A two‐step inoculation of Candida etchellsii to enhance soy sauce flavour and quality

Summary Effects of novel two-step inoculation to enhance soy sauce special flavour in Candida etchellsii were investigated at the cell growth phase. The first-stage consists of a 5% culture inoculum of log phase cells at 30-day. Subsequently, a 20% culture inoculum of stationary phase cells was added at 60-day. The resulting amino nitrogen and soluble salt-free solid yield reached 9.15 ± 0.12 and 269.60 ± 3.15 mg L−1 in 30 °C incubator experiments, increased by 23.1% and 17.6%, respectively, as compared to the control without culture inoculation. Maximal free amino acid yield of 58.21 ± 1.77 g L−1 was achieved, and 39 types of volatile flavour compounds content was 17.81 ± 0.45 g L−1, which were 1.76% and 178.7% higher than the control. A novel two-step inoculation using the C. etchellsii yeast was developed and optimised. It was proven to be a feasible reproducible process for industrial application for the improvement of the flavour and quality of soy sauce production.