Fermentation Cover Brine Reformulation for Cucumber Processing with Low Salt to Reduce Bloater Defect

摘要

Reformulation of calcium chloride (CaCl_2) cover brine for cucumber fermentation was explored as a mean to minimize the incidence of bloater defect. This study particularly focused on cover brine supplementation with calcium hydroxide (Ca[OH]_2), sodium chloride (NaCl), and acids to enhance buffer capacity, inhibit the indigenous carbon dioxide (CO_2)- producing microbiota, and decrease the solubility of the gas. The influence of the cover brine formulations tested, on the cucumber fermentation microbiota, biochemistry, CO_2 production, and bloating defect was studied using metagenetics, HPLC analysis, a portable gas analyzer and bloater index, respectively. Cover brine supplementation with Ca(OH)_2 and acetic acid resulted in complete fermentations with final pH values 0.5 units higher than the un-supplemented control. Lactic acid production increased by approximately 22%, possibly inducing the observed reduction in the relative abundance of Enterobacteriaceae by 92%. Ca(OH)_2 supplementation also resulted in an increased relative abundance of Leuconostocaceae by 7%, which likely contributed to the observed increment in CO_2 levels by 25%. A 50% reduction on acetic acid formation was detected when cover brines were supplemented with Ca(OH)_2 and 690 mM (4%) NaCl. No significant difference was observed in bloater index as the result of Ca(OH)_2 or NaCl supplementation in cover brines, given that the CO_2 levels remained at above the 20 mg/100 mL needed to induce the defect. It is concluded that the modified cover brine formulation containing Ca(OH)_2 and NaCl enables the complete conversion of sugars, decreases production of CO_2 and levels of Enterobacteriaceae, but insignificantly reduces bloater index.