Biopolímeros sustentáveis a partir de opuntia cochenillifera: inovação tecnológica com potencial de impacto social e econômico em regiões semiáridas.

Abstract

The use of cacti in human nutrition is emerging as a promising approach for the development of functional foods. The technological exploration of cacti as additives and ingredients in the food industry not only enhances the value of native species from the Brazilian semiarid region, but also boosts the region's economic growth by encouraging cactus farming. This thesis investigated the physicochemical, biological and application properties of Opuntia cochenillifera mucilage, including its extraction, modification by fermentation and use in edible coatings. The mucilage was extracted from cladodes using water at room temperature and continuous stirring, without the use of aggressive solvents, showing cell viability greater than 70% at concentrations of 0.05 to 5000 μg/mL, according to MTT (3-[4,5-dimethylthiazol-2-yl] 2,5 diphenyltetrazolium) and SRB (sulforhodamine B) assays. Rheological studies showed non Newtonian rheological behavior with shear thinning and sensitivity to variations in temperature, pH and concentration. Despite biological safety, it revealed insufficient antioxidant potential against oxidative stress. Fermentation with Lactobacillus gasseri at 37 °C for 24 h promoted a reduction of monosaccharides such as galactose (-21.9%), arabinose (-20.5%) and glucose ( 0.8%). The fermented mucilage particles (MOCF) became denser, with a smaller average size (48.36 ± 48.57 µm) compared to the unfermented mucilage (57.77 ± 21.96 µm), greater solubility, thermal stability and emulsification capacity (60% in MOCF versus 40% in MOC). In practical application, the fermented mucilage was combined with starch to develop edible coatings, evaluated in minimally processed melons stored at 5 °C for 12 days. The films showed high water solubility (96.43%) and greater water vapor permeability (6.13 g/kPa.h.m²), while the coated fruits maintained firmness, less mass loss and greater retention of phenolic compounds and antioxidants, extending shelf life and preserving quality. The results highlight O. cochenillifera mucilage as a sustainable, safe and versatile biopolymer with promising applications in food, cosmetics and pharmaceuticals, contributing significantly to innovative and environmentally friendly solutions. Furthermore, these findings demonstrate that fermentation effectively modifies mucilage, expanding its use in diverse technological applications.