Determination of volatile components in fermented soybean prepared by a co-culture of Bacillus subtilis and Rhizopus oligosporus

Fermented soybeans are traditional foods widely consumed in many countries (i.e., Natto in Japan, Jang in Korea, Kinema in India, Douichi in China, and Thua Nao in Thailand). In this study, an attempt was made with an expectation to improve the fermentation process using a co-culture of Bacillus subtilis and Rhizopus oligosporus. Initially, the raw soybeans were washed, sterilized by autoclaving, and inoculated with two inoculaii) 50:50 comprised of acids and esters (55.62%), alcohols (16.22%), aldehydes (7.80%), pyrazine (3.65%), ketones (2.55%), furans (1.67%), and aromatic compounds (1.46%)and iii) 0:100 included acids and esters (66.50%), alcohols (15.44%), aldehydes (2.59%), ketones (2.72%), furans (1.89%), aromatic compounds (1.80%), pyrazines (1.35%), and sulphur containing compounds (0.24%) respectively