Effects of different freshness on the quality of cooked tuna steak

The variation in quality of yellowfin tuna (Thunnus albacores) steaks of different freshness after cooking were studied by analyzing K value, adenosine triphosphate (ATP)-related compounds content, histamine content, sensory quality, E-nose and E-tongue analysis. The results indicated that when the freshness of raw tuna steak decreased from sashimi grade to cooking grade, IMP content significantly decreased whereas HxR content significantly increased after cooking. With the decrease of freshness, K value of the 4th day sashimi-grade tuna and the 6th day cooking-grade tuna increased from 18% and 24% to 27% and 45% respectively after cooking. The higher histamine content in raw tuna steak, the more significantly increased histamine level of cooked tuna was observed. Raw tuna steaks with sashimi grade have significant variation from those with cooking grade in odor and taste by E-nose and E-tongue analysis after cooking The sensory evaluation showed that the freshness of tuna steak significantly influence the cooking quality (p < 0.05). Industrial relevance: Tuna is well appreciated worldwide because of its high nutritional value and potential health benefits. Canned tuna is one of the most widespread and recognized fish commodities in the world. The species utilized commonly for canning are skipjack, yellowfin and albacore tuna. Cooking tuna steak is normally used as semi-manufactured products in canned tuna industry. Control of the cooking unit operation is critically important to producing cooked muscle for tuna industry. However, freshness of raw tuna steak may have close connection with the quality of cooked tuna steak. This research paper presents the effects of different freshness on the cooking quality of tuna steak. Finding in this research showed primary knowledge of mastering the freshness of raw tuna steak for ensuring the quality of cooked tuna steaks in canned tuna industry.