EFFECT OF CALCIUM SALTS ON THE FIRMNESS OF

326 FLORIDA STATE HORTICULTURAL SOCIETY, 1966 Table 1. Naringin in grapefruit rind (Percent of fresh weight extracted by two methods) 3 hours; the filtrate is diluted color de veloped measured. LITERATURE CITED Soxhlet % 0.93 0.92 0.89 1.05 0.87 0.88 0.90 Method of extraction Kesterson-Hendrickson 0.88 0.90 0.89 1.00 0.83 0.82 0.84 1. Davis, W. B. 1947. Determination of flavanones in citrus fruits. Anal. Chem. 19: 476-478. 2. Hendrickson, R., J. W. Kesterson. 1957. Chemi cal analysis of citrus bioflavanoids. Proc. Fla. State Hort. Soc. 70: 196-203. 3. Kesterson, J. W., R. Hendrickson. 1953. Narin gin, a bitter principle of grapefruit. Fla. Agr. Exp. Sta. Bui. 511. 4. Ting, S. V. 1958. Enzymic hydrolysis of naringin in grapefruit. J. Agr. Food Chem. 6: 546. EFFECT OF CALCIUM SALTS ON THE FIRMNESS OF CANNED GRAPEFRUIT SECTIONS12 R. W. Olsen8, R. W. Barron4, R. L. Huggart4, AND F. W. WENZEL3 Abstract A series of s of canned grapefruit sec tions was prepared during four citrus seasons to determine the effect of added calcium salts on the firmness of the sections. The commercial syrup s had 63% firm sections as compared to 86% when calcium was added. Cal cium chloride imparted a bitter flavor to sections did not firm them as well as the calcium. The dietetic s containing water calcium cyclamate had 40% firm sections a better flavor than the with water only which contained only 27% firm sections. The addition of calcium to the cylamate increased the firm sections to over 50%.. Florida Agricultural Experiment Stations Journal Ser ies No. 2548. lcooperative research by the Florida Citrus Experiment Station Florida Citrus Commission. 2Some financial assistance for this investigation was made by Abbott Laboratories American Maize-Products Company through the establishment of a joint grant-inaid. 3Florida Citrus Experiment Station, Lake Alfred. 4Florida Citrus Commission, Lake Alfred. Introduction Canned grapefruit sections are one of the major grapefruit products processed in Florida. During the 1964-65 season, over 2.5 million box es of seedy grapefruit were used in the produc tion of canned grapefruit sections. Any im provement in quality, together with possible lower costs due to automatic peeling machines mechanized sectioning ing equip ment, could result in greater consumer dem for this product. Calcium salts have been used for a long time for firming certain food products. However, most of the literature concerning firming has been related to tomato products, such as des cribed by Hanson (2) Hall Dennison (1). Other published reports, including that by Kertesz (3), showed the effect of calcium on the firmness of plant tissue. The only published report on the use of calcium salts to firm canned grapefruit sections is that by Singleton (5). He showed that calcium cyclamate would give favorable results depending upon the date of ing. As a result of this limited data, it was decided to investigate more fully the firming

OLSEN ET AL: GRAPEFRUIT SECTIONS CALCIUM 327 properties of calcium in the form of chloride, cyclamate salts on canned grape fruit sections. Experimental Procedures Description of s. Because of the great variability in the quality of grapefruit sections, even from the same lot variety of fruit, large experimental s must be processed to obtain results of any practical significance. To check the effect of the ing date on the firm ness of the canned sections, the s were processed at monthly intervals during the citrus season. The following s were prepared: 1. Water or juice (dietetic) (control). 2. Water or juice calcium cyclamate (dietetic). 3. Water, calcium cyclamate calcium (dietetic). 4. Sugar syrup (control). 5. Sugar syrup calcium chloride. 6. Sugar syrup calcium. Ten cases (24/303) of each of these s were prepared. Ten cases of the commercial were also taken from the line at each time of ing. The above s were all that could be pro cessed in one day at the commercial plant. Hence only one level of each chemical was used. The level of calcium cyclamate used, 0.27% by weight of net contents, was suggested by Olsen (4) ; the calcium level, 0.25%, by American Maize-Products Company the calcium chlor ide level, 0.088%, from unpublished sources. The Brix amount of syrup varied slightly according to commercial practice at the time of ing. The first s were prepared during the 1961-62 season. Since the project was started late in that season, only two series of five s each were prepared. Packs put up during the next two seasons were limited because of the 1962 freeze. Finally, s were processed dur ing the entire ing period of 1964-65. Table 1 shows the season month in which all of the s were prepared, although this table includes data for only the syrup s. Preparation of s. Packs were prepared at a nearby cannery using commercial fruit, al most entirely Duncan or seedy grapefruit. Only current commercial processing methods, includ ing commercial heat treatment, were used for practical reasons. In the preparation of the s, empty cans were picked up from the plant a few days ahead so they could be coded on the bottom; also, a wide black b was en circled on each can to more readily recognize them as they came from the can cooler. The appropriate liquid, with or without the added calcium salts, was then filled into the cans. The cans were then taken to the processing plant where they were placed directly on the line con taining cans partially filled with commercial syrup hence were distributed at rom throughout the sectionizing line. The sectionizers were all told that these cans were to be filled exactly as a normal since some com panies in the past have used bed cans for broken sections. The filled closed cans were Table 1. Effect of season time of ing on the firmness of canned grapefruit sections Type of Season 1961-62 it Month Oct. Nov. Dec. Jan. Feb. Percent firm sections 89.4 94.5 Mar. 76.2 83.3 1962-63 75.3 78.4 ii 78.9 89.2 1963-64 54.4 ti 70.5 1964-65 n 57.0 87.9 68.2 38.2 95.2 86.9 72.1 91.6

328 FLORIDA STATE HORTICULTURAL SOCIETY, 1966 collected as they came from the cooler, then sorted placed in cases. Examination of s. The character of ap proximately 1000 sections from each (48/303's) was determined initially after the products had been stored from two weeks to one month at 80 F.; also, after storage for four eight months. The firmness was determined by subjective examination. Each section was sorted visually by hling feeling into four groups designated firm, soft, ricey fragile. A count was kept of the number of sections sorted into each group. The total weight of each type of section was recorded, as well as the volume weight of the drained liquid. Other characteristics as degree Brix of syrup, flavor, ph, total acid vitamin C were also determined. Samples of some s were also given to the USD A Agricultural Marketing Service for grading. Results Discussion Because of time space limitations, this paper will only present a summary of the per tinent data. Examination of the 45 s in volved approximately 125,000 sections which were graded individually; but, due to the heter ogeneous nature of the product, this was neces sary to obtain significant practical results. Also, for ease of discussion interpretation, only data for the firm sections will be considered. The remainder of the sections were soft, ricey or fragile. A commercial was also taken off the line at the some time that each of the experi mental s in bed cans was taken. The reason for this was to compare the commercial with the bed syrup to determine whether the bs on the cans would have any effect on the type of sections that the sectionizers ed. A comparison of these s show ed that the bed cans did not influence the sectionizers. s. Table 2 shows the typical dis tribution in two s of 48 cans each, com paring a syrup one with syrup calcium. The necessity for examining 48 cans may be readily seen since an examina tion of only one or two cans might show a false effect of the firming properties of the calcium salt. As this particular data shows, one can of sections containing syrup calcium was the poorest even though this showed Table 2. Effect of the addition of calcium on the distribution of firm sections in each can of a grapefruit section Firm Type of sections in can % calcium Number of cans 0-20 0 1 21-40 4 0 41-60 14 5 61-80 17 9 81-100 Total = 13 48 33 48 a great improvement in the firmness of the sec tions than was found when only syrup was used. The advantage of using calcium in the sugar syrup for canned grapefruit sections may be readily seen by comparing an average or "sample" can of sections with without calcium added. This "sample" can is made up from the average data obtained during the four ing seasons involved the exam ination of about 50,000 individual sections. The "sample" can, using syrup only, would contain a total of 18.9 sections in each 303 can of which 11.9 (63%) sections would be acceptable to the consumer. The phrase, "acceptable to the con sumer," in this report is relative only to the firmness, texture or appearance of the section not to the flavor. The "sample" can con taining added calcium would have 18.8 sections per can including 16.2 (86%) sections acceptable to the consumer. In other words, the consumer would find 7.0 sections unacceptable in the syrup against 2.6 in the can with calcium. For these "sample" cans, the drained weight would be 9.5 oz. for the syrup ed sections 9.4 oz. when calcium was used. It appears that syrup calcium remove slightly more fluid from the sec tions than does syrup alone. Table 1 shows the effect of ing date on the firmness of sections with without the addition of calcium to the syrup. Those sections with calcium apparently are fairly consistent in firmness, whereas the firm ness of those without the calcium varies over a much greater range. This difference showed up very well during the 1964-65 season in which the syrup in December had only 38.2% firm sections compared to that of 86.9% for the calcium. Nothing could be established as to the best month for ing canned sections since seasonal other factors affect the characteristics of grapefruit. It does

OLSEN ET AL: GRAPEFRUIT SECTIONS CALCIUM 329 Table 3. Effect of storage during the 1964-65 season on the firmness of canned grapefruit sections calcium Time of storage - months Month ed Initial 4 8 Initial 4 8 Percent firm sections Oct. Nov. Dec. Jan. 57.0 68.2 38.2 72.1 47.1 73.5 60.1 62.6 45. 2 69. 7 45. 1 47. 3 87.9 95.2 86.9 91.6 72.3 93.5 85.2 92.7 80.4 96.4 81.0 90.4 seem likely that the ing period could be extended somewhat by using calcium salts. As to the effect of storage on the firmness of these sections, it was mentioned previously that the s were examined initially after storage for 4 8 months. Table 3 shows the results of these examinations for both the com mercial syrup the calcium s for the 1964-65 season when products were processed in four different months. Apparently the firm ness of the sections did not change with storage as the results follow no set pattern. However, in averaging all of the stored s, there was a slight tendency for the syrup s to become less firm for the calcium s to remain unchanged during storage. Calcium chloride was used as an additive only during the 1961-62 season since the amount used imparted a bitter flavor. This was detected by the Station flavor panel noted in the USDA graded samples. The firming action of the cal cium chloride was not quite as marked as that of the calcium in the amounts used. Dietetic s. In regard to the dietetic s, a "sample" can of sections, ed in wa ter, would have 19.5 sections with 4.3 sections acceptable to the consumer, whereas the can ed in water calcium cyclamate would have 19.3 sections with 7.2 firm sections; how ever, when calcium had been added also, there was a total of 19.7 sections including 10.2 firm sections. Since calcium was used during only two seasons, this represents the compilation for only these seasons to get a fair comparison. When data from three seasons are compared, a "sample" can of the water would contain 18.8 sections with 5.0 (27%) firm sections 18.7 sections with 7.4 (40%) firm sections with the calcium cyclamate addition. The drained weight of a "sample" can of the water would be 10.44 oz. compared to 10.64 oz. with calcium cyclamate added. These two s will have a higher drained weight than that of the syrup due to osmotic action. The s with calcium had even a slightly higher drained weight. The loss of firmness during storage in the dietetic s was more marked with the water s having 6.2, 4.5 4.4 firm sections per can for the initial, 4 months 8 months, re spectively. The s with cyclamate had 8.8, 7.4 6.1 firm sections per can for the same storage periods. As may be readily seen, the sections generally become less firm upon storage. However, the firmness of the s with both calcium cyclamate calcium did not vary to any marked extent during storage. Grapefruit juice was used, instead of water, in the dietetic s only during the 1962-63 season since it was found impractical for our purpose to obtain juice when needed. The only other characteristics of the s which showed any differences were a slightly higher vitamin C content in those s with juice added, more sweetness better flav or in the cyclamate s than that in the con trol. Acknowledgments The authors wish to thank Cypress Gardens Citrus Products, Inc., Winter Haven, Florida, for their aid in processing the canned grapefruit sections used in this investigation. For initially grading the canned sections, appreciation is ex pressed to Joseph McAllister, USDA Consumer Marketing Service, Fruit Vegetable Division, Processed Food Inspection, Winter Haven, Florida. Thanks are also expressed to

330 FLORIDA STATE HORTICULTURAL SOCIETY, 1966 Mrs. Irene Pruner for her help during the evalu ation of these products. REFERENCES 1. Hall, C. B. R. A. Dennison. 1960. The rela tionship of firmness pectinesterase activity of tomato fruits. Proc. Am. Soc. Hort. Sci., 75, 629-631. 2. Hanson, A. R. 1952. Factors which condition firm ness in tomatoes. Food Research, 17, 370-379. 3. Kertesz, Z. I. 1939. The effect of calcium in plant tissues. Canner, 88, No. 7, 26-27. 4. Olsen, R. W. 1960. Cyclamates in citrus products. Proc. Florida State Hort. Soc, 73, 270-271. 5. Singleton, G. 1959. Some recent work on citrus sections. Proc. Florida State Hort. Soc, 72, 263-267. FLAVOR FORTIFICATION AND STORAGE OF FOAM-MAT DRIED GRAPEFRUIT CRYSTALS1 R. E. Berry, 0. W. Bissett, C. J. Wagner, Jr.2 Abstract The effectiveness of a number of different flavoring additives with foam-mat dried grape fruit crystals has been studied. These included sweetening agents as well as grapefruit flavoring agents. It was found that calcium cyclamate at a level of 0.3% or a combination of calcium cyclamate with sodium saccharin at a level of 0.2% was equivalent in sweetness to a grape fruit sample where the Brix/acid ratio had been adjusted to 13 by the addition of sucrose. When these samples were compared by storage the sucrose sweetened sample was found to have a storage stability of nine weeks before a detectable difference occurred at 85 F, whereas the synthetic sweetener samples had de veloped detectable differences at six weeks. Among other flavoring agents studied were grapefruit cold-pressed peel oil, essence oil, a commercial grapefruit flavoring, "locked-in" oil. Although satisfactory initial flavors were obtained with all of these materials, none of the first three had a storage stability equivalent to that of the "locked-in" oil. In an additional study to determine the level of grapefruit oil which would be preferred by inexperienced tasters it was found that consid erably higher oil levels were preferred than had been expected. The preferred oil level found in this study was 0.012%. It was also shown that the higher oil levels appear to be more appeallcooperative research of the Florida Citrus Commission, the Western Southern Utilization Research De velopment Divisions, Agricultural Research Service, U.S. Department of Agriculture. 2U.S. Fruit Vegetable Products Laboratory, Winter One of the laboratories of the Southern Utilization Research Development Division, Agricultural Research Service, U.S. Department of Agriculture. References to specific commercial products do not con stitute endorsement. ing to non-users, particularly. A study with freeze-dried grapefruit juice used as a flavoring additive indicated that when added at as low as 10% level, freeze-dried grapefruit juice is an effective flavor enhancer. Based on results of this study, it would appear that "locked-in" oil crystals are probably the most suitable flavor ing agent for grapefruit foam-mat dried crys tals, especially from the stpoint of stability. During the past few years considerable in terest has developed in the use of the foam-mat drying process for the production of citrus crystals. Although considerable problems were encountered with storage stability in orange crystals, the production of grapefruit crystals has been developed to a point where they appear to be commercially feasible (2). Relatively large quantities of foam-mat dried grapefruit crystals have been produced during the past two years on pilot-plant foam-mat drying equipment at the Fruit Vegetable Products Laboratory in Winter Haven. A large number of grapefruit crystal samples were distributed throughout the citrus industry during the past year in a trade journal (1). Considerable commercial interest has been shown through requests for samples technical information. Information was needed as to types of flavoring agents which might be used in conjunction with grapefruit crystals for flavor fortification. Recently, considerable concern has also been shown in the use of grapefruit products as diet foods. Because of this, many inquiries have been received pertaining to the compatability of various diet sweetening agents with grapefruit crystals concerning the use of sugarsweetened grapefruit crystals. Before commer cial use of these mixtures could become practial, storage data were needed concerning the relative storage stability of sweetened grape fruit crystals as compared to unsweetened