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.

Rapid Salt‐Assisted Microwave Demulsification of Oil‐Rich Emulsion Obtained by Aqueous Enzymatic Extraction of Peanut Seeds

“…In addition, the obtained by‐products, such as proteins, have good functional properties and do not contain toxic substances . In the past decades, AEE has been widely studied for soybeans, peanuts, sunflower seeds, rapeseed, walnut, moringa oleifera seed, and other edible oil crops.…”

Soy milk oleosome behaviour at the air–water interface

“…Moreover, disruption of oleosomes with proteases can improve the quantity and quality of the free oil. 11 Showing that a simple trypsin treatment is able to break open the otherwise extremely stable oil bodies is an important step in the direction of safer, more efficient and more environmentally friendly oil extraction. Secondly, oleosomes are attractive for genetic engineering and biotechnology, where they are used as plant expression systems for recombinant proteins or peptides, e.g., antibodies or vaccines.…”

(In)correct Use of Statistics

“…What else would you expect? Similarly, the fatty acid compositions of the oil extracted from oleosomes [3] under different conditions do not differ significantly from each other but a significant difference is reported between these oleosome oils and a commercial soybean oil purchased locally. So what.…”

“…Instead of presenting their measurements as means plus standard deviation in a table, some authors present them as a histogram where a bar at the top of the rectangles indicates the standard deviation. Figure 2 in [3] is a good example of this kind of presentation, since it also includes letters near the bars that indicate to what extent the values differ significantly from each other. Like in the tables above, the standard deviations at the top of these bars have not the same length so they represent the standard deviation of the replicate measurement rather than the standard error of the mean.…”