Study On Key Technology In Texturing Of North Pacific Squid Protein

The development and utilization of low-value aquatic protein always attracts much more attention from all countries in the world. The utilization form of aquatic protein doesn't break from traditional means of food processing till now and the products are still mainly fish meal. Thermoplastic extrusion cooking technology can fundamentally solve the problems of low-value aquatic protein such as single variety, poor edibility and low protein utilization ratio and so on. And it is helpful to develop new aquatic protein products with good edibility and high nutritional value.Research on thermoplastic extrusion cooking on texturing of low value aquatic protein are conducted by following trials, results from the trials conducted indicate the following points:The waste scrap from the North Pacific squid processing as experimental material was carried out preliminary study on processing of texturized by extrusion in low value aquatic protein. Effect of several processing variables including feed moisture, barrel temperature, and screw speed on extrusion texture index and chewness was investigated. The optimal extrusion cooking conditions were obtained through single-factor experiments as follows: feed moisture 40%~45%, barrel temperature 130~140℃and screw speed 20~30 Hz.On the basis of the single factor experiment, a three-factor quadratic regression rotation combination design was adopted to analyze effects of feed moisture, barrel temperature, screw speed and their interactions on both texture index and chewness as well as optimized. Based on this approach and experimental data, the quadratic regression models of texture index and chewness were deduced. Effect of extrusion process parameters on in vitro digestibility of extruded squid protein using a twin screw extruder was also studied. Then analyses of variance were conducted with response surface analysis, and the optimal extrusion cooking conditions were obtained as follows: feed moisture was 40%, barrel temperature was 140℃and screw speed was 25Hz. Polynomial regression equations of process variables with two properties were obtained with R2=0.889 and R2=0.882, respectively. Both of two regression equations were highly credible. Polynomial regression equations of process variables with in vitro protein digestibility were obtained with R~2=0.896. Regression equations were highly credible. Compared with normally processing methods, extrusion cooking showed the highest protein digestibility.Effect of extrusion process parameters on the functional properties of extruded squid protein using a twin screw extruder was studied employing Response Surface Methodology. As input variables, twin extrusion cooking running parameters examined were feed moisture, barrel temperature and screw speed. Meanwhile, as output variables, functional properties of the resultant extrudates included water holding capacity and oil holding capacity. Results showed that feed moisture, screw speed and interaction of feed moisture and barrel temperature had all significant influence on both water holding capacity and oil holding capacity. Interaction of feed moisture and screw speed had just significant influence on water holding capacity. Polynomial regression equations of process variables with two functional properties were obtained with R2=0.890 and R2=0.979, respectively. Both of two regression equations were highly credible.Effect of extrusion process parameters on the physical properties of extruded squid protein using a twin screw extruder was studied employing Response Surface Methodology.,Twin extrusion cooking running parameters, feed moisture, barrel temperature and screw speed were examined as input variables. Meanwhile, as output variables, physical properties of the resultant extrudates included moisture and bulk density. Results showed that moisture content of extrudates were affected intensely by feed moisture which had positive correlation. Interaction of feed moisture and barrel temperature had significant influence on both water content and bulk density. Polynomial regression equations of process variables with two physical properties were obtained with R2=0.952 and R2=0.815, respectively. Both of two regression equations were highly credible.