99A-37 |
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K. Y. Yoon, E. E. Woodams, and Y. D. HANG. Food Science & Technology, Cornell Univ., New York State Agricultural Experiment Station, 630 W. North St., Geneva, NY 14456-1371 Research has shown that probiotic bacteria can colonize and proliferate in the intestinal tract of humans to prevent the growth of intestinal pathogens. Lactic acid bacteria have been added to a variety of dairy-based products for their probiotic human health benefits. Recently consumers' demand for non-dairy-based probiotic products has increased. The objective of this study was to determine the suitability of beet juice as a substrate for the production of a non-dairy-based probiotic product by lactic acid fermentation Beet juice was obtained with a Loomis Press. Four lactic cultures, Lactobacillus acidophilus LA39, Lactobacillus casei A4, Lactobacillus delbrueckii D7, and Lactobacillus plantarum C3, were used in the experiments. Probiotication of beet juice was carried out in test tubes (25 x 200 mm), each containing 15 mL of sterile beet juice. The juice was inoculated with a 24-hr-old inoculum and incubated at 30 degree C. Lactic acid was measured by titrating samples with 0.1 N NaOH to pH 8.2. Sugar was analyzed by the phenol-sulfuric acid method. Colony forming units (CFU) were determined by the standard plating method with MRS agar. All four lactic cultures were found capable rapidly utilizing beet juice for cell synthesis and lactic acid production without nutrient supplementation. The log viable cell counts (CFU/mL) reached greater than 9 after 48 hr of growth at 30 degree C. However, only Lactobacillus acidophilus and Lactobacillus plantarum reduced the pH from an intial value of 6.3 to <4.5. Extending the fermentation time beyond 48 hr did not result in a significant increase in the population of viable cells. The lactic cultures did not lose their viability at 4 degree C for several weeks. From the results of this study, it is concluded that beet juice could serve as a substrate for the production of a non-dairy based probiotic product that has a pH of < 4.5 (high acid) and contains a significant number of viable beneficial lactic acid bacteria.
Session 99A, Biotechnology: General
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