基于紫薯花青素/茜素的猪肉新鲜度智能指示膜研究

Development of intelligent indicator films based on purple sweet potatoanthocyanin/alizarin for monitoring pork freshness

环境因素和微生物污染引起的食品腐败变质,不仅威胁公众健康,还造成食品资源浪费。将天然色素用于制备颜色指示型智能包装,可以监测食品品质变化。该文以羧甲基纤维素和马铃薯淀粉为成膜基材,添加紫薯花青素、茜素及其混合物制备智能指示膜,比较分析了膜的物理性能、机械性能、微观结构、颜色稳定性和pH响应性。结果表明,随着紫薯花青素和/或茜素的添加,羧甲基纤维素/马铃薯淀粉膜的厚度增加、水分含量降低、透光性下降、拉伸强度增加而断裂伸长率降低。扫描电子显微镜结果表明色素的加入使基膜的微观结构更加致密。将负载紫薯花青素和/或茜素的指示膜用于猪肉新鲜度监测,结果表明,在4℃贮藏环境下,随着时间延长,猪肉的pH值和挥发性盐基氮含量不断上升,6 d后均超过可接受限值,表明猪肉开始腐败,指示膜呈现肉眼可见的颜色变化。该研究为肉品新鲜度智能指示膜的开发提供了参考。

Food spoilage caused by environmental factors and microbial pollution not only threatens public health but also causes waste of food resources.Natural pigments were applied to prepare color indicator intelligent packaging,which can monitor the changes in food quality.In this work,intelligent indicator films were prepared by using carboxymethyl cellulose(CMC)and potato starch(S)as the solid substrate,and purple sweet potato anthocyanin(PA)and/or alizarin(Alz)as the freshness indicator.The physical properties,mechanical properties,microstructure,color stability,and color responses to pH of the indicator films were characterized and compared.The addition of PA and/or Alz into the CMC/S film resulted in an increase in thickness and tensile strength but a decrease in moisture content,light transmittance,and elongation at break.Scanning electron microscopic examination showed that the presence of PA and/or Alz made the microstructure of the substrate membrane denser.Finally,the films were used to indicate the freshness of pork stored at 4℃.The total volatile basic nitrogen(TVB-N)content and pH value of pork samples increased over time.In particular,after 6 days,the TVB-N and pH values all exceeded the acceptable limit,indicating the occurrence of pork spoilage.Meanwhile,the prepared indicator films showed a visually variable color change.Results showed that the developed colorimetric indicator film could provide a convenient,non-destructive,and visual method to estimate pork freshness during storage.Overall,these results can help develop intelligent indicator films for monitoring meat freshness.