Effects of Different Extraction Methods on Yield, Polyunsaturated Fatty Acids, Antioxidants, and Stability Improvement of Chia Seed Oil: A Review

Abstract

There has been an increasing trend in the use of chia seed oil (CSO) rich in polyunsaturated fatty acids (PUFA), mainly α-linolenic and linoleic acids, accompanied by antioxidants like tocopherols, phytosterols, carotenoids and polyphenols, which may benefit to human health. Various conventional (solvent and mechanical pressing) and alternative extractions (supercritical fluid extraction using carbon dioxide and ultrasound-assisted method) have been utilised to extract oil from chia seed based on selected conditions and types of solvent, which affect the oil yield and nutritional composition. Alternative extractions like ultrasound-assisted with solvent (time: 40 min, temperature: 50°C and solvent-to-seed ratio: 12 ml of ethyl acetate/g of chia seed) and supercritical fluid extraction (SFE) using carbon dioxide enriched with 10% acetone (time: 300 min, temperature: 70°C and pressure: 280 bar) can be applied to improve the amount of oil (up to 27.1% and 33.9% for ultrasound-assisted with solvent and SFE, respectively) and PUFA extracted from the chia seed. SFE is recommended as a highly desirable alternative to traditional methods (Soxhlet and pressing) for extracting tocopherol and phytosterol from CSO. Incorporating acetone with SFE could enhance the number of polyphenols and carotenoids in CSO compared to pure supercritical carbon dioxide. However, CSO is highly susceptible to oxidation due to its high concentration of PUFA (more than 80%). Recent research on the nutritional qualities of CSO has explored the impact of improvement techniques to prevent loss of nutritional quality. Therefore, natural antioxidants and blends of vegetable oils have been applied to improve CSO’s oxidative stability and shelf life.