OPTIMIZED SUPERHEATED HEXANE EXTRACTION OF GRAPESEED OIL

Abstract

ABSTRACT Superheated hexane extraction (SHHE), Soxhlet extraction and cold pressing technique were compared for the extraction of oil from grapeseed in terms of their efficiency and fatty acids profile. The SHHE efficiencies, affected by four factors and three levels including temperature (80, 100 and 120C), mean particle size (0.25, 0.50 and 1.00 mm), solvent flow rate (0.5, 1.0 and 2.0 mL/min) and extraction pressure (10, 20 and 30 bar), were optimized using Taguchi design approach. The optimum conditions as obtained from signal‐to‐noise ratio analysis were 100C temperature, 0.25 mm mean particle size, 1.0 mL/min flow rate and 30 bar pressure. The SHHE showed a higher extraction efficiency (23.13 w%) than Soxhlet extraction (13.40 w%) and cold pressing (5.29 w%) and resulted in a much shorter extraction time. The obtained fatty acid profiles using the three extraction methods were nearly the same. PRACTICAL APPLICATIONSSuperheated solvents such as water have been utilized in several applications such as analytical procedures, soil remediation, extraction of flavors, fragrances and antioxidants from natural resources, hydrolysis of carbohydrates, and have been used as a reaction medium, among others. In addition, superheated hexane may be used for extraction of edible oils from oil bearing materials such as grape and pomegranate seeds. Thus, it may provide an alternative and a more efficient solvent extraction process in food and beverage production.