【摘要】 本文以养殖的罗非鱼为对象,在-3℃±0.5℃空气微冻条件下,通过对鱼肉鲜度指标K值、细菌数及pH值的测定,探讨微冻鱼的质量的变化情况,并与冰藏鱼作比较。同时还对微冻鱼肌肉作组织切片,观察其冰结晶,并与-18℃冻结鱼及新鲜鱼作对照。实验结果表明,-3℃微冻法比冰藏法温度仅低3℃,但鱼肉鲜度指标K值上升缓慢,细菌繁殖受到抑制,大大延长了罗非鱼的保藏时间,贮藏期可达一个月左右。鱼肉pH值与鱼的鲜度之间无明确的相关关系。-3℃微冻鱼肌肉中的冰结晶是慢冻型的,对肌肉组织有损伤,但其冻结率比-18℃冻鱼低,未冻结部分的肌肉组织与新鲜鱼的肌肉组织相接近。更多还原

【Abstract】 Effect of partial freezing on keeping freshness of tilapia was investigated. Changes in K value, an index for estimating freshness, bacteria number and pH value were followed during storage at -3±0.5℃. The results were compared with that ice storaged. The cut sections of muscle tissue were observed under microscope and compared with fresh and the fish frozen at -18℃.The results obtained were summarized as follows:1. Though the temperature of partial freezing was only three degrees lower than ice storage, the preservation effect was shown much better. In the case of tilapia, storage period could be prolonged to one month.2. There was no definite intercorrelation between pH and freshness.3. The ice crystal formed in fish muscle storaged at -3±0.5℃ was the type of slow freezing, frozen water percentage was lower than that of storaged at -18℃ and muscle tissue of non-frozen part seemed no difference from fresh muscle.更多还原