Bitterness of green mussel (Perna viridis) hydrolysate as influenced by the degree of hydrolysis

Green mussel (Perna viridis) was hydrolysed with alcalase under two different conditions consisting of pH7, E/S5% or pH 9, E/S 3% at 60°C for two hours. Hydrolysis at pH 9, E/S3% resulted in a higher degree of hydrolysis (DH) than pH7, E/S5% with degree of hydrolysis of 37.00% and 28.33%, respectively. The green mussel hydrolysates were characterized by molecular weight of 38 kDa and 18 kDa, respectively. Hydrophobic group analysis by using FTIR detected the presence of amine group which contributed to the bitterness of hydrolysates produced under both conditions. Sensory evaluation indicated that both hydrolysates were slightly bitter but did not exceed the bitterness of the standard caffeine solutions. Further analysis should be done on the hydrolysis process of green mussel to produce hydrolysate with improved sensorial properties thus make it more applicable as flavoring agent in food product.