Quality Changes During Storage of Cook-chilled Soybean Sprouts

Sous vide and packaged cook-chilled soybean sprouts were evaluated for physicochemical quality changes and microbial safety during storage for the purposes of shelf-life extension and industrial application. The physicochemical changes assessed were color, texture, and ascorbic acid concentration. The quality of soybean sprouts became worse with increased periods of storage and better in storage temperature of $3^{\circ}C$ more than in $10^{\circ}C$. The concentration of aerobic bacteria decreased from $2.1{\times}10^8$ to $6.0{\times}10^2\;CFU/g$ after pasteurization, but increased during storage. These bacteria are the same shape as anaerobic and hsychrophilic bacteria, but none of these other organisms were detected after heat treatment. The physicochemical qualities of soybean sprouts and microbial safety were better for products stored at $3^{\circ}C$ than at $10^{\circ}C$. In the case of short storage periods, heat treatment at $70^{\circ}C$ for 2 min was most effective for quality and microbial safety.