Majdinasab Marjan, Hosseini Seyed Mohammad Hashem, Sepidname Marziyeh, Negahdarifar Manizheh, Li Peiwu
1Department of Food Science and Technology, College of Agriculture, Shiraz University, Shiraz, 71441-65186 Iran.
2Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, 430062 People's Republic of China.
J Food Sci Technol. 2018 May;55(5):1695-1704. doi: 10.1007/s13197-018-3082-5. Epub 2018 Mar 2.
Alginate is a non-toxic, renewable, and linear copolymer obtained from the brown algae that can be easily shaped into beads. Its good gel forming properties have made it useful for entrapping food and pharmaceutical ingredients. In this study, alginate beads were used in a novel application as a colorimetric sensor in food intelligent packaging. Colorimetric sensor was developed through entrapping red cabbage extract as a pH indicator in alginate beads. The pH indicator beads were used in rainbow trout packaging for monitoring fillets spoilage. Color change of beads during fish storage was measured using the CIELab method. The alginate bead colorimetric sensor is validated by measuring total volatile basic nitrogen (TVB-N) levels and microbial populations in fish samples. Moreover, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were evaluated during storage. Results indicated that increasing the bacterial population during storage and production of proteolytic enzymes resulted in protein degradation, accumulation of volatile amine compounds, increase in the pH and finally color change of alginate beads. The values of TVB-N, pH, PV and TBARS increased with time of storage. The results of TVB-N and microbial growth were in accordance with color change of beads and CIELab data. Therefore, the proposed system enjoys a high sensitivity to pH variations and is capable of monitoring the spoilage of fish or other protein-rich products through its wide range of color changes. The alginate beads containing the red cabbage extract can, thus, be used as a low-cost colorimetric sensor for intelligent packaging applications.
海藻酸盐是一种从褐藻中提取的无毒、可再生的线性共聚物，它可以很容易地制成珠子。其良好的凝胶形成特性使其可用于包裹食品和药物成分。在本研究中，海藻酸盐珠子被用于一种新颖的应用，即作为食品智能包装中的比色传感器。通过将红甘蓝提取物作为pH指示剂包裹在海藻酸盐珠子中来开发比色传感器。pH指示剂珠子用于虹鳟鱼包装中以监测鱼片的腐败情况。使用CIELab方法测量鱼储存期间珠子的颜色变化。通过测量鱼样品中的总挥发性碱性氮（TVB-N）水平和微生物数量来验证海藻酸盐珠子比色传感器。此外，在储存期间评估了过氧化值（PV）和硫代巴比妥酸反应性物质（TBARS）。结果表明，储存期间细菌数量的增加和蛋白水解酶的产生导致蛋白质降解、挥发性胺化合物的积累、pH值升高，最终导致海藻酸盐珠子颜色变化。TVB-N、pH、PV和TBARS的值随储存时间增加。TVB-N和微生物生长的结果与珠子的颜色变化和CIELab数据一致。因此，所提出的系统对pH变化具有高灵敏度，并且能够通过其广泛的颜色变化监测鱼或其他富含蛋白质产品的腐败情况。因此，含有红甘蓝提取物的海藻酸盐珠子可作为一种低成本的比色传感器用于智能包装应用。
