Abstract:
Our objectives were to produce surimi from economic freshwater fish and to evaluate the effects of trehalose (tre), sucrose (su) and sorbitol (sor) as cryoprotectants in surimi quality and glassy state system. Freshwater fish used in our research were Labeo rohita and Cirrhina microlepis. Both of them are lean-fat fish and show similar protein pattern. Species of fish (2 species) and optimum conditions for gel setting [4 levels of gel setting temperature (30, 40, 50 and 60 ํC), 3 levels of setting time (30, 60 and 120 min.)] were studied. The gel was then heated at 85 ํC for 30 min. to prepare kamaboko. It was found that interaction between fish species and gel setting temperature affected the hardness and cohesiveness of surimi gel significantly (p is less than or equal to 0.05). Springiness was affected by species and gel setting temperature while whiteness of surimi gel was not effected by species, gel setting temperature and time (p > 0.05). Judging from the numerical values of hardness, cohesiveness, springiness and whiteness, surimi gel was then prepared from Cirrhina microlepis. The gel was set at 40 0C for 30 min. followed by heating at 85 0C for 30 min. To study the effects of trehalose, sucrose and sorbitol on Tg and surimi quality. The amount of cryoprotectants was varied as su:sor (4:4); su:sor:tre (4:3:1), (4:2:2), (4:1:3); su:tre (4:4) and tre (8) % w/w. It was found that the Tg of surimi with trehalose was higher than that of surimi with other cryoprotectants. However, each cryoprotectant and its amount didnt affect hardness, cohesiveness, springiness, color and whiteness of surimi gel significantly (p > 0.05). Judging from the value of Tg, surimi was then prepared using su:sor (4:4); su:sor:tre (4:2:2) and su:tre (4:4) % w/w as cryoprotectant. To evaluate the effects of frozen storage on protein denaturation, physical appearance, sensory quality and stability of Tg surimi were studied. It was found that each cryoprotectant didnt affect protein pattern from surimi throughout 150 days of frozen storage. While it significantly affected hardness, springiness, L* values and whiteness of surimi gel. From the sensory evaluation, using 9 points hedonic scale, the overall acceptance score of surimi prepared from each cryoprotectnt ranged from 6.83-7.63.