91C-12 |
Ultrasound-assisted extraction of oil from soybeans |
H. LI1, L. Pordesimo, and J. Weiss. (1) Colloidal and Interfacial Food Science Laboratory, University of Tennessee, 2605 River Drive, Knoxville, TN 37996 Various investigators have shown that application of ultrasound can be used to enhance extraction of phytochemicals from plant sources while reducing processing time and solvent consumption. Based on these studies we suggest that ultrasound could also be used to enhance extraction of lipids from plant seeds such as soybean. An improved oil yield could enhance profitability of soybean farmers and reduce processing costs. Objective: To determine the influence of ultrasound intensity and application time on yield and quality of hexane-extracted soybean oil. Ground soybeans, adjusted to 11% moisture content, were sieved (4mm screen) to ensure uniform sizes. 100g of soybean flakes were added to 150ml hexane. The mixture was sonicated at intensity levels ranging from 0.1-40W/cm2 for 0.5h, 1h and 2h while being kept at 25°C. A control group (no sonication) was run parallel for 0.5h, 1h, 2h, and 4h. Oil was recovered after distillation at 110±5°C from the miscella through vacuum assisted filtration and yield was determined. Oil quality was analyzed using GC analysis. As processing time increased from 0.5 to 4h, yield increased from 5.00g to 7.37g. Application of ultrasound at 40W/cm2 decreased processing time from 4h to 2h, that is the maximum yield (7.41g) was already obtained after 2h using ultrasound. Oil yields increased with increasing ultrasonic intensities from 5.00g to 6.04g to 6.40g at 0, 1.5 and 40W/cm2 respectively during the first 30 minutes of sonication. Increasing the process temperature during sonication from 25 to 50°C reduced the required time to reach maximum yield (7.4g) to 1.5h. GC analysis of sonicated and non-sonicated soybean oil treated at high ultrasonic intensities (40 Wcm2) did not show significant differences in fatty acid profiles. Ultrasound has the potential to significantly increase oil yields particularly in the early stages of the extraction process while retaining a high oil quality.
Session 91C, Food Engineering: Food process engineering
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