Abstract: In order to systematically study the quality changes of oysters during steaming, the basic chemical components and cooking loss of oysters were measured at different steaming times (2, 4, 6, 8 and 10 min), the texture properties were analyzed by texture profile analysis (TPA), and the volatile components were determined by headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Meanwhile, sensory evaluation was carried out using a trained panel and instrumental assessment was performed using an electronic tongue and an electronic nose. The results indicated that during steaming, the water and crude fat contents of oysters were significantly reduced, and the total sugar and crude protein contents were significantly increased; the flavor, taste, and appearance changed significantly. Based on the sensory quality and the internal temperature, the steaming degree was divided into six levels. The TPA results showed that the hardness and elasticity of the abdominal tissue and adductor muscle of oysters were significantly enhanced after 4 min of steaming (P < 0.05). Totally 48 volatile flavor substances were identified in steamed oysters, belonging to eight chemical classes. During the steaming process, the amounts of aldehydes and ketones increased first and then decreased, and the amounts of esters and ethers decreased continuously and significantly. The odor activity value (OAV) analysis and principal component analysis (PCA) showed that dimethyl sulfide, (E,Z)-2,6-nonadienal, (E,E)-2,4-heptadienal, (E,E)-2,4-decadienal and E-2-nonenal were the key flavor substances in steamed oysters. According to the taste activity value (TAV), betaine, soluble sugars, free amino acids, and nucleotides made significant contributions to the taste of steamed oysters, and their contents significantly changed during the steaming process (P < 0.05). In summary, this study provides reference for quality control during the steaming of oysters.

Key words: oyster; steaming degree; eating quality; sensory evaluation; flavor