Development and characterization of films based on okra polysaccharides and whey protein isolate

Due to the harmful effects of plastics on nature, consumers prefer natural products, hence causing an increase in the interest in edible films. In this study, the extraction of polysaccharides from fresh and dried okra was first investigated, followed by the preparation and characterization of edible films containing okra polysaccharides and whey protein isolate. Effects of temperature, extraction time, and solid-solvent ratio on extraction yield were investigated, and optimum conditions were determined using the response surface method. The optimum extraction parameters of polysaccharides from fresh okra (FOP) were achieved at an extraction time of 90min, solid-solvent ratio of 0.10, and temperature of 22.71 degrees C, while the optimum extraction of polysaccharides from dried okra (DOP) was at an extraction time of 90min, solid-solvent ratio of 0.02, and temperature of 20.98 degrees C. FOP's extraction yield was 15.1% +/- 0.948%, while DOP's was 12.6% +/- 0.0032%. The polysaccharide content of FOP and DOP was 67.635% +/- 1.203% and 69.077% +/- 0.026%, respectively. It was determined that the viscosity value of FOP was 0.1169 +/- 0.0223Pa.s, while DOP's was 0.0473 +/- 0.004Pa.s. Polysaccharides obtained at optimum extraction conditions were combined with whey protein isolate and glycerol as a plasticizer to form edible film blends. The physical, thermal, and mechanical properties and microstructure of films were determined to characterize prepared films. The addition of okra polysaccharides to the film formulations increased the film thickness, crystallinity degree, and roughness of the prepared films, as well as the barrier properties of the films against water vapor.