Abstract
This study focuses on the development and characterization of a novel biodegradable edible film made from soy protein isolate enriched with alginate-glycyrrhizin nanogel(GL-ALG NGP). Nanoparticles of particle sizes below 100 nm were synthesized using glycyrrhizin(GL), calcium chloride and, sodium alginate(SA) through the reverse micro-emulsion/internal gelation method. Soy protein isolate (SPI) based films were prepared by a simple casting procedure by incorporating GL-ALG NGPs in SPI solution in different ratios of (SPI: GL-ALG NGPs) 5:0, 5:1, 2:1, 1:1, and 1:1.5. Glycerol was used as a plasticizer in the film-forming solution. The effects of the proportions of GL-ALG NGPs addition on the thickness, mechanical properties, water vapor permeability, UV barrier performance, antioxidant activity, and antimicrobial property of the obtained films were studied. The GL-ALG NGPs were analyzed using Dynamic Light Scattering. Microstructural studies of obtained films were performed using Scanning Electron microscopy. Results show incorporation of GL-ALG NGPs in soy protein-alginate complex produced smoother, compact, and more continuous matrices as compared to pure SPI films. The test results indicated that blending of SPI with GL-ALG NGPs in the ratio 1:1 increased tensile strength of obtained films by 185%, reduced water solubility to 23.59%, and water vapor permeability to 0.3087 g-mm/m2-d-kPa. Obtained films exhibited good UV barrier performance, antioxidant activity and inhibited the growth of E. coli, S. aureus, Enterobacter sakazakii, and A. niger. So, soy protein isolate-based films enriched with GL-ALG NGPs are active biodegradable edible films that can be used to extend the shelf life of food products.
Emulsifying properties and antioxidant activity of soy protein isolate conjugated with tea polyphenol extracts
