Optimization of ultrasound-assisted hexane extraction of perilla oil using response surface methodology

- RSM was used to optimize UAE conditions of perilla oil.
- The optimum UAE conditions are 41.26 °C, 17.11 min, liquid-to-solid ratio 7.02:1, at 400 W.
- Linolenic, linoleic, and oleic acid were the main fatty acids in perilla seed oil.
- Perilla oil had high iodine and low acid and peroxide values.
- Perilla oil decomposition began at 320.2 °C, with two stages at 421.3 °C and 466.6 °C.

Response surface methodology (RSM) was used to optimize ultrasound-assisted extraction (UAE) conditions of perilla seed oil including extraction temperature, time, and liquid-to-solid ratio. The results revealed that extraction time had a significant effect on oil yield. Based on the RSM results, the optimum conditions included an extraction temperature of 41.26 °C, an extraction time of 17.11 min, and a liquid-to-solid ratio of 7.02:1. Under these conditions, the maximum oil yield was 36.27%. The physical and chemical characteristics of perilla oil were evaluated. Perilla had high iodine and low acid and peroxide values, indicating that the seed oil has the good qualities of an edible oil and can be stored for a long period of time without deterioration. The fatty acid profile of perilla oil included saturated (6.99%), monounsaturated (16.76%), and polyunsaturated fatty acids (76.25%). Linolenic (63.93%), linoleic (12.32%), and oleic acid (16.65%) were the main fatty acids in perilla seed oil. The thermal stability experiments revealed that perilla oil decomposition began at 320.2 °C, with two stages at 421.3 °C and 466.6 °C. Based on its physical and chemical properties, perilla oil should have applications in the cosmetic, pharmaceutical, and food industries.