The effects of cryoprotectants on the freezing storage of kimchi sauce during long-term distribution and its feasibility for the preparation of kimchi

This study evaluated the feasibility of using frozen kimchi sauce prepared with cryoprotectants (Car: carrageenan and Tre: trehalose) for long-term distribution and subsequent production. Kimchi quality correlated with kimchi sauce quality. Kimchi yangnyeom sauces were prepared with or without cryoprotectants and stored under refrigerated (4°C, R) or frozen (−18°C, F) conditions for up to 24 weeks. At each storage interval, freshly salted kimchi cabbage (brined in 15% NaCl for 7 h) was mixed with the stored sauces to manufacture kimchi, which was fermented at 4°C until analysis. The titratable acidity of all kimchi remained below the optimal ripening threshold (0.7–0.9%) until 4 weeks of storage. Conversely, all kimchi had pH levels below optimal ripening criterion (pH of 4.2–4.5) following 12 weeks of storage. At 8th week, CarR, TreR, and TreF approached optimal ripening considering both pH and titratable acidity simultaneously. TreF exhibited the highest reducing sugar concentration (p < 0.05). Control and Car group kimchi had lower reducing sugar concentrations. Total aerobic and lactic acid bacteria exhibited a typical kimchi fermentation trend, with no significant microbiological differences among kimchi sauces. Thus, frozen storage of trehalose-prepared kimchi sauce may help preserve fermentation stability during long-term distribution.