The Study On The Preparation Of Crisp Fishbone And Fine Bone-meat Paste Of Tilapia

In order to make full use of the Tilapia fish steak which was produced as one of the by-products during Tilapia fish filletting, two feasible product styles and their preparation procedures were brought forward in this paper. The following results were achieved:1. The bone-meat proportion, nutirmental composition and the distribution of hardness of the Tilapia fishbone were analyzed. It were calculated that Protein coefficient 5.99 for the fish meat, 4.89 for the fishbone and converting coefficient of hydroxide-proline to collagen 13.66 for the fishbone, which could provide a reference to calculate the protein content for this kind of fish.The amino acid score of the Tilapia fish steak is 120, which meets the requirement of daily metabolic activity for adults on amino acid. The Tilapia fish steak is rich in calcium and phosphor with proximate ratio of calcium to phosphor 2∶1. Hardness distribution of Tilapia fishbone was firstly showed in a new way in this paper.2. High pressure steam cooking with acetic acid can soften the fishbone more efficiently than that without acetic acid, and this method can decrease the hardness of fishbone to a eatable level. Mass remains of dry matter especially of protein was decreasing while prolonging the cooking time and raising the acetic acid concentration. It was firstly showed that the relationship between the hardness of fishbone and hydroxide-proline dry base content(Hyp) could be described by the following equation: Hardness= 4.0704×Hyp-0.5892,R2 = 0.8875. Statistics analysis shows that the positive relationship between hardness and Hyp dry base content is highly significant (P<0.01 ). High pressure steam cooking with acetic acid could soften the fishbone by denaturalizing and dissolving its collagen. Optimized conditions, showed as (acid content, cooking time) , for high pressure steam cooking with acetic acid are (3%,45min)(,6%, 25min)(,9%, 20min)and(12%, 15min). In these conditions, maximum dry mass remains (51%-55%) with the hardness of the fishbone decreasing to a eatable level (2.96-4.26kg/cm)was detected. The crisp fishbone was finally prapared by combining the procedures of cooking , seasoning and drying. Sensory descriptions were as follows: the color is even brown, strong aroma of baking and marine product; flavor of lasting salty marine product; crisp and easy chewing.3. Fine and smooth Tilapia fish bone-meat paste can be prepared by the combination procedures of high pressure steam cooking with acetic acid, colloid grinding and ultra-high pressure microfluidization. The cut up fish steak was firstly treated with high pressure steam cooking:acid content 3%,cooking time 90min, cooking temperature 126℃,and then treated by colloid grinder then by ultra-high pressure microfluidization with pressure of 120MPa. In this condition, the mean particle diameter of the fish bone meat paste could be as low as 11.8μm. Then,the paste was condensed to water content 60.3% before seasoning, package and pasteurizing. The fish paste was fine and smooth ,with good smearing ability and sensory quality.