236 FLORIDA STATE HORTICULTURAL SOCIETY, 1970 SAUERKRAUT FERMENTATION OF SOME FLORIDA CABBAGE CULTIVARS Richard F. Matthews and R. P. Bates Food Science Departrnent, IFAS University of Florida Gainesville Abstract The cabbage cultivars,, King Cole, Green Boy and were evaluated in sauerkraut fermentation. The washed, shredded cabbage containing 2.25 percent added salt was fermented at 65 F until acid develop ment ceased. Total invert sugars in the fresh cabbage ranged from 2.46 to 3.46 percent. Re ducing sugars accounted for 90 percent or more of the total sugars. Volatile acid developed during fermentation ranged from 0 to 0 percent for the four cultivars. Total titratable acidity developed was 0.83 to 1.30 percent and the ratio of volatile to non-volatile acid ranged from 0.13 to 0.24. Taste panels rated the sauerkrauts from the four cultivars as less acceptable than a standard commercial sauerkraut. Flavor and color were major factors contributing to their lower accept ability. Introduction Florida produces a substantial volume of winter cabbage for the fresh market. Some years supplies are in excess of fresh market require ments and cabbage is available which could be processed for sauerkraut. However, production of sauerkraut from Florida cabbage has not been reported in the literature. Bulk sauerkraut as described by U.S.D.A. Grade Standards (14) is, "the product of char acteristic acid flavor, obtained by the full fer mentation, chiefly lactic, of properly prepared and shredded cabbage in the presence of not less than two percent nor more than three percent of salt. It contains, upon completion of the fer mentation, not less than 1.5 percent of acid, expressed as lactic acid." The sauerkraut fermentation and the accom panying chemical changes are due to the growth of a sequence of heterofermentative and homo- Florida Agricultural Experiment Stations Journal Series No. 3767. fermentative bacteria. In normal fermentations a final total acidity of 1.7 to 2.3 percent acid, as lactic, is attained with a ratio of acetic acid to lactic acid of about one to four (6). Canned sauerkraut as described by the U.S.D.A. Grade Standards, (15), "is prepared from clean, sound, well matured heads of the cabbage plant (Brassica, oleracea var. capitata L.) which have been properly trimmed and cut; to which salt is added and which is cured by natural fermentation." Quality factors for de termining grade include color, cut, defects, character and flavor. Sauerkraut of Grade A, Grade B, or Grade C must have a minimum acidity (calculated as lactic acid) of 1.0 percent and a salt concentration between 1.3 and 2.5 percent. Experimental Methods The cabbage cultivars, King Cole, Green Boy and were obtained from the Potato Investigations Laboratory, Hastings, Florida and the cultivar from a com mercial producer in the Naples area. The cab bage was picked at fresh market maturity and transported the following day to Gainesville. It was stored at approximately 70 F for 24 hours before processing for sauerkraut fermen tation. The experiment was replicated three times, data was subjected to analysis of variance, and significance determined at the 0.05 level. For processing, the outer leaves were re moved and the cabbage washed by cold water sprays. The cabbage was shredded into pieces of approximately 1/32" thickness. The core was ground and mixed in with the shredded leaves. Salt, at a concentration of 2.25 percent, was mixed uniformly with the shredded cabbage. Twenty pounds of the salted cabbage was firmly packed in five gallon polyethylene containers and the surface covered with a sheet of polyethylene weighted with water to displace air and insure anaerobic conditions. The containers were maintained at 65±2OF during the fermentation period. During fer mentation, liquid samples were taken twice each week from each container for analysis of vola tile and total acidity.
MATTHEWS AND BATES: SAUERKRAUT FERMENTATION 237 Samples of the shredded cabbage, before salt addition, were taken for sugar analysis and the residual sugar after fermentation was also de termined. The fermented sauerkraut was heated to 165 F, filled into No. 303 cans, reheated to 165 F and sealed. Taste panel studies were conducted four weeks after canning. The experimental samples and a reference sample of a commercial sauer kraut were presented to the panelists, who were asked to compare the experimental samples with the reference sample and rate of overall ac ceptability. Panelists also indicated major fac tor (s); flavor, color, or texture, responsible for differences in sample acceptability. Analytical Procedures 1. Reducing Sugars A 100 g sample of shredded cabbage was blended for two minutes in a Waring blender with 100 ml of boiling distilled water. This slurry was filtered and the filtrate collected. The residue was washed four times with 100 ml portions of boiling distilled water. The total filtrate was brought to final volume and an aliquot analyzed by the A.O.A.C. Sec. 29.035 procedure for reducing sugars (5). 2. Total Invert Sugars Fifty ml of cab bage extract from (1) was acidified with 10 ml of HC1 (1:1), maintained at room temperature for 24 hours, neutralized with NaOH, and an aliquot analyzed as for reducing sugars (5). 3. Total Titratable Acidity A liquid sam ple was taken with a sterile pipette from each container. A five ml aliquot was titrated with 0.1 N NaOH and the total acid expressed as grams lactic acid per 100 ml. 4. Volatile Acidity Volatile acid as grams acetic acid per 100 ml was determined on a 10 ml sample by the A.O.A.C. Sec. 11.034 pro cedure (5). Results and Discussion Sugars Reducing sugars accounted for 90 percent or more of the total sugar content of the four cultivars. This concentration of reducing sugars is in agreement with findings by other workers (1, 12, 13). The total invert sugars for the cultivars ranged from 2.46 percent for King Cole to 3.46 for (Table 1). Values above 3.0 percent should have been sufficient to de velop the 1.5 percent acid required by the U.S.D.A. Grade Standards for bulk sauerkraut. Table 1. REDUCING AND TOTAL INVERT SUGARS Cultivar King Cole Green Boy OF FLORIDA CABBAGE Reducing Sugars (percent) 2.k6 2.73 2.99 3.06 CULTIVARS. Total Invert Sugars (percent) 2.h6 2.86 3 ^6 Peterson et. al. (10) analyzed 19 lots of cab bage for sauerkraut and found the average total sugar to be 3.38 percent. Seven lots of the cabbage were used in sauerkraut fermentation and a mean of 1.76 percent sugar in the cabbage was required to produce 1.0 percent acid in the sauerkraut. With a sugar to acid conversion rate of 1.76 the sugar content of the cultivar King Cole 2.46 percent would be insufficient to produce 1.5 acid in the sauerkraut. Substantially all the sugar in the cabbage was utilized during fer mentation. The residual invert sugar content of the sauerkraut was King Cole 0.10 percent, 0.04 percent, Green Boy 0.04 percent, and 0.03 percent. Volatile Acidity The volatile acidity in creased rapidly for all cultivars during the first ten days of fermentation and after 21 days had attained near maximum level (Fig. 1). Volatile acid, as percent acetic, at the end of the fer mentation was 0 King Cole, 0, 0.15 Green Boy, and 0 (Table 2). These values are low when compared with values of high quality commer cial sauerkraut (6, 8). Pederson, (8), analyzed 332 commercial krauts and related chemical composition and quality of the canned sauerkraut. High quality kraut had a volatile acidity range of 0.15 to 0.30 percent and a volatile to non-volatile acid ratio of 0.20 to 0.30. In a series of nine canned sauerkrauts (6) receiving a U.S.D.A. Grade score of A, the mean value for volatile acidity was 0.24 percent and the range was 0.20 to 0.32 percent. The mean ratio of volatile to non volatile acidity was 0.27 with a range of 0.21 to 0.30. The ratio of volatile to non-volatile acidity has been used as an index of kraut quality (4) and unusual ratios have been related to ab normal krauts. The ratio of volatile to non-
238 FLORIDA STATE HORTICULTURAL SOCIETY, 1970 GREEN BOY MARKET PRIZE * KING COLE - LITTLE ROCK 20 23 30 35 40 FERMENTATION PERIOD (DAYS) Fig. i. Volatile acidity production of cabbage cultivars during sauerkraut fermentation. volatile acid of our cultivars was 0.24 King Cole, 0.21 Green Boy, 0, and 0.13., which received the highest taste panel acceptability rating, had a ratio of 0 and a volatile acid content of 0 percent. Both values are lower than those cited (6, 8) for high quality canned sauerkrauts. Table 2. VOLATILE ACID DEVELOPMENT DURING FERMENTATION OF FLORIDA CABBAGE CULTIVARS.* Total Acidity The total acidity increased rapidly during the first seven days of fermenta tion for all cultivars (Fig. 2) and after 18 days near maximum acidity had been reached. Total acidity as percent lactic acid, at the end of the fermentation period was 1.30, 1.00 Prie, 0.96 King Cole, and 0.83 Green Boy (Table 3). Table 3. TOTAL ACID DEVELOPMENT FERMENTATION OF FLORIDA CABBAGE CULTIVARS.* 1 u 7 11 Ik 21 27 32 It kl 55 61 King Cole.09.13.lk.05.09.10.08.13.lk.15.17 Days 1 k 7 11 lk 18 21 27 32 1*1 k7 55 61 King Cole.05.kk.63.77 77.Qk 95 96 Green Boy.Ok.52.76.79.82.86.8U 83 83 83.06.57 78 92.93 95 L.OO 97 98 1.00 percent acid as acetic (mean values of 3 observations) * percent acid as lactic (mean values of 3 observations).07.kl.87 1 L.21 1.25 l.uo 1.37 1.37 1.30
MATTHEWS AND BATES: SAUERKRAUT FERMENTATION 239 I TOTAL ACIDITY (%) 1.60 - GREEN BOY MARKET PRIZE - KING COLE LITTLE ROCK 20 25 30 35 40 FERMENTATION PERIOD (DAYS) Fig. 2. Total titratable acidity production of cabbage cultivars during sauerkraut fermentation. These levels are all below the 1.5 percent acid required for U.S.D.A. Bulk Sauerkraut. Only the acid levels of and meet the minimum acidity requirement of 1.0 percent for U.S.D.A. Grade A, B, or C Canned Sauerkraut. The low sugar content of King Cole would limit its reaching the desired acid level in a normal lactic fermentation. The poor acid development in the other cultivars in dicates the possibility of an abnormal fermen tation. Introduction of air during sampling could have adversely affected the fermentation. Taste Panel Evaluation The panel rated the sauerkrauts from the experimental cultivars against a standard commercial sauerkraut- and all were less acceptable than the standard (Ta ble 4). The experimental samples were rated as slight to moderately inferior to the standard. The panelists were asked to indicate the ma jor factor (s); either flavor, color, or texture, responsible for differences in sample acceptbility. Table h. TASTE PANEL ACCEPTABILITY RATINGS OF SAUERKRAUT. King Cole 1.40- Green Boy- Reference Sample 7.U7 6.73 6.93 6.27 5.27 REPLICATIONS 7.60 7-33 7.07 6.87 k.dj Mean* 7.70 7.te b 7M 7 b 7.33 7 b 6.53 6.56 b ^.80 U.98 a score of 0-k indicates degree of preference for experimen tal sample score of 5 indicates equal preference with reference sam ple score of 6-9 indicates degree of preference for reference sample * Treatment means followed by the same letter are not dif ferent at the 0.05 level of significance. Differences in acceptability were attributed to flavor and color, texture was not a major factor. Color Color of the fermented sauerkraut was not evaluated objectively, however there were color differences noted among the samples. The sauerkrauts from the cultivars Green Boy,, and King Cole had a greenish hue. The sauerkrauts from and the
240 FLORIDA STATE HORTICULTURAL SOCIETY, 1970 reference standard were a light straw-white color. Conclusions In exploratory work utilizing four Florida cabbage cultivars for sauerkraut fermentation, none of the cultivars produced a sauerkraut equal in acceptability to a standard commercial sauerkraut. This lower acceptability was at tributed to poor flavor and color. Low acid development was a problem with all cultivars. The sugar content of one of the cabbage cultivars was insufficient to develop the desired acid content. Improper acid development in the other cultivars indicated the possibility of an abnormal fermentation. Further experimental work, including the characterization of microflora during the fer mentation period, is required to determine if acceptable sauerkrauts can be produced from Florida cabbage cultivars. Acknowledgment Appreciation is expressed to Dr. J. R. Shumaker, Potato Investigations Laboratory, IF AS and A. Duda and Sons for supplying the cab bage cultivars; to Mrs. Elsia Breland for con ducting the taste panels and to Mr. Richard Johnson for product analyses. LITERATURE CITED 1. Janes, B. E. 1949. Composition of Florida-grown vegetables. Tech. Bull. 455. Fla. Ag. Expt. Sta., Gainesville, Florida. 2. Laboratory Manual for the Canning Industry. 1956. National Canners Assoc. Washington, D.C. 21-13. 3. Larmond, E. 1970. Methods for sensory evaluation of food. Publication 1284. Canada Department, of Agri culture, Ottawa, Canada. 4. Nicolaisen, W. and R. Pieper. 1956. Neue methode zur rechtzeitigen erkennung einer rotverfarbung beim sauerkraut. Ind. Obst-u. Gemuseverwert. 41:355-356. 5. Official Methods of Analysis, 10 ed. 1965. Assoc. of Offic. Agr. Chemists, Washington, D.C. 6. Pederson, C. S. and M. N. Albury. 1969. The sauer kraut fermentation. Bull. 824. New York State Ag. Expt. Sta., Cornell University, Geneva, New York. 7 Pederson, C. S., W. H. Peterson, and E. B. Fred. 1930. The effect of pure culture inoculation on the quality and chemical composition of sauerkraut. New York State Ag. Expt. Sta., Geneva, New York. Tech. Bull. 169. 8. Pederson, C. S., W. H. Peterson, and E. B. Fred. 1940. The relation between quality and chemical composition of canned sauerkraut. New York State Ag. Expt. Sta., Geneva, New York. Bull. 693. 9. Pederson, C. S., W. H. Peterson, E. B. Fred and C. D. Kelly, 1936. Accuracy of certain methods used in analysis of sauerkraut. Food Research 1: 277. 10. Peterson, W. H., E. B. Fred and J. A. Viljoen. 1925. Variations in the chemical composition of cabbage and sauerkraut. The Canner 61(4): 19-21. 11. Peterson, W. H., C. A. Elvehjem, and L. A. Jami son. 1925. Variation in the mineral content of cabbage and sauerkraut. Soil Sci. 20: 451-457. 12. Peterson, W. H., H. B. Parmele and E. B. Fred. 1927. Some of the factors which influence the composition of cabbage and their relation to the quality of sauerkraut. Soil Sci. 24: 299-307. 13. Stamer, J. R., M. H. Dickson, J. B. Bourke and B. O. Stoyla. 1969. Fermentation patterns of poorly fer menting cabbage hybrids. Appl. Microbiol. 18: 323-327. 14. U. S. Standards for grades of bulk sauerkraut. 1967. Federal Register, May 24, 1967. (32 F. R. 7568). 15 U.S. Standards for grades of canned sauerkraut. 1963.'Federal Register, May 13, 1963. (28 F.R. 2573). CELERY ACCEPTABILITY IN TOMATO-CELERY JUSCE BLENDS R. P. Bates Food Science Department, IF AS University of Florida Gainesville AND C. W. Wilson, III U.S. Fruit-Vegetable Products Laboratory Winter Haven Abstract Tomato-celery juice blends were prepared using Florida tomato and celery juices, 5 ppm Florida Agricultural Experiment Stations Journal Series No. 3721. volatile celery oils or combinations of celery oil and juice. Blends hot filled into enameled cans were stable for at least 18 months. Hedonic flavor ratings indicated no significant prefer ences between treatments or between experi mental packs and commercial tomato based products. Gas chromatographic analyses indi cated that added celery essence oil was readily detected, but did not enhance the acceptability of the blend flavor relative to the tomato-celery juice sample. At the 16.5% level celery juice reduced the color and consistency of the tomato juice base. The use of either 5 ppm celery es sence oil or 16.5% celery juice in tomato juice produced tomato-celery blends whose quality and acceptability were comparable to commercial