热处理对罗非鱼皮酸溶性胶原性质的影响

摘要

The effect of thermal treatment time on physicochemical properties and film-forming ability of acid-soluble collagen (ASC) from tilapia skin was investigated.No significant difference in UV absorption or molecular weight distribution of ASC was observed during thermal treatment.With increasing thermal treatment time,the specific viscosity of ASC was decreased,and the denaturation temperature and thermal transition temperature were decreased from 32.6 to 27.0 ℃ and from 38.15 to 29.19 ℃,respectively.When thermal treatment time was more than 10 min at 42 ℃,The results of turbidity experiments indicated that the ASC did not possess fibril-forming ability after 10 min treatment at 42 ℃.Furthermore,the fibril formation of natural collagen was also hindered by thermally denatured collagen.On the other hand,the tensile strength of collagen films was increased from 30.81 to 41.33 MPa,the elongation at breaks from 8.95％to 11.59％,and the transparency value from 2.42 to 3.33 with increasing thermal treatment time.Based on the results of scanning electron microscopy,it was found that the fibrous structure of collagen films was gradually converted to a wrinkle-like structure during thermal treatment.From the above results,it could be concluded that the fibril-forming ability of ASC from tilapia skins was decreased after thermal denaturation,while the film-forming ability was increased.%考察热处理时间对罗非鱼皮酸溶性胶原(acid-soluble collagen,ASC)理化性质和成膜能力的影响.结果发现,热处理时间对胶原的紫外吸收和分子质量分布没有明显影响;随着热处理时间的延长,ASC的比浓黏度发生下降,变性温度和热转变温度分别从32.6℃和38.15℃下降至27.0℃和29.19℃.浊度实验结果表明,当ASC在42℃条件下热处理超过10 min后,ASC不具备成纤维能力.而且,热变性的胶原还会阻碍天然胶原的纤维形成.另一方面,随着热处理时间的延长,胶原膜的抗拉伸强度从30.81 MPa增加至41.33 MPa,断裂延伸率从8.95％增加至11.59％,透明度值从2.42增加至3.33.根据扫描电子显微镜观察的结果,发现胶原膜的纤维状网络结构随着热处理逐渐转变成类似皱纹的纹理结构.以上研究结果表明,经过热变性后,罗非鱼皮ASC的成纤维能力下降,但成膜能力却出现上升.