【作者】 刘美华；

【导师】 陈丽娇；

【作者基本信息】 福建农林大学 ， 农产品加工及贮藏工程， 2004， 硕士

【摘要】 本文研究了大黄鱼在不同处理（-3℃涂膜盐水微冻、-3℃不涂膜盐水微冻、-6℃涂膜盐水微冻、-6℃不涂膜盐水微冻）条件下其品质的变化。通过对贮藏过程中感官指标、微生物指标、理化指标的变化和组织显微结构的比较分析，评价不同处理对大黄鱼鲜度的影响及各处理方法的可行性。实验结果表明： 一、微冻能很好地保持大黄鱼的各鲜度指标，保持较低的K值、细菌总数、T-VBN值，其贮藏期限可达30d以上；-3℃涂膜盐水微冻贮藏30d时细菌总数为1.07×10³个／g，T-VBN值为15.3mg／100g，均达国家二级标准。 二、大黄鱼涂膜（1％海藻酸钠+2％CaCl₂）后，采用浓度为12％、已降温至（-8±0.3）℃的低温盐水微冻，以不涂膜组作对照。研究发现：涂膜与微冻相结合处理的大黄鱼，其细菌总数、T-VBN值比不涂膜组同期值低，说明涂膜处理可以很好的抑制细菌的增长，维持大黄鱼较低的T-VBN值。 三、海藻酸钠涂膜剂对维持大黄鱼的外观有重要作用。经涂膜处理，-3℃涂膜盐水微冻贮藏的大黄鱼在贮藏27d时感官评分为一级标准，比不涂膜对照组推迟了6d。在贮藏30d时，涂膜大黄鱼仍能保持其独特的金黄色。 四、采用-3℃涂膜盐水微冻后，大黄鱼在贮藏30d时肌肉盐度为1.03％，比-3℃不涂膜对照组肌肉盐度降低了1.48％。涂膜盐水微冻能明显改善盐水微冻造成的鱼肉偏咸。 五、-3℃涂膜盐水微冻的大黄鱼在贮藏30d时，其肌肉持水力下降为85.22％，比不涂膜对照组提高了3％。涂膜可以提高低温盐水微冻大黄鱼的肌肉持水力。 六、大黄鱼盐水微冻过程中Ca²⁺-ATPase活性降低比较大，在一定 福建堆林大李硕士含位伦灰程度上影响其作为鱼糜制品原材料的加工适宜性。 七、大黄鱼微冻过程中体内冰晶形成较均匀，组织受损程度比冷冻 （一20℃）贮藏的明显减轻;大黄鱼在一3℃微冻与一6℃微冻相比，前者鱼肉组织的肌原纤维间隙小，两者均未出现纤维断裂情况。 八、四种处理中，细菌总数都呈先降后增的趋势;K值逐渐上升;Caz+一ATPase活性逐渐下降:pH值先降后升:T一vBN值逐渐上升。但同期数值有所不同。更多还原

【Abstract】 The quality changes of Large Yellow Croaker (PseucCosciaena crocea) during partial freezing by chilled salt water were studied in this paper. By analyzing and comparing the changes of sensory assessment, bacteria counts, physical-chemical indexes and tissue structure, the feasibility of Large Yellow Croaker storage by partial freezing was discussed. The results showed as follows:1. Partial freezing could restrain the growth of bacteria significantly, keep the T-VBN and K value at relatively low level. Total bacteria counts were 1.07X103CFU/g and T-VBN value was 15. 3mg/g after stored 30 days. The two indexes attained to the second grade of the national standard.2. Large Yellow Croaker was treated by freezing in 12% salt water at -8C after coating with 1% sodium alginate solution +2% Calcium Chloride solution, then storing at - 3C and -6C. Total bacteria counts and T-VBN value were lower than that of the contrast group, that indicate coating could restrain the growth of bacteria significantly, keep the T-VBN and K value at relatively low level.3. Coating with sodium alginate solution could keep the appearance of Large Yellow Croaker good and prolong the storage time. The appearance of Large Yellow Croaker on the 30th day kept original golden.4. After treated with salt water at low temperature, the salt content of Large Yellow Croaker stored at ~3C was 2.51% on the 30th day, but the salt content of coating Large Yellow Croaker was1. 03% on the 30th day. Coating could decrease the salt content of Large Yellow Croaker during salt water partial freezing.5. The water holding capacity of coating Large Yellow Croaker stored at -3C was 85. 22% on the 30th days which was 3% higher than that of the contrast group. Coating could strengthen the water holding capacity of Large Yellow Croaker during salt water partial freezing.6. Ca2+-ATPase activities of Large Yellow Crocker by salt water partial freezing decreased greatly.7. The changes of myofibrillar tissue of Large Yellow Croaker by partial freezing are lighter than freezing at -20C. Comparing Large Yellow Crocker storage at -3C with storage at -6C, the spaces among myofibrillar were smaller. Changes of myofibrillar tissue of Large Yellow Croaker by partial freezing were petty.8. Large Yellow Croaker stored by the four treating methods, its bacteria counts decreased fast during the first 15 days, then increased slowly. K value always fell down, T-VBN value increased slowly, Ca2+-ATPase activities dropped fast. But the data was different at the same period.更多还原