“ Methods of Determining the Optimum Stage of Maturity for Picking Green-wrap Tomatoes gapieanéa 1955 eta/tat e815 TEXAS AGRICULTURAL EXPERIMENT STATION R. D. LEWIS, DIRECTOR. COLLEGE STATION. TEXAS SUMMARY An objective method of determining the mature green stage 0f a tomato would be useful to t tomato industry. Such a method should be based on external physical or visual factors that can judged rapidly without injury to the fruit. ' Three approaches to finding a suitable method were considered in this experiment. SPECIFIC GRAVITY. As the tomato matures, the seed cavities d-evelop a jelly-like substance - I the weight increases. With increase in weight the specific gravity increases. The increase in r cific gravity may be used to indicate a point or rather a range at which the tomatoes could be separt into groups which would ripen within a given time. a COLOR. A second method concerned a change in skin color and flesh from green to red as ,3 tomato matures. The fruit ripens from the center outward with the blossom end ripening first. | " was measured on the tomato at picking time at the blossom end, the middl-e section and the stem m MATURITY CLASSES. The variability of maturity of the green-wrap tomatoes at harvest . counts largely for the great difference in the time required to ripen a given lot. Variability in t turity necessitates handling many tomatoes several times. Each time the ripe and green tomatoes v separated, the green ones are returned to the ripening rooms. This operation is repeated until all t tomatoes are ripened or spoiled. Analysis of the data indicates a high correlation between specific gravity and the width of the matoes. Specific gravity was related to relative humidity in which the fruit was grown, except j the earliest of the four tagging dates. The length and width of the tomato were related. There w a multiple correlation of r = 0.95 among specific gravity, width, length and weight of the tomatoes t The average specific gravity of tomatoes increased as the days from tagging increased and A specific gravity decrease-d as the days of storage increased. Tomatoes with a specific gravity a 0.949- were 33 days or more from tagging and could be expected to ripen within 15 days. This indica, that there may be a physiological state of maturity at about 33 days from tagging which the to ‘ should reach to reduce the time required for ripening under the conditions of this experiment. ' idea seemed to be substantiated throughout the work by specific gravity, length, width and weigh all indicating that the average tomato should be approximately 33 days from fruit set to be ex - _ to ripen within 15 days. ‘ The average width data indicate the greater the diameter the better the maturity 0-f thef A tomato with an average diameter of 21/8 inches or more- should ripen in 15 to 18 days. This concl :~ was substantiated by data compiled from actual operation of a ripening room of a tomato I»? plant. The repack plant data consisted of 19 lots of tomatoes totaling 331,922 pounds which coul identified by sizes. Eleven of these 19 lots, or 264,187 pounds of fruit, were in the grade size grou of 6 >< 6 or larger with a minimum fruit diameter of 21/8 inches. The remaining 8 lots of 67,735 pou’. were in the grade size grouping of 6 >< 7 or smaller with maximum f.ruit diameter of 2% inches. ' Ninety percent of the larg-er tomatoes ripened in less than 12 days, while 70 percent of the s _ tomatoes required 16 days to ripen. The difference between the time of ripening for the experim q tomatoes and those from the ripening room of the tomato repack plant was due to the differen » the method used to assess the degree of ripeness. ' The industry by refusing to buy the small tomatoes, sometimes referred to as tube size toma would benefit through handling only the larger size tomatoes which are more mature, and needin percent less time to ripen 20 percent more of the larger tomatoes. The data on 655,480 pounds of tomatoes passed through the ripening room of a tomato repack ~ showed that 50 percent were removed the first time over the grading belt. The second and third t over the grading belt, 23 and 7 percent were removed. The remaining 20 percent required f0‘ more times over the grading belt. "- Q i Methods of Determining tloe Uptimum Stage of i; Maturity for Picking Green-wrap Tomatoes H. B. SOREN SEN, Asssitant Professor Department of Agricultural Economics and Sociology THE FRESH TOMATO CROP IN TEXAS IS VALUED AT lover 12 million dollars annually. The industry ‘started about 1890 near Jacksonville in East Texas and has expanded t0 almost all sections of the State. Until about 1915, tomatoes were shipped 1i in a “pink” or “turning” stage. With high prices early in the season and a good demand for toma- toes, farmers started picking their tomatoes a lllittle greener each year. Most tomatoes in Texas ' jre now marketed in the “green-wrap” stage. The tomato fruit is considered mature while ‘still in a green stage; it will ripen to a red color Sifter removal from the plant. The maturity of 5.. green-wrap tomato cannot always be determined ccurately through observation of external char- iacteristics, but an experienced person usually can etermine “green mature” fruits. The maturity of a lot is determined by cutting a representative sample. By U. S. Standards for fresh tomatoes, “Mature means that the contents of the seed ‘cavity have begun to develop a jelly or glue-like consistency and the seeds are well developed.” fCutting and checking the contents of the seed cavity of a few fruits results in spoilage because of the cut tomatoes, and leaves doubtful the ma- turity status of the entire lot. An objective method of determining the ma- ture green stage would help in clearing the market 10f immature green-wrap tomatoes. Such a meth- rod should be based on external physical or visual factors that can be judged rapidly without injury to the fruit. An experiment was conducted to jdevelop a method for determining stages of ma- turity of tomatoes by objective methods and to find a relationship of repacking time to maturity 1» harvest. Three approaches were considered: As the tomato matures the seed cavities de- l elop a jelly-like substance and the Weight in- "reases. With increase in Weight the specific ravity increases. The increase in specific grav- ty may be used to indicate a point or range at hich the tomatoes can be separated into groups hich will ripen within a given time. a The second approach deals with change in skin color and flesh from green to red as the to- j ato matures. The tomato ripens from the cen- :. r outward with the blossom end ripening first. l. olor was measured on the tomato at picking time at three points: the blossom end, the middle sec- tion and the stem end. The variability of maturity of the green-wrap tomato at harvest accounts in large measure for the great difference in the time required to ripen a given lot. Variability in maturity necessitates handling many tomatoes several times. Each time the ripe and green tomatoes are separated, the green ones are returned to the ripening rooms. This operation is repeated until all the tomatoes are ripened or spoiled. REVIEW OF LITERATURE Development oi a Tomato The tomato, Lycopersicon esculentum, is na- tive to the tropical regions of the Americas. Early explorers carried the seedto Europe about 1500, where the tomato was used first as a novelty, later for_ medicinal purposes, and in about 1800, for culinary purposes. By 1840, it was accepted for fresh-eating purposes in America (11). Experiments with the Gulf State Market vari- ety showed that the fruits reach the mature green CONTENTS Page Summary .................................................................... __ 2 Introduction ________________________________________________________________ __ 3 Review of Literature ________________________________________________ __ 3 Development of a Tomato ____________________________________ __ 3 Use of Specific Gravity ......................................... __ 4 Separation of Tomatoes by Skin Color ______________ __ 4 Pressure or Compressibility of Tomatoes ........ .. 4 Ripening Operation ______________________________________________ __ 4 Materials and Methods ____________________________________________ __ 4 Tagging of Tomato Blossoms ____________________________ __ 5 Specific Gravity ____________________________________________________ __ 5 Color Test .............................................................. __ 5 Ripening Storage Period .................................. 5 Pressure or Compressibility Tests ____________________ __ 6 Visual Inspection Rating ____________________________________ __ 6 Results and Discussion ............................................ __ 6 Specific Gravity of the Tomatoes ______________________ __ 6 Length, Width and Weight of Tomatoes ........ .. 7 Color of Tomatoes ................................................ __ 3 Maturity of Tomatoes .......................................... __ 8 Pressure or Compressibility of Tomatoes ........ -. 10 Visual Inspection Rating .......... _; ________________________ __ 10 Relationship of Maturity to Repacking Costs. 11 Acknowledgments ...................................................... __ 12 Literature Cited ........................................................ __ 12 stage about 27 days after fertilization. As a to- mato matures it increases in almost all quantita- tive and qualitative measurements, including size, weight and specific gravity. Lutz (6) reported that specific gravity, total acidity and hydrogen- ion concentration increase and resistance to punc- ture decreases with stage of maturity, with varia- tions in each item. He also reported that a picked immature tomato ripens only 1 day earlier than a vine-ripened tomato. Use of Specific Gravity Specific gravity is an indirect means of de- termining the dry-matter content of a substance. One method of determining specific gravity is the ratio of the weight in air of a substance times the known specific gravity of the liquid used to the weight in air of the substance minus the weight of the substance when submerged in the liquid. Lutz (6) and Nettles (7) determined the specific gravity of tomatoes by placing them in successive alcohol-water mixtures of known spe- cific gravity and noting the most dense mixture in which the fruit sank. Nettles (7 ) later used the method in which the weight of the fruit in air is divided by the volume of the fruit as it displaces its volume in water. Kunkel et al. (5) reported the use of specific gravity to separate potatoes into different cooking quality groups. The potatoes were separated into the various cooking classifications by floating them in solutions of known specific gravity. The floatersof the lowest ‘specific gravity were con- veyed to a tank with a solution of a higher spe- cific gravity. The floaters from the second solu- tion were separated from the sinkers and the sink- ers in each solution were kept separate. In this way, the potatoes were placed in three grades based upon specific gravity. Nylund (9) found a direct relationship between hollow heart and the specific gravity of potatoes. Nichols and Reed (8) found that flesh texture and color are cor- related with specific gravity of prunes. Kelly and Smith (4) suggested in 1944 that specific gravity could be used conveniently for de- termining the maturity of fruits and vegetables such as apples, pears, peaches, plums, cherries, grapes, citrus fruits, potatoes, tomatoes, cucum- bers, cabbage, melons and peas. Separation of Tomatoes by Skin Color Skin color may be a means of determining maturity of green-wrap tomatoes. Desrosier et al. (1) reported that color grading is used success- fully on red apple varieties and canning tomatoes. Francis (13) reported that the ratio of red to green in the skin of McIntosh apples showed a marked variation with the size of the apple. Little is known about the color of a green- wrap tomato. Visual observations show that as the tomato increases in Thaturity it changes in shade from a green immature to a mature green- wrap. It might be possible to use a color indicator s 4 to separate immature from mature tomatoes with some variability because of some fruit being a shaded. Pressure or Compressibility of Tomatoes It is believed that the more mature tomatoes will not ship satisfactorily because they cannot withstand the pressure of the package without. bruising. Lutz (6) found that resistance to punc- ture decreased slightly after the mature green- stage was reached. He added that the pressurej test showed no consistent relation between ma- turity and pressure readings of tomatoes. Hamson (3) stated that pressure tests may be used to obtain a rapid, accurate evaluation of differences in firmness of tomatoes. He also; reported that an increase in firmness results. largely from a“ greater content of pectin in fleshy A tissue of firm fruits. Ripening Operation Differences in the degree of maturity of green-wrap tomatoes at harvest time account inf large measure for the great variability in the; time required to ripen a given lot. . Wright and Gorman (13) found that “Under, average market conditions, tomatoes are usually ripened at about 68°, 4 or 5 days being required for mature green tomatoes.” According to Sorensen (10), tomatoes are first graded in the ripening room when 60 percent are ready for sale as indicated by color. The green and pink tomatoes are separated so that the “pinks” can be processed the next day. The. green tomatoes are replaced in the ripening room until about 7O percent show enough color to jus- tify being handled again. ‘ MATERIALS AND METHODS The tomatoes used in these studies were grown on Lufkin fine sandy loam at College Sta-r, tion in the spring of 1954. Samples were takeni during the growing season for specific gravity; length, width and weight measurements. Skin color readings were made with a photo volt re-, flection meter on the stem, blossom end and mid- dle section of tomato fruits. Compressibility of the tomato fruit after ripening, percent moisture and loss of weight in storage also were recorded, The effect of weather on each of these ‘conditions? for each stage of maturity and the four dates of tagging of blossoms was recorded. The experi- ment was designed to correlate seasons of pro- duction and varieties of tomatoes, but this phas was eliminated after the spring and fall of 1953i because of uncontrolled weather conditions an the variability among varieties. . I The Rutgers variety was used for the sprin growing season of 1954. With the specific grav ity, length, width, weight, weather and taggin and picking dates, an attempt was made to fin, an objective method for determining when a if; mato has reached the mature green stage an will ripen within a given time. " agging oi Tomato Blossoms _ T0 measure the maturity of the tomatoes in days from fruit set, day-old open blossoms were arked with identifying tags and fruits were ;icked at varied stages of maturity of 24, 27, 30, ' 3, 36, 39 and 42 days from tagging. The tagging operation covered four different rdays, April 21, 23, 27 , and May 3, when 600, 800, {.1200 and 800 flowers were tagged. a A cardboard container, 12% inches wide by glfiinches long by 31/43 inches deep with crossed glividers, giving 2O compartments 3 >< 3 >< 31/; _ fnches, was used to maintain individual fruit rec- irds. The dividers were arranged to provide four glows with five compartments per row, Figure 1'. sample, of 2O tagged tomatoes represented each tage of maturity for each tagging date. g The front end of the box was labeled. The omatoes were numbered from left to right and lront to back. The number assigned to the cell r compartment of the box was the number as- igned to the tomato. A “cross” was placed in the bottom of each i ell as the tomato was eliminated. pecific Gravity A To determine the specific gravity of a whole fmato fruit the following measurements are Needed. L 1. Liquid weight is the weight of the tomato when it is placed in a solution with a spe- cific gravity less than that of the tomato. The tomato will not float and the weight can be determined. In these experiments the tomato was placed in a wire basket that was attached to a scale. The weight of the tomato in the liquid was recorded. The equipment used for determining spe- cific gravity of the tomatoes is shown in Figure 2. 2. Specific gravity of the liquid used. Nine- ty-five percent ethyl alcohol was used for Figure 1. Cardboard container used to maintain iden- W oi tomatoes in the experiment. c Figure 2. Equipment used to determine specific gravity. this experiment because it has a specific gravity of approximately .800. The spe- cific gravity of the liquid was determined at the start of each lot of 20 tomatoes by the use of hydrometers. The formula used for determining the spe- cific gravity of each tomato was: Specific gravity = - Weight in air >< specific gravity of liquid weight in air -~ weight in liquid Color Test There is a visual change in the skin color of tomatoes as they mature. Color tests were made to determine if they could be used to measure the stage of maturity of green-wrap tomatoes. To determine the change of color of the to- mato during the ripening process, the color of the tomato skin and the flesh underneath the skin were recorded numerically by photoelectric deter- minations made with a photo volt reflection meter No. 610, Figure 3. The color of the tomato fruit was measured at the stem end, the middle area and the blossom end. Three readings were taken at each location and averaged. Ripening Storage Period After physical and color tests were complet- ed, the tomatoes were placed in storage and allow- ed to ripen at 64° F. with a relative humidity of 58 to 60 percent. The storage facilities consisted of the chilled rooms operated by the Department of Agricultural Engineering. The boxes of toma- toes were placed on racks in the room to allow good circulation of air. The storage period varied from 6 to 30 days, but as the tomatoes ripened they were checked at 3-day intervals until all had ripened. Figure 3. Photo volt reflection meter used to record color. Pressure or Compressibility Tests Pressure-testing equipment indicated the amount of penetration a tomato would stand be- fore breaking, Figure 4. The pressure area was constant for the entire experiment. At the com- pletion of the ripening period, the following data were recorded for the pressure-test phase: 1. Diameter of tomato in centimeters. 2. Grams of weight used. This usually held constant, but when the condition of the tomato indicated that it would not with- stand the normal weight used, less weight was applied. 3. Pressure-test reading. The formula for measuring the resistance of the tomato x to the pressure test was: Resistance I pressure test reading diameter ofgtomato >< grams of weight used I centimeters per gram. Figure 4. Equipment used to determine compressibility of the tomatoes. 6 The percentage moisture was determined r each tomato after all other measurements we g completed. The formula used was the ovend material weight divided by the wet materiy, weight. 5 Visual Inspection Rating An attempt was made to correlate the speci ic gravity of the tomato with a visual observatioy by cutting and inspecting the tomatoes. A A number of tomatoes of unknown stage ~ maturity were used in the visual inspection ratin Each tomato was cut across the middle secti and rated according to one of the four classifi tions used in the visual inspection rating. A Very (green) immature tomatoes-no se or very immature. No glue or jelly-like consi tency in the cavities. 3 Immature-immature seed, white and eas' cut by the knife. A jelly-like substance starti to form. » Ma/tzarew-seed not easily cut by the knif The glue or jelly-like substance formed. T classification determines the maturity of tomat under the present system. Good mat/writzk-seed well filled and not easl cut by the knife. J elly-like substance well form in the locules. At the time of visual inspection, puffiness the tomato was recorded each time it was noted] s a "1 RESULTS AND DISCUSSION Specific Gravity oi the Tomatoes Table 1 indicates that the few tomatoes wit a very low specific gravity greatly influenced average of the group. The extremely low on‘ cannot be separated from those below the aver without a further specific gravity separation. Considerable variation of specific gravity w found within each maturity date. No correlations were found between speci gravity at each maturity date and the three c, readings, or between length and air weight of tomatoes. There was a correlation of .67 betw specific gravity and minimum temperature, for maximum temperature, and .70 for differen in temperature. I Table 2 shows very high correlations betw specific gravity and the width of the tom The good correlation may be accounted for by fact that as the tomato increases in maturity the cavities or locules become filled with the =3, or glue-like substance, the width of the to increases. There was a good correlation between cific gravity and the sum of the relative humi for three of the four tagging dates, April April 27 and May 3. The correlations were .80 and .98, respectively. The other tagging o; April 21, showed no correlation. ' w 4'. a ‘TABLE 1. PERCENT OF TOMATOES ABOVE AND BELOW THE AVERAGE FOR EACH MATURITY DATE ' Percent above and Maturity below the average in days specific gravity Above ' Below 24 67.5 32.5 27 59.3 40.7 30 65.8 34.2 33 60.0 40.0 36 60.0 40.0 39 63.7 36.3 42 64.4 35.6 ngth. Width and Weight of Tomatoes The outstanding characteristic of the Rut- ers tomato is its flat shape. Of the 1,040 toma- es measured in 1954, 84 percent were 2 to 3 ches wide, 14 percent were 3 or more inches ,'de and the rest were less than 2 inches; 12.8 rcent were 1 inch long and 87.2 percent were 2 _'l 3 inches long. ~ . Figure 5 shows a good correlation between é e length and Width of the tomatoes for each ge of maturity. The most rapid gain in length “f: width is up to approximately 33 days from gging of l-day-old flowers. This is the period = most rapid development and the tomato cannot “ considered a mature green-wrap at 33 days of e. . Weather definitely affected the length of the mato. Table 3 shows that the weather factors y: a fair correlation with three of the dates of “gging; April 21 showed no correlation. The - ther may have been too cool at the time of the 1 st tagging date (April 21) to have any recog- able effect on the tomato. Only the tagging ' te April 23 had a correlation between length humidity and maximum and minimum tem- rature. There was a good correlation between the ‘ th and the weight of the tomato. The correla- in between the weight and length was less, Ta- 4. _ There was a definite relation between specific ‘vity and width of the tomato, also between the e (width and length) and weight. The multiple V: elation coefficient measured the combined ef- "t of the three independent variables on the av- "ge specific gravity of the tomatoes for each ge of maturity. The importance of the three Li»: 2. CORRELATIONS BETWEEN SPECIFIC GRAVITY = AND WIDTH or EACH LOT or TOMATOES FOR EACH MATUBITY Average Average iMaturity specific width in Correlation m days gravity inches (R2) 24 .93595 2.4 .99 27 .9381l 2.5 .98 30 .94206 2.7 .99 33 .94950 2.7 .99 36 .951 13 2.6 .98 39 .95503 2.7 .99 42 .96752 2.8 .99 2 R0 /’ 2.60 / 8 / I 2.40 O Z ";--——Il 22g . ’__a"s_‘ If f": s‘, o" 2.00 J/z vnuru LENGTH Ocn-nncoc L80 24 27 3O 33 36 39 42 45 MATIRITY DAYS FRGII TAOOINO Figure 5. Average length and width of tomatoes by days of maturity. independent variables on the average specific gravity is shown in the simple correlations in Tables 2 and 4. The multiple correlation coeffic- ient, R 1.234 = 0.95, indicates a high degree of association between the average specific gravity of the tomatoes for each stage of maturity and average width, length and weight. The square of the coefficient, R 1.234 = 0.90, indicated the proportion of the squared variability in the average specific gravity of the tomatoes for each stage of maturity explained by these three factors. The coefficient of determination is 0.90, or 90.0 percent. The unaccounted for variability is expressed by the coefficient of nondetermination, 0.10 (1-0.900 = 0.10). The coefficient of nondeter- mination is the proportion of the squared varia- bility in the average specific gravity of the to- matoes for each stage of maturity not explained by the three other factors. This unaccounted for variability may be due to error, or some other un- explained factors. The size of the tomato seems to affect the specific gravity. A higher average specific grav- ity was recorded with the larger size (above 2.5 inches) and decreased as the size decreased (be- low 2.25 inches). There were high correlations between the weight and size of the tomato. There was a good correlation between Weight of the tomatoes at picking and one tagging date (April 23) and weather (humidity and temperature), but this TABLE 3. CORRELATION BETWEEN WEATHER AND LENGTH OF THE TOMATO AT DIFFERENT TAG- GING DATES Weather Tagging dates fed" April21 April 2a April 21 May3 Maximum temperature .17 .59 .64 .65 Minimum temperature .02 .59 .64 .63 Differencel .12 .07 .65 .09 Relative humidity ,_ .02 .81 .83 .66 1 Difference between daily maximum and minimum tempera- tures. .1 TABLE 4. CORRELATION BETWEEN LENGTH AND WIDTH WITH THE WEIGHT OF THE TOMATOES AT EACH STAGE OF MATURITY TABLE 5. CORRELATION BETWEEN WEIGHT OF y TOMATO AT TAGGING DATES AND T l‘. ATURE AND HUMIDITY I Width Length Maturity Width Length In dQYS grams ' average, R2 average. R2 inches inches 24 106.7 2.4 .89 2.0 .74 27 119.9 2.5 .79 2.1 .53 3U 141.9 2.7 .91 2.1 .72 33 152.3 2.7 .35 2.2 .85 35 149.4 2.5 .92 2.1 .58 39 161.2 2.7_ .90 2.2 .51 42 155.1 2.8 .85 2.3 .57 varied considerably with the different dates of tagging. The ratio between length and Width and the weight of the tomato is very high when compared with the specific gravity for the average of the lot of tomatoes that are 24 and 27 days from tag- ging. By 30 days from tagging the ratio had de- creased rapidly, indicating that the length and width growth has slowed down and the Weight of the tomato has increased. Color oi Tomatoes The skin color and flesh of the tomato change from dark to light green during the ripening pro- DAYS or sroaaee —---— oars 0F uanmmr -—-— 55 ,4‘ auossom '_—¢ ,0! END x x t so ‘i’ U) (D Z 45 Q 5 m "‘___§ ‘i’ I! a: = Q‘ uuoou: g 4V ~_=____'! O 35 3O ___ sun ___‘~ / stem \Z ' ~ ‘w’, 25 v DAYS OF STORAGE 6 9 I2 l5 I8 2| 24 27 3O DAYS OF MATURITY 24 27 3O 33 36 39 42 Figure 6. Average blossom. middle and stem end color reading on a photo volt reflection meter on tomatoes by days oi maturity and storage. 8 Diiteren ~12 Tagging Humidity Maximum Minimum between _A dates temperature temperature and mim t April 21 .34 .32 .30 .37 April 23 .81 .81 .81 .83 April 27 .57 .56 .56 .54 May a .66 .ss .67 .65 cess. The color change starts at the blossom‘ and spreads towards the stem end. About i time the stem“ end becomes lighter in color V, blossom end shows pink. The pink develop red and spreads to the stem end. ‘ Figures 6 and 7 give the average color of maturity group and the average color of th matoes with time during ripening in storage. blossom-end color reading is highest at 33 from tagging, but this would not be a good g sure for determining maturity as the color is l for the 6 to 9 days of storage. The middle, ~ end and total average color readings may be to indicate maturity. The average color re, decreases with the number of days in sto The charts indicate that the color readings higher when the tomatoes are more than 30 ; from tagging and were in storage less tha" days. - The color of the tomatoes that were vis inspected was constant. The very immatu _ matoes had a slightly higher color readin this would not be a reliable measure for separ the immature from the mature tomatoes. i The average color for blossom, middl stem end of all the tomatoes at the end of the age period when the tomatoes were ripe is s in Figure 8. The tomatoes that required. 15 days to ripen had a uniform color and = days of storage increased the color uniformi creased. This also may indicate that the physiologically mature tomatoes are the one ripen in about 12 days of storage. When the tomatoes were separated into_ size groups of above 2.5 inches, 2.25 to 2.5 i, and below 2.25 inches, the average color >5’ increased as the size of the tomato incr This indicates that size may have a relation -_ color readings of the tomatoes. E Maturity, oi Tomatoes The number of days it takes to ripen a T wrap tomato is very important. In 1954, 76, cent of the tomatoes ripened in 18 days o The remaining 23.7 percent required up to =‘ ditional 12 days under the conditions of j tests. If the tomatoes had been grown und ferent environmental conditions, such as te ture, the days from blooming to ripeningf have been different. Elimination of this of approximately 24 percent would reduce t time and effort in the ripening of the toma The ripening period decreases as the V‘ the fruit increases. Tomatoes when harvi days from tagging 1-day-old blossoms plus 23 ys required for ripening are available for the Vrket in‘ 47 days. This is about the same num- pr of days required for tomato fruits harvested = 30 days of age and which ripen in 17 days. To- - 5. toes harvested at 24 days from fruit set do not I f more than half a day earlier than tomatoes jrvested at 30 days. Six days less storage time re required for the more mature tomatoes. iirty-day-old tomatoes were larger, heavier and ,_re more uniform in color on ripening. This y indicate that the tomato should reach a phys- ogically mature green stage to decrease the rip- iing period. . Figure 9 shows that as the number of days storage increases the average specific gravity ;each group decreases. This verified the belief ‘t the more mature tomatoes have a higher spe- ic gravity and mature tomatoes will ripen more 'ckly. The fact that specific gravity for ripen- tomatoes was higher than the average indicates re is less variability between the specific grav- ;of the ripened tomatoes than at stages of ma- ‘ty. At the start of this experiment, it was hoped t a definite point on the specific gravity scale ild be used to separate the tomatoes into lots “t required different storage periods. It ap- k rs now that a range rather than a specific point st be used. a Figure 9 shows that, with a specific gravity :.949, tomatoes are over 33 days from the tag- ' of l-day-old open flowers and the tomatoes ve this point will ripen in '6 to 15 days. Lutz in Mississippi indicated that with Gulf State i ket tomatoes the mature-green stage was _' hed about 27 days after fruit set. This ex- "ment does not attemptto define ‘the number ays from fruit set to a mature-green stage; it mpts to indicate the point on the specific grav- gscale at which the average tomato would rip- which may be approximately 33 days or more m tagging and the tomatoes would ripen in 6 ii 5 days. . The size of the tomato seems to indicate in t- respects its maturity. Figures 10, 11 and v g 45.0 " 43D .¢41.o __ ~ I,’ x ' ‘ ~~_ _--— I’! g 11-; ___- c 390 ‘\‘ I = \\ ¢¢"-‘ $51.0 DKYS OF STORKK I3I$_ , DAYS or MATURITY i1- '50 , STCRAQ 6 9 l2 l5 l8 2| 24 27 3O MATLRITY 24 27 3O 33 36 39 42 qigugre 7. Average color reading on a photo volt re- meter on tomatoes by days o! maturity and storage. 540 srossoa can con-c- MIODLE Iii STEM END ooooooooo no 52.0 _ I.‘ I I’ .‘\~/ soo i’, ' ' I w / 2 48o I’ i ‘ I’ / g 46.0 \\ _1 I {>1 \ I / 44.0 \ ,1’, __ \\/ v i, m“. ‘U ... m-‘I 42-0 I x’ . ma." “w”, 40.0 f’ m” 6 9 I2 24 27 3O l5 ‘ ~ DAYS OF STORAGE Figure 8. Average color reading on a photo volt re- flection meter for blossom, middle and stem end of toma- toes on ripening by days of storage. 12 show the average length, width and weight of the tomato at each stage of maturity and the average original length, width and weight of the tomatoes that ripened in each storage period. The length data indicate that the average to- mato of 2 2/16 inches or more will ripen in 15 to _18 days. Below this length the time of ripening increases. The average tomato does not reach the desired length until about 33 days from tagging of 1-day-old flowers. ' ‘ The average width data show that the greater the diameter, the better the maturity. The di- ameter decreases with each increase in storage up to 15 days, tapers off to 21 days of storage and then drops rapidly. The average width indicates that there may have been a period of 15 to 21 days of storage. The actual ripening operation supports this information and is presented in a later section. The weight of the tomato also shows to some extent the maturity. The average weight of the tomato increases with the increase in days from fruit set. The average weight of the tomatoes that ripened in 6 days was high and as the num- ber of days required to ripen increased the aver- age weight decreased. Figure 13 shows that it is .970 \\ E \ ‘fl’ 3r .950 4'" ““~ 5:) j/ \ E 4(- \ g s30 » ‘ l, ,1‘ ‘~__ \Y BIO DAYS 0V STMAII O-Q-‘P- DAYS W NAHMITYiI .890 . [JAYS IN STORMI 6 9 l2 I5 l8 2| 24 2T 3C- DAYSOFMATLRITY 24 27 3O 33 36 ' - 39 ' 42 Figure 9. Average specific gravity oi tomatoes by days oi maturity and storage. 9 2.50 2.30 LENGTH IN lNCHES i\ f} t.__ 7 2J0 } -_ Muc- / ~__‘\ 1.90 \‘ ens or steam: unnu- \ oars or urrunlrv ——-—- \ L70 DAYS IN STORAGE 6 9 l2 l5 l8 2| 24 27 30 DAYS CF MATLRITY 24 27 3O 33 36 39 42 Figure l0. Average original length of tomatoes by days oi maturity and storage. possible that the tomatoes should be at least 36 days old to reach the average weight that ripened in 18 days of storage. Figures 9 (specific gravity), 10 (length), 11 (width) and 12 (weight) indicate that the aver- age tomato should be approximately 33 days from fruit set to ripen in 15 days. Tomatoes steadily lose weight as the number of days of storage increases and the percent mois- ture changes. Table 6 shows that the tomatoes requiring only 6 days of storage may not have had as much moisture as others. After 9 days of storage, the amount of moisture decreases with increasing length of storage. The compressibil- ity or resistance to pressure of a tomato increases with the storage period. It is possible that with the loss of weight (mainly as loss of moisture) the compressibility increases up to a point. Pressure or Compressibility of Tomatoes After 30-33 days of age, the pressure the tomato fruit will stand decreases as maturity and the length, width, weight, and specific gravity increase, Table 7. This verifies the generally accepted idea that as the tomato approaches maturity the size of fruit increases and the fruit tends to become soft- er. When the tomatoes are about 33 days of age they have a resiliency similar to that of rubber. 2.90 §~~__ 27o "“~_ _ ~~_ .... cn- ~ s tn 5b.?‘ é 250 I \_ m s g \/ \\ lg 2.30 > “a \ 2.lO ‘g nus or steam: ---- x on: or uxrumrv i " \‘ L90 DAYS IN STORAGE 6 9 l2‘ l5 I8 2| 24 27 3O DAYS OF MKTURITY 24 21 so 32s as 3e 42 Figure ll. Average original Width of tomatoes by days oi maturity and storage. '10 |-_____ 16o \ \\\ mo “‘~~\ / m \ ’ 3 ~_____ i5 |2o \ \- e \/ \ g |oo ‘ 5 eo OAYIOFITQAM Dona-IQ DAYSWNAHRITV i so DAYS N STORAGE s 9 I2 n5 I8 2| 24 21 5 DAYS OF MATlRITY 24 27 3O 33 36 39 42 Figure l2. Average original weight of tomato‘ days oi maturity and storage. The smaller the tomato, the higher the f sure or compressibility will be for tomatoes 2.25 inches, as compared with 2.25 to 2.5} above 2.5 inches. Figure 13 indicates that age pressure in 1,000 grams per cm. is hi 24 days from fruit set and decreases until". tomato reaches approximately 33 days from .5 set. The amount of pressure a tomato will s. decreases as the tomato increases in age a fruit set. Pressure test determinations also v made after the storage period. The amou pressure a tomato will stand increases as; number of days in storage increases. The amount of pressure a tomato will ' stand increases from 6 up to 12 or 15 da, storage, at which time it reaches approxi the same pressure as that of the tomatoes are 30-33 days of age. Visual Inspection Rating Five hundred fifty-four tomatoes of un f maturity were inspected visually after the; cific gravity, weight, length and width m ments had been recorded. The percent tomatoes in each classification was very ' ture, 2.9; immature, 36.8; mature 43.1; and maturity, 17.1. a 4 23000 g; /"\ 3 / \ ’ w 21000 i ’ _ I g ___ _>’\/% . Z -" o usooo 1' as ,1’ ° w’ Q r/ooo A , w: or mam " nus onmum oAva or aroma: 6 9 J2 l5 I8 2| 24 nan or NATURITY 24 27 3O 33 36 39 42 DAYS are. mean: rm Figure 13. Compressibility of tomatoes by maturity and storage. 3. g TABLE 6. AVERAGE PERCENT MOISTURE AND LOSS OF v MOISTURE AND PRESSURE TEST FOR DAYS IN STORAGE. Days in . Loss oi Calc. storage Molsture weight pressure 1 6 91.9 '1.6 .174 9 94.2 3.9 .197 12 94.3 3.5 .203 15 93.4 4.4 .203 18 93.1 6.5 .210 21 93.9 7.1 .209 24 93.9 8.1 .225 27 92.3 9.4 .205 30 92.1 13.4 .199 11.000 grams per cm. About 40 percent were placed in the imma- ure group and the rest were classified as mature omatoes. g During the inspection, the tomatoes also were lassified as puffy and nonpuffy. The percent of uffy tomatoes for the four classification groups as 62.5, 39.7, 23.8 and 15.8, respectively. The specific gravity for all tomatoes and for ose nonpuffy and puffy is shown in Table 8. uffy tomatoes lower the specific gravity" of each oup of tomatoes. The weight of the tomato increases with ma- ; rity principally because the locules become filled ith a jelly-like substance as it matures. Table 9 'ves the average weight of the tomatoes in each ting group and shows the variability of the eight of the tomatoes. Puffy tomatoes weighed ore than nonpuffy tomatoes only in the extreme mature and mature groups. Table 10 gives the average length and width , tomatoes for each visual inspection group. This ble indicates that there is little difference in e between puffy and nonpuffy tomatoes. eight and size are not a good means of separ- ing the puffy tomatoes from the group. (lationship of Maturity to Repacking Costs _ A load of tomatoes does not ripen uniformly. ta were obtained in 1953 from the ripening ms of the E. A. Brown Tomato Company, San tonio, Texas. This information was obtained l actual timing of each load, recording the vol- 1 e, amount removed, number of times required LE 7. COMPARISON OF THE PRESSURE A TOMATO A WILL STAND FOR VARIOUS CONDITIONS AND STAGES OF MATURITY “my Average Average Average Average Average days weight, width, length. calc. specific grams inches inches pressure 1 gravity 107.3 2.4 2.0 .215 .936 118.9 2.5 2.1 .210 .938 141.9 27 2.1 .197 .942 151.7 2.7 2.2 .207 .949 144.0 2.6 2.1 .198 .951 162.0 2.7 2.2 .209 .955 166.0 2 8 2.3 .206 .967 l" grams per cm. TABLE 8. AVERAGE SPECIFIC GRAVITY OF ALL. NON- PUFFY AND PUFFY TOMATOES IN EACH VIS- UAL INSPECTION RATING Rating All N onpufly Puffy 1 .91987 .94167 .9068 2 .93170 .93917 .92036 3 .94207 .94405 .93575 4 .95621 .95861 .94340 to run the tomatoes over the grading belt, and time and number of employees used. During the experimental work, 655,480 pounds of tomatoes were checked. An average of 50 percent of the tomatoes were removed in the first run, 23 percent in the second run and 7 per- cent in the third run. Approximately 20 percent of the tomatoes were still green and not ready for retail sale. The number of days of storage in- creased with each succeeding run or reworking of the tomatoes. Considerable variation was noted in checking the number of days in storage in the ripening op- eration. Nineteen lots with 331,922 pounds of tomatoes were designated by size. There were 11 lots with 264,187 pounds in the grade-size grouping of 6 >< 6 or larger (6 >< 6 refers to ar- rangement of tomatoes by size), and 8 lots with 67,735 pounds in the grade-size grouping of 6 X 7 or smaller. There were 6 tomatoes along the width and length of the lower layer in the container. There was an apparent difference in the amount of time required to ripen the toma- toes in each group. - The 6 >< 6 or larger tomatoes required an average of 12.2 days from shipping to ripen 89.9 percent of the group. An average of 15.9 days was needed to ripen 69.3 percent of the smaller tomatoes (6 >< 7 or smaller), The number of times required to handle the tomatoes varied with the two groups, Table 11. The size of the tomato was a fair indication of maturity. With an average length of 2.15 (U. S. Standard 2 2/16 inches and larger the average tomato could be expected to ripen in 6 to 15 days. The average width of approximately 2.6 ( 2 10/ 16) inches and longer could be expected to ripen in about 6 to 21 days. The data presented in this section show that tomatoes of 6 >< 7 or smaller require more time to ripen than tomatoes of grade size 6 >< 6 or larger. The U. S. Standard grades for green-wrap tomatoes (11) give the minimum and maximum diameter for 6 >< 6 as 2.5 to 2.9 inches and 6 >< 7 size tomatoes as 2.25 to 2.6 inches. TABLE 9. AVERAGE WEIGHT IN GRAMS OF ALL. NON- PUFFY AND PUFFY TOMATOES IN EACH VIS- UAL INSPECTION RATING Rating A11 Nonpufly Puffy 1 100.3 119.3 88.9 2 119.7 119.3 120.3 3 133.9 132.5 138.5 4 173.8 175.7 163.4 11 TABLE 10. AVERAGE WIDTH AND LENGTH OF ALL. NON- PUFFY AND PUFFY TOMATOES IN EACH VIS- UAL INSPECTION RATING Width. inches Length, inches R . “m”! All Nonpufly Puffy All Nonputfy Putty 1 2.94 2.4a 2.27 1.99 2.01 1.9a 2 2.59 2.52 2.55 2.09 2.0a 2.12 9 2.a9 2.a2 2.51 2.1a 2.14 2.21 4 2.99 2.90 2.9a 2.94 291 2.99 The U. S. size of 6 >< 6 or larger has a min- imum diameter 2.5 inches and a maximum 0f 2.9 inches. For the 6 >< 7 or smaller tomato, the U. S. diameters are 2.25 to 2.6 inches. The overlapping of these two sizes should be noted. Using the maximum size of 2.625 inches, the width size in Figure 11 showed that the average tomatoes above this size ripened in 6 to approximately 15 days. This corresponds to the 12.2 days as the average time required to ripen 89.9 percent of 6 >< 6 or larger tomatoes. The 6 >< 7, or smaller size, averaged 15.9 days to ripen 69.3 percent of the tomatoes. There is a slight difference in ripening time between the experimental data and the data from the tomato repack plant. This is mainly because of the difference in classification of ripeness. In the repack plant a tomato was classified as ripe when it still had some green color; in the experi- ment, a tomato had to be uniformly red to be classified ripe. Other data previously presented indicated that the shape of the Rutgers tomato is flat, causing the width to be the larger dimension. It also was shown that the tomato increased in size as the number of days from fruit set increased. The average size of 2.50 inches Was found when the tomato was 30 or more days from fruit set. TABLE 11. NUMBER OF TIMES TOMATOES WERE HANDLED AND PERCENT REMOVED IN EACH OPERATION 6 >< 6 or larger size 6 >< 7 or smaller size No. of times handled Percent No. of days Percent No. of days removed to ripen removed to ripen Run No. 1 49.0 69.3 Run No. 2 37.0 i Run No. 3 3.6 i- Total runs 89.9 12.2 69.3 15.9 Remainder 1 10.1 30.7 Total 100.0 100.0 1 Individual lots were small and mixed together. causing the lots to lose their identity. 12 Acmowtznandznrs This bulletin was adapted from a dissertati submitted to the faculty of the Graduate Sch of the A & M College of Texas in partial ful ment of the degree of doctor of philosophy. Much credit is due R. L. Smith, Jr., =- of the Statistical Laboratory of the Texas A cultural Experiment Station, and his employ for the handling of the data on punchcards. Analysis of the data and preparation of 5 manuscript were done in part with funds r vided by the Research and Marketing Act of 1 LITERATURE CITED 1. Desrosier, N. W., F. W. Billerbeck, and R. B. 1952. Color grading of red apple varieties with Purdue color ratio meter. Amer. Soc. of Hort. v 60:209-212. = 2. Francis, F. J., 1952. A method of measuring the i color of apples. Amer. Soc. of Hort. Sci. 60:213 3. Hamson, A. R., 1952. Measuring firmness of t toes in a breeding program. Amer. Soc. of - Sci. 60:425-433. i 4. Kelly, W. C., and Ora Smith, 1944, Specific ; determinations as an aid in research. Amen of Hort. Sci. 44:329-333. ‘ 5. Kunkel, Robert, P. F. Gifford, A. D. Edgar and Binkley, 1952. The mechanical separation of po a into specific gravity groups. Colorado Agr. Exp. Bulletin 422-A. a. Lutz, J. N., 1944. Maturity and handling of wrap tomatoes in Mississippi. USDA Circular -‘ '7. Nettles, V. F., 1950. The relationship of s gravity to tomato fruits to their stage of ma 1 Amer. Soc. of Hort. Sci. 55:343-345. ‘ s. Nichols, P. F. and H. N. Reed, 1932. Relativf specific gravity of the quality of dried prunes. gardia 6:561-583, No. 6. v 9. Nylund, R. E. and J. M. Lutz, 1950. Separati hollow heart potato tubers by means of size gr specific gravity and X-ray examination. Amer. Jour. 271214-222, No. 6. 10. Sorensen, H. B., 1953. Tomato losses from ha retail store. Tex. Agr. Exp. Sta., Progress ' 1548. 11. Thompson, H. C., 1939. Vegetable crops, Mc Hill Book Company, New York. ' 12. U. s. Grade Standards, 1949. PMA seetfs. 19. Wright, R. 0., and E. A. Gorman, 1940. The rill and repacking of mature-green tomatoes. l Circular 566. '