Herbaceous peony seed oil: A rich source of unsaturated fatty acids and γ‐tocopherol

Herbaceous peony ( Paeonia lactiflora Pall.) seed oil (HPSO) was extracted from seeds by ultrasonic‐assisted extraction (UAE). Changes in the oil yield, fatty acid (FA) composition, retinol and tocopherol (α‐, γ‐, and δ‐tocopherol) contents of HPSO at the different developmental stages and in tested cultivars were examined, and the microscopic structure of HPSO droplets was also observed. The results showed that the HPSO yield increased with the seed development and reached its maximum level at the mature stage with values from 29.04 to 34.98% for different cultivars. The unsaturated fatty acid (UFA) contents were between 88.36 to 94.58%. Among the UFAs, the contents of oleic acid (27.19–45.06%), linoleic acid (20.59–37.59%), and α‐linolenic acid (13.59–30.87%) were relatively high. The average γ‐tocopherol content was 337.47 ± 57.42 µg/g, accounting for approximately 92.97% of the total tocopherol content. Transmission electron microscopy (TEM) observations of the HPSO microscopic structures indicated that the quantity and size of the oil bodies increased with the development of endosperm cells in P. lactiflora . This report was the first to study the HPSO, and the results will provide theoretical guidance for the exploitation and utilization of P. lactiflora resources. The content of UFA (A) was more than 90% in HPSO, and the content of γ‐tocopherol was 353.67 ± 0.22 µg/g, accounting for about 93% of total tocopherols content (B).