The flavor attributes of hydrolysate prepared from skipjack tuna (Katsuwonus pelamis) head as affected by enzymolysis and deodorization strategies

This study investigated the effects of three enzymolysis strategies, alcalase, neutrase, and acid protease in combination with flavourzyme (AF, NF and CF) on the flavor properties of skipjack tuna ( Katsuwonus pelamis ) head. The effects of three deodorization methods, yeast (y), activated carbon (a) and β-cyclodextrin (β) on the hydrolysate properties were also studied. The hydrolysis degree (45.23 ± 2.25 %) and protein recovery (71 ± 3.5 %) of AF were the highest. Sensory evaluation and volatile compound analysis reveal that AF possessed favorable taste and flavor characteristics. Yeast, activated carbon and β-cyclodextrin significantly improved the flavor profile of hydrolysate. Gas chromatography mass spectrometry analyses indicate that yeast effectively reduced the concentrations of octanal and nonanal by 63 ± 0.34 % and 47 ± 0.02 %, while promoting the formation of the aromatic compounds 1-nonanol (0.87 ± 0.01 mg/L) and phenylethyl alcohol (0.62 ± 0.06 mg/L). Moreover, yeast resulted in 77.6 % ± 1.05 increase in umami-amino acids and 19 ± 0.94 % decrease in bitter-amino acids in NF-y. Thus, enzymolysis strategy by alcalase or neutrase with flavourzyme coupled with deodorizing strategy by yeast could be applied for producing value-added hydrolysate from skipjack tuna head.