Saline as solvent and ethanol-based purification process for the extraction of proteins and isoflavones from wet okara.

Okara, the solid byproduct of water-soluble soybean extract production, is a potential source of proteins and isoflavones. This study investigated different experimental configurations for extracting these compounds from wet okara, including lipid removal with ethanol at different stages of the recovery process, sequential crosscurrent extraction, and using a saline MgCl2 solution as the solvent. Three washes with a 60:40 ethanol:water (w/w) solution after isoelectric precipitation significantly increased protein content by reducing lipid content (60 %). The crosscurrent approach using 0.05 M MgCl2 yielded okara proteinaceous material with 248 µg/g daidzein and 236 µg/g genistein, along with a 3 % increase in protein content, attributed to enhanced extraction of 7S globulins. These configurations notably affected the functional properties of the protein materials. Overall, this research provides detailed insights into the composition and properties of proteins extracted from wet okara, facilitating their specialized application in food products.

Valorization of the baru (Dipteryx alata Vog.) processing chain: Technological properties of defatted nut flour and oil solubility in ethanol and isopropanol.

Baru, a Brazilian Cerrado native fruit, stands out for its high nutritional value. Considering that reports about its technological potential are scant, this study aimed to add value to the processing chain. For that, ethanol and isopropanol were evaluated in terms of their suitability to solubilize baru nut oil (BNO), extract baru nut cake oil (BNCO), and obtain a protein-rich defatted flour. The BNO solubility in alcohols was adequately described by nonrandom two-liquid (NRTL) parameters, and the highest solubilization capacity was achieved with absolute isopropanol. Alcoholic extraction did not affect the BNCO tocopherol content (80-112 mg/kg oil) or its fatty acid composition. Both protein solubility and thermal stability were negatively affected by solvent hydration, temperature, and contact stages. However, the materials exhibited adequate water and oil absorption capacities (3.5 and 1 g/g sample), as well as improved foaming capacity and stability, confirming their potential for use in several food formulations.

Profile and content of isoflavones on flaked and extruded soybeans and okara submitted to different drying methods.

Isoflavones (IFs) are biocompounds found in considerable amounts in soybean grains. However, to originate soybean-based materials, the grains must be subjected to numerous thermal and mechanical treatments, which can impair the IFs content. The influence of these treatments was investigated and a protocol for IFs extraction and quantification is proposed. Sequential extractions were performed on industrially pretreated soybean samples (broken, flakes, and collets), on okara submitted to different drying methods (freeze-drying, forced convection, and under vacuum), and on soybean oils extracted with hexane and ethanol. ß-glucosides levels were decreased by the thermal processes of lamination, expansion, and drying, while the aglycone forms were not affected. Lyophilization was identified as the most viable drying method for the quantification of IFs in okara. Soybean oils extracted with ethanol presented significant amounts of aglycone. Furthermore, two stages of extraction were sufficient for the recovery of the IFs from different matrices.