Development Of Ready-to-eat Penaeus Shrimp

Influences of high pressure (HP) treatment on the texture, color, moisture content of pre-cooked peeled shrimp products and its sterilization were investigated. Effects of pressure and HP treatment time on microorganisms and quality of the shrimp product were evaluated respectively. It was found that E. coli, Staphylococcus aureus, Salmonella, Bacillus subtilis and Listeria innocua inoculated in shrimps was reduced by 7.1, 7.0, 7.2 ,4.3 and 8.8 logs respectively at 600 MPa for 15 min. High pressure showed certain effect on physical and chemical properties of pre-cooked peeled shrimp products. As the pressure increased, the moisture content and the L-values decreased, the a-value did not change a lot, while the hardness, springiness and chewiness increased significantly. During storage at 4°C, the hardness of HP treated samples increased somewhat while springiness didn't changed. The a-value increased slowly and then decreased significantly. Sensory evaluation shows that pre-cooked peeled products with HP treatment at 400 MPa for 15 min were most favorable after 60 day storage at 4°C, and were still acceptable after 120 day storage. The HP treated products became more acceptable because of the texture improvement.Based on these studies, the process for shrimp products with a prolong shelflife at 4°C was obtained as followed: live shrimps were washed with pressed water, headed, tailed, heated in water at 100°C for 2 minutes, peeled, washed with water, drained, soaked in seasoning for 1 hour, drained and vacuum-packaged, and then treated with HP at 400 MPa for 15 minutes and stored at 4°C.The effect of drying parameters, namely microwave power, vacuum pressure and mass load on the drying kinetics were investigated. The mathematical model for microwave-vacuum drying (MVD) of shrimp was developed. Results show that the drying characteristics were affected mainly by microwave power and mass load, while vacuum pressure had little effect on the drying rate. With the increase of microwave power and the decrease of mass load, drying rate increased. The drying rate initially increased rapidly and then reduced slowly, and finally dropped sharply with the reduction of moisture content during MVD. Page's model developed by regression analysis of the experimental data was found to be in good agreement with the experimental results.Orthogonal experiments were carried out to The optimize such parameters as microwave power, mass load and vacuum pressure for MVD of shrimpal. Based on these studiess, the process for shrimp products with a long shelflife at room temperature was obtained as following: live shrimps were washed with pressed water, headed, tailed, heated in water at 100°C for 40 s, peeled, washed with water again, drained, soaked in seasoning for 1 hour, dried by MVD (348.92W, 16 minutes, 100g, -80kPa), vacuum-packaged, sterilized at 90°C for 15 minutes and stored at room temperature. After 5 month storage at room temperature, the shrimp products by MVD were safe and favorable.