Analysis of the Fermentation Characteristics of Oyster-derived Lactic Acid Bacteria and the Application in the Preparation of Oyster Oil Vinegar Sauce

This study aimed to investigate the effects of oyster-derived lactic acid bacteria (LAB) and commercial starter cultures on the quality attributes of oyster hydrolysate. The fermented oyster hydrolysate-based seasoning can satisfy industrial demand. Four different fermented oyster hydrolysates were prepared: The unfermented group (UF), commercial fermented group (CF), oyster-derived LAB fermented group (7KI), and the mixed fermentation of oyster source with commercial starter culture (7KIC). The contents of basic nutritional components, total amino acids, and taste-active nucleotides were characterized. Subsequently, the optimal formulation for the oyster oil vinegar sauce was determined, and the nutritional composition and mineral content were systematically analyzed. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to elucidate the differences in flavor composition between different oil vinegar sauces. The results showed that the 7KI and 7KIC groups with oyster-derived LAB exhibited high protein and low carbohydrate profiles compared to the other groups. Significant increases in acidity and soluble solids content were observed in the 7KI and 7KIC groups (P<0.05). The amino acid score of the 7KIC group reached 87.63, significantly higher than UF (62.13) and exceeding CF and 7KI by 4.14 and 4.34 points, respectively. Nucleotide analysis revealed that 7KI and 7KIC effectively removed hypoxanthine (Hx), outperforming CF in efficiency. Using 5 g of 7KIC-inoculated fermentation broth as the substrate, the optimum addition amount of ingredients was determined as soy sauce 40% (2 g), apple vinegar 60% (3 g), xylitol 6% (0.3 g) and lemon juice 30% (1.5 g) by mass ratio. The product contained high taurine (2.34±0.04 mg/g) and zinc (443.84±21.08 mg/100 g) contents. The volatile compounds, such as 1-octen-3-ol (mushroom odor), methyl succinate, and propyl butyrate (fruity odor), were identified in fermented products, contributing to the fruity odor and oyster characteristic odor. In conclusion, fermentation using oyster-derived LAB can enhance the quality of oyster hydrolysate, offering novel insights for the development of fermented oyster-based products.