Valorização do okará para obtenção de fibras dietéticas e seu uso em filmes comestíveis para embalagens alimentares

Abstract

In response to growing environmental concerns and the pursuit of sustainable innovations, this study explores the potential of agro-industrial waste as alternative raw materials for the production of edible films. In this context, the potential use of okara, a by-product of soybean processing, was investigated as a source of dietary fiber for enriching carboxymethylcellulose (CMC) edible films, aiming at waste reduction and the development of renewable packaging through casting techniques. The performance of CMC films enriched with okara fiber was compared with films containing conventional and emerging dietary fibers such as pectin, inulin, and β-glucan. Additionally, the inulin, β-glucan, and okara matrices were evaluated for their capacity to carry Lactobacillus Casei, with the aim of producing films with probiotic properties, which are known to promote numerous health benefits and extend the shelf life of foods. Okara fiber was extracted by acid hydrolysis at 121°C, resulting in a yield of 5.31% relative to the initial dry weight. The incorporation of Lactobacillus Casei into the matrices did not affect the properties of the films, except for the probiotic viability, which was 50% for inulin and βglucan, contrasting with 2% observed for okara fiber. X-ray diffraction (XRD) analysis of the produced films indicated a maximum crystallinity of 5% for all films produced, evidencing a predominantly amorphous structure. Scanning electron microscopy (SEM) confirmed the uniformity and absence of defects in the samples. The film enriched with okara fiber presented essential characteristics for food preservation: thickness, water vapor permeability, and thermal stability comparable to those of the other tested dietary fibers. The optical properties of this new material indicated the capability to block up to 70% of UV light, offering additional protection for light-sensitive items. Solubility tests revealed that okara and β-glucan films demonstrated higher solubility, while mechanical tests indicated that β-glucan films outperformed others in tensile strength, reaching a stress of 27.5 MPa. This work contributes to advances in the utilization of agro-industrial waste with potential applications in the food and packaging industries.