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J. Imm and C. M. LEE. Dept. of Food Science and Nutrition, University of Rhode Island, Kingston, RI 02881

Sea clam (Spisula solidissima) processing by-product (CPB), mainly belly, makes up about 30% of the soft flesh and is normally discarded. Because of its significant volume and high protein (11%), it appeares to be a good raw material for enzyme-assisted flavor production. However, no information is available on hydrolysis condition for production and compositional characteristics of hydrolysate flavor from CPB. The present work is important considering high demand for clam flavor and a need of quality standardization. Our objectives were to obtain an optimum enzymatic hydrolysis condition and to determine compositional characteristics as affected by processing variables. CPB was subjected to various combinations of commercial enzymes and hydrolysis conditions. Enzymes evaluated were Flavourzyme (FZ), Neutrase (NT), and Alcalase (AC), all obtained from Novo Nordisk. Resulting hydrolysates were analyzed for free amino acids and nucleotides and compared with clam meat and juice. Flavor profiles of hydrolysates were obtained using quantitative descriptive analysis (QDA) and the concentration of taste active amino acids. Predominant taste active free amino acids (TAFAA) found in hydrolysates were Arg, Ala, Gly, Glu and Met. Highest TAFAA (>22%) were formed by 3% FZ, 2% FZ + 1% AC, or 2% FZ + 1% NT + 1% AC. TAFAA well predicted overall liking of hydrolysates when evaluated in the form of clam chowder. The overall liking was greatly improved by blending hydrolysate with juice at a 2:3 ratio. Maximum yield with a desirable flavor profile was obtained by hydrolysis at 55°C for 4 hr following pasteurization in steam for 30 min to reach the internal temperarture of 86°C. Presently discarded processing by-product in significant volume could be commercially utilized by converting it to a high-value clam flavor. Identified taste active free amino acids can be appropriately adjusted to provide a most desirable flavor profile.