| Ponkan is a popular fruit, which is used to process into canned food, beverage, and etc. However, its citrus seed has not been used compeletely. Nowadays, the byproducts of a variety of fruit at home and abroad have been were analyzed, but the study on the aspect of Ponkan seed is little. Therefore, oil extraction process of Ponkan seed and chemical composition were analysised and determined in this paper.In order to make full use of agricultural waste materials-Xiangxi Ponkan seed and increase the extraction efficiency of seed oil from its powder, the influences of time, temperature, pressure and the flux of CO2 on the yield of seed oil from its powder with the supercritical CO2 fluid extraction technique were studied according to the Box-Behnken central composite experimental design based on the single factor test. Analyzed the mathematical model which established by response surface methodology (RSM), and the same time, relationships between studied factors and response of Ponkan seed oil extraction yield were described. Based on the canonical analysis, the optimum conditions were obtained as follows:the extraction pressure is 34.4 Mpa, the flux of CO2 is 25.8 L/h, the extraction time is 147.6 min and the temperature is 39.3℃. Under the optimized extraction conditions, the predictive maximum yield of seed oil is 45.95% and the average validation value is (45.12±1.36)%(n=3), so the model would be used to predict the extraction results well.Gas chromatography (GC) was used to determine the fatty acids of Xiangxi Ponkan seed oil. The oleic acid, linoleic acid and palmitic acid fell in the range of 30.88%, 26.11% and 29%, respectively. The unsaturated fatty acids was high than 70%. Then near-infrared spectroscopy (NIRS) was used to analysis the citrus oil. Absorption maxima were clearly observed at 5801,5677,4331,4258 cm-1 together with small absorption band at 7174 and 8269 cm-1. By comparison, NIR and GC methods were validated each other, and the same results can be obtained in our work, which demonstrated that our extraction and analysis methods were reliable and accurate. The results indicated that Hunan citrus seed extract oil has a high nutritional value and can do further development and utilization.Soxhlet extraction was used to extract Xiangxi Ponkan seed, and the content of its nutrient components were determined. After oil extraction, the amino acids, protein, starch, moisture content, ash and mineral elements in powder samples were analyzed. The total Amino acids content was to 12.11 g/100g, the highest concentration of glutamic acid was to2.53 g/100g. The content of water, crude protein, total sugar and ash was to 8.15±0.02, of 24.52±0.96,11.52±0.87,6.73+0.07, respectively. High content of Ca, Fe, Cu, Zn and other minerals were contained in oil sample, the study of this paper will provide a theoretical basis for the comprehensive utilization of Xiangxi Ponkan. |
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