The effect of adding Gracilaria on flavor and quality of low-salt fermented soy sauce

With the increasing awareness of health, there are higher expectations of customers for the unique flavor, umami, and nutritional value of soy sauce. To explore the potential application of edible seaweed in soy sauce, this study utilized high nutritional value seaweeds to ferment soy sauce and investigated the effects of the addition of Gracilaria on the physicochemical properties and flavor substances of soy sauce. The contents of amino acid nitrogen and total nitrogen in Gracilaria soy sauce were 0.8 g/100g and 1.4 g/100g, respectively, which were higher than those in traditional soy sauce. The free amino acid content of Gracilaria soy sauce (17.82 mg/g) was 1.35 times higher than that of traditional soy sauce, the organic acids content of Gracilaria soy sauce (15.78 mg/mL) was 1.12 times higher than that of traditional soy sauce. Compared with traditional soy sauce, the addition of Gracilaria promoted the accumulation of pyrazines and acids in soy sauce, which contributed to the seafood-like flavor. In general, the addition of Gracilaria to ferment soy sauce can improve the quality and give it a unique flavor. This study can provide a reference for improving the quality and flavor diversity of soy sauce by using seaweed as a fermentation substrate. • Gracilaria can be fermented to increase amino acid nitrogen of soy sauce. • Gracilaria addition inhibit putrescine production during soy sauce fermentation. • Pyrzine is key for identifying traditional soy sauce and Gracilaria soy sauce. • Gracilaria addition during fermentation can give soy sauce seafood-like flavor.