Characterization of Anthocyanin Associated Purple Sweet Potato Starch and Peel-Based pH Indicator Films

Abstract

In food packaging, smart indicator films based on natural resources have greatly attracted researchers to minimize the environmental issues as well as to satisfy consumer preferences for food safety. In this research, pH-sensitive films were prepared using purple-fleshed sweet potato starch (SPS) and sweet potato peel (SPP). Two categories of the film (i) SPS and (ii) SPS/SPP, were fabricated via solvent casting technique, incorporating different concentrations of commercial purple sweet potato anthocyanin (CA) at 0%, 1%, 1.5%, and 2% (w/v) and the physicochemical, mechanical, thermal, and morphological properties of the films were investigated. The thickness, water solubility, and swelling degree of the films increased with the increment of CA, whereas there were no significant changes in the water content (WC) of the films. Water vapor permeability (WVP) was decreased for SPS films while statistically similar for SPS/SPP films. The addition of CA reduced the tensile strength (TS) and tensile modulus (TM) yet increased the elongation at break (EaB) of the films as compared to films without CA. The FTIR results confirmed the immobilization of anthocyanin into the film. In SEM images, roughness in the surfaces of the CA-associated films was observed. A reduction of thermal stability was found for the films with anthocyanin except for the SPS/SPP CA 2% film. Furthermore, the CA-associated films showed a remarkable color response when subjected to pH buffers (pH 1 to 12) and successfully monitored chicken freshness. The fastest color migration was observed in acidic conditions when the films were immersed into aqueous, acidic, low fat, and fatty food simulants. The findings of this work demonstrated that the developed pH indicator films have the potential to be implemented as smart packaging to monitor food freshness and quality for safe consumption.

Robust Electrospinning-Constructed Cellulose Acetate@Anthocyanin Ultrafine Fibers: Synthesis, Characterization, and Controlled Release Properties

“…As shown in Figure 4 , the swelling degree of the CA UFs was ~553%, and that of the CA@Anthocyanin UFs displayed a higher swelling degree of ~574%. This result was in agreement with the previously reported works [ 35 , 36 ], where anthocyanin has the excellent hydrophilic nature.…”

The Structuring of Sage (Salvia officinalis L.) Extract-Incorporating Edible Zein-Based Materials with Antioxidant and Antibacterial Functionality by Solvent Casting versus Electrospinning

“…essential oil as active compounds [54]. Compared to the films based on some of the frequently used biopolymers, the materials developed in our study were less soluble and more swollen than chitosan film incorporating rosemary extract (28% solubility and a 170% swelling degree) [55] and starch film incorporating purple sweet potato anthocyanin (60% solubility and a 148% swelling degree) [56].…”

Smart Biopolymer-Based Nanocomposite Materials Containing pH-Sensing Colorimetric Indicators for Food Freshness Monitoring

“…Ultraviolet and visible light can negatively impact the quality of foods containing photosensitive ingredients, such as many natural pigments and nutrients. Therefore, the ability of packaging materials to prevent light from passing through them and reaching the food is often important [ 17 ]. For this reason, we measured the ability of the anthocyanin-loaded biopolymer films to block the penetration of light waves ( Figure 1 ).…”