Study On Controlled Freezing-point Storage And Modified Atmosphere Packaging Technology Applied To The Preservation Of Surimi-based Products

Surimi-based products such as fish-ball are far popular and traditional consumed in China. But they are difficult to be industrialized for lack of all-round quality control and suitable preservation technology. In present research, microbial contamination during process of fish-ball was detected, quality changes of fish-ball were shown, and modified atmosphere packaging was studied. The main object of this study was to search for effective indicators of decomposition and technical parameters of Controlled Freezing-point Storage combined with Modified Atmosphere Packaging, and also establish HACCP system on the base of SSOP. Results summarized as following:1. Aerobic bacterial counts, total volatile basic nitrogen (TVB-N) value and 2-thiobarbituric acid (TBA) value of fish-ball stored at different temperatures increased with storage time. All of them changed more quickly as the storage temperature increased. Changes of aerobic bacterial counts, TVB-N value and TBA value with storage time and storage temperature fixed the first order chemical reaction model and Arrhenious equation significantly. TVB-N value, TBA value and total acid could be used as chemical indicators of decomposition with aerobic bacterial counts together.2. Modified Atmosphere Packaging inhibited bacteria growth, protein decomposition and fat acid oxidation to a large degree. The inhibition was strengthened with increasing concentration of CO2 in the package, and 75%CO2+25%N2 was shown the best of all the CO2 concentration studied. It extended shelf-life by 1.5 times more than air packaging and had no negative effect on the quality.3. Controlled Freezing-point Storage extended shelf-life of fish-ball to 40 days, which was 5 times more than refrigerate storage. And also Controlled Freezing-point Storage combined with Modified Atmosphere Packaging extended shelf-life to more than 50 days, while had no negative effect on the quality, either. Stored at -1?癈 with 75%CO2+25%N2 or 100%CO2 packaging was shown the best.4. The composition of the microflora of fish-ball changed much in modified atmosphere package. Only bacillus spp. and few other genera were obtained from the original products. During storage at 5℃ and -1℃, most of them were still the gram-positive groups in products with air packaging, whereas the gram-negative groups became dominant in which with CO2 packaging.5. The freezing-point of fish-ball decreased with the moisture content falling, and was also affected by different sort and quantity of sugar and starch used. It was proved that with 80-85% moisture content, 2-5% sucrose and 10% modified starch, the freezing point could be lowered to some degree, which was favorable to the storage temperature control.6. Of all the processes, heat, cooling and storage were found to be the critical control points, and thereby the HACCP system was established.