LIPID NANOENCAPSULATION OF BIOACTIVE COMPOUNDS FROM FERMENTED BREWERS SPENT GRAIN EXTRACTED BY NON-CONVENTIONAL TECHNIQUES

Brewers Spent Grain (BSG) is a lignocellulosic byproduct that is a source of bioactive compounds, present mainly as bound phenolics. There is evidence of the valorization of BSG with solid state fermentation (SSF). Extractions based on pressurized fluids (PF) and microwave-assisted (MW) employ alternative methodologies recovering compounds. Lipid nanoparticles have high potential for application as compound delivery systems. The objective was to extract bioactive compounds from fermented (BSG-F) and non-fermented (BSG-N) BSG with non-conventional and nanoencapsulation techniques. SSF was conducted with Aspergillus oryzae. PF and MW were performed at temperatures between 50-150ᵒC. The extracts were rotary evaporated and quantified. Antioxidant capacity (AC) was evaluated by DPPH. The extracts were encapsulated with carnauba or beeswax using two techniques: simple emulsion and double emulsion. Encapsulation efficiency was determined with reducing capacity by Folin-Ciocalteu. PF achieved greater efficiency in extraction yield. The increase in temperature had a positive influence, especially PF with higher yield at 150ᵒC. High temperatures enhance the solvent as viscosity and surface tension decrease with higher temperatures, increasing transport to the matrix and accelerating extraction. Fermentation was responsible for a 3.4% higher extraction result in the last two PF points. The results presented surpass results published with conventional techniques (20x). The highest encapsulation efficiency, 40%, was obtained with BSG-N PF extract in a lipid mixture composed of 90% carnauba wax and 10% Crodamol, dispersed in an aqueous phase containing Tween-80, using the simple emulsion technique. It is concluded that non-conventional techniques with high temperature have shown promise. It is worth noting that in miniemulsions containing nanoparticles, the bioactive properties of the 60% of the unencapsulated extract may still be available, with the encapsulated 40% being responsible for the controlled release. Furthermore, the biotransformations of the fungus differentiate the profiles of the samples, which are future perspectives.