Study On Modified Atmosphere Packaging Of Refrigerated Surimi-Based Product

Surimi-based products processing is an important pathway for significant improvement on the refined-processing technologies of aquatic products and for the comprehensive utilization of aquatic resource. The surimi-based products have been one of the fastest growing products in China aquatic processing. However, due to the rich nutrition and high water content, they get rotten easily, such as fish ball. In traditionally, they are stored and transported in frozen condition, with high energy cost and environment unfriendly. Now days, holding the surimi-based products in refrigerated temperature will have been a main trend. Thus, it is of great significance……The study of refrigerated surimi-based products and related processing technologies are of energy efficiency and low-carbon economic.In view of the facts above, the fish ball as a typical and great output surimi-based product was studied in modified atmosphere packaging (MAP) on the refrigerated storage.The qualities of the surimi-based product fish ball were evaluated by the analysis of the biochemical, physicochemical, sensory parameter and texture index of the fish ball. Then some key factors of the modified atmosphere packaging of the gas composition, gas ratio, ratio of the gas volume and materials weight (V/W), temperature, and packaging materials were optimized for prolonging the shelf-life of the refrigerated fish ball. Finally, the microbiological changes of the refrigerated fish ball with MAP were determined. The fresh mechanism of MAP in the fish ball was discussed preliminarily by the inhibiting the dominant spoilage bacteria. The main conclusions are shown as follows.1. Modified atmosphere packaging (50% CO2+50% N2) was better than vacuum packaging and air packaging in keeping the favorable quality of refrigerated fish ball(P<0.05), which the total bacterial count and TVB-N values were reduced, and the stable of pH and sensory quality were maintained. The shelf life of the fish ball packed with 50% CO2 +50% N2 was extended to 42d. It was two times of that of the fish ball in vacuum packaging, and three times of that of the fish ball in air. During the storage, coliform group and pathogenic bacterial were not determined in MAP fish ball, and it was a safety package for fish ball.2. Non oxygen MAP (60% CO2+40% N2) could extend the shelf life of the fish ball to over 47 days at 0℃. A better quality in the fish ball in non oxygen MAP was showed in total bacterial count, pH values, chewiness and other indicators than that in oxygen MAP(60%CO2+10%O2+30%N2) with the shelf life of 37 days. In the non oxygen MAP, the higher concentration of CO2 had inhibited more strongly the total bacterial count in fish ball, and had prolonged better the shelf life of the fish ball. The concentration of CO2 above 75% was benefited to keep good quality of refrigerated fish ball. However,100% of the CO2 could cause the flat containers depression and deformation. Thus, the non oxygen MAP only with CO2 and N2 was more suitable to maintain the quality of refrigerated surimi-based products and appropriate CO2 concentration should be selected in practice.3. It was showed that the different ratios of the gas volume and materials weight (V/W), different temperatures and packaging materials affected significantly quality of the refrigerated fish ball(P<0.05). The shelf life of refrigerated fish was extend, only with the V/W increases in MAP. The total bacterial count, sensory quality and chewiness were well maintained with both V/W=4:land V/W=3:1. The better quality of fish ball was kept at the lower refrigerated temperature. It was indicated that the growth of bacterial was most restrained and a most favorable sensory quality was maintained on the condition of MAP combined with the temperature of-2℃. The preservation effect on the quality of fish ball decreased with the drop of their barrier properties for the three MAP materials PVDC/CPP, PET/CPP and PP/CPP, which the PVDC/CPP and PET/CPP were better than PP/CPP in bacterial, pH value, TVB-N value, sensory and texture properties.4. It was showed that the refrigerated surimi-based products of MAP was safe, longer in shelf life and more energy saved, which was a packaging technology with wide application prospect and popularization value in fish ball. Considered the practical application, the optimization parameters of MAP for chilled surimi-based products were:non oxygen, 75% CO2+25%N2, V/W=3:1,0～3℃, PET/CPP, and the shelf could be as long as 42 days to 56 days.5. MAP extended the shelf life of Collichthys fish ball by inhibiting the growth of the dominant spoilage bacteria under vacuum packaging and air packaging at the refrigerated temperature,. These dominant spoilage bacteria mainly were Micrococcus and Staphylococcal, Photobacterium phosphoreum and Lactic acid bacteria, the next were Pseudomonas sp. and Saccharomyce, which were inhibited by CO2 probably. Meanwhile, the dominant spoilage bacteria of Collichthys fish ball under MAP mainly were Lactic acid bacteria, Micrococcus and Staphylococcal, Photobacterium phosphoreum. The higher concentration of CO2 was the better effect of inhibition was found in Micrococcus and Staphylococcal, Photobacterium phosphoreum, Lactic acid bacteria, Pseudomonas sp., Saccharomyce, Enterobacter and Enterococcus. Concentration of CO2 above 75% could well inhibit the growth of Micrococcus and Staphylococcal, Photobacterium phosphoreum and Lactic acid bacteria. However, the effect of inhibition became weak for the low than 50% CO2. While low concentration of CO2 was from 25% to 50%, Pseudomonas sp., Saccharomyce. Enterobacter and Enterococcus was inhibited clearly.