14C-4 |
Inhibition of yeast in cucumber pickle brine by hexanoic acid and hexenoic acid |
T. DOAN and R. W. Buescher. Dept. of Food Science, Univ. of Arkansas, 272 Young Ave., Fayetteville, AR 72704 Excessive growth of yeast in commercial cucumber pickle brine causes economic loss due to reduction of lactic acid, off-flavors, softening, and bloating of pickle products. Sorbic acid is currently used to inhibit yeast growth in cucumber tanks. However, studies have demonstrated that the dien-conjugated structure of sorbic acid renders it susceptible to degradation. Hexanoic acid and hexenoic acid, on the other hand, have no and one double bond, respectively. Thus, they are expected to be more stable than sorbic acid. Hexenoic acid was also found to be a degradation product of sorbic acid in pickle brine. Our research objectives were to determine the efficacy of hexanoic and hexenoic acid in yeast inhibition and their stability in commercial pickle brine. Commercial recycled brine with initial yeast population of 4 logs CFU/ml was used for testing effectiveness and stability of sorbic, hexanoic and hexenoic acid. Petri-film (3M) was used to determine yeast's CFU at 24 and 48 hours of observation period. Stability of the yeast inhibitors and residual levels was determined by HPLC. Result showed that hexanoic acid--at 300ppm-and hexenoic acid-at 350ppm, effectively inhibited film yeast growth for more than 30 days. Within 24 hours, sub-surface yeast population was reduced to less than 1 log CFU/ml by 300ppm hexanoic acid, and to less than 2 logs CFU/ml by 350ppm hexenoic acid. The effect of hexenoic acid was similar to 350ppm sorbic acid, which also reduced yeast population to 1 log CFU/ml within 24 hours. Hexanoic and hexenoic acid appeared to be more stable than sorbic acid in pickle brine. From this study, hexanoic and hexenoic acids have the potential to replace sorbic acid as yeast inhibitors in commercial cucumber pickle brine.
Session 14C, Food Microbiology: Food mycology
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