Influence of different extraction methods on the chemical composition, antioxidant activity, and overall quality attributes of oils from peony seeds (Paeonia suffruticosa Andr.)

Peony (Paeonia suffruticosa Andr.) seed oil is full of nutrition and exerts positive effects on human's health. The study detected and compared the quality, lipid characteristics, and antioxidant activities of peony seed kernel and shell oil using three extraction techniques (cold pressing, supercritical fluid extraction, and ultrasonic-assisted solvent extraction). Results indicated that the peony seed oil was rich in alpha-linolenic acid (43.19-44.24%) and gamma-tocopherol (403.31-535.15 mg/kg). The extraction methods and shells significantly affected the beneficial phytochemicals (polyphenols, phytosterols, and tocopherols) and antioxidant activities (p < 0.05). Meanwhile, the highest lipid yield was obtained using ultrasonic-assisted solvent extraction (30.60%), while pressing showed the lowest value (17.12%). Supercritical fluid extraction had higher tocopherol (492.68-576.40 mg/kg) and phytosterol (3421.18-4006.23 mg/kg) than other methods. Additionally, ten individual polyphenols were quantified, with the number of catechin being higher. Although the pressing led to a lower lipid yield, its extracts presented a significant higher polyphenol content. In general, peony seed shell oils had a significant advantage in obtaining polyphenols, while seed kernel oil showed higher sterol and tocopherol content. The above information is valuable for manufacturers to select suitable approaches to produce peony seed oil with the required quality attributes and chemical compositions for targeted end-use.