38 Journal offood Protection Vol. 42, No.. Page 38-42 Uanuary, 979) Copyright 979, International Aociation of Milk, Food, and Environmental Sanitaria Evaluation of Sauerkraut-Like Product From Direct-Acidification of Cabbage D. LONERGAN and R. C. LINDSAY* Department of Food Science Univerity of Wicoin-Madion Madion, Wicoin 53706 (Received for publication April7. 978) ABSTRACT Direct acidification of cabbage uing acetic, citric, glucono-deltalactone, or lactic acid wa evaluated a a mea of producing auerkraut-like product. Direct acidification with citric acid gave the mot acceptable product for incorporation into auerkraut-containing food. but none of the acid gave frehly-prepared product with auerkraut-like flavor and odor. Seory evaluatio with laboratory panel howed that citric acid-acidified cabbage and naturally fermented auerkraut were comparable when cooked with frankfurter or incorporated into a three-bean alad. Crip texture and abence of trong odor were attribute of directly acidified cabbage that would be deirable for ome applicatio of thee product. Development and acceptance of auerkraut-like product from cabbage by direct acidification could lead to an expanded ue of cabbage in contemporary food, epecially if unique propertie can be identified. Other advantage of direct acidification over natural fermentation could include honer production time, elimination or reduction of wate brine, and better control over proce variable. Natural lactic acid fermentation of cabbage take 3 to 4 week or longer, and involve a complex microbial ucceion (8, 9, 3). Although infrequently encountered in modern proceing, pink, rancid, oft, or dark kraut occur from defective fermentatio, and greatly reduce acceptability (6, 7). A precedent for production of preerved vegetable product by direct acidification exit for proceed dill pickle. our pickle, or weet pickle uing alt tock (2. 7), and for freh-pack dill pickle uing cucumber (J). Additional meaure may be incorporated to extend helf-life, and thee include blanching, pateurization, addition of preervation, and refrigeration. Short-term home preervation of cabbage by ome ethnic group i achieved by acidification along with refrigeration, and ome limited commercial-cale production of acidified, hredded cabbage i currently practiced (5). The latter practice involve repacking in freh brine at the time of 'Supported by the of Agricultural and Life Science and the Department of Food Univerity of Wicoin-Madion. Seory Evaluation Laboratory, ditribution, and addition of either orbic acid, odium benzoate, or ulfur dioxide to retard poilage and to retain a raw appearance in the finihed product. The purpoe of thi invetigation wa to prepare directly acidified cabbage product, and to evaluate their characteritic a food. MATERIALS AND METHODS Product formulatio Initial formulatio ued in directly acidifying cabbage were baed on the compoition data (Table ) of Pederon et al. (9) for auerkraut. Five acidification ytem were prepared and evaluated. One lot wa prepared with a mixture containing lactic acid (85 %) and acetic acid (glacial) which wa added to hredded cabbage to reult in a final calculated concentratio of.45% (w/w) lactic acid and 0.45% (w/w) acetic acid. A econd lot wa prepared with citric acid (crytalline monohydrate) which wa added at a rate to give.5% (w/w} citric acid in the finihed product. A imilar lot wa prepared except that lemon juice (RealemonR) wa ued to provide.5% of citric acid. Glucono-delta-lactone, a low-releae acid, wa added to another lot to reult in a tina! concentratio of.5o/o (w/w} acid a citric acid. Finally, a lot wa prepared with a mixture of acetic, citric and lactic acid which were added at a level o that a final concentration of 0. 75% (w/w) lactic acid, 0.25% (w/w) acetic acid and 0.50 (w/w)citric acid wa achieved. Efhanol (95%) wa included in all formulatio to reult in a 0.5% (w/w) concentration in the finihed product. Sodium chloride wa alo added to all ample to give a final concentration of 2.0% (w/w). Cabbage obtained locally wa prepared by removing the outer leave of each head, and then each wa wahed and cored. Cabbage wa hredded by licing at approximately V. inch interval with an electric licer, and thi wa followed by chopping reulting leaf trip into TABLE. Approximate compoition of auerkraut and auerkraut Component Sauerkraut ( 0 io. w/w) Sugar 0.78 Salt 2 2.00 Total acidity.48 Acetic acid 0.40 Lactic acid.37 Ethanol 0.48 Calcium 0.04 Phophoru 0.03 Adapted from Pederon et a!. (9). 'From Pederon (6). Sauerkraut jui< e (%,w/w) 0.69 2.00.67 0.45.45 0.50 0.04 0.03
ACIDIFIED CABBAGE EVALUATED 39 approximately '!. inch length with a knife. After hredding, appropriate ingredient were added, and the mixture were packed in cloed polyethylene container, and tored at 4 C for at leat week before evaluatio to allow product equilibrium. The effect of blanching upon the texture U2} of citric acid-acidified cabbage wa invetigated uing a team tunnel with the belt peed varied to give the deired blanch time. Blanching wa done after the cabbage wa hredded and acidifted, but before equilibration in refrigerated torage. Product temperature immediately after blanching were determined with a mercury thermometer. Freezing wa alo invetigated a a method of altering the texture of the product. For thi apect citric acid-acidified cabbage ample were frozen at either -40 C or -8 C for 2 h, and thi wa followed by torage at 4 C. Determination of eory propertie Seory evaluatio of the product prepared in the initial phae were carried out by five experienced food profeional a informal, decriptive evaluatio. The more detailed evaluatio of the citric acid-acidified product were conducted under controlled laboratory conditio, and employed 24-29 panelit experienced in eory evaluatio of food. Panelit were eated in individual booth in the laboratory, which wa equipped with indoor fluorecent lighting (78 footcandle). Water wa available for the judge to ue at their own decretion. Sauerkraut and frankfurter item were prepared with both naturally fermented commercial auerkraut and citric acid-acidified cabbage. One kg of auerkraut wa combined with even commercially prepared all meat frankfurter that were cut into l-inch piece. were warmed to an internal temperature of 79 C with a team table before evaluatio. Three-bean alad were prepared with both citric acid-aciditied cabbage and naturally-fermented auerkraut. Three cup of auerkraut were combined with t:<cup of fine cut green pepper, one cup of fine cut freh celery talk, y, cup fine-cut white onion, one can (6 oz) of red kidney bea, hcup granulated white ugar and V.tp each of alt and pepper. were equilibrated at 5 C for 24 h. Citric acid-acidified cabbage containing naturally produced auerkraut juice wa prepared by combining three cup of citric acid kraut and - I /8 cup natural kraut juice, and allowing equilibration at 5 C for 24 h before evaluation. Both three-bean alad and plain auerkraut item were removed from refrigeration (ca 5 C) and erved to panelit a chilled item. Although not identified to panelit, a naturallyfermented, canned, commercial ample of auerkraut wa included in eory evaluation eio for direct comparion of attribute. For erving, 2 oz of each ample were portioned into ampling cup coded with three digit random number. Five-ounce clear platic ampling cup were ued for the warmed, auerkraut-hot dog ample, while 4-oz. polyethylene-coated paper cup were ued for the three-bean alad and the unheated ample. The ample were evaluated with a quantitative decriptive analyi (} ballot which included cale for inteity of acid flavor, inteity of weetne, type of flavor, overall texture and overall preference. For tatitical analyi of eory data, individual decriptive cale on the ballot from each panel evaluation eion were coded on a even-point bai. A value of.0 wa aigned to the extreme left end of each line, and a value of 7.0 wa aigned to the extreme right end of each correponding line. Each panelit' marked judgment were then coded with the appropriate intermediate numerical value (30 mm per whole number with 3-mm increment). Coded value from the ballot were punched into computer card, and data were analyzed by the Univerity of Wicoin 0 computer for analyi of variance appropriate for a randomized complete block deign (0}. Individual tatitical analye were done for each quality attribute of the ample evaluated in a panel eion. Mean core for each ample attribute, F-value for the whole comparion of ample attribute, and leat ignificant difference (LSD) for attribute of each pair of ample were obtained (0} when a ignificant F -value wa found for the whole comparion. Chemical analve Titratable ~cidity wa determined by AOAC method (}, and ph meaurement were made with a Corning Product Model2 Reearch ph Meter. RESULTS AND DISCUSSION The titratable acidity and ph data for the initially prepared acidified product are in Table 2 along with thoe of the comparative naturally-fermented auerkraut ample. From thee data it i apparent that not all the added glucono-delta-lactone diociated into gluconic acid. Thi acidulant give a low releae of acid, and in the hredded cabbage ytem two week at 4 C allowed only partial diociation of glucono-delta-lactone. The data for the other ample how that the ph and titratable acidity of the product approximated thoe of the naturally-fermented auerkraut. acidified with acetic and lactic acid exhibited a tart tate which wa followed by a lightly weet aftertate. Thi weet aftertate could have been due to the preence of ugar which normally would have been removed by metabolim of the fermenting microorganim in the natural production of auerkraut. The odor of thi experimental ample wa not pronounced or objectionable, but did not reemble that of auerkraut. It wa characterized a reembling that of acetic acid, e.g., lightly vinegar-like. A mixture of acetic, lactic, and citric acid reulted in a product with mildly acid tate, a noticeable cabbage-like flavor, and a weet aftertate. The odor wa imilar to that of the ample acidified individually with acetic and lactic acid. Glucono-deltalactone yielded the leat acceptable product of thoe prepared. The tate wa only lightly tart, and a weet aftertate wa noted along with a hint of putrefaction which could have been caued by the low releae of acid. Acidification of cabbage with citric acid reulted in the mot tart flavor of the acidulant ued, and wa even TABLE 2. Chemical characteritic of initial experimental product. decription Natural Sauerkraut 3.50.45o/olactic acid & 0.45 o/o acetic acid 3.03 0.75%actic, 0.25% acetic & 0.5o/ocitric 3.5.50 o/o citric acid 2.95 Glucono-delta-lactone 3.50 In juice expreed from ample. ph Titratable acidity meq/ loom! 5.0 25.0 2.5 23.5 ll.l Percent acid.35 (a lactic) 2.24 (a lactic).94 (a lactic).50 (a citric) 0.8 (a citric} Calculated acid addition (Percent) 2.8 (a lactic}.88 (a lactic).50 (a citric}.50 (a citric)
40 LONERGAN AND LINDSAY more tart than the naturally fermented auerkraut. A weet aftertate wa not noted in thi product, and the vegetable-like flavor and acid tate were clean, and very lightly citru-like. Panelit coidered thi ample to be the mot acceptable of the acidified product evaluated, but again it characteritic did not imulate thoe of natural auerkraut. Apparently the procee involved in the diappearance of cabbage flavor compound and development of the characteritic fermentation flavor compound of auerkraut (4) are retarded or inhibited in directly-acidified cabbage preparation. of each of the acidified product were alo cooked, but thi did not caue liberation of auerkraut tate or odor. Further, even when ample which were acidified with acetic and lactic acid were refrigerated for 6 week, they did not develop auerkraut tate or odor. The texture of the directly acidified product wa very crip, and reembled that of frehly-hredded cabbage. Thee ample appeared much firmer and criper than the naturally-fermented auerkraut, but the texture of both were imilar after cooking. Blanching hredded cabbage before acidification with citric acid and ubequent equilibration reulted in a product with a texture imilar to that of naturally-fermented auerkraut before cooking. However, the texture of the blanched citric acid-acidified ample varied according to location in the equilibration container. The upper layer were ofter than the lower layer. Blanching time of about 3 min appeared adequate to impart the auerkraut-type of texture. After 3 min in the team tunnel (96 C), center of ample were 42 C, and the urface were 85 C. Freezing the ample H8 or 40 C) alo reulted in a ofter, more auerkraut-like texture. However, both freezing treatment that were ued increaed the oftne of the product exceively, and were not coidered deirable. In the econd phae of the invetigation, citric acid-acidified cabbage wa prepared a decribed for the initial tudie. Thi product wa evaluated by eory panel, and the reult are in Table 3. It can be een that the panelit could not detect a difference in the inteity of acidity or weetne between the natural auerkraut and the citric acid-acidified cabbage. Statitically ignificant difference were oberved, however, for flavor type, texture, and preference. Abolute value of mean core for flavor type howed that citric acid-acidified cabbage had a reaonably pronounced, green vegetablelike flavor, while the natural auerkraut exhibited much le of thi flavor. The ofter texture of the natural auerkraut could be attributed to canning a well a fermentation effect. Served chilled and without additional preparation, natural auerkraut wa preferred ignificantly over the citric acid-acidified cabbage. The lower preference for the direct acidified product may be partially attributed to panelit being unfamiliar with it ditinctly different propertie. When the two auerkraut product were cooked with frankfurter, much le differentiation in preference wa oberved (fable 3), although the abolute preference core for the natural auerkraut wa till lightly higher. It can be een alo that the other attribute were cored quite imilarly for the two product, and upport the preference data. It can be reaoned, therefore, that frankfurter flavor component a well a textural and flavor effect of heating reulted in development of TABLE 3. Decriptive panel evaluation of citric acid-acidified and natural auerkraut erved chilled, and cooked with frankforter. Decriptive cale decription Sweetne 2 Texture 4 preference 5 Served chilled Natural auerkraut Citric-acid-acidified auerkraut 3.40a 4.6b LSD (5%) 0.75 0.48 0.50 Served w/frankfurter Natural auerkraut Citric acid-acidified auerkraut 6 Extremely flat, bland; 7 Extremely pro,nmmc ~a Extremely lacking weetne; 7 =Extremely weet. Lack green vegetable character; 7 Extremely green, vegetable-like. Extremely oft. oggy; 7 Extremely crip, firm. 5 Scale: Dilike extremely; 7 Like extremely. 6 ignificant; =not ignificant; N 24. a,bmean core for a given panel eion in the ame column with the ame upercript are not ignificantly different at the five percent level.
ACIDIFIED CABBAGE EVALUATED 4 imilaritie between the directly acidified and the natural product in the frankfurter combination item. Voluntary comment given by panelit in thee two panel evaluatio indicated that ome panelit pecifically liked the more crip texture and le pronounced ulfury flavor of the citric-acid-acidified cabbage. Still, other found the naturally-fermented, traditional auerkraut the much-preferred product. Since the characteritic flavor of naturally-fermented auerkraut wa abent in the citric acid-acidified cabbage, addition of natural auerkraut flavor via juice from a normal fermentation wa invetigated. Data in Table 4 how that the natural auerkraut wa preferred, but addition of natural auerkraut juice improved the abolute preference core for the citric acid-acidified product although the increae wa not tatitically ignificant. A with earlier evaluatio of chilled auerkraut ample, acidity and weetne mean core were imilar in product from each preparation method. Mean core for the flavor-type attribute clearly how that addition of auerkraut juice to the citric acid-acidified ample altered the overall flavor by leening the green, vegetable-like flavor. Voluntary comment by panelit indicated alo that ome of the characteritc of natural auerkruat flavor were imparted to the citric-acid-acidified product by the juice. Additio of the auerkraut juice to directly-acidified cabbage would be helpful to alleviate dipoal problem for thi material a well a to provide a natural flavoring ource. Of the acid evaluated citric acid provided the mot deirable acidulant propertie for the acidification of cabbage, and even though food-grade, pure citric acid wa ued, lightly citru fruit-like flavor reulted. Further tudie uing lemon juice a a naturally-derived acidulent were carried out, and the reulting product wa cored imilar to citric acid-acidified cabbage in all apect evaluated. Thee reult indicated that lemon juice could be ued for acidifying cabbage in direct-acid proceing. However, ome panelit commented that a. bitter flavor wa noted in the lemon juice-acidified ample, and thi wa attributed to bitter flavor component from the peel that were preent in the lemon juice ued. Avoidance of thi flavor character probably would improve the quality of lemon juice-acidified cabbage. Citric acid-acidified cabbage wa included a an ingredient in a three-bean alad, and the reult of the panel evaluation of thi item are in Table 5. It can be een that the citric acid-acidified ample received a higher abolute core, but it wa not tatitically preferred over the natural auerkraut. Since the acidity TABLE 4. auerkraut. Decriptive panel evaluation of citric acid-acidified cabbage, citric-acid-acidified cabbage with natural auerkraut juice, and natural decription Flavor Sweetne Decriptive cale Texture preferenc-e Served chillled Natural auerkraut Citric acid-acidified auerkraut Citric acid-acidified auerkraut with natural kraut juice ( --------------------------- ---.. ------------- ----------- ---Me an Score---------- --- --- -... --- ----- - - ---} 4.99a 4.93a.o2a 3.33a 2.62a 3.45a 3.26a 4.73b S.62b 3.4a 4.06c 5.42b 4.37a 3.ob J.ob LSD (5%) 2 0.46 0.29 a lited in Table 3. 2 =ignificant; not ignificant; N 29. a. b, cmean core in the ~me column with the ame upercript are not ignificantly different at the five percent level 0.47 and natural auerkraut erved in a three-bean alad. decription flavor Sweetne Texture preferenc-e Three bean alad Natural auerkraut Citric-acid-acidified auerkraut ( -- --- ------ --------- ----- -----------------.. - ---------Me an Score -- - -- -- - ---- -... ----- ------- -------) 3.90a 3.68a 4.0a 4.27a 4.07a 4.43a LSD (5o/o) 2 0.66 0.38 Same a lited in Table 3. 2 =ignificant; =not ignificant: N = 29. a,bmean core in the ame column with the ame upercript are not ignificantly different at the five percent!.evel.
42 LONERGAN AND LINDSAY and weetne attribute were cored imilarly, it can be concluded that flavor-type and texture played role in overall preference indicatio. The green, vegetable-like flavor and cripne of the citric acid-acidified cabbage were compatible with the alad, and ome voluntary panelit comment indicated an aociation of the alad with colelaw rather than auerkraut alad. Apparently the polyphenolae enzyme ytem of the cabbage ued in thi tudy wa effectively inhibited by the low ph and chelating effect of citric acid. All of the directly-acidified auerkraut-like product appeared off-white in color, and did not exhibit noticeably green coloration due to the preence of chlorophyll. Nonenzymatic browning dicoloratio, ometime encountered a a defect in canned naturally proceed auerkraut, were alo not oberved in any of the directly acidified product. However, thi probably reflect an abence of heat-initiated reactio during the proceing ofthe directly-acidified item. In ummary, thee tudie have hown that directacidification of cabbage gave auerkraut-like product that howed potential ue in ome food applicatio. Direct-acidification product did not exhibit the typical, pronounced auerkraut flavor and aroma, and were characterized by more crip texture than canned naturally-fermented auerkraut. Thee attribute could be ued advantageouly in development of additional acidified cabbage product, epecially alad item. However, further teting of coumer reactio and evaluation of helf tability would be appropriate before the exteion of commercial production of directlyacidified cabbage product. ACKNOWLEDGMENTS The author thank J. H. von Elbe and S. L. Karow for uggetio and aitance in the conduct of thi pro jed. REFERENCES. Anon. 960. Official method of analyi of the Aociation of Official Agricultural Chemit. 9th ed., Wahington, D.C., p. 27. 2. Deroier, N. W. 970. The technology of food preervation. AVI Publihing Co., Wetport, Conn.. 493 pp. 3.Jelen, P., and W. M. Breene. 973. Texture improvement of freh-packed dill pickle by addition of lactoe and ucroe. J. Food Sci. 38:99:0. 4. Lee, C. Y., T. E. Acree, R. M. Butt, and J. R. Stamer. 974. Flavor cotituent of fermented cabbage. Proc. IV Int. Congre Food Sci. and Technol. :75-78. 5. Moore, W. R. 978. Peronnel communication. 6. Pederon, C. S. 938. The ga producing pecie of the genu lactobacillu.j. Bacteriol. 35:95-08. 7. Pederon, C. S. 97. Microbiology of food fermentatio. AVI Publihing Co., Wetport, Conn., 283 pp. 8. Pederon, C. S. and M. N. Albury. 969. The auerkraut fermentatio. New York State Agr. Expt. Sta. Bull. 824. 9. Pederon, C. S., E. B. Fred, and J. A. Viljoen. 925. Variation in the chemical compoition of cabbage and auerkraut. Canner 6., No.4: 9-2. 0. Steel. Robert, G. D., and J. H. Torrie. 960. Principle and procedure of tatitic. McGraw-Hill, New York, 48 pp.. Stone, H., J. Side!, S. Oliver, A. Wooley, and R. C. Singleton. 974. Seory evaluation by quantitative decription analyi. Food Techno!. 28():24-34. 2. Voiril, F. 972. The blanching of vegetable and fruit. Food Proce. Indut. 4(490):27-33. 3. Work, P. 947. Vegetable produetion and marketing. John Wiley, New York. 460 pp.