Characterization of taste and micronutrient content of rock oysters (Crassostrea nippona) and Pacific oysters (Crassostrea gigas) in Japan

In this study, we characterized, for the first time, the taste and typical micronutrient content of rock oysters (Crassostrea nippona) and compared these to those of Pacific oysters (Crassostrea gigas). Rock oysters were collected in July and August and Pacific oysters in December 2015 in Japan. All samples were homogenized using a blender and Polytron homogenizer. In the rock oysters, some taste qualifies, such as initial tastes (acidic bitterness, umami, and saltiness) and richness of aftertaste, were higher than in Pacific oysters (determined by Taste Sensing System) (P < 0.05). In contrast, 5'-inosinate and succinic acid did not differ between Pacific and rock oysters. Glycine and some bitter tasting amino acids were more abundant in rock oysters than in Pacific oysters (P < 0.05). The concentration of palmitic acid (C16:0), heptadecenoic acid (C17:1), and stearic acid (C18:0) in rock oysters were higher than in Pacific oysters (P < 0.05). Moreover, vitamin B-2, vitamin B-12, zinc, and taurine content in rock oysters were higher than in Pacific oysters (P < 0.05). We conclude that rock oysters may be richer in taste and micronutrients content than Pacific oysters.