Investigating influence of aquaculture seawater with different salinities on non-volatile taste-active compounds in Pacific oyster (Crassostrea gigas)

The oyster is well-known for its delicious taste and nutritional benefits. However, the taste of oysters in the market is relatively monotonous at present. In order to develop more tastes of oysters, this study explored the taste compounds (organic-acids, 5 '-nucleotides and free amino acids) of Pacific oysters (Crassostrea gigas, triploid oyster) obtained from aquaculture at three different salinities (25 parts per thousand, 28 parts per thousand and 32 parts per thousand). The results showed that the contents of 5 '-nucleotides (52.59 mg/100 g) in the test samples from the aquaculture salinity of 28 parts per thousand were higher than those in the salinity of 25 parts per thousand and 32 parts per thousand. The contents of free amino acids (1760.47 mg/100 g) in the 32 parts per thousand sample were higher than those in the salinity of 25 parts per thousand and 28 parts per thousand ones. In addition, the taste activity value (TAV) and equivalent umami concentration (EUC) of three samples were calculated. The relationship between EUC and sensory evaluation was also investigated. The results showed that the highest TAV of the major free amino acids and 5 '-nucleotides was observed in the 28 parts per thousand salinity oyster sample. A positive relationship was established between EUC and sensory score of overall taste as well as umami, respectively. Our results suggested that 28 parts per thousand was the optimal aquaculture salinity with regards to the oyster's taste, and it was the most commonly accepted. The study may be helpful to guide rational development of diversified flavors of oyster.