Preparation of sugarcane bagasse nanocellulose hydrogel as a colourimetric freshness indicator for intelligent food packaging
PengLua,b, Yang Yanga, RenLiua, Xin Liua, Jinxia Mab, MinWua, Shuangfei Wanga
College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning 530004, China
A sugarcane bagasse nanocellulose-based hydrogel was developed as a colourimetric freshness indicator for monitoring spoilage of chicken breast. Nanocellulose was prepared from sugarcane bagasse cellulose filaments by TEMPO-mediated oxidation, and then used to form a strong self-standing hydrogel matrix through Zn2+ cross-linking. The hydrogel worked as a carrier for pH-responsive dyes (bromothymol blue/methyl red), which changed colour according to the freshness of the chicken sample. CO2 levels were found to increase with the spoilage of chicken, relative to rising levels of micro-organisms. The indicator hydrogel optical colour changed from green to red on the third day, as the log CFU/g passed the limit of acceptability for human consumption and emission of complicated volatiles. This new design of colourimetric freshness indicator made with a nanocellulose hydrogel has a quick response to chicken spoilage and is expected to facilitate the utilisation of bagasse nanocellulose as a value-added material in intelligent packaging.
Keywords: Nanocellulose hydrogel, Freshness indicator, Intelligent packaging, Chicken spoilage