Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology,1 Shuefu Road, Neipu, Pingtung, Taiwan 91201; Department of Marine, Faculty of Fisheries and Marine, Universitas Airlangga, Campus C UNAIR, Mulyorejo, Surabaya 60115, Indonesia.
Chung Hwa University of Medical Technology, 89 Wenhua 1st, Rende, Tainan, Taiwan 71703; Pao-Can Biomedical Co., Ltd., 20 Shangding, Yongkang, Tainan, Taiwan 710.
Int J Biol Macromol. 2022 Jun 30;211:316-327. doi: 10.1016/j.ijbiomac.2022.05.076. Epub 2022 May 11.
Increasing trends in food safety awareness drive consumer demands for fresher healthier diets and has led to the development of low-cost pH-sensitive indicator films to evaluate deterioration levels in fresh foods. Arrowroot starch/iota-carrageenan-based films were combined with 10, 30, 50% Kyoho skin extract (KSE) to produce indicator films with halochromic abilities. The KSE indicator films were characterized based on their physico-mechanical, functional, and crystallinity properties; thermal stability; and their pH-dependent color changes in in situ anthocyanin-based monitoring of shrimp freshness. All KSE indicator films displayed compact structure under scanning electron microscope analysis and increased tensile strength, exhibited UV-vis barrier ability, and presented low water wettability. Moreover, FTIR signaled strong hydrogen bond interactions among polymers and KSE that strengthened peak crystallinity in XRD analysis and lowered weight loss at melting temperature, which indicated thermal stability of the indicator films. Furthermore, pH-sensitivity of the indicator films integrated with natural KSE anthocyanin demonstrated color changes from purple to red under acidic conditions, purple to green in an ammonium environment, and yellow appeared in high alkaline conditions. Finally, this study demonstrated the food packaging and halochromic capacity of biopolymer-based pH-sensitivity of the KSE indicator films in real-time monitoring of shrimp at room storage temperatures.
食品安全意识的提高推动了消费者对新鲜、健康饮食的需求，促使人们开发出低成本的 pH 敏感指示剂薄膜，以评估新鲜食品的变质程度。以蕉藕淀粉/角叉菜胶为基础的薄膜与 10%、30%、50%的巨峰果皮提取物（KSE）相结合，生产出具有变色能力的指示剂薄膜。根据 KSE 指示剂薄膜的物理力学性能、功能特性和结晶性能、热稳定性以及在原位基于花青素的虾类新鲜度监测中的 pH 依赖性颜色变化来对其进行表征。在扫描电子显微镜分析下，所有 KSE 指示剂薄膜均显示出紧密的结构，拉伸强度增加，具有 UV-vis 阻隔能力，且具有较低的水分润湿性。此外，FTIR 表明聚合物与 KSE 之间存在强氢键相互作用，这增强了 XRD 分析中峰结晶度，并降低了熔融温度下的重量损失，表明了指示剂薄膜的热稳定性。此外，与天然 KSE 花青素结合的指示剂薄膜的 pH 敏感性显示出在酸性条件下从紫色变为红色、在铵环境下从紫色变为绿色以及在高碱性条件下变为黄色的颜色变化。最后，本研究证明了 KSE 指示剂薄膜在室温储存条件下实时监测虾类时的生物聚合物基 pH 敏感性和变色能力的食品包装应用。
