Study On Preparation And Application Of Fresh Ice For Prawn

The prawn is well known and consumed because its flesh is delicate, tasting, and nutritious. Blackspot and metamorphose are seriouslyaffecting its quality and value. However, the technology of fresh ice forprawn can well solve these problems caused by blackspot andmetamorphoses, and improves the quality and product value.In this study, two kinds prawn were collected from local market assample, which are Penaeus Vannamei and Solenocera Melantho. Afterbasic nutrients determination and investigation, the method forconcentration of SO₂ examination was confirmed. The concentration ofsodium pyrosulfite, glycerol and sodium alginate was chosen as the keyfactor to set up single factor and orthogonal experiment for confirmingthe best condition of preparation technique of fresh ice for prawn. In thisresearch, fresh ice was studied for keeping fresh of Penaeus Vannameiand Solenocera Melantho, the varieties of fresh indicators andconcentration of SO₂ in each part of prawn body were examined duringthe progress. The results were as follows:1. Selecting Japanese standard (distillation-titration) as themeasurement method for concentration of SO₂ higher than 100mg/kg, and Chinese standard as the second method for analyzing whenconcentration of SO₂ less than 100mg/kg.2. According to the single factor and orthogonal e发xperiment, the bestcomposition of fresh ice was obtained: sodium pyrosulfite (5000mg/kg), glycerol (0.07ï¼…) and sodium alginate (0.03ï¼…).3. The fresh ice for prawn improved the appearance of prawn, especialfor the ratio of blackspots. The fresh ice group comparing with the blankgroup shows that Penaeus Vannamei turned blackspots delayed threedays, and the Solenocera Melantho's black spots appeared delayed fourdays.4. Fresh ice for prawn had beneficial effectiveness on inhibitinggrowth and propagation of bacteria, decreasing bacteria survival number, prolonging shelf life of prawn.5. K value seemed to be applicable as a freshness index for PenaeusVannamei. K value is gradually going up along with the increasingstorage time (R²=0.9945).6. The SO₂ residue content was low in both entire body of PenaeusVannamei and Solenocera Melantho, particularly, in flesh of prawn, up to30 mg/kg. So long as a bit more disposed, the prawn can be a goodproduct accorded to food safety and sanitation standard.