草鱼冰藏期间新鲜度及热加工性质的变化

Changes in Freshness and Thermal Processing Properties of Grass Carp(Ctenopharyngodon idellus) Fillet during Ice Storage

以草鱼(冰藏0、1、3、7 d)作为研究对象,探讨冰藏期间鱼肉新鲜度如pH值、挥发性盐基氮(total volatile base nitrogen,TVB-N)值、可溶性肌浆蛋白(soluble sarcoplasmic proteins,SSP)值、可溶性肌纤维蛋白(soluble myofibrillar proteins,SMP)值和色泽(L*、a*、b*)的变化规律,以及在巴氏杀菌条件下(80、90℃,10 min)蒸煮损失率、收缩面积比及色泽的变化。结果表明:草鱼冰藏过程中,TVB-N值由11.8 mg/100 g增加至16.87 mg/100 g,略低于淡水鱼上限值20 mg/100 g;pH值在前3 d由6.72降低到6.52,之后上升至6.56;SSP值无明显变化,SMP值在前3 d逐渐增加,之后轻微下降;鱼肉色泽变化值(ΔE)逐渐升高,表明鱼肉在冰藏7 d期间新鲜度逐渐下降。在热加工过程中,鱼肉逐渐变成白色,蒸煮损失率、收缩面积比和ΔE值随鱼肉冰藏时间的延长而缓慢下降。

The objective of this study was to use grass carp fillets（stored in ice for 0, 1, 3 or 7 days） to investigate the changes in freshness indicators including pH, total volatile base nitrogen（TVB-N）, soluble sarcoplasmic proteins（SSP）, soluble myofibrillar proteins（SMP） and color（L＊, a＊, b＊） as well as in cooking loss, area shrinkage and color of fish fillets following pasteurization treatment（80 or 90 ℃ for 10 min）. The results showed that TVB-N value continuously increased from 11.8 to 16.87 mg/100 g over the storage period, slightly lower than the maximum limit of 20 mg/100 g for freshwater fish, while pH of fish fillets decreased from 6.72 to 6.52 during the first 3 days, and then slowly increased to 6.56. While SSP value did not changed obviously, SMP value increased in the first 3 days and then slightly decreased. The color difference value（ΔE） of fish fillets gradually increased with storage time. The above observations implicated a decrease of freshness during 7 days of ice storage. During thermal processing, the fish fillets gradually turned white. The cooking loss, area shrinkage and ΔE value slowly decreased with the extension of storage time.