FREEZE-DRYING TECHNOLOGY ENHANCES NITRITE AND ANTIOXIDANTS IN BIOTRANSFORMED PLANT EXTRACTS

The search for natural alternatives has driven the use of vegetables as sources of bioactive compounds with antioxidant and preservative properties. Beets (Beta vulgaris) and arugula (Eruca sativa) stand out for their pigments, natural and phenolic nitrates. Microbial fermentation favors the release of bioactive metabolites and can promote the biotransformation of nitrate into nitrite, expanding its technological potential. In turn, freeze-drying, with the addition of maltodextrin, contributes to the preservation and stability of these compounds. This study investigated how freeze-drying affects the concentration of nitrite and bioactive compounds in fermented beet and arugula extracts. The vegetables were crushed (1:1 m/v) for 5 minutes, filtered, pasteurized at 80 °C/15 min and inoculated with 0.025% of the Lyocarni SBM-11 crop (Staphylococcus xylosus, S. carnosus and Lactobacillus sakei), being incubated in a shaker (40 °C, 150 rpm, 24 h). The extracts were lyophilized with 10% maltodextrin as a carrier agent. The liquid (ER and EB) and powder (PR and PB) samples were analyzed for color (CIELAB), nitrite content, total phenolics by the Folin-Ciocalteu method and antioxidant activity (DPPH, ABTS and FRAP). The variables were submitted to statistical analysis with comparison of means using Tukey's test (p < 0.05). The lyophilized treatments showed higher luminosity in relation to the liquid extracts, indicating greater visual clarity. The arugula powder (RP) exhibited a more intense green hue (a = 9.00), while the beet powder (CP) exhibited closer to reddish hues (a = -2.06)