[关键词]
[摘要]
本研究以紫薯淀粉/聚乙烯醇(PVA)复配作为成膜基质,并添加紫薯花青素提取物(PSPE)制备可用于牛奶新鲜度检测的智能复合包装膜。通过对复合膜机械、光谱和显色等方面性能的研究,研究表明PSPE的加入使复合膜的机械性能提高,浓度为24%时,复合膜的断裂伸长率最大,为87.73%,抗拉强度和厚度适中;复合膜的紫外-可见光谱(UV-Vis)与色素溶液的光谱变化规律一致,表明PSPE与成膜基质相容性好,生理活性高;傅里叶红外光谱(FT-IR)表明PSPE的羟基基团与成膜基质中的羟基基团形成分子间氢键相互作用,而化学组分未受影响。将复合膜应用于牛奶新鲜度检测,新鲜牛奶中复合膜呈现淡紫色,随着时间的推移牛奶逐渐变质,pH下降,复合膜颜色变红变浅。因此,PSPE复合膜可以实现牛奶腐败的智能指示,研究可为牛奶新鲜度智能指示膜的开发提供参考。
[Key word]
[Abstract]
The sweet potato starch/polyvinyl alcohol (PVA) combined with purple sweet potato anthocyanin extract (PSPE), was used as a film-forming substrate for the preparation of intelligent package films to analyze the freshness of milk, and the mechanical, spectral and color properties of composite films were studied. Results showed that the addition of PSPE improved the mechanical properties of composite films, and at the concentration of 24%, the composite films had a maximum elongation at breakof 87.73% with moderate tensile strength and thickness. The change of ultraviolet-visible spectrum (UV-Vis) of the composite films was consistent with that of the pigment solution, indicating that PSPE exhibited good compatibility with the film-forming substrateand the physiological activity was high. Fourier transform infrared spectroscopy (FT-IR) showed that the hydroxyl groups of PSPE interacted with the hydroxyl groups in film-forming substrate to form intermolecular hydrogen-bonding interactions without affecting the chemical components. In addition, an application test for analyzing the freshness of milk was conducted by using composite films.The results showed that the composite films presented a lilac color in fresh milk and then became reddish and lighter with time, which led to pH decreasing and milk deteriorating. Therefore, the PSPE composite films could realize the intelligent indication of milk spoilage, and the research could provide a reference for the development of intelligent indicator films for milk freshness.
[中图分类号]
[基金项目]
国家科技支撑项目(2015BAD17B04);国家自然科学基金项目(31671844);江苏省重点项目(BE2016306);苏州市科技计划(SNG201503);江苏省大学生创新训练计划重点项目(5551360009、5551360022)