Efeito do bioprocessamento enzimático de pães sobre o metabolismo de seus compostos fenólicos em indivíduos eutróficos e com obesidade

Abstract

The bioavailability of phenolic compounds may be limited by their form in the food matrix and by the high interindividual variability in metabolism, influenced by various factors, among which the composition of the gut microbiota stands out, differing between eutrophic and obese individuals. Strategies such as hydrothermal treatments and enzymatic bioprocessing, applied either individually or in combination, have shown promise in releasing phenolic compounds from the insoluble fraction, thereby positively affecting their bioaccessibility and bioavailability. In this thesis, the production kinetics of the enzymes amylase, peptidase, xylanase, and feruloyl esterase through solid-state fermentation of agro-industrial co-products (cocoa bran, wheat bran, and brewer’s spent grain) were initially evaluated for potential application in the bioprocessing of whole grain bread. All fermented co-products exhibited activity of the target enzymes, with brewer’s spent grain and wheat bran standing out due to higher xylanase (547.9 ± 11.4 U/g) and feruloyl esterase (1732.2 ± 278 mU/g) activities within the first 48 hours of fermentation. The bioprocessing of breads with these fermented co-products led to increases of 159% and 198% in soluble ferulic acid content, respectively, demonstrating that enzyme production via solid-state fermentation is a sustainable and effective approach for valorizing agro-industrial by-products and enhancing the nutritional quality of breads. As an alternative to enzyme production through fermentation, the effects of autoclaving and enzymatic bioprocessing—applied individually or in combination—were also assessed. The commercial enzyme Pentopan® 500 BG, used industrially to improve bread volume and appearance, was employed; it exhibited xylanase (15.0 ± 0.6 U/mg) and feruloyl esterase (6.7 ± 1.5 mU/mg) activities. Additionally, different drying methods were tested to identify the most effective technique for releasing ferulic acid, aiming at developing a bread with higher potential for clinical study application. The combination of autoclaving and enzymatic bioprocessing, along with drying at 95 °C for 30 minutes, promoted an 11-fold increase in the content of soluble phenolic compounds in wheat bran. The application of this processed bran in bread formulation resulted in products with soluble ferulic acid content (9.02 mg/100 g) exceeding values reported in the literature. Finally, a randomized, blinded, crossover clinical study (n=9) was conducted, involving eutrophic (n=5) and obese (n=4) individuals, who consumed both a control bread (soluble ferulic acid dose = 2.16 ± 0.27 mg) and a bioprocessed bread (ferulic acid dose = 11.13 ± 0.37 mg). Bioprocessing increased the glycemic response in obese volunteers, did not alter urinary excretion of hippuric acid over 48 hours, but significantly 11 impacted ferulic acid excretion, increasing it 14-fold. Body mass index did not appear to influence the excretion profile of the metabolites analyzed, which may be attributed to the small sample size or to the lack of detection of colonic metabolites, typically excreted later and related to gut microbiota activity.