Characterization of the byproduct obtained from the ethanol soybean extraction

CARELLI, A.A.; OTERO, N.; CARRIN, M.E.; BAUMLER, E.R.

Córdoba

Congreso; VI Congreso Internacional de Ciencia y Tecnología de Alimentos; 2016

Ministerio de Ciencia y Tecnología de Córdoba-UNC

Nowadays, there is a trend in the oil industry toward the use of renewable solvents. It has been demonstrated that ethanol soybean oil extraction would produce a meal richer in proteins -as main product- than that obtained using hexane. Among the compounds extracted with the oil when ethanol is used, there are carbohydrates and phospholipids. It would be of great interest to recover both, since carbohydrates have been found to be prebiotic materials, and phospholipids, a source of nutraceutical compounds. The aim of this work was to characterize the byproduct recovered from the extracted material obtained from the ethanol soybean oil extraction. Soybean press-cake was subjected to ethanol extraction in a batch system at 60 ºC using a solid:ethanol ratio= 1:10 (w/v), considering different contact times (0-960 min). The miscella obtained, containing the total extracted material (oil and other compounds), was fractionated using hexane. The hexane-insoluble fraction containing the ?defatted extract? of interest was recovered by solvent evaporation. Its phospholipid content was analyzed according to AOCS standard norms, while its sugar composition (HPLC-IR) was determined by difference between the sugar content of the soybean press-cake before and after the ethanol extraction. Protein and fiber contents for the soybean press-cake and defatted meal were determined by standard analytical methods. The results indicated that the defatted extract consisted of sugars and phospholipids, with sugars being the major component (92.37±1.79% d.b. at 960 min). The amount of extracted sugars showed an upward trend over time, reaching 23% of total sugars present in the soybean press-cake at 960 min. At all the times considered, sucrose and stachyose were the predominant sugars (over 80%). As for phospholipids, phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine and phosphatidic acid were detected. Although the major phospholipid in the soybean oil was phosphatidylcholine, the highest percentage in the case of the defatted extract corresponded to phosphatidylinositol (66.67±8.51% at 960 min). Protein and fiber contents of the soybean press-cake were not affected by ethanol extraction. The results demonstrated the possibility of obtaining a byproduct rich in sugars from the ethanol extraction of soybean oil. In addition, the quality of the soybean meal improved, requiring a less intense post-treatment since it was more concentrated in protein than that obtained by the conventional process.