Study on the regulation of ammonia accumulation by endogenous haloarchaea in shrimp paste post seasoned with rebaudioside A

Shrimp paste relies on post-seasoning to enhance its flavor, commonly using sucrose. In this study, a mixed sweetener strategy comprising 0.04 % rebaudioside A (RA) and 2 % sucrose was established to achieve the goal of sugar reduction. Interestingly, a significant increase of ammonia in shrimp paste seasoned with 0.05 % RA as the only sweetener was detected, and slightly reducing the RA concentration eliminated this effect. Four endogenous archaea and five bacteria strains were identified from shrimp paste. All the endogenous haloarchaea, but none of the bacteria, were shown highly sensitive to RA. Further investigation indicated that all archaea strains could utilize ammonia nitrogen or nitrate nitrogen as their sole nitrogen source, suggesting that the inhibitory of haloarchaea increased ammonia in RA-seasoned shrimp paste. Moreover, the inhibitory concentration of RA for haloarchaea closely matches RA's critical micelle concentration in different salinities. In summary, this study propose a combined seasoning strategy of RA and sucrose to reduce sucrose levels in post-seasoning shrimp paste. The discovery of inhibitory activity of RA to haloarchaea provides insights into the selection and utilization of sweeteners in pickled foods.