Research Of Enzyme-assisted Pressing Conjugation And Powderation Of Sunflower Seed Oil

Sunflower seed is a kind of high quality oil resources and the fourth largest oil crop in the world.The oil contains 90%unsaturated fatty acids,vitamin E,phytosterols,phospholipids and carotene,which can delay aging,regulate metabolism and reduce cholesterol.CL A is a secondary derivative of LA with different configurations.It has important physiological functions such as anti-cancer,promoting metabolism,regulating immunity and promoting growth.It is necessary to gain CLA by the method of synthesize,because there are few sources of natural CLA.Sunflower seed oil is a good raw material for preparing CLA which contains 50%-69%LA.Although CLA is rich in physiological function,its low oxidative stability impeded the development of CLA in the market.Therefore,the preparation of CLA powder with strong stability is particularly important.This paper mainly studies the utilization of sunflower seed resources and the development of high economic benefit products.The aim is to obtain the product with high resource utilization,distinctive features,good quality and low energy consumption by exploring the method and optimum technology of preparing sunflower seed oil,CLA and CLA powder.The results are as follows:(1)The preparation of sunflower seed oil by enzyme-assisted pressing:Firstly,the oil in the raw material was released by enzymatic interpretation,and then sunflower seed oil was extracted by low-temperature pressing.Through single factor experiment,the optimum technology was cellulose dose of 0.7%,pH of 4.5,liquid-solid ratio of 25%,temperature of 55?,time of 2.5 hours.Under the optimum condition,the oil yield of sunflower seed is 3.48 times higher than that of traditional cold pressing method and the oil extraction rate is 85%.The result of gas chromatography shows that the content of LA is 68%.Scanning electron microscopy shows that the cell wall of sunflower seeds was destroyed after enzymatic hydrolysis,and the structure of oil cells became larger and looser,so that the oil could be released better in the subsequent pressing process.All physical and chemical indicators of oil meet the national food safety standards.This method not only effectively improves the low oil yield of cold pressing method,but also successfully retains the natural aroma and taste of oil.Moreover,it is also an innovation of traditional oil-making methods.(2)The preparation of CLA by microwave-assisted alkali isomerization:The LA in sunflower seed oil was converted into CLA by alkali isomerization with heating mode of microwave,which instead traditional oil bath heating.Through single factor experiment and response surface experiment,the optimum technology was microwave power of 465.771W,microwave time of 33.408min,alkali-oil ratio of 0.442:1,oil-soluble ratio of 3:1.And the theoretical optimum conversion rate is 96.93%.Considering the practicability of the actual operation,the actual technology was microwave power of 450W,microwave time of 33.4min,alkali-oil ratio of 0.44:1,oil-soluble ratio of 3:1.The actual optimum conversion rate is 96.15%and the yield of CLA is 90.33%.The result of gas chromatography shows that the content of CLA is 61.43%.All physical and chemical indicators of oil meet the national food safety standards.This method shorts the heating time by five times.And it not only improves the experimental efficiency,but also reduces the energy consumption to a large extent.(3)The preparation of CLA powder by saturated aqueous solution of P-CD:The hydrophobic and hydrophilic properties of ?-CD can make lipid molecules wrapped into the cavity structure of ?-CD.Through single factor experiment,the optimum technology was molar ratio of CLA and ?-CD of 3:2,inclusion temperature of 60?,inclusion time of 2 hours.And powdering rate of CLA is 84.86%.The CLA powder was characterized by SEM,FTIR,XRD,DSC and TQ and results as follows:Firstly,new image of hexahedron formed by CLA powder;Secondly,the general structure of CLA is the same as that of P-CD and this indicates that it is an inclusion state rather than a simple physical mixing.Thirdly,the thermal stability of CLA powder is higher than that of CLA oil.The bioavailability experiment showed that the bioavailability of CLA powder was 1.53 times higher than that of CLA oil.The powder CLA was more conducive to the release of pharmacodynamics in the blood and the bioavailability.?-CD not only has a moderate size of molecular hollow structure cavity,but also has low cost and low production cost.Therefore,it can make CLA powder products better integrate into the market and increase its application possibility in different fields.