| Blunt-snout bream is rich in protein and is a valuable source of food protein with tender meat. Due that the moisture content is higher and raw material is easy to corrupt, so developing the new processing technology of canned blunt-snout bream is particularly important. In this paper, with fresh blunt-snout bream as the material, the processing technology, the best prescription and the change during the storage were studied, which will provide technical support to blunt-snout bream deep processing industry. The main research contents and results were as follows:(1)The initial protein denaturation temperature which reached57.6℃of fresh fish was determined by DSC; With the ingredients of fresh blunt-snout bream for analysis, it was concluded that blunt-snout bream belongs to the high-moisture, high-protein and low-fat seafood. Through single factor and orthogonal experiment, the best technology of the curing of blunt-snout bream was determined as:4%of salt content,15℃of the curing temperature and60min of the curing time.(2)From the drying curves and drying rate curves of blunt-snout bream under the temperature of45,50,and55℃,it was concluded that the smaller the thickness of the fish, the drying rate was larger; the higher the temperature, the water content of blunt-snout bream dropt faster and the drying rate was greater. If the drying temperature was too low, the drying rate was too low and the drying time was too long; If the drying temperature was too high, it could lead to different degree of browning of the surface of fish; It was particularly important to choosing suitable drying temperature.(3) Thin layer heat drying of fresh blunt-snout bream was investigated. Meanwhile the suitable mathematical model which can be used to describe the relationship of moisture ratio and drying time was established by Origin7.5in this paper. The result showed that the model of Logarithmic could better describe the thin layer drying process of blunt-snout bream. The drying temperature of the dorsal muscles and abdominal muscles of blunt-snout bream was50℃, and the best drying time were7.95h and6.08h. Constructed the study of the change of texture and color during drying process at50℃, the hardness, gumminess, chewiness of product were significantly decreased and the change of springiness, cohesiveness of product were little with the extension of the drying time; The value of L of product declined overall and the value of a*and b*increased in the early stage of the drying, but latter changed little.(4) By Lg(43) orthogonal test, the main flavoring ingredients for the can were studied. The result showed that:the factors impacting on the sensory score of the Can were ordered as:citric acid addition>sugar addition>malic acid addition>acetic acid addition, with the sugar and citric acid addition having significant impact. The result showed that the best formula of sweet-sour taste was determined as:6%of sugar content,0.2%of citric acid content,3%of acetic acid addition,0.1%of malic acid addition. The color of the product is bright and the sweet-sour taste is appropriate after the entrance, which was in line with the requirements of most of modern people.(5) The quality of canned dried-wuchang fish of sweet and sour taste changed under different storage conditions; The moisture content, sensory evaluation, the index of texture as hardness, springiness, chewiness, gumminess and the index of color as L decreased with the extension of storage time; The value of pH first decreased and increased then with the extension of storage time; The value of a*increased with the extension of storage time and the value of b*first increased and then decreased. The AV of physicochemical indexes changed were adjusted to first order kinetic model, and the Arrhenius equation of AV was k=216.8704e[-(22.24×103)/RT] through fitting. The shelf lives of vacuum-packed canned-wuchang fish were432.8d、352.5d、219.2d and163.7d separately at4,10,25and35℃. |
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