Preservation of Okara (Soybean residue from soy mash) by Lactic Acid Fermentation

Abstract

Okara is a by-product of tofu manufacturing. Lactic acid bacteria was used as starter cultures in order to prevent microbiological deteriolation of okara. Yogurt was added to okara as starter coltures with or without 1% glucose. It was difficult to prevent the spoilage of okara in aerobic condition. But in facultatively anaerobic condition such as packing in a polyethylene film bag or a screw-cap bottle, okara was fermented by lactic acid bacteria, lowering its pH value below 4.2 resultng in inhibition of the growth of spoilage bacteria at least 4 days at 37°C. Dried starter of lactic acid bacteria, especially Lactobacillus plantarum was more suitable than yogurt in respect to utility. Optimum fermentation conditions for preventing the microbiological deteriolation of okara were inoculation of 106 dried lactic acid bacteria/g with 1% glucose and semi-anaerobic incubation at 30-37°C.