculture, 1956; National Live- stock and Meat Board, Meat Judging Handbook). “Conformation” refers to the form or shape of the carcass and may be expected to have little relationship to tenderness. “Quality” includes ‘maturity or age of the animal, marbling, texture, color and firmness. “Finish” refers to the amount, distribution, firmness and texture of ex- terior and interior fat. The Meat Judging Hand- book discusses the Way in which these factors are used in assessing USDA grades. Since marbling and maturity are the two most important factors consider- ed in evaluating quality, variations in these two factors together with varia- tions in conformation can be combined in chart form to indicate, by grades, the manner in which a superiority in de- velopment of quality is permitted to compensate for an inferior development of conformation and vice versa. This chart is used in carcass grading and in the teaching of carcass grading, Figure 2. Marbling and maturity are the two factors which have been considered most closely related to eating quality of meat (tenderness, flavor and juiciness). Flavor and juiciness will not be con- sidered in this report. The importance of marbl- ing and maturity in the above system of grading is responsible for the assumption that USDA» car- cass grades should be related to tenderness. Rec- ommendations for cooking beef cuts have taken into consideration not only the cut of meat but the grade of carcass from which it came. Dry heat methods of cooking (broiling and roasting) were considered suitable only for nat- urally tender meat—that with no tough connec- tive tissue. Such cuts were thought to include rib and loin, if they came from Prime, Choice and Good grade carcasses, and a few other cuts (top round, rump and blade chuck) but only if they came from Prime and Choice grade car- 3 casses. Such cuts from the higher grade car- casses were considered to be naturally tender be- cause of the absence of tough connective tissue. Moist heat methods of cooking, such as brais- ing, were recommended for the “less tender” cuts -rib and loin from carcasses below the Good grade; top round, rump and blade chuck from carcasses below the Choice grade; and other cuts, such as bottom round, from carcasses of all grades. The less tender cuts were thought to contain so much or such tough connective tissue that they could be made tender only by “cooking for a long time by moist heat.” Connective tissue in the meaty cuts Was thought to be made up largely of collagen, a protein which was supposed to be changed into gelatin only when subjected to moist heat for a long time. The theory was that the moisture in the moist heat was needed This theory to hydrolyze collagen into gelatin. A — Extremely abundant C — Abundant E — Slightly abundant G— Modest I — Traces Illustrations a d a p t e d fr o m negatives furnished by New York State College of Agri- culture, Cornell University. I Figure 1. Illustrations of typical marbling referred to in the official U. S. Standards for grades of carcass beef. (Se- lected from the pictures published in the chapter on Beef Grading in the Meat Iudging Handbook, National Livestock and Meat Board, 1958, which was prepared by I. G. Pierce and associates, Standardization and Grading Division, Agri- cultural Marketing Service. U. S. Department of Agriculture. 4 has been applied to meat cookery for many However, raw meat contains about 70 pej water and some drips out as it cooks. The l” therefore, for an additional source of moi during cooking seemed questionable. Temperature is another factor which thought to influence tenderness of cooked .5 A so-called “principle” off-meat cookery s that high heat toughens protein. This was g posed to be applicable only to the proteins of muscle fibers. It was used as a basis for r; mending that meat be cooked at low cooking g peratures and to low final meat temperatur well. According to this theory internal Y temperatures of around 142° F. (rare) sh give more tender muscle fibers than those ari 176° F. (well-done), yet beef muscle reaches r peratures much higher than 176° F. when i, braised by the usual household methods. For stance, water simmers at 194° F. and boil 212° F. The steam above water boiling in a5‘ covered with a heavy well-fitted lid may slightly above 212° F. During braising, meat exposed to these temperatures for times , enough to reach them. Cover et al. (1957) g heat penetration curves which indicated that a . penetration into 1-inch steaks was relatively i” during braising so that steaks of 0.5 pounds age weight reached 212° F. in only 15 to 20 y utes cooking time and those of 0.6 pounds a‘ V age weight in only 2O to 38 minutes coo time. Cooking times longer than these W0‘ mean that the meat was held for the rest of _ time at 212° F. If a steak weighing about o half pound were braised for 45 minutes, it mi be held at 212° F. for 25 to 30 minutes. A peg nent question is: “Are beef muscle fibers tou ened during braising ?” Although low cooking temperatures were 5 vised for all meat cookery, a wide variety of peratures were classified as “low.” Temp tures around 400° F. were considered “loW” broiling but “high” for roasting. Temperatu; around 250° F. were considered “low” for ro, ing but a temperature of even 212° F. (boili was considered “high” for braising. Thus, for moist heat methods the recommi ded cooking temperatures will be lower but meat temperatures will be higher than for heat methods. As a result, the theories used recommending cooking procedures could be vf fusing when actual temperatures are conside t A clear understanding of the chemical and .2 ical factors involved in meat cookery is long of due. 1 i One of the difficulties in cooking meat that it will be tender is that muscle fibers connective tissue are so mixed in beef muscle ti g both must be subjected to whatever cooking ti; ditions are selected. Thus, for steaks which p Q A sumably have tough connective tissue, the co. ing method recommended is one which insures; tigation. I ivelys high internal steak temperature for a iively long time. The purpose is t0 tenderize connective tissue but this cooking condition d, supposedly, also toughen the proteins in- each muscle cell of the steak. As a result, retically, the muscle fibers of a braised steak » ld be toughened at the same time that the p; ective tissue is tendered. Lehmann (1907) gnized this problem more than 5O years ago. i Satisfactory tenderness must include tender le fibers as Well as tender connective tissue. use the usual recommendations mentioned i; not always produced tender meat, these old- heories of tenderness seemed to need further A refinement in thinking and working with ‘erness of beef has become necessary. n known for more than 50 years that tender- j‘; is influenced by two structures in meat— g ective tissue and muscle fibers; that these structures are not uniformly distributed in "cles; and that some cooking methods may erize connective tissue while toughening mus- xzfibers. It became apparent that one score for erness was not adequate for following ten- ess changes precisely and this method of test- was abandoned. Instead, a panel rated the It has Figure 3. Panel members testing tenderness subjectively in booths made from small tables and plywood panels. En- tire room is kept quiet. meat for tenderness of connective tissue, for soft- ness and for crumbliness of muscle fibers (Cover 1959), Figure 3. A mechanical cutting device was used to obtain shear force values. In this manner, four ways were provided for character- izing the tenderness "of the beef used in this study. The relationship of carcass grade and fat- ness to each of these Ways of testing tenderness was studied but was reported only for tenderness of connective tissue and shear force values. MINIMUM MARBLING REQUIREMENTS (WITH NORMAL COLOR, TEXTURE AND FIRMNESS OFLEAN FOR APPLICABLE GRADE AND MATURITY) .» FOR THE PRIME, CHOICE, GOOD, STANDARD, AND CGAMERCIAL GRADES OF BEEF, BY SPECIFIED DEGREES OF CON FQRMAT ION AND MATUR“! cancass CONFORMATION “"79"” 530"" i. oaans EQUIVALENT 1 a b c d e f ‘ Slightly Moderately ff Minimum Prime or better abundant abundant Abundant l P . _ _ _ Moderately Very "me Mid-point Choice‘ abundant Abundant abundant '7 I Very E xtre me 1y i Minimum Choice‘ Abundant hbundant abundar! f Minimum Choice i ,1 or better Small Modest Moderate < Choke Slightly Moderately g Mid-point Good‘ Moderate abundant abundant p" Moderately Very Mid-pain; Standards abundant Abundant abundant 1 Mid-point _ Good or better Traces Slight Small i 99°13 High Standard‘ Slight Small Modest Slightly Minimum Standard‘ Modest Moderate abundant ’ Mid-point _ Practically ,7 Sgandafd 9f bggggf. DCVOld dCVOld TIQCCS a Practically , WWW‘ High Utility‘ devoid Traces Slight Minimum Utility‘ Slight Smill Modest , . Minimum Commercial \ ‘ or better Small Modest Moderate r Sli htl C°""“°'°m Mid-point Utility‘ Modest Moderate ‘bridal; _ Slighfl)’ Moderately _ Minimum Utility‘ M°d¢ffll¢ abundant abundant i, negates or uaaguug MATURITY snows 1, Egrremely abundanr 7, Modgst a. Red, porous, chine bones; soft, pearly-white cartilages. 2. Very abundant 7'1, ‘-3. Srmll amour]; b. intermediate maturity for Prime, Choice, Good or Standard grades. 3. Abundant 9. 5118b; amomr c. Approaching maximum maturity for Prime, Choice, Good or Standard grades.g..i,;ij__ 4, Modemmly abundant 1()_ Trams d. Cartilages slightly mcre than moderately ossified. , WIIEQ 5- Slightly abundant 11. Practically devoid ¢- C"‘il°8°5 ""1? ¢°mPI¢WIY °$$m¢d~ 6. Moderate 12. Devoid f. Hard, white, chine bones; cartilage: entirely ossified, outline of cartilages barely visible. I Example only. Illustrates the extent to which more than minimum quality must be present to compensate for less than minimum conformation. June, 1956 Figure 2. Minimum marbling requirements for grades of beef, by specified degrees of conformation and maturity. (Courtesy of Standardization and Grading Division, U. S. Department of Agriculture.) Experimental Conditions Meat was available from 57 steers in 1956. Shear force values for all were reported by Cov- er, King and Butler (1958). However, judges’ scores were complete for only 55 and only these 55 steers are included in this report. Records were complete for 36 steers in 1958. All of these steers were produced at Substation No. 23, Mc- Gregor, Texas. This substation was formerly known as the Bluebonnet Farm, and the steers known as the “Bluebonnet Steers”; they will be referred to in this way throughout this bulletin. After Weaning, they were full fed on a ration containing 66 percent concentrates, with weights recorded at monthly intervals until slaughter. All were in gaining condition at slaughter. Although feed was before them at all times, the rate of gain varied considerably among the animals. This is caused primarily by differences in the in- herent ability to gain and usually prevails in any group of steers. A record of such differences in rate of gain was one of the purposes of the pro- duction phase of these tests. Each year all of the steers were slaughtered within a period of 1 Week and the carcasses pro- cessed in the meats laboratory of the Department of Animal Husbandry. The ages at slaughter ranged from 13 to 16 months. Weights of the chilled carcasses used in 1956 averaged 492 pounds with a range of 301- 637. Those used in 1958 averaged 469 pou with a range of 370-561. i All carcasses were graded and placed in upper, middle or lower third of the grade by supervisor of the Texas-Oklahoma area of ~ Meat Grading Branch, Agricultural Marke Service, USDA. Specifications for USDA~ y carcass grades were revisefd in June 1956, arating the Commercial grade into Standard, young animals, and Commercial, for older o Steer carcasses grading Commercial in the tests would have graded Standard under prj, specifications and are so classified here. In I ‘ the carcasses graded as follows: 4 Choice, Good, 26 Standard and 1 Utility; in 1958, Good and 19 Standard. Production proceduf" were standarized and no attempt was madei obtain an equal number of animals in each gri A measure of marbling was obtained on i carcasses—percent ether extract of the trimmi ribeye from the 9-10-11 rib cut. This rib cut made along the bony structure according to pf; cise directions to provide uniformity of cutt’; among many animals. Ether removes the fa ' substances in meat and the percentage of ether extracted material from trimmed samples is regarded as a chemical measure a marbling. Since the percent ether extract w», a obtained on the trimmed “eye” muscle from 9-10-11 rib cut, percent ether extract was thou 7i: to be closely related to the marbling of Figure 4. Longissimus dorsi muscle in loin steaks used for tenderness testing, taken from steaks shown on cover. Le USDA Standard Carcass; Right. USDA Prime Carcass. 6 ch is a major criterion 0f grade determination hought to be a good indicator of the tender- of the meat. These data do not include an * number of animals with each percentage y er extract. The percentages obtained were 70f the results of research on the production p ese animals. éThe carcasses were aged at about 36° F. On Seventh day after slaughter, steaks contain- nly one large muscle were cut from loin and dim round. The steaks were cut 1-inch thick, med free of bone, wrapped individually, froz- t -20° F. and stored at 0° F. until the tests yd be made, Figures 4 and 5. The steaks were ed under standardized conditions by using "moist and dry heat methods. Thermometers used to obtain steak temperatures and the or pot temperatures. Standardized methods fcooking steaks were needed so that specific bles could be studied. A dry heat method was needed for cooking which would be similar to home broiling i have the advantage of easy standardization. use oven temperatures are more easily stand- 'zed than broiler temperatures, cooking in the , compartment of a well-ventilated gas oven p was considered. These oven units have glass is through which oven and steak thermom- s could be read. In them, an oven temper- e could be maintained within less than 4° F. iation (i1° C.) while in the broiler the actual ‘perature often fluctuated 50° F. or more from a desired temperature. Preliminary work indi- j» considerable spattering of fat when steaks 7e cooked in these ovens at 400° F., the “low” . perature recommended for broiling. There much less spattering when the oven temper- are was lowered to 350° F. Even this lower perature is higher than that recommended for ting beef (300° F.) Adequate venting of the ns prevented the accumulation of moisture i» the steaks browned nicely. Because the broiler ts were lined with bright foil and open wire p s were used, the steaks browned on the un- side without turning. The heat transfer ap- , red to be by radiation from the hot oven walls Y. the bright hot foil, by convection from the t foil as well as from the hot gases from the a bustion chamber (although these gases were ected considerably by the large size of the iler pan), and by conduction from the hot iler rack. A In the tests reported here, the oven with the iler pan, foil and wire broiler rack in place thin it was regulated at 350° F. before cook- p0,; was begun. Cooking was done with the oven hrs closed—one‘steak per oven. Steak temper- res were read through the glass oven door. l. rare steaks were removed at a steak temper- A re of 142° F. and ‘NGll-dOIIQ ones at 176° F. is method of cooking steaks is practical for time use. It has been called “oven broiling” by author in other publications, but for this bul- Figure 5. Round steak with Biceps femoris muscle used tor testing separated from rest of steak. letin it will be called “oven-cooking.” This is a dry heat method of cooking. It also may be call- ed “air cookery” as distinguished from steam, water or fat cookery. A moist heat method was needed which would approximate home conditions and yet have the steak surrounded by only one cooking med- ium for good control of experimental conditions. Since rate of heat penetration into meat differs with the cooking medium and rate of heat pene- tration seems to affect tenderness, steaks cooked half in water and half in steam might present a problem in sampling for technical studies. The braised steaks for 1956 were browned and then cooked in steam on a rack over boiling water. Browning before braising was done in this laboratory in the following way: a heavy pot was preheated to 475° F. in a standardized manner over a gas flame. One tablespoon of cook- ing oil was added and the steak was browned 1 minute on each side. However, preliminary work in 1957 on steaks from 30 steers indicated that browning before steaming had little or no effect on weight loss, cooking time, juiciness or tender- ness (Table 1). A smoother cooking routine is possible when browning is omitted, reasons the 1958 braised steaks were not brown- ed. Only one steak was cooked in each pot. Ther- mometers of special design were used to follow the steak temperatures. Half of the braised steaks were removed at an internal temperature of 185° F. For the others the cooking was con- tinued to an internal temperature of 212° F. and for 25 minutes thereafter. The steaks which were removed at 185° F. were underdone. The meat and the juice were slightly pink. The steaks, which were cooked to an internal temper- ature of 212° F. and held there for 25 minutes, were very well-done. They were used to simu- late the conditions in many homes where brais- ing time may be from 45 to 60 minutes. This is a moist heat method of cooking. It may be called 7 For these < “steam cookery”‘as distinguished from water, fat or air cookery. Weights, cooking time and weight losses are given in Table 2. Steaks oven-cooked to only 176° F. were well-done but those braised to a slightly higher internal temperature of 185° F. were medium-rare. Similar meat temperatures did not produce the same degree of doneness in air as in steam. The red color of meat is caused by pigments, principally myoglobin. Change in these pigments is thought to begin around 149° F. and to be complete at around 176° F. with the gray color of cooked meat. Roasts cooked very slowly in air at an extremely low oven tempera- ture of 176° F. will become gray in color at 158° F; roasts cooked in air at a normal oven temper- ature of 300° F. will be gray in color at 176° F. (Cover, 1943). The full explanation of this is not known exactly although there has been some work on this problem (Tappel, 1957; Bernofsky, Fox and Schweigert, 1959). It is thought that the amount of red color left in the meat depends on the meat temperature and on the time the meat is held at that temperature. The steaks braised in steam required only 10 to 15 minutes to reach 185° F. while the oven-cooked ones re- quired 55 to 70 minutes to reach 176° F. Similar readings on the thermometer were reached much more quickly in steam than in air. Evaporation of moisture from the meat surface takes place freely in air, but evaporation from the surface of the meat probably does not take place at all in steam. The heat, which is needed to evaporate meat juice from the surface, slows the cooking of the meat in air, but this heat (latent heat of evaporation) is not lost when meat is cooked in steam. Therefore, the internal temperature tends to rise more rapidly in steam than in air. In a previous study, Cover and Shrode (1955) cooked thin steaks (three-fourths inch) well-done in a broiler which had been preheated to 200° TABLE 1. CHANGES IN CERTAIN VARIABLES WHEN BRAISED STEAKS WERE BROWNED AND NOT BROWNED Averages of 30 steers Variables Loin 283:]: Raw weight Browned 206 g. 272 g. Not browned 188 g. 267 g. Total cooking time Browned 48 min. 52 min. Not browned 51 min. 53 min. Weight loss Browned 35 ‘X, 37 ‘X, Not browned 34 ‘X, 37 ‘X, Shear iorce values Browned 10.2 lb. 5.7 lb. Not browned 10.8 lb. 5.7 lb. Tenderness of con- Browned 8.8 6.6 nective tissue Not browned 8.9 6.2 Tenderness of Browned 5.7 6.8 muscle fibers Not browned 5.7 6.6 Iuiciness Browned 2.1 2.7 Not browned 2.0 2.7 TABLE 2. WEIGHT, COOKING TIME AND WEIG y OF STEAKS Method Raw To‘?! y. Cut of Doneness‘ weight, 6091111191 ' cooking pounds tune‘ i minutes 1956 data (55 steers) Loin Oven-cooked Rare g_ f 0.4 24 Well-done *- 0.5 56 Braised Medium-rare 0.4 11 Very 0.5 46 we11.done Bottom Oven-cooked Rare 0.6 29 round Well-done 0.6 70 Braised Medium-rare 0.6 15 Very 0.6 50 well-done 1958 data (36 steers) Loin Oven-cooked Rare 0.4 28 Well-done 0.5 61 Braised Medium-rare 0.4 14 Very 0.5 51 well-done Bottom Oven-cooked Rare 0.6 28 round Well-done 0.6 68 Braised Medium-rare 0.6 16 Very 0.6 52 well-done ‘The final meat temperature of these steaks was 142- oven-cooked rare; 176°F. for oven-cooked well-done.‘ i for braised medium-rare; and 212°F. and held there l minutes for braised very well-done. 7. ; C. (392° F.). Thermometers were inserted_ the steaks but internal meat temperatures ~ not used as the end point of cooking. The ;j was browned well on one side (25 minu turned and browned on the other side (10 utes). The meat temperature reached 75-78 (167-172° F.) in the first 25 minutes. It d" ped about 5° C. (9° F.) when the steak was ed and did not recover by the end of the coo, period. The drop in temperature is believ have been caused by rapid evaporation from‘ freshly turned moist surface. '3 Tenderness of the meat in the tests I measured subjectively with a panel and 0b tively with a shearing device. Tenderness s 5 obtained from judges have usually been reco T as a single measure. In an effort to get .7‘ precise records on tenderness differences, . tenderness of the beef used in this study" characterized in four ways: A panel, rated. meat for tenderness of connective tissue, for)‘; ness and for crumbliness of muscle fibers; sj force values were obtained with a Warner-B ; ler shearing device. 7 ' Tenderness Characterized by? t Scores for Connective Tissue According to the older theories about derness, the more tender connective tissue ~ found in the so-called “tender cuts.” These w,“ j. with little connective tissue, such as 10in, h were well-marbled and from carcasses of 1 grade. Tougher connective tissue was g ght to occur in 10in cuts with little marbling ‘from the lower grade carcasses and to occur 1 ially in certain muscles with a lot of con- give tissue, such as bottom round. It was ght that tough connective tissue could be 4 tender only by long slow cooking in “moist ’ Scores for tenderness of connective tissue in _ study were based on a scale in which the est score was the most tender. This indi- w that only a tiny amount of soft connective e was felt. This tender connective tissue is ily masticated and is not considered objec- able. The lowest score was given to a large _unt of hard connective tissue which cannot masticated. It must be gulped or discarded. s likely to be called “gristle” by most people. tough connective tissue is highly objection- I. This method of scoring should be regarded (a somewhat crude attempt to record oral evi- g of connective tissue. More sophisticated ring patterns may come later. ‘i In 1956 an 11-point scale was used (0-10). 1958 it was reduced to a 9-point scale by omit- 4 the zero and 10 of the 11-point scale (1-9). NECTIVE TISSUE RELATED TO CARCASS GRADE “ USDA carcass grade was plotted against re for tenderness of connective tissue. Graphs re made for each of the four conditions of king for each of the two cuts. The data for '- 1956 steers are given in Figures 6 and 7 (loin 4 bottom round, respectively) and for the 1958 rs in Figures 8 and 9. Each of these figures ; four parts: the two upper ones for oven- gking rare (A) and well-done (B); the two er ones for braising medium-rare (C) and v well-done (D). Had high carcass grade been closely related tender connective tissue, the dots in Figures through 9 would have fallen along a line ex- ding from the lower left toward the upper ht. There is little or no evidence of such a ‘nd in any of the four conditions of cooking '_ either of the two cuts in either year. Carcass Sade, therefore, seemed to have little practical ationship to tenderness of connective tissue. 'eover, USDA carcass grades did not identify 5 of the tender conective tissue successfully. ese findings cast doubt on the value of USDA rcass grades as a means of indicating tender- i, s of connective tissue. NNECTIVE nssus RELATED TO RCENTAGE OF ETHER EXTRACT Marbling refers to the light specks of fat in e red muscle tissue. The fatty substances were moved with ether and the amount removed in is way (extracted) was calculated as a per- centage of the dry weight of the muscle. The percentage of ether extract is called a chemical measure of marbling. The percentage of ether extract in the trim- med ribeye muscle in the 9-10-11 rib cut was plotted against score for tenderness of connec- tive tissue. Graphs were made for each of the four conditions of cooking within each of the two muscles. The data are given in Figures 10 and 11 (loin and bottom round, respectively) for the 1956 steers; and in Figures 12 and 13 for the 1958 steers. These graphs show no trend from the lower left to the upper-right which would have occur- red had tender connective tissue been associated closely with high percentage of ether extract. Moreover, the tender connective tissue was not identified successfully by percentage of ether ex- tract of the ribeye muscle in the 9-10-11 ribs. From these data, marbling of the ribeye in the 9-10-11 rib cut as measured by percentage of ether extract seems of doubtful practical value in choosing meat with tender connective tissue. CONNECTIVE TISSUE RELATED TO CUT AND CONDITION OF COOKING Tenderness of connective tissue for each cut and condition of cooking may be observed in Fig- ures 6-9 or 10-13. Loin steaks (Figures 6, 8 or 10, 12) scored high for tenderness of connective tissue for each of the conditions of cooking (A,B,C,D). Cook- ing by moist heat (C,D) did not seem to improve further the tenderness of connective tissue in these loin steaks. Bottom round steaks contrasted sharply with loin steaks from the same carcass in that scores for tenderness of connective tissue were affected markedly by condition of cooking (Figures 7, 9 or 11, 13). The bottom round steaks cooked rare in the oven (A) contained tough connective tis- sue which became more tender (more easily mas- ticated) when oven-cooked well-done (B). Brais- ing to medium-rare (C) tendered the connective tissue about as much as did oven-cooking well- done. The greatest tendering of connective tis- sue occurred when bottom round steaks were braised very well-done (D). Average scores for tenderness of connective tissue by cuts and conditions of cooking in each year are given in Table 3. Significance of the differences was determined by analyses of vari- ance, a statistical measure of the uniformity of the difference. The actual scores vary from year to year. Changing from an 11-point scale in 1956 to a 9-point scale in 1958 could have caused some of this variation, other causes of variation were: differences in animals, in personnel on the pan- els and in personnel doing the cooking. Yet the similarity in trends for the 2 years is remarkable. These trends are: 1) in loin steaks, tenderness of 9 connective tissue vvas not affected by condition of very Well-done than medium-rare in both cooking in either year; 2) in bottom round steaks, and 3) connective tissue in bottom round’ the connective tissue Was more tender oven-cook- tougher than that in loin under all conditio ed well-done than rare and more tender braised cooking except braising very well-done. TENDERNESS or comcrrvz TISSUE, 1.0m smxs scomas IENDERNESS 0F CONNEGIIVE TISSUE, B. ROUND STEAKS, USDA LARGE AMT. rmnnm AMT. SHALL AMT. SMALL Am, rm! m, usm. LARGE Am‘. 1421mm m, SHALL m1‘. SMALL AMI‘. m! a amass or or OF or FAIRLY or GARCASS 0F 0F 0F 0F FAIRLY * " GRADE man 0,1‘, 21mm c_:r_ rum c3, son c,'.r, son c,r, cum: xuuw c,'r, mm cgr, Flint ch‘, son c,r_ soar o 1 2 ' a 4 s a 1 a 9 1o o 1 2 a a s s 1 s OVBN~COOKED ovau-cooxso A, mu: (e15c, or 14m.) t, mu (are, or 142'? ) + - I ' ' ' ' o r + - ' 5 0 ' ' cnorca ' 9 " cnozcs ‘ 9 - - o - - - o + - o Ill + ~ 00000 I G003 - O . .- GOOD - COO h — ~ o o I 000 - — - o o’ o + p O + - O . O .0‘ O s-rmm- 0000a Summ- o I out 0U 0o - - 00D — - - 00o o + ~ ~ + — ummr ' * umm " - - , L , _ 0 , " ' " , O. . . n, WELL-DONE (sow, or 175%,) a, HELL-DONE (so°c, or 176°1-"_) + - I I I I I 001 + - I l in ' I caorcs ' 9i 0110102 ' 9 - - o ~ — - o + - I. + - 0 ‘I0 0o o G009 “ U‘ coop “ 0O ‘IQ O - - I000 - - o 0 coo o o o + - .0 + - o coo o ooo o 0 I smmymu)" O O“ STANDARD - O ‘O O OO - ~ 00o 1 — - o l o + - ~ + — UTILITY ' ' UTILITY - " . , , . , O “ - . . . 9 . amrsz-zn BRAISED c, rmznnm-maz arc, or 1.85°F,) c, AEDIUMJKARE (aswc, or 185°F,) + " I I l I I Q" + “ I I I O I CHOICE ‘ 9 ' cuoxcr: * 9 ... _ .- - _. . + - 0'50 + - I 0o 0 00o a GOOD - I 0 GOOD - 0o o fl I - - ' 0o | — - ol O o o o + - OI.“ + - I I o col o 0o smmm, ~ 0 0 0'.» STAWARD - o o 0 o 0o I00 - - 00o r — - I o o + - - + - ITIILITY ' ' UTILITY — - l l _ _ _0 - — - i _ , o _ n, VERY WEIIL-DONE uoojc, or 212"r,_ + uoiggc 130R 2s muurss) n, view want-noun (1oo°_c_ or 212°1=_I+ legume roa 2; + - I + - CHOICE ' ‘J CHOICE ' ... _ .- _ _ + - + - OO O coon " . coon ' — - 090 — - 0 o + - 0 0 h? + - o o o smmmrm ' ' ."' smmmw " 9 —~ - I 0m _ - + ' q + ' UTILITY * ‘ urzurr " _ 5 l 1 1 | l . n _ ' l . 1 . | Figure 6. Carcass grade plotted against tenderness of Figure 7. Carcass grade plotted against tenderness! connective tissue for four conditions of cooking. Loin steaks connective tissue for four conditions of cooking. Bot from 55 Bluebonnet steers, 1956. round steaks from 55 Bluebonnet steers, 1956. ' 10 raunznmzss or commcrrvz TISSUE, 1.0m srmxs, SCORES SMALL m, snau. m, smm. m, um man rum FAIRLY ma. c,r, c,:r, son: c,'r, son C-TL 3 4 5 6 7 s 9 ovsu-coom-zn A, was (arc, or 142°r,) + - l I - HI Q. - - - ll oooo ‘oli- + - O . i“ ‘I . smunmm- o — i " - _ , ,0 b ' n, wan-room: (8o°c, or 176W.) _"i + I I - _ coon " F ‘ * - - n. dl a e + — ofiflo - Lsmnnm" - - , , 0o, BRAISED c, mama-mm: (are, or 1zs°1=,)_ - 1 - o o0 ~ oolol 00lo- o o o o IQQIB o m . - . I I ' ‘l _ n, VERY wart-non: (1oo°c, or: 212w‘, + 2s urmmas) + ‘ I ' -. 1:001) " 99 It l " - I ollol C 0 + - oolllo Q - STANDARD" 9 ‘ - , , o _o ~ Figure 8. Carcass grade plotted against tenderness of nnective tissue for four conditions oi cooking. Loin steaks 9- 36 Bluebonnet steers, 1958. jElATlON OF RESULTS TO OLDER THEORIES The theories that connective tissue is most nder (most easily masticated) in carcasses of 'gh USDA carcass grade and in carcasses with _e;greater degree of marbling in ribeye were otsconfirmed in these tests. The data from both ears were in remarkable agreement on these oints. These two older theories on how to select g. eat with tender connective tissue seem to be of ‘oubtful practical value for animals such as those sed in this study. 1 _ The older theories and recommendations bout cooking methods which are suitable for the o-called “tender” cuts seem to need revision. a he connective tissue in these loin steaks did not ‘ eem to be affected by these four conditions of rzunmmzss or CONNECTIVE nssuz, n, ROUND s-rmxs, SCORES USDA macs SMALL ma, smu. Ara, SMALL AMT, rm CARCASS m, man rum FAIRLY m1‘, 01mm: mm c,'r, c,-r, sorr 0,1, sosr c,'r, c,'r 2 3 4 5 6 7 8 9| OVEN-COOKED A, RARE (arc, or 142°1=,) + l I F “ coon * 99 ‘ -o o a“ lo o ~ + - 0| Con“ q ~ STANDARD ' 9 “ — - o o , _ , n, WELL-DONE (ao°c, or 176W.) + ' ' I w G001) * 0 . “ - - 0 I Q o0 Id - + - o lo J fl o smurmu) " 9 ‘ — - , o o , , BRAISED c, MEDIUM-RARE (ss°c, or 1s5°r,) + _ . . . coon " 9 ' - ~ o o “.0 o o - + - 0 o lo U 0 - smmmu) " 9 .. _ l . g I L , n, VERY WELL-DONE (1o0°c, or 212°F, + 2s mwrss) + _ . . . GOOD - 0o o — — - o o0 I o‘ o o — + - o o1 o “I I ~ smmmnn " 9 ‘ - - l l o0, Figure 9. Carcass grade plotted against tenderness oi connective tissue for {our conditions o! cooking. round steaks from 36 Bluebonnet steers, 1958. Bottom cooking. Thus, the old recommendations that dry heat methods of cooking be used for only those loin steaks from carcasses of Prime, Choice and Good grades and that moist heat methods be used for the lower grades to soften the connec- tive tissue seem unwarranted for young animals such as those used in these studies. With bottom round steaks, the results from research could be regarded as in line with the older theory that tendering of heavy connective tissue takes place only at low temperature in moist heat, but other temperature considerations should be pointed out. temperature (212° F.) was much lower than the oven temperature (350° F.) and one of the moist heat conditions gave the greatest tendering, the Although the braising ll mm 317mg"; Tziwsnnszias or CONNECTIVE TISSUE, 1.0m stems’ sconizs or tum macs AMT, neuron AMT, srmu. AMT, smu. m, rm: mar, m 9-40-11 or or or or mmr or an; cu-r man c.r, rum 0,1", FLRM c,r, sorr c_r, SOFT c.r, 1. on masts o 1 2 3 l» 5 6 7 a 9 1o 0VEN~CO0KED A, mm (61°c or 11mm 20 15 0 . 1 4 B, WELL-DONE ($09G, or 176°]? ) T’ I LZQ .,, 15 _. 10 0 . 1 BRAISED ,)1UM-RARE (85°C, or 18.91".) I I E n, vmv WELL-DONE (Lo0°c_ or 21 Pr, +_uo1.nm; roa 25 uzwrzs) I I l l 20 . 10 _ ' .3 5 _ , o l I o l 1 l 1 | Figure 10. Ether extract plotted against tenderness oi connective tissue ior iour conditions oi cooking. Loin steaks from 55 Bluebonnet steers. 1956. increase in meat temperature seemed to be the effective condition for tendering connective tis- sue. Steaks cooked to similar meat temperatures by dry heat in air in an oven or by moist heat in steam appeared to have similar scores for ten- derness of connective tissue. Those cooked t0 the lowest meat temperature (142° F.) had the toughest and those cooked to the highest meat temperature (212° F.) had the tenderest connec- tive tissue. Thus, the higher the meat temper- ature, the greater the tendering of the connective tissue. Meat temperatures as high as 212° F. cannot be obtained in air with the usual house- hold equipment because of the cooling effect from evaporation of meat juices from the surface? High meat temperatures could be obtained easily and quickly with moist heat methods, using either 12 _ E-mm EXTRACT TENDERIIESS or CONNECTIVE TISSUE, n, ROUND srmxs, n; 0F RIBEYE LARGE m1. 1421mm m. SHALL m. smu. m, mu if, m 9-10-11 or or or or FAIRLY or 1 m; cm man c,r, mm c,r, 1mm c r, sort c,1, son c '/_ [my 54315 0 1 2 3 h 5 6 7 6 9 ‘ ovsu-cooun ' A, RARE (6l'C, or 14Z°F,) 2o _ o 1s _ i o on 10 _ fir‘ . . o " 5 1 o o o o 5 - a g.» i», . o o o: o 1| 0 . . 9 . . ‘a, wan-nous (sow, otI176°F ) I 2o - o l5 _ . o ' o o 1o _ o. l. .0 o o 1 0 o o 5 I . . 0o o 5 - o . o 5 “o . o 5 . o . ' 0 0 . . I amussn s! MEJIUM-RIARE (85°C, or: 185".) ' 2o - o 15 o n .0 0 10 _ ‘ Q . .0 g. ' ol o o o o 0 o o o‘ ' o‘ o ' 5 - r ‘ o on u o I . a _ 2 0 . . . U . . n, vain: watt-nous (LO0°C, or 21z°1-‘, i 1101mm roa 2s mmrrzs 20 15 - 1o 5 o Figure ll. Ether extract plotted against tenderness connective tissue for four conditions of cooking. Bolt round steaks from 55 Bluebonnet steers, 1956. ‘ water or steam. Accordingly, if high meat te peratures were to be secured, the homemaker h to use moist heat methods. Thus, the moistu in the moist heat methods appears to have be needed t0 obtain high meat temperature rath than to furnish the xvater needed for the che ical change (hydrolysis) of collagen into gelati This is a simple explanation but the uncriti y, application of a borrowed theory delayed it f0 many years. 1In an unpublished study, Cover heated roasts for abo 3 days in ovens regulated at 125° C. (257°F.). The me temperature reached 96° C. (2050 F.) during the seco day. On the third day, the meat tempeature had n reached 97° C. (2070 F.) and the cooking was disco“ tinued. The roast was dry, hard and browned to t center. i 12111211 TENDERNESS 0F CONNECTIVE TISSUE, fgq3AgT LOIN STEAKS, SCORES =1 RIBEYE LARGE SMALL AMT SMALL AMI, SMALL AMT. TINY i 9-10-11 AMT, mm) FIRM FAIRLY AMT, a "rm cur man 0.1. (LT. SOFT QT. sort .§¢y 3Ag15 C,T, C.T. ' 7. 1 2 3 4 5 6 7 8 9 OVEN-COOKED A, 1mm: (61°C.'or 142's.) g I I I 1s _ ' _ o 10 _ _ 8 . _ o cl ' 5 u - I 5 1| . .. a o o!" 0 , . B, WELL-DONE (80%. or 176°F,) 1s k 0 _ o 1o , z ,8"; ‘. o o: '5 o ' 5 ’ l o ‘.00 l o 0 0 . . 9. BRAISED c, MEDIUM-RARE (85°c. or 185W.) _ 15 _ 9 _ o 1° ~ o o‘ - . §:'l‘; s _ , , .°'¢¢° " _ JO o 1 1 . 1 . n. VER" WELL-DONE lr1oo°c or. 212°1x+ 25 r-ggums) ., t 15 _ 0 _ i 1| o 10 _ . ' ‘ _ 0 o ‘o’. 88 ‘D 5 - & o: . - é O o o V o l I 1 . Figure 12. Ether extract plotted against tenderness oi nnective tissue ior four conditions of cooking. Loin steaks Am 36 Bluebonnet steers. 1958. a That degradation of collagen in muscle tis- ‘ esdoes not require moist heat, in the sense of _1-~ moisture, has been indicated by chemical sts in this laboratory. Irvin and Cover (1959) und that about 25 percent of the collagen nitro- en in raw meat was lost when loin and bottom »und steaks were oven-cooked rare to only 142° . (Figure 14.) These tests were made on 26 the 1956 steers and the oven-cooking of the steaks was done as described here—for a I ort time by a dry heat method. Cover and mith (1956) reported that about 45 percent of a e collagen nitrogen in raw meat was lost when in and bottom round steaks from 13 steers were ETHER TENDERNESS OF CONNECTIVE TISSUE, EXTRACT B, ROUND srmxs. scosss or RIBEYE LARGE smu. AMT. SMALL AMT. $144111. AMI. TINY m 9-10-11 Am, mm FIRM FAIRLY AMT, 111s cur HARD C.T. 0,1, son 0,1", sorr may BASIS C-T- C.T. 7° 1 2 3 4 5 6 7 8 9 OVEN-COOKED A, ma: (61°c. or 1112's,} I I I 1s _ e _ o 1o 0 0 .'phg.h 5 I. ' o0 i .. ' ' .. 8' '- 0 ' l l B, WELL-DONE (8o°c. or 116w.) 1s _ _ o 1o _ t ‘ O8. _ do . 5 - o: . - a ,1 0 . 0 . . BRAISED c, MEDIUM-RARE (are, or 185w.) 1s _ 0 _ o 10 Q - . -. ~ a‘; 0 o o s _ g B _ a , 0 _. 0 . . , D VER‘ WFT r. 41am; §10n°c or 212°}? + 25 MIQLIIIES) 15 _ 9 - o 1o _ . i - Pa!‘ 1 - 5 - o o o ol ‘o’ Q l 1 o! Figure 1B. Ether extract plotted against tenderness oi connective tissue tor four conditions of cooking. Bottom round steaks from 36 Bluebonnet steers. 1958. cooked well-done by dry heat in a broiler (Fig- ure 15) but under conditions much less Well standardized than those of Irvin and Cover. Whether similar observations Would be obtained with meat taken from animals older or younger than these is not known. That higher temperatures and longer time of heating influence tendering of connective tis- sue has been shown by Winegarden ct al. (1952). They used strips of connective tissue taken from the external portion of the aponeurotic sheet. This sheet is a large triangular piece of connec- tive tissue from the flank region and the exter- nal portion is the upper and superficial part 13 which is composed 0f the aponeurosis of the ex- ternal oblique muscle. Moist strips about three- eighths inch in width were heated in water for 1, 2, 4, 16 and 64 minutes at each of the following constant temperatures: 60°, 65°, 70°, 75°, 80°, 85°, 90° and 95° C. (140°, 149°, 158°, 167°, 176°, 185°, 194° and 203° F.). Shearing tests on the heated strips indicated that, at 65° C. (149° F.), soften- ing was slight after 1, 2 and 4 minutes of heat- ing but much greater after 16 and 64 minutes. At higher temperatures, softening took place much more rapidly (within 1 to 4 minutes) and to a greater extent than at 65° C. If the connec- tive tissue in muscle is similar in this respect to the tissue used by Winegarden et al., high meat temperatures would be more effective for tender- ing connective tissue than low, meat tempera- tures. Perhaps the reason that low rates of heat penetration in roasts have been effective for ten- dering (Cover 1937, 1941a, 1941b, 1943) lies in the length of time the meat was held at temper- atures which favored degradation of collagen. TABLE 3. SCORE FOR TENDERNESS OF CONNECTIVE TIS- SUE BY CUT AND CONDITION OI-‘ COOKING Average scores tor tenderness of con- Cuts and conditions of nective tissue’ k‘ 1 °°° ‘m’ 195s 195a data data Doneness Loin Oven-cooked Rare 9.2 7.5 Well-done 9.6 7.5 Sig. oi dit. n.s. n.s. Braised Medium-rare 9.5 7.2 Very well-done 9.4 7.4 Sig. of dit. n.s. n.s. Bottom Oven-cooked Rare 3.1 2.5 .. round Well-done 5.5 3.3 Sig. of dit. *** *** Braised Medium-rare 5.0 3.3 Very well-done 9.3 6.9 Sig. oi dii. *** *** Cuts Oven- Rare Loin 9.2 7.5 cooked Bottom round 3.1 2.5 Sig. of dit. *** *** Well-done Loin 9.6 7.5 Bottom round 5.5 3.3 ’ Sig. of dii. *** *** Braised Medium-rare Loin ~ 9.5 7.2 Bottom round 5.0 3.3 Sig. of dif. *** *** Very well-done Loin 9.4 7.4 Bottom round 9.3 6.9 Sig. oi dif. n.s. ** n.s., ** and *** indicate significance above 5 percent level, at 1 percent and 0.1 percent levels respectively. ‘The final meat temperature was 142°F. tor oven-cooked rare; l76°F. tor oven-cooked well-done: l85°F. for braised medium- rare,- and 2l2°F. and held there for 25 minutes tor braised very well-done. zThere were 55 steers in I956 and 36 in I958. An 11-point Tiage tor scoring was used in 1956 and a 9-point scale in 14 When tendering was most pronounced, penetration curves were most flattened. normal household oven temperatures é 1937, 1941b) this flattening o-r low rate d penetration occurred between 65° C. and (149° F. and 176° F.). It is not surp‘ therefore, that several hours in this temp range caused tendering of the connective in those roasts with muchxconnective tiss The connective tissue scores report show large differences between cuts cook, and also within one cut cooked under d’ conditions. It should be pointed out tha nective tissue scores are subjective evide the ease of mastication of the connective They may distinguish between little and i of the same kind of connective tissue or th‘ reflect differences in the kind of connecti» sue. They do not distinguish Well between i tity and kind of connective tissue. A 2v. system which would make this distinctio not yet been developed. Perhaps it may 1 layed until the chemistry of connective ti muscles is further advanced. Possible ca tough connective tissue may include a hig centration of one form of collagen; a highe portion of a dense form of collagen in to less dense forms; the presence of othe ; nective tissue proteins in addition to coll or some combination of these three. At p. it seems advisable not to exclude any of 1 v possibilities. Although the work reported: appears to favor the theory that a high c tration of one form of collagen was the ‘ cause of toughness, such an interpretation; have to be modified later. _ Tenderness Characterized b 5 Scores for Crumbliness of Muscle Fibers I The muscle fibers were affected in a? worthy way by some of the conditions of. ing. It is usually thought that tender m cut easily by the teeth into small, soft, irre shaped pieces during mastication. Under‘ tain conditions of cooking, however, the , ments were so small, hard and dry that the. felt mealy or even powdery in the mouth. , seem unusual adjectives to apply to meat. f of mealy texture probably has undergone; found physical and chemical changes in the 1 ture of the muscle fibers. Scores for c ness, if obtained in a systematic Way, might vide a possible method of recording these changes. Such a systematic record might i lated later to histological and chemical in. gations. Because this characteristic is ex, ingly complex, considerable work remains =' done on selecting adjectives which charac y; it most adequately. For that reason only a IIHlllllIIlllllllllllllllllllllll GRAMS COLLAGEN NITROGEN PER 100 GRAMS TOTAL NITROGEN IIIIIIIIllllIlIllIIIIIllllllllllllIlIIIIIlllIIllIIIIIIIIIIllIIIIIIIIIIIIIIIIIIIIIIIIIIIIII RAW COOKED ‘RAW I-OIN BOTTOM ROUND I Figure 14. Collagen nitrogen content of l-inch steaks ' and oven-cooked rare to an internal temperature oi ° F. (26 of the 1956 steers, Irvin and Cover 1960). ume of the work already done will be pre- p: ted here. a Low scores for crumbliness were given When e muscle fibers did not break readily across 1 long axis-—a characteristic of tough muscle ers. Moderate scores Were given when the I: broke fairly easily across the long axis pd into rather small pieces. High scores were ven when the fibers broke readily across the , g axis and into very small pieces. With the ghest scores the meat seemed “mealy” or even owdery” in the mouth—an undesirable sen- tion to the authors. High scores for crumbli- ss Were associataedfi with tiny, hard, dry par- cles which seemed to roll out of the connective sue network. If this network disintegrated, é e entire piece of meat crumbled easily on pres- g re by the teeth. In 1956 an 11-point scale was used (0-10). n 1958 it was reduced to a 9-point scale by 3,2 3.0 2.8 2,6 2.4 22. 2,0 1.8- 1.6 1.4 102 1.0 % .\\ Q \\ (( RAW COOKED RAW COOKED LOIN BOTTOM ROUND .1- 5 0 b‘ m Iii 0 Q B? m Figure l5. Collagen nitrogen content of 3/4 raw and broiler-cooked well-done without thermometers (l3 oi the 1954 steers, Cover and Smith 1956). omitting the zero and 10 of the 11-point scale (1-9). CRUMBLINESS RELATED TO CUT AND CONDITION OF COOKING Average scores for crumbliness of muscle fibers by cuts and conditions of cooking in each of the 2 years are given in Table 4. Significance of the difference was determined by analyses of variance. The actual scores vary with the year. The change from an 11.-point scale in 1956 to a 9-point scale in 1958 could have caused some of this variation. Other ‘causes could be differ- ences in animals, in personnel on the panels and in personnel doing the cooking. Yet the simi- larity in trends for each of the years is remark- able. These similar trends are: 1) in loin steaks, crumbliness of muscle fibers increased with done- ness during oven-cooking but not during brais- ing; 2) in bottom round steaks, crumbliness of muscle fibers increased With doneness during both oven-cooking and braising; 3) the most 15 crumbly muscle fibers were in bottom round steaks braised very well-done; 4) the muscle fibers in the two cuts were similar in crumbliness when oven-cooked rare but those 0f bottom round were more crumbly than those of loin when the steaks were oven-cooked well-done or braised very well-done. The reason is not clear why muscle fibers which are thoroughly cooked are more crumbly in bottom round than in loin. This peculiarity of the muscle fibers of bottom round, however, may account for the suitability of this cut for braising. Since braising very well-done is the most successful of the four conditions of cooking for tendering connective tissue and is also the most successful for developing crumbliness of muscle fibers in bottom round, it is not surpris- . ing that such steaks may often be “cut with a fork”-a highly desirable attribute in the opin- ion of some consumers. Other consumers object to this crumbliness. Further research should be undertaken to learn the cause of this controversial character- TABLE 4. SCORE FOR CRUMBLINESS OF MUSCLE FIBERS BY CUT AND CONDITION OF COOKING Average scores ior crumbliness oi Cuts and conditions oi muscle iibers’ - 1 °°°kmg 195s 195a data data Doneness Loin Oven-cooked Rare 5.3 3.3 Well-done 6.3 4.6 Sig. oi dii. *** *** Braised Medium-rare 6.2 4.5 Very well-done 6.5 4.6 Sig. oi dii. n.s. n.s. --~-Bottom Oven-cooked Rare 5-5 3-7 round Well-done 7.1 5.9 Sig. oi dii. *** *** Braised Medium-rare 6.7 5.6 Very well-done 8.0 7.1 Sig. oi dii, *** *** Cuts Oven- Rare Loin 5.3 3.3 eqoked Bottom round 5.6 3.7 Sig. oi dii. n.s. n.s. Well-done Loin 6.3 4.6 V, Bottom round 7.1 5.9 Sig. oi dii. - ** *** Braised Medium-rare Loin 6.2 4.5 Bottom round 6.7 5.6 Sig. oi dii. n.s. *** Very well-done Loin 6.5 4.6 Bottom round 8.0 7.1 Sig. oi dii. *** *** n.s.. **. and *** indicate significance above 5 percent level, at 1 percent and 0.1 percent levels respectively. ‘The iinal meat temperature was 142°F. ior oven-cooked rare: 176°F. ior oven-cooked well-done; 185°F. ior braised medium- rare." and 212°F. and held there ior 25 minutes ior braised very well-done. I “There were 55 steers in 1956 and 36 in 1958. An 11-point scale ior scoring was used in 1956 and a S-point one in 1958. 16 istic in cooked meat and how it may be con =1 ed. With this information available, crur ness could be obtained when desired but av when not desired. i “Fork” tenderness, which has been r sometimes as a test of doneness, may be i enced to some extent by crumbliness of m fibers. _ 1F ‘.1 3i Tenderness Characterized by. Scores for Softness Softness of meat seems to have two asp_ One aspect is the muscular effort needed to . the teeth into the meat. High scores for kind of softness would indicate that the t sink easily into the meat, as into well-sof -.' chewing gum or into the crumb of tender c, bread. Meat which is juicy may have this , of softness but meat which is dry and cru , may also have this kind of softness because j tle pressure is needed for the teeth to sink ' it. - ~ The other aspect of softness is the way meat feels to tongue and cheek. Meat whic soft in this way is probably juicy also. Cons, ers may tend to swallow soft juicy meat with‘ being aware of the muscle fibers or the con . ' tive tissue. It slips down so easily that th who enjoy rare meat may almost be said '3 “drink” their meat. In the first attempt to score softness (1 data), the two aspects of softness were not se rated. In the second attempt (1958 data), o tooth pressure was used as a measure of w. ness. Much more work needs to be done on t‘ characteristic. For this reason only a brief . sume of the work already done will be presen here. In 1956 an 11-point scale was used (0-1 In 1958 it was reduced to a 9-point scale by o t; ting the zero and 10 of the 11-point scale (1- SOFTNESS RELATED TO CUT AND CONDITION OF COOKING Average scores for softness by cuts and ditions of cooking in each of the 2 years are gi j, in Table 5. Significance of the differences determined by analyses of variance. The act ' scores vary somewhat with the year. The cha ’ from an 11-point scale in 1956 to a 9-point s : in 1958 could have caused some of this variati Changes in definition of softness could have Y‘ some effect also. Nevertheless, similar tre- for these 2 years may be observed: 1) in I; steaks, softness decreased with doneness f, oven-cooking and perhaps for braising also; V, in bottom round steaks, softness decreased wi doneness for oven-cooking but increased Wi doneness for braising; 3) bottom round ste were softer than loin steaks only when braii well-done. The round steaks may have been er than the loin steaks when braised very l-done because of the more extreme crumbli- s 0f the muscle fibers. This extreme crumb- ss of the muscle fibers in bottom round steaks , this method of cooking permitted the teeth to . in easily—the criterion of softness in the f» data and probably the predominate one in * 1956 data. l. “Fork” tenderness, which has been used J. etimes by homemakers as a test of doneness y be influenced to some extent by softness. Tenderness Characterized by i Shear Force Value Shear force value is the most widely used jective method of measuring tenderness. The ‘ear force values were obtained on a specially epared sample of meat. This sample was pre- red by turning back and forth under slight iessure a metal cylinder (one-half inch in di- eter, sharpened at one end) along the grain j the meat. This gave a one-half inch core of eat about 1 inch long. This core of meat was t across the grain with the knife of the electri- Ally powered mechanical device (Warner-Bratz- ' l. Shearing Device). The knife is v-shaped and 4: a smoothly rounded cutting edge. The force eded to do the shearing (cutting) is register- .» in pounds on a dial. Higher shear force values dicate tough meat and low values indicate ten- meat. Cutting a core with the grain of the meat quires considerable care. The direction of the ain is found by pulling fibers from the outside ge of the steak. For l-inch loin steaks, the rer has to be slanted from the perpendicular 1 follow the grain of the meat. The direction f the slant for the portion of the steak nearest e spines is different from that for the end rthest from the spines. For l-inch bottom and steaks, where the grain of the meat runs ore nearly parallel to the surface than it does loin steaks, the samples have been taken in ifferent ways. With the 1956 data the corer as inserted almost perpendicular to the top rface of the steak, even though it did not fol- 1 the grain closely. Shear force was measured yycarefully adjusting the position of the core .,;r’the machine so that the shearing was done f ross the grain. With the data for 1958 a sec- ‘on from each end of the steak was cut with a lnife and turned on its side. Then the corer was lanted to follow closely the grain of the meat. i he cores for bottoignround in 1958 followed the rain as closely as did those from the loin. HEAR FORCE VALUE RELATED TO CARCASS GRADE A USDA carcass grade was plotted against hear force value in Figures 16 and 17 for the 956 steers, and Figures 18 and 19 for the 1958 TABLE 5. SCORE FOR SOFTNESS BY CUT AND CONDI- TION OF COOKING Average scores tor Cuts and conditions oi softnessz ¢<><=kinq‘ 195s 195s data data Doneness Loin Oven-cooked Rare 7.5 7.0 Well-done 5.2 5.7 Sig. of dit. *** *** Braised Medium-rare 4.9 5.6 Very well-done 4.7 5.1 Sig. of dif. n.s. ** Bottom Oven-cooked Rare 7.6 6.4 round ' Well-done I 5.2 5.3 Sig. of dit. *** *** Braised Medium-rare 4.7 5.0 Very well-done 5.9 5.8 Sig. of dif. *** *** Cuts Oven- Rare Loin 7.5 7.0 cooked Bottom round 7.6 6.4 Sig. of dif, n.s. *** Well-done Loin 5.2 5.7 Bottom round 5.2 5.3 Sig. oi dit. n.s. ** Braised Medium-rare Loin 4.9 5.6 Bottom round 4.7 5.0 Sig. of dif. n.s. *** Very well-done Loin 4.7 5.1 Bottom round 5.9 5.8 Sig. of dit. *** *** n.s., **. and *** indicate significance above 5 percent level, at 1 percent and 0.1 percent levels respectively. ‘The final meat temperature was l42°F. for oven-cooked rare: 176°F. for oven-cooked well-done; 185°F. for braised medium- rare; and 2l2°F. and held there for 25 minutes tor braised very well-done. zThere were 55 steers in 1956 and 36 in 1958. An 11-point scale tor scoring was used in 1956 and a 9-point one in 1958. steers. In the previous graphs low scores for tough steaks were placed at the left of the graphs, while high scores for tender steaks were at the right. To avoid confusion in comparing trends in shear force values with trends in panel scores, the high shears indicating tough meat were placed at the left and the low shears indi- cating tender meat at the right. For the individual who likes rare steaks, the tenderness of the loin steaks from most of these animals would have been reasonably satisfactory regardless of carcass grade, when they were oven-cooked rare. This was indicated by the low shear force values (A) in Figures 16 and 18. However, some individuals will not eat rare meat. When loin steaks were cooked under the other three conditions (B, C. D) some of the carcasses would have given reasonable satisfaction for ten- derness. These loin steaks of satisfactory ten- derness were not limited to carcasses of high USDA‘ grade. Yet a tendency toward high shear (tough meat) with the more thoroughly cooked meat was noticeable in some carcasses from Standard and Good grades. The wide variation in tenderness of different carcasses falling in 17 USDA sums FORCE VALUES, 1.0m srmxs, rounns CARCASS Toucfl l MEDIUM l rzunsa in»: 23222120191817161514131211109s7654 OVEN-COOKED I A, RARE (arc, or 14217,} cnorcn “ v " - o + 00000] O coon - ll I'll -» ‘on o o + - Q I O - STANDARD O 1O OI § - o0 o o + _ UTILITY * T‘ . . . . . . . . . . . . . . . . . 9 . . n, warn-nous (sow, or _17s'z-*,) cuorca ‘P ‘ + - o o Q o o GOOD “ COO Q“ - - no o o no o + - o o 0cm o0 c n STANDARD " 9 9 OI II — - o o o o + _ UTILITY ' _ _ I I I _ l I I I _ I |,| l I I l I _ _ BRAISED . . 9- ."EPL’.“'—“FRE.. . . . . . + I I cnorcn * t’ _ _ . _ + - Q QQ O0 coon ' 9959 _ _ . . + - o ‘Q IIIO - STANDARD ' Q O O U O CID. -— - 0o o o - . + .- uTILITr ‘ n, vzmz wan-noun (1oo°c, or 212W, + uoLnm: FOR 25 MINUTES) cnorczz ' 9- - - o + - o o0 no: o0 4 GOOD - Q o 0 o0 — o o o on o O O - + a on o Q o o_ o ~ STANDARD - I I o I o cu o - — o o o o ~ + UTILITY ‘ _ ' Figure 16. Carcass grade plotted against shear“ iorce value for four conditions oi cooking. Loin steaks from 55 Bluebonnet steers, 1956. each of these grades indicates that factors other than those which determine USDA carcass grade are involved in tenderness. SHEAR FORCE VALUE RELATED TO ETHER EXTRACT Percentage of ether extract in trimmed rib- eye muscle was plotted against shear force value in Figures 20 and 21 for the 1956 steers, and 18 USDA SHEAR roacs VALUES, BOTTOM ROUND srmzs, r CARCASS TOUGH I MEDIUM damn: 23222120191317161514131211109a'1i OVEN-COOKED A, RARE (eve, or 142°1=,) + CHOICE ' O " - o + I O . O’ GQQD ' U” C. O - - o col 0o + - no o -o= SIQNDARD ' ICOII CO l; ' - 1 o o o 1 + _ UTILITY _- T I l l I I l l I l I I l l l l l 0| n, WELL-DONE (80'c. or new.) + O CHOICE ' 9 — - o + - I coon " I 9 i - - o“ o + 9 b STANDARD I 9 I v; — 0 o o 0 ’ + l- UTILITY ' - I l l I l I ll l I l I I I l“ l l l BRAISED C, MEDIUM-RARE (85'C, or 185°I‘,) I I I I I I I I I I I I I I I + - o CHOICE 9 - o + _ coon " Q I - - I + not STANDARD ' . — o no + ‘ w UTILITY i > I l l I l l l I I I l l l l , l l Li’: n, VERY WELL-DONE (1o0'c, or 212W, + 110mm; roa 25 MI + O CHOICE t 9 = _ _ . .1’ + - l“ coon - ‘i; + - i. STANDARD " 9 9‘9_§ — - I 0o + - p’ UTILITY I Figure 17. Carcass grade plotted against sh it value tor tour conditions of cooking. Bottom rounds-L from 55 Bluebonnet steers. 1956. Figures 22 and 23 for the 1958 steers. a graphs show that steaks from many ca 1 with low percentage ether extract in ribeyef. not only tender but as tender as those fromf carcasses with higher percentage ether e It seemed that marbling as measured by * extract could have had little practical eff shearing tenderness of meat. SHEAR roacz VALUES, 1.0m srzsxs, roumus roucn [MEDIUM l TENDER 23222120191817161514131211109 8 7 6 5 OVEN-COOKED A, RARE (_61°C, or 142°]? ) 00 00i- 1:. 00 Q rohfilo . . . . . . . . 1 . . P . . . 9 . 1 . . 3'. ‘iHJfDQNE 389°C: °'. 17.°°F.') . , e 4 0 0 0 - 0 0 Q 0Q0 0 I ~ Q o 00o I o o I Q0 0 — - r 0 . Q . . U. . . . . . . . . . . l mmrsso I ‘c, I gonna-mas (are, or 1.85115)‘ I I r L Q o - - 0 o 0 Q00 0 00 d0 0 - o 0 o0 0 00Q b 0 an ~ , - 9 . . . . .9 . . . . . . . ‘ n,‘ velar WELL-TDONIE (_10o°c,I m; 21I2°P', + 25 MIMITES). l . . . _ — Q 0 $ 0 00 0 k — + ~ 0 Q Q l0 Q Q 0 0| ,,,., - 0 " '9. . . . . l 9 . . . 1 . . . . . . . p. Figure 18. Carcass grade plotted against shear iorce ue for four conditions oi cooking. Loin steaks from 36 iebonnet steers, 1958. A AR roncs VALUE RELATED TO a mo counmou or cooxmo o Shear force values for each cut and condi- gn 0f cooking may be observed in Figures 16 l ough 23. The range of shear force value was E ch wider for loin than for botton round steaks. Loin steaks (Figures 16, 18 or 20, 22) had e lowest shear force values (most tender) en oven-cooked rare (A). When they were en-cooked well-done (B) they had somewhat (her shear force values indicating that the eat was somewhat tougher. Cooking by moist did not seem to be effective for obtaining iformly low shear force values (tender meat) these loin steaks. t Ranges in shear force values for bottom round yaks (Figures 17, 19 or 21, 23) oven-cooked ell-done (B) in both years were much narrower I‘ those for loin steaks. This is true also for ttom round steaks. braised to 185° F. (C) and t 212° F. (D). High internal temperature of the eak appears to have had less toughening effect V. bottom round steaks than in loin steaks. Some lssible implications of these observations will be 'scussed in a subsequent technical article. Shear force values averaged by cuts and con- itions of cooking in each of the 2 years are usm p sums roacz VALUES, BUITOM noum) srmxs, rourws CARCASS fi roucu l MEDIUMl TENDER ems 23222120191817161514131211109a76s wsu-cooxzn I I ‘A,’ Ram; (ape, or: 192"? )' + _ _ cow . o o o — - - I 0 n01 0 - + O . OiOQ smmmnn “ ' ' a; unto-noun (sow, 01" 119°?) _ I I ‘ I T + " l i I ‘ i I I I i I I coon ' . i l — - . 0 0 0 Q D ~ + - ab’ b ‘O srmmn ' ' - - , , , , , l , . . , . . P . 9 BRAISED c, MEDIUlM-RARE (are, or: 1p5°IF.)_ _ _ ' I c000 “ ' l. - - o 0 o o 0 to + _ 0 “I0 0 smuman ” ' n, vsnr WELL-DONE (1oo°c, or 21_2°r_, +_ zslmiwurizs). + " i I I i r I i I i i A coon ' ' . - - 0 0 Q Q0 i ' .,. - I 0 00%. l... ‘ smunaan " ' i - l _ A A I _ l _ ‘ l _ _ 0 l , _ ,0 , Figure 19. Carcass grade plotted against shear force value tor iour conditions of cooking. Bottom round steaks from 36 Bluebonnet steers, 1958. given in Table 6. Significance of the differences was determined by analyses of variance. The actual shear force values vary from year to year as would be expected. The trends which were similar within each of the years are: 1) loin steaks had lower shear force values (more ten- der) when oven-cooked rare than by any of the other three conditions of cooking; 2) bottom round steaks had lower shear force values (more tender meat) than loin steaks when both were oven-cooked well-done and when both were braised very well-done. RELATION OF SHEAR FORCE VALUES TO PANEL SCORES For some time there has been considerable speculation about the relationship of the objec- tive measurement shear force value to the sub- jective measurement panel score. Do shear force values and panel scores measure the same thing? Do they follow the same trends when used to- gether? When panel ratings were based on one com- posite score for tenderness, some workers have reported that the agreement between the two measures of tenderness was close but others have found it to be less close. Coefficients of corre- lation between score for tenderness and shear 19 2mm zxmxcr 0;.- Rlgm sama roaca VALUES, 1.0m srmrs, vouuns m 9-10-11 an cu-r roucn MEDIUM TENDER znarmsrs 23222120191111716151413121110 9 a 1 a s 4 ovzu-cooxsn A, ma; (ave, or: 142a,) Z0 1 15 - 10 _ 5 I 0 l l j l l I I I I I l l n, wart-nous (sow, or 176°P,) 20 15 10 ‘Q o ‘ a 5 o0 o o Q ‘ Q o l l l I l BRAISED c, MEDIUM-RARE (arc, or: 1as°r,) 2o 15 1o ' Q o o 5 t’ ' s > 0............‘. ... n, VERY wsu-nomz (1oo°c, or: 212's, + uownc roa 2s muons) I 141*’ x I | | I 1 | 1 | l I I 1 I I 2o o 15 o a . o 10 _ o .0 o: o ‘ _ o‘ ' . o‘. Q o . o o o o 5 ~a 0 o . o" . ‘o’. o‘o o o o . c °............Q. . Figure 20. Ether extract plotted against shear force value tor {our conditions oi cooking. Loin steaks from 55 Bluebonnet steers, 1956. force value which have been reported for beef are: 0.9 for 50 muscles cooked in lard at 250° F. (Ramsbottom and Strandine, 1945); -.839 and -.891 for broiled and braised loin steaks and -.730 and -.863 for broiled and braised bottom round steaks (Cover and Smith, 1956); -.369 for steaks oven-cooked at 232° C (450° F.) and -.404 for braised steaks (Paul, Bean and Bratzler, 1956). When attempts were made in this study to relate shear force value to tenderness of connec- tive tissue and to the other components of ten- derness, problems were encountered which are beyond the scope of this bulletin. They will be discussed in a subsequent technical paper. It is apparent that there is no simple answer to the question, what components of tenderness do shear force values measure? 20 stoma meme-r (,1.- RIBEYE sum: roncs vALuzs, BOTIOM aouun smxs, POUNDS m 9-10-11 n15 cur mucu nnnrun rsunn znarmszs 2322212019181716151413121110 9 a 7 6 s.‘ ovzu-cooxan A, mm (arc, or: 142w.) 20 1s _ 3» 10 O 5 O I l a, WELL-DONE (ao°c_ or 176°! 2o 15 10 5 0 0 l l l l I I l l BRAISED c, moron-alas garc, or 1as°r I I 4-1" | I 20 15 10 5 0 ............. . n vmr wan-noun (1oo°c, or 212T, + 110mm; ron 25 T I I I I I I I I I I I I I 20 15 10 . 5 o I I l l l l l I I l l I Figure 21. Ether extract plotted against shear to value for tour conditions of cooking. Bottom round ste from 55 Bluebonnet steers, 1956. = Although, shear force value may later a shown to be less than a perfect measure of t0 l tenderness for all cuts, it could continue to ha a place as a research tool. The data obtain with this method vary in such remarkable with cuts and method of cooking that they m‘ stimulate new work of a basic nature. Discussion Tenderness in this study has been related. carcass grade and marbling in two ways: sh’ force value and score for tenderness of conn tive tissue. Because other research workers " need statistical measures for comparison wi‘ their own data, the coefficients of correlation carcass grade and ether extract with each of t two measures of tenderness are given in Table ~ SHEAR FORCE VALUES , LOIN STEAKS, POUNDS l 11 I roucn rmnrun rsnnsa ‘IS 232221201918171.6151111312111098765 ovsn-cooxsn ~r A, RARE (61°C, or 142°F,)‘ (15 . o ‘° . 1 '1" o o > . g 5 > .. g Q . 1 ’ 8 :7 0 1 1 1 I 1 1 1 l I 1 I 1 . 1 1 1 1 1 - B, WELL-DONE (80°c, or 176°1=,) l 15 0 A o 1o Q o o . ' o o.’ O 0 o 1 o o ‘a ' 1 ' 5 o . o o — o o o D 0 1 I 1 1 1 1 1 1 1 1 1 1 1 BRAISBD c, 11112911111 RARE gave, o; 18_5°F|_‘ _ 1s . ° ' o . m _ . 7 o ' o o ' ‘:1 . .0 o.’ 0 o o l 5 - . o o “ o . o. o o. 1 o . l 1 L l I I I l I I I I l I I I I I n VERY HELL-DONE g100°c, or 213%‘, i 25 mmrrss‘ v .' 15 _ . o 10 u Q _ 0 . t .0 o 8' . g I 5 - g ’ o. o ' - Q ' 0o . o 0 .1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Vrgure 22. Ether extract plotted against shear force 7 for four conditions of cooking.’ Loin steaks from 36 nnet steers, 1958. ES Significant coefficients for shear force value carcass grade were obtained in only 5 of j 6 categories but in these 5 the tenderer meat ‘associated with the higher carcass grade. An y may be noted in oven-cooked loin steaks. coefficients were not significant for rare but ' significant for Well-done in both years. ft importance, if any, should be attached to t observation is not clear at present because he wide range in shears within the grades ed well-done (Figures 16 and 18). More- in 1955 with 31 steers and in 1957 with 30 rs the coefficients were not significant for -done oven-cooked loin steaks. t When the relationship of carcass grade to ire for tenderness-of connective tissue is con- red, significant" coefficients were obtained in 3 of the 16 categories—one of which was site in sign. This means that in the two gories with positive coefficients, the more k er connective tissue was associated with car- ises of higher grade but in another category Sh a negative coefficient the meat with the ETIIER EXTRACT 0F RIBEYE SHEAR FGICE VALUES, BGITOM ROUND STEAKS, POUNDS IN 9-10-11 RIB CUT TOUGH MEDIUM TENDER ‘LDRYBASIS 232221201918171615141312111098765 WEN-COOKED A, RARE (61°C, or 142°F,) l5 Q Q o 1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 1. 1 I ‘an WELL-DOE Qwc, or 176°r,) 15 _ - I I s _ o D o .‘ =0 o 1 1 1 1 1 1 1 1 1 1 1 1 1. 1 1 1 1 1 m BRAISED C, MEDIUM-RARE (85°C, O!‘ 185°F, 15 _ O 5 _ O O o l 1 I I I I I I I I I ‘ D. VhkYfilEhL-DONE §100°C. or: 212°?‘ + 2 15 _ 9 10 5 o I 1 1 I I I 1 1 I 1 1 1 . 1 Figure 23. Ether extract plotted against shear force value for tour conditions of cooking. Bottom round steaks from 36 Bluebonnet steers, 1958. tougher connective tissue was associated with carcasses of higher grade. These data are plot- ted in Figures 6, 7, 8 and 9. USDA official grades have been regarded as indicators of meat “quality.” Since homemakers regard tenderness as an indispensable character- istic of “quality,” they expect it in meat from carcasses of high USDA grades. tional and educational literature contains such statements as “If you want your steaks to be tender, buy U. S. Prime or U. S. Choice grades.” In view of the research results in this and prev- ious publications such recommendations do not identify all of the carcasses with reasonably ten- der meat. Work to discover causes of tender- ness or toughness in meat so that this character- istic may be labeled in buying and selling can be regarded as looking toward quality control for the beef industry. It has possibilities of effect- ing savings to the homemaker, the retailer, the packer and the producer. MARBLING A Marbling was measured in this study by the percentage of ether extract on the dry basis. The 21 Much promo- . coefficients for ether extract with shears were significant in only 4 of the 16 categories (Table 7) but in these 4, the tenderer meat was associa- ted with the higher percentage of ether extract (marbling). These data are plotted in Figures 20, 21, 22 and 23. When ether extract and score for tenderness of connective tissue are considered, significant coefficients were obtained in only 3 of the 16 categories and for one of them there was a change in sign. Thus in the only category with a posi- tive coefficient the more tender connective tissue was associated with higher ether extract but in the two categories with negative coefficients the more tender connective tissue was associated with lower ether extract. These data are plotted in Figures 10, 11, 12 and 13. Marbling of the ribeye muscle has been one of the most respected visible indicators of ten- derness. It is one of the characteristics consider- ed in the USDA grading system. In view of the research results presented in this and other pub- lications (Cover, King and Butler, 1958; Cover, Butler and Cartwright, 1956; Hankins and Ellis, 1959; Wellington and Stouffer, 1959) marbling TABLE 6. SHEAR FORCE VALUES BY CUT AND CONDI- TION OF COOKING Average shear force - 2 Cuts and conditions of values m pounds cooking‘ 195s 195s data data Doneness Loin Oven-cooked Rare 7.4 8.7 Well-done 11.8 13.4 Sig. of dif, *** *** Braised Medium-rare 9.7 13.5 Very well-done 12.5 14.9 Sig. of dif. *** n.s. Bottom Oven-cooked Rare 8.9 7.3 round Well-done 9.0 9.0 Sig. of dii. n.s. * Braised Medium-rare 9.0 8.9 Very well-done 7.4 8.0 Sig. of dif. *** n.s. Cuts Oven- Rare Loin 7.4 8.7 cooked Bottom round 8.9 7.3 Sig. of dif. *** n.s. Well-done Loin 11.8 13.4 ‘ Bottom round‘ 9.0 9.0 Sig. of dif. *** *** Braised Medium-rare Loin 9.7 13.5 Bottom round 9.0 8.9 Sig. of dif. n.s. *** Very well-done Loin 12.5 14.9 Bottom round 7.4 8.0 Sig. oi dif. *** *** n.s., *, and *** indicate significance above 5 percent level. at 5 percent and 0.1 percent levels respectively. ‘The final meat temperature was 142°F. for oven-cooked rare; 176°F. for oven-cooked well-done, 185°F_ for braised medium- rare: and 212°F. and held there for 25 minutes for braised very well-done. “There were 55 steers in 1956 and 36 in 1958. 22 is not an infallible indicator of tenderness. haps the toughness or tenderness of the .a fibers in beef may be an inherent charact of the fibers themselves. If so, tough fiber make the meat seem tough while tender i may make the meat seem tender, regard] the fat distribution as marbling. Furthe search in this area is indicated. 1 CONDITIONS o|= COOKING A l Control of tenderness by methods of n has been thought to be possible. Conditio cooking such as temperature, time and kij cooking medium are under the control 0_ homemaker. An examination of these cond'_ in this and previous publications (Cover '5 1943; Cover et a1. 1956, 1957, 1959) indi that different cuts do not respond alike to? one set of cooking conditions. A loin steak; be tender broiled rare but a bottom round 5 will be tough when broiled rare. The res results indicate that the connective tissue in is tender and small in amount but that in u round it is tough and present in large amo This gives a structural basis for classifying r two cuts. Traditionally this has been the i, for classifying cuts into tender and less te' However, if both cuts are braised very well —a method suggested for tendering the v connective tissue in bottom round—we find i bottom round steaks have become tender j loin steaks tough. The basis for this diffe , does not lie in the amount of connective t for it is now tender in both cuts. The other j ture in meat which contributes to toughny the muscle fiber. The muscle fibers in _g steaks appear to be toughened by heat much t. than those of bottom round steaks. The ml fibers of the two cuts differ in some inhe” manner which is not clear at present. How, this inherent tenderness difference between t. cle fibers of different cuts from the same mal should stimulate further research of a t nature. The degree of tendering of connective t“ appears to depend on the meat temperature r g ed and also on either the time to reach this perature or on the time the final meat tem ture is maintained. The time to reach those “f temperatures, which are effective for tendeg connective tissue, depends not only on the’ j perature of the cooking medium but on the . of cooking medium. For cooking media suc ; water or steam (moist heat), the rate of 4 penetration is high even at low cooking tem -.. tures (194-212° F.) . For a cooking medium s, as air, the rate of heat penetration is low t. for cooking temperatures (257° F.) which “y considerably higher than the moist heat temp a tures. Thus moist heat methods, such as b j ing, have high rates of heat penetration and meat temperatures quickly reach the tempera ' of the medium. For the rest of the cooking t, iod the meat is held at the temperature of > 7. CORRELATION OF SHEAR FORCE VALUE AND SCORE FOR CONNECTIVE TISSUE WITH U.S. CARCASS GRADE AND ETHER EXTRACT Cuts and conditions Coefficients of correlation Shear force value versus‘ Score for tenderness of connective tissue versus’ o! cooking U.S. Percent U.S. Percent carcass ether extract carcass ether extract grade" dry basis grade“ dry basis 1956 data (55 steers) Oven-cooked Rare —.257 n.s. —.226 n.s. +.141 n.s. —.005 n.s. Well-done ——.319 * —.257 n.s. +.034 n.s. —.029 n.s. Braised Medium-rare —.492 *** —.404 ** +.l95 n.s. +.l83 n.s. Very well-done --.227 n.s. —.l75 n.s. +.203 n.s. +.274 * Oven-cooked Rare ~.180 n.s. l—.231 n.s. —-.1l9 n.s. —.30l * Well-done +.064 n.s. +.065 n.s —.209 n.s. +.101 n.s. Braised Medium-rare —.236 n.s. —.139 n.s —.068 n.s. —.065 n.s. Very well-done +.255 n.s. —.050 n.s +.045 n.s. +.127 n.s. 1958 data (36 steers) Oven-cooked Rare —.254 n.s. —.304 n.s. +.087 n.s. —.024 n.s. Well-done —.416 * —.4l4 * +.560 *** —.466 ** Braised Medium-rare —.384 * —.375 * +.306 n.s +.231 n.s. Very well-done —.456 ** —-.4l8 * +.336 * +.256 n.s. Oven-cooked Rare +.218 n.s. —.165 n.s. —-.005 n.s. —.l37 n.s. d Well-done +.067 n.s. +.078 n.s. -—.416 * —.294 n.s. l Braised Medium-rare +.052 n.s. —.040 n.s. —.238 n.s. —.099 n.s. Very well-done —.058 n.s. +.010 n.s. +.121 n.s. +.056 n.s. “r 1* um I I i tive coefficients. I carcass grade are indicated by positive coefficients. vdard 13-15, Good 16-18, Choice 19-21 and Prime 22-24. king medium. Thus moist heat methods are '1 venient for obtaining the high meat tempera- es needed for tendering the connective tissue ckly, even though the moisture in the moist y methods is not needed to furnish Water for chemical change (hydrolysis) of collagen into tin. _ f “Simmering” (194-203° F.) is often referred as low temperature cookery and much to be ferred to “boiling” (212° F.) which is spoken gas high temperature meat cookery. Meat tem- g atures reach 194-203° F. during “simmering” 212° F. during boiling. Gentle boiling and orous boiling take place at the same temper- g re (212° F.). Vigorous boiling is accompan- Lby severe agitation which may break the meat small pieces or strings. It should be noted " this may be the result of the mechanical 1 ting and not of the temperature, per se. “Sim- ring” (194-203° F.) is thought to tender con- ptive tissue and leave muscle fibers tender, .- ile “boiling” has been thought to tender con- » tive tissue butf; to toughen muscle fibers. ughening of muscle fibers is indicated in this dy by low scores for crumbliness. This tough- ing appeared to have already taken place by g time a meat temperature of 176-185° F. had l‘ n reached and little if any further toughening pk place between 185° F. and 212° F. Thus it indicate significance above 5 percent, and at 5 percent, 1 percent, and 0.1 percent levels, respectively. or force values were in pounds needed to shear a one-half inch core of meat. Because tender meat is represented by low - values and tough meat by high shear values, correlations between tender meat and high carcass grade are indicated by use connective tissue is represented by a high score and toughness by a low score, correlations between tender meat and ill carcass grades were coded to one-third of each grade as follows: Canner 1-3, Cutter 4-6, Utility 7-9, Commercial 10-12, appears that the recommendation that braising be done at the low temperature of simmering rather than at the high temperature of a gentle boil is of questionable value. Further Work along this line is indicated when equipment suitable for controlling temperatures at 190° F. i- 2° F. is available. a References Bernofsky, (1., Fox, J. B., and Schweigert, B. S. Biochemistry of myoglobin. VII. The effect of cooking on myoglobin in beef muscle. Food Research, 24, 339 (1959). Bureau of Human Nutrition and Home Econom- ics, United States Department of Agriculture. Beef. Facts for consumer education. AIB 84, 1952. Cover, Sylvia. The effect of temperature and time of cooking on tenderness of roasts. Texas Agri. Exp. Sta. Bul. 542 (1937). Cover, Sylvia. Comparative cooking time and ten- derness of meat cooked in water and in an oven of the same temperature. J. Home Econ., 33, 596 (1941a). Cover, Sylvia. Effect of metal skewers on cook- ing time and tenderness of beef. Food Re- search, 6, 233 (1941b). 23 Cover, Sylvia. Effect of extremely 10W rates 0f heat penetration on tendering of beef. Food Research, 8, 388 (1943). Cover, Sylvia, Butler, O. D. and Cartwright, T. C. The relationship of fatness in yearling steers t0 juiciness and tenderness 0f broiled and braised steaks. J. Animal Science 15, 464 (1956). Cover, Sylvia, Bannister, Jo Anne, and Kehlen- brink, Ella. Effect of four conditions of cook- ing on the eating quality of two cuts of beef. Food Research, 22, 635 (1957). Cover, Sylvia, King, G. T., and Butler, O. D. Ef- fect of carcass grades and fatness on tender- ness of meat from steers of known history. Texas Agri. Exp. Sta. Bid. 889 (1958) ' Cover, Sylvia and Shrode, Myrtis Conry. The ef- fect of moist and dry heat cooking on palata- bility scores and shear force values of beef from animals of different levels of fleshing. J. Home Econ., 47, 681, (1955). Cover, Sylvia and Smith, W. H., Jr. The effect of two methods of cooking on palatability scores, shear force values, and collagen con- tent of two cuts of beef. Food Research, 21, 312 (1956). Cover, Sylvia. Scoring for three components of tenderness to characterize differences among beef steaks. Food Research, 24, 564 (1959). Hankins, O. G. and Ellis, N. R. Proc. Am. Soc. Animal Production, 314 (1939). Irvin, Lanell and Cover, Sylvia. Effect of a dry heat method of cooking on the collagen con- tent of two beef muscles. Food Tech. 13, 655 (1959). Lehmann, K. B., Studien iiber die Zahigkeit des Fleisches und ihre Ursachen. Arch. f. Hyg. 63, 134 (1907). 24 National Live Stock and Meat Board. Judging Handbook. October, 1958. i National Live Stock and Meat Board. Manual. Sixth ed. - Paul, Pauline, Bean, Maura, and Bratzler; Effect of cold storage and method of f on commercial grade cow_ beef. M ' State Uni. Tech. Bid. 256 $11956). Ramsbottom, J . M., Strandine, E. J ., and Ki H. Comparative tenderness of represen beef muscles. Food Research, 10, 497, ( h‘ Tappel, A. L. Reflectance spectral studies l hematin pigments of cooked beef. F0‘ search, 22, 404 (1957 ). United States Department of Agriculture. ,} grades for beef. Leaflet No. 310 (195 United States Department of Agriculture, cultural Marketing Service. Official p States Standards for Grades of Carcass; Service and Regulatory Announcements; S. 99, (1956). 7f Wellington, G. H. and Stouffer, J. R. marbling. Its estimation and influen tenderness and juiciness. Cornell Uniif‘ Agri. Exp. Sta. Bul. 941 (1959). ‘ Winegarden, Margaret W., Lowe, Belle, p J., Kline, E. A., Plagge, Alma R., and " er, P. S. Physical changes of connecti ' sue of beef during heating. Food Res 17, 172 (1952). l Acknowledgment This study was supported in part by S ern Regional Project SM-19 “Motivating F) in Consumer Purchases of Beef as Related iii jective Measurements Used to Predict Bee ceptability.”