改良壳聚糖涂膜技术对草鱼肉抑菌保鲜效果的研究

壳聚糖溶液涂膜是一种新兴的保鲜技术,具有较好的保鲜效果和优越性,但尚存在成膜较慢、不易操作、膜层厚度难控制等缺点,因而改善涂膜液的组成和涂膜技术是涂膜保鲜的关键。本文研究了新的涂膜方式和添加易挥发的乙醇来改进壳聚糖涂膜液的成膜和抑菌效果。通过改变不同乙醇浓度、壳聚糖浓度和涂膜方式等条件,分析其对冷藏过程中草鱼肉的微生物菌落总数和TVB-N值的影响。结果表明,涂膜溶液中含有75%的乙醇时,不仅对冷藏草鱼肉的抑菌效果好,而且还具有减菌作用,使样品初始微生物菌落总数降低超过51%;壳聚糖浓度为1.0%时,涂膜液的成膜效果及对草鱼肉的抑菌效果均较好;此外,涂膜方式对其效果影响不明显,但喷雾涂膜处理相对方便、经济。因此,以含有75%乙醇的壳聚糖酸性涂膜保鲜剂喷雾涂膜是一种成膜和抑菌效果均好的改良型鱼肉保鲜技术。

An Improved Chitosan Coating Method for Bacteriostasis and Preservation of Grass Carp During Refrigerated Storage

Chitosan coating is a new preservation technology with good preservation effect and superiority, but has some disadvantages, such as slow speed of film forming, difficulty in the operating and controlling the film thickness. Thus, improving the composition of coating solution and the coating technology is important for its preservation effect. The improved preservative and antibacterial effects on refrigerated grass carp meat was investigated by using new coating method with adding volatile ethanol. By varying the concentrations of ethanol and chitosan in coating solution, as well as coating methods, the total bacteria colony and TVB-N of the fish during its cold storage were studied. The results showed that the coating solution containing 75% ethanol had better antimicrobial and bactericidal effects with a decrease of >51% in initial bacterial count of fresh fish meat. The best chitosan concentration was 1.0% comprehensively considering its film-forming ability and antibacterial effect. In addition, the coating methods showed little difference in affecting the preservation of Grass carp, while spray coating pattern was relatively convenient in operation and economical in coating solution. These findings demonstrated that spray coating using acidic chitosan solution containing 75% ethanol was an effectively new fish preservation technology.