Characterisation and Colour Response of Smart Sago Starch-Based Packaging Films Incorporated with Brassica oleracea Anthocyanin

Abstract

To meet the need for food products to be safe and fresh, smart food packaging that can monitor and give information about the quality of packaged food has been developed. In this study, pH-sensitive films with sago starch and various anthocyanin concentrations of Brassica oleracea also known as red cabbage anthocyanin (RCA) at 8, 10, 12, and 14% (w/v) were manufactured using the solvent casting process. Investigation of the physicochemical, mechanical, thermal, and morphological characteristics of the films was performed and analysed. The response of these materials against pH changes was evaluated with buffers of different pH. When the films were exposed to a series of pH buffers (pH 3, 5, 9, 11, and 13), the RCA-associated films displayed a spectacular colour response. In addition, the ability of the starch matrix to overcome the leaching and release of anthocyanins was investigated. Higher concentrations of RCA can maintain the colour difference of films after being immersed in a series of buffer solutions ranging from acidic to basic conditions. Other than that, incorporating RCA extracts into the starch formulation increased the thickness whereas the water content, swelling degree, tensile strength, and elongation at break decreased as compared to films without RCA. The immobilisation of anthocyanin into the film was confirmed by the FTIR measurements. The surface patterns of films were heterogeneous and irregular due to the presence of RCA extract aggregates, which increased as the extract concentration enhanced. However, this would not affect the properties of films. An increase in thermal stability was noted for the anthocyanin-containing films at the final stage of degradation in TGA analysis. It is concluded that RCA and sago starch formulation has great potential to be explored for food packaging purposes.

A Review on Reinforcements and Additives in Starch-Based Composites for Food Packaging

“…In this regard, food packaging containing an indicator film can detect changes in the quality or freshness of the product, and respond by providing a visual warning to consumers. Briefly summarized, food spoilage can be tracked by alterations in pH as a reaction to the growth and metabolism of microorganisms or the development of organic acids and/or volatile amines (e.g., lactic acid formation in milk or ammonia/amino-sugar formation in meat) [320]. Commonly used synthetic indicators, such as bromothymol blue, methyl red and xylenol dyes, are known to be toxic and cancerogenic to human health [321].…”

Utilising N‐glutaryl chitosan‐based film with butterfly pea flower anthocyanin as a freshness indicator of chicken breast

“…[19][20][21][22] Starch, Ch, bacterial cellulose and chitin whiskers have been used in previous studies as materials used in freshness indicators. 2,14,15,23,24 Ch is a polysaccharide with properties used in many research as film material. 9,23,25,26 Yan et al have previously reported research on Ch film and BPA to monitor fish freshness.…”

“…Natural biopolymer materials are widely used as the matrix in indicator film because of their biocompatibility, non‐toxic and biodegradable properties 19–22 . Starch, Ch, bacterial cellulose and chitin whiskers have been used in previous studies as materials used in freshness indicators 2,14,15,23,24 . Ch is a polysaccharide with properties used in many research as film material 9,23,25,26 .…”

The Characterization of Biodegradable Films and Food Packaging

“…Another important contribution was made by Amariei et al [11], who evaluated the possibility of replacing polyethylene-based packaging for foodstuffs with a biodegradable alternative prepared via a mixture of alginate and agar, to which either ascorbic acid or calcium chloride was added. Furthermore, Che Hamzah et al (2022) [12] extracted anthocyanins from Brassica oleracea and used them in the preparation of pH-sensitive sago starch films. According to their results, the films exhibited a noticeable color response at different pHs.…”