Quantity and Quality of Free Oil Recovered from Enzymatically Disrupted Soybean Oleosomes

Abstract The operational variables impacting the quantity and quality of free oil recovered from isolated soybean oleosomes by enzymatic extraction were evaluated to optimize this process. Those variables were: protease concentration (0–2.5%), protease hydrolysis time (3 vs. 18 h), and slurry destabilization time (30 min vs. 3 h). Analysis of interactions between these variables and the yield of free oil revealed that the protease concentration was the most significant variable. The quantity of free oil extracted by using 3 h of oleosomes hydrolysis and 30 min of slurry destabilization was not significantly different from that using 18 h of oleosomes hydrolysis and 3 h of slurry destabilization. The optimum conditions, 0.5% Protex 6L, 3 h of hydrolysis, and 30 min of destabilization, resulted in 90% free oil. Oils extracted by the aqueous process had a fatty acid composition similar to conventional hexane‐based process with oxidative stability indices ranging from 9 to 12 h. Enzyme assisted aqueous extraction resulted in a high quality oil which has 88% less free fatty acids than hexane‐extracted oil. The optimal conditions generated 85.5% soybean storage proteins in skim with peptides smaller than 6.5 kDa and the degree of hydrolysis of 19.5%. The present study demonstrates that oil can be extracted from soybeans efficiently without hexane or other petroleum solvents.