| Herbaceous peony (Paeonia lactiflora Pall.), a perennial herbaceous plants belonging to the paeoniaceae family. In China, P. lactiflora is a traditional famous flower with a long history of more than 4000 years. So far, the research and application of P. lactiflora was mainly focused on the ornamental value of flower and the medicinal value. However, the research and development on P. lactiflora seed (HPS) rarely involved. In the process of ornamental and medicinal cultivation, a large number of HPS was produced in the meantime every year. Since most of the by-product was not brought into rational utilization except that a small amount was used for propagation, resulting in a huge waste of resources. At present, research on P. lactiflora seed oil (HPSO) was still at the initial research period. This study was to ’Hang Shao’ and other 17 cultivars (or strains) HPS as test materials, explored the optimization methods of HPSO extracting conditions, determined the main physical and chemical properties of HPSO, analyzed the difference of HPSO fatty acid and tocopherol in different varieties and different developmental stages, and observed the microscopic structure of HPS droplets in different developmental stages. The results of this paper are as follows:1 To extract HPSO, optimizing the ultrasonic assisted extraction method by L9(34) orthogonal experiment. The results show that the impact factors of oil yield were:solid-liquid ratio> time> temperature. The optimum conditions were solid-liquid ratio (1:13g/mL)+time (1.5h)+temperature (70℃).2’Hang Shao’ seed oil (ultrasonic assisted extraction method) has a relative density of 0.9124±0.0049 g/cm3, an acid value of (1.52±0.19) mg NaOH/g, a saponification value of (176.30±5.47) mg NaOH/g, an iodine value of (122.29±7.71) g/100g, a peroxide value of 0 meq/kg.3 Average oil content of 17 cultivars (or strains) HPS were 32.44%±1.57%, which ranged from 29.05%-34.98%, and the highest and lowest cultivars were ST11 and ST10, respectively. In the 15 kinds of fatty acids, linoleic acid (20.59±0.80-37.58%±.53%), a-linolenic acid (13.59±1.66-30.87%±3.06%) and oleic acid (27.19±6.48-45.06±0.19%) have significant difference (P＜0.05). The average content of unsaturated fatty acids (UFA) was 91.41%±1.61%, and the highest and the lowest cultivars are ’hongmanao’ and ST5 respectively. The average content of y-tocopherol was (337.47±57.42) μg/g, accounting for 92.97% of total tocopherols. The average content of retinol was very low, only (1.19±3.42) μg/g.4 During the ’Hang Shao’ seed development, saturated fatty acids (SFA) content was decreased, the mature period content reached the lowest value (8,45%±2.39%); monounsaturated fatty acids (MUFA) content was increased, the mature period content reached the highest value (40.07%±4.31%); polyunsaturated fatty acids (PUFA) content was decreased, the mature period content reached the lowest value (51,48%±1.15%). Palmitic acid content was always low and appeared a downward trend, the mature period content reached the lowest value (5.42%±1.16%); α-linolenic acid content decreased continuously, the mature period content reached the lowest value (20.20%±0.69%); linoleic acid content showed little change, the mature period content reached 31.20%±0.42%; oleic acid content increased continuously, the mature period content reached the highest value (38.56%±5.14%). In HPSO, retinol content was drastically reduced and almost disappeared in S4. γ-tocopherol content was always high, the mature period content reached (353.67±0.22) μg/g; α-tocopherol content reached its highest level (24.39μg/g±1.15μg/g)in S2; δ-tocopherol content decreased continuously, the mature period content reached the lowest value (10.42 μg/g±0.28μg/g).5 Transmission electron microscopic (TEM) observations indicate that the cell walls were thickened gradually during the HPS development, and the quantity and size of oil bodies were basically increasing in P. lactiflora endosperm cells, resulting in the accumulation of oil increased continuously. In S1 and S4, we were not observed protein body in P. lactiflora endosperm cells, the reason is not clear yet. |
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