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Protein concentrates from rice bran (DRBC – Defatted rice bran, EDRBC – Deffated rice bran extruded and hydrolyzed, HDRBC – Deffated rice bran hydrolyzed DRB and EHDRBC – Deffated rice bran extruded and hydrolyzed) exhibit not only good content of protein and promising nutritional properties but also appropriate profiles of amino acids to meet daily intake requirements of histidine, lysine, leucine, threonine and valine, in agreement with recommendations issued by the FAO. The average of protein concentrates had a Dig (digestibility) 51% and PDI (Protein Dispersibility Index) 97%. Extrusion resulted in protein concentrate whose content of protein (73%), Dig (65.6%) and recovery (72%) were higher than other pretreatments and had the highest sum of essential amino acids (28.7 g aa .100 g-1protein). The combination of pretreatments – extrusion and the enzymatic one (EHDRBC) – led to 70% protein, 72% recovery, 67% Dig and low prolamin (30%) in the protein fraction. These concentrates have amino acid profiles similar to commercial whey protein and are good ingredients that may be added to formulations to increase soluble and digestible protein.

This study aimed to (i) assess the influence of moisture and particle size on the release of phenolic compounds from brewer's spent grain by Rhizopus oryzaefermentation, (ii) determine the release kinetics of these compounds, and (iii) characterize brewer's spent grain before (BSG) and after (BSGF) fermentation. BSG and BSGF were evaluated for chemical composition, phenolic profile, and antioxidant and technological properties. The release of methanol-soluble phenolic compounds (MSPC) was influenced by both moisture and particle size, with the highest value (300.25 mg 100 g−1) obtained at 71% moisture and a 50:50 mixture of particles measuring 0.50 and 0.30 mm. This maximum MSPC content was obtained after 48 h of fermentation, being 761% higher than that contained in BSG. Catechin was the major component of the MSPC fraction (37.08 mg 100g-1), whereas ferulic acid (36.38 mg 100g-1) was the predominant component of the bound phenolic fraction. BSGF showed higher ash (8%) and protein (17%) content, but lower soluble dietary fiber (10%) and lipid content (67%) than BSG. Fermentation altered the protein fractions of the residue, increasing the proportion of albumin and globulin and decreasing that of prolamin and glutelin. These changes resulted in improved technological properties (oil absorption, water solubility, and swelling volume) and antioxidant activity. It is concluded that the proposed fermentation method can contribute to expanding the utilization of BSG, thereby diversifying its applications, and adding value to the production chain.

This study aimed to investigate the capacity a cellulolytic complex produced by Rhizopus oryzaehas to provide functional compounds from lignocellulosic material. Its characterization upon soybean meal (SBM) and corn husk (CH) was carried out. The effect was estimated in terms of cellulose reduction and protein and starch digestibility, besides the content of phenolic compounds (PC) and their profiles. Enzymatic hydrolysis caused 34% cellulose reduction in SBM whereas, in CH, it was 55%. In CH, the reduction promoted PC release (21%). The greatest change in the antioxidant activity after hydrolysis was found in phenolic compounds soluble in methanol (PCSM), a fact that could be attributed to concomitant reduction in ferulic acid and increase in hydroxybenzoic acid. In SBM, the activity of the cellulolytic complex caused increases in protein (74%) and starch (95%) digestibility. Therefore, available protein in SBM can be used as food supplement and thickener whereas PC derived from CH may be applied as food additive.