| Oat is a big kind of Cereal crops, and its annual production ranks fifth in the cereal crops. It’s a kind of delicacy what can be used to not only eat, but also cure because of its unique nutritional value and health care function. The main product is oatmeal in the processing, but fat is easily broken down into free fatty acids and other products under the effect of lipase in the processing of oatmeal storage and it can lead to rancio taste, and be bad for the smell of oat. In addition, there are a lot of unsaturated bond that is very unstable in the product. They were broken down into aldehydes, ketones and other substances, which affect the shelf life of oatmeal due to the deterioration of the oats. Therefore, slowing down and stopping the fat oxidation and rancidity of the oats in order to extend the shelf life of oat products were the problem to be solved eagerly in oat product development during the processing of oats and other products.Therefore, the oils in all processes were extracted by the method of solvent extraction firstly, and then determine the changes of various physical and chemical indicators of the oats oil in the processing secondly, in the end the composition and content of fatty acids were analyzed, the influence of the different machining operations on oat oil physical and chemical properties and the composition were discussed. Supercritical CO2 extraction technology parameters were optimized by using response surface oats, and the oil composition and content of fatty acids from oats diced were analyzed by using GC-MS. Research provided certain theoretical reference for oats and oat oil product development and it is of great significance for improving existing oatmeal production processing and exploring the new way of processing. Research results were as follows:(1) Fat content, iodine value, refractive index showed a trend of increase along with the processing; Water content, specific gravity, acid value, peroxide value showed a trend of decrease firstly and then increased along with the processing; saponification value showed a trend of increases firstly and then decrease along with the processing. To sum up, the physical and chemical indicators of the diced oat oil were the best, which could be used in further development and utilization as oat oil products.(2) The highest levels of unsaturated fatty acids were oleic acid, which were more than 50% in oat oils, and followed by the linoleic acid, which were more than 20%. Oat oil fatty acid species and composition were same in different stages of processing, including oleic acid, linoleic acid, stearic acid, peanut acid. The relative contents of unsaturated fatty acid were 84.52%,85.64%,86.14%,85.03% in shell, baking, pelletizing and flake oat sample respectively.(3) The optimum technology parameters of Supercritical CO2 extraction for the oats diced grease were charge amount of 50 g, static time of 74min, dynamic time of 160 min, pressure of 45MPa and temperature of 50℃.(4) Quadratic multinomial regression mathematical model for extracting oat oil by Supercritical CO2 fluid extraction technology were established:Y=54.55+0.56X1+1.02X2+1.49X3+2.07X4-031X3X4-0.93Xi2-0.53X22-0.58X32-0.72X42(5) Nine kinds of fatty acids were identified in the diced oat oil by GC-MS analysis. Fatty acids were mainly composed of oleic acid, linoleic acid, stearic acid and peanut acid for the oils extracted by Supercritical extraction and solvent method. Accordingly, the relative contents of unsaturated fatty acids were 87.49% and 86.14% respectively. The oat oil extracted by supercritical CO2 method can get higher content of linoleic acid (one of the essential fatty acids human body) and the total unsaturated fatty acid content. |
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