Abstract:
This study focused on effect of biopolymers on oil absorption in frozen fish finger from threadfin bream and surimi. Threadfin bream used was composed of 82.7% moisture, 15.66% protein, 0.66% fat, 0.64% ash, 0.31% carbohydrate, 17.56 mg/100g total volatile base (TVB) and 54.06% (of total protein) salt soluble protein. Surimi was composed of 80.23% moisture, 15.69% protein, 0.09% fat, 0.84% ash, 3.15% carbohydrate and 500 g.cm gel strength. Batter was formulated form wheat flour and corn flour. Wheat flour was composed of 12.80% moisture, 11.09% protein, 0.20% fat, 75.47% carbohydrate and 0.46% ash. Corn flour used composed of 10.57% moisture, 0.18% protein, 0.02% fat, 89.09 % carbohydrate and 0.14% ash. Initially, change in quality of palm olein during frying were studied. Sixteen pieces of coated fish finger were fried at 170 OC, 4 min and 30 secs each, for a total of 120 min. Quality of palm olein were checked every 30 min by determining viscosity and free fatty acid. Later the flour in batter formula was substituted with hydroxypropyl methylcellulose (HPMC) at 0.2, 0.4, 0.6 and 0.8% (by flour weight), high amylose corn starch at 5, 10, 15 and 20% (by flour weight) and eggwhite powder at 1.5, 3.0, 4.5 and 6.0 (by flour weight). The best quality products were selected by determining apparent viscosity of liquid batter, moisture of batter and core, oil content of batter and core, hardness and color of batter,and the product sensory quality. Finally, the efficiency of the three biopolymers were compared. The result showed that, the increase of viscosity and free fatty acid contents did not affect oil absorption in the products. As quantities of HPMC increased the apparent viscosity of liquid batter, the product moisture and lightness increased while the oil content, hardness, yellowness, redness and sensory quality decreased. The optimum HPMC quantity was 0.4% (by flour weight), at this level, the total oil content of product was 14.02%. As quantities of high amylose corn starch increased the apparent viscosity of liquid batter, the oil content and hardness decreased while the product moisture and sensory quality increased. The optimum high amylose corn starch quantity was 10% (by flour weight), at this level, the total oil content of product was 14.32%. As quantities of eggwhite powder increased the apparent viscosity of liquid batter, the oil content, lightness and sensory quality decreased while the product moisture, yellowness, redness increased. The optimum level of eggwhite powder was 3.0% (by flour weight) and, at this level, the total oil content of product was 13.37%, Finally, the efficiency of three biopolymers were compared, it was found that the best material was 3.0% (by flour weight) eggwhite powder.