The Research Of Pitaya Seeds

In this study, the research and development of pitaya seeds, which come from pitaya deeply processing wastes, was carried out, what will provide some valuable reference datas for pitaya deep processing enterprises to further use pitaya seeds effectively. The main research contents and results as follows:(1) Basic nutrients and content of pitaya seeds were detected and analysised. The results show that main nutrients in pitaya seeds are fat, protein and starch, which were34.05g/100g,19.87g/100g and21.05g/100g, respectively. The high content of fat decided pitaya seeds can be used as high oil crops, and their by-product meals can be made for protein-rich animal feed.(2) Supercritical carbon dioxide extraction process of pitaya seeds oil was studied by central composite experimental design and response surface on the basis of single factor test, and the oil extraction yield of pitaya seeds was30.21%, which mean that the pitaya seeds oil extraction rate reached to88.72%in the optimum conditions:material grinding was40mesh, material packing volume was400g(1L extraction kettle), extraction pressure was25MPa, extraction temperature was40℃, and the extraction time was3.5h. The regression equation model of pitaya seeds oil’s yield with the main factors of supercritical carbon dioxide extraction was builded by response surface analysis. The model was significantly and fit better on the test, which would has a certain value to the industrial production.(3) Oils was extracted from pitaya seeds on different years, barley germ, olive, sunflower and hemp seeds, and the extraction conditions were the optimum conditions of supercritical carbon dioxide extraction. Chemical compositions and relative content of pitaya seeds oil was compared with the other oils by GC-MS. The results show that main fatty acid of these five kinds of oils were palmitic acid, stearic acid, oleic acid and linoleic acid. The unsaturated fatty acids’ relative content of total fatty acid was76.96%, which was close with sunflower oil(87.01%) and slightly higher than barley germ oil and olive oil, and the linoleic acid was up to45.21%, which was far more than the "liquid gold" olive oil (6.67%) and barley close with germ oil and hemp seeds oil. In addition, the relative content of retinene in pitaya seeds oil was2.95%which was after hemp seeds oil, but higher than the others. What’s the most surprising is that squalene, a rare bio-active ingredient in vegetable oils, was found in pitaya seeds oil, which relative content up to6.76%. Therefore, pitaya seeds can be used as raw materials for health food.Fatty acids of pitaya seeds oil in2009and2010, which have been methylated were detected by GC-MS. The results demonstrated that the total content of major fatty acid composition was little difference, but some less ingredients such as linolenic acid, myristic acid and shark oleic changed greatly. Therefore, in order to further improve the research of pitaya seeds, we need to discuss on pitaya seeds oil’s components with different years, seasons and different origins.(4) Analysis of physical and chemical properties of oils confirmed that all of the Iodine value and saponification value of the five kinds, and refractive index and relative density of pitaya seeds oil were in line with the characteristic indicators of the green edible oil. In addition, the acid value and peroxide value were in line with the physical and chemical indicators of the green edible leaching oil. Therefore, oils extracted by supercritical carbon dioxide can be avoided deacidification, bleaching, etc. refining process.(5) Two compounds were isolated and purified from pitaya seeds meals’ butanol extract. The two high levels compounds were identified as β-sitosterol(48.0mg) and allantoin(465.7mg), which will provide a scientific experimental basis to further development and utilization of pitaya seeds.