College of Food Science and Engineering, Northwest A&F University, Yangling 712100, Shaanxi, China.
Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA.
Food Res Int. 2022 Nov;161:111832. doi: 10.1016/j.foodres.2022.111832. Epub 2022 Aug 28.
The use of petroleum-based food packaging materials is causing environmental damage and increasing greenhouse gas production. Consequently, there is a great interest in developing smart and sustainable alternative materials. In this study, an agricultural waste product (purple corncob extract, PCCE) was used as a raw material to prepare environmentally friendly pH-sensitive packaging materials. Natural pH-sensitive pigments (anthocyanins) and lignin-containing cellulose nanocrystals (LCNC) were extracted from the purple corncobs. A cationic biopolymer (chitosan) was used as a scaffolding material to assemble the film matrix. Composite film (LCNC-PCCE-chitosan) was produced using a simple solvent casting method. Fourier transform infrared spectroscopy and scanning electron microscopy analyses showed that the PCCE and LCNC were well dispersed within the chitosan matrix and they interacted with the matrix through hydrogen bonding and electrostatic interactions. The addition of LCNC improved the hydrophobicity and mechanical properties of the film and imparted antioxidant activity and UV-blocking properties. The presence of anthocyanins in the PCCE endowed the film with a sensitive and reversible pH response, which could be well used to monitor changes in the freshness of pork and shrimp products.
石油基食品包装材料的使用造成了环境破坏，并增加了温室气体的产生。因此，人们非常关注开发智能和可持续的替代材料。在本研究中，使用农业废弃物（紫色玉米芯提取物，PCCE）作为原料来制备环保的 pH 敏感包装材料。从紫色玉米芯中提取了天然 pH 敏感颜料（花青素）和含木质素的纤维素纳米晶体（LCNC）。阳离子生物聚合物（壳聚糖）用作组装膜基质的支架材料。通过简单的溶剂浇铸法制备了复合膜（LCNC-PCCE-壳聚糖）。傅里叶变换红外光谱和扫描电子显微镜分析表明，PCCE 和 LCNC 很好地分散在壳聚糖基质中，并通过氢键和静电相互作用与基质相互作用。LCNC 的添加提高了薄膜的疏水性和机械性能，并赋予了抗氧化活性和紫外线阻挡性能。PCCE 中的花青素使薄膜具有敏感且可重复的 pH 响应，可用于监测猪肉和虾类产品新鲜度的变化。
