Lipids Of Oat, Their Changes During Germination And Preparation Technics Of Microencapsulation

Oat（Avena satival L） has long been considered good potential for development as a healthy source,due to its compositions against blood fat,water-soluble colloid,balanced proteins.Especially,oats contain much higher levels of lipid than any other cereal grain, What is more,the content of unsaturated acid constitutes a measurable portion,wich have a good functions of nutriton.The objective of this study was to systematically analyze the composition of lipids in twelve different oats and compare the oat lipid characteristics with different extract methods.And the metabolizism of lipids during the process of oat germination was also studied preliminarily.In addition,the technology parameters of oat oils microencapsulation were optimized for preparing the functional oat oil products.The details in the contents and results of the thesis were as follows:（1） Oat selections with oil ranging from 4.1%to 11.1%.The groat weight and starch were negatively correlated with oil percentage,whereas VE and protein were positively correlated with oil concentration.Detected by GS,oleic,linoleic and palmitic acids constitutes a measurable portion.Total lipid content of the oats was positively related to the proportion of stearic and oleic acids and negatively correlated with proportion of palmitic,linoleic and linolenic acids.At the same time,oleic acid was commonly the major fatty acid in the NL,whereas linoleic acid usually predominated in the PL and GL.（2） With the solvent systems ranging from non-polar solvents to polar solvents,the production of oat oil is increased and more than the yield of SCF-CO2.Non-polar solvents such as ether or n-hexane are effective in removing the so-called neutral lipids,they are poor solvents for extracting polar lipids,which are more effectively extracted with polar solvents.Compared with solvent systems,the obtained oil has the following several traits: the light color,the low acid value,the low sponification value and so on.The quality of this oil is obviously superior to the solvent extraction.However it has lower concentration of VE.The parameters of extracting oat oil with SCF-CO₂ is the following:the press 38.25MPa,the temperature 47.30℃,the rate of CO₂ flow,3 mL/min.（3） During in the germination of oat,dry weight decreased at first two days.With the formation of new tissues,it increased slowly,but the change was not significant.At the same time,fresh weight increased quickly due to the absorbed water,and no changes on a dry weight basis were observed in protein.Total of lipids and starch decreased wheras free amino acid and soluble sugar increased during the period of germination.Meanwhile, activity of lipase in oat increase to the highest when soaked for 8h,and then decreased with the lasted time,and the activity levels after four days germination were slightly lower than those in the un-germination grains.Due to the formation and transformation of membranes during germination,GL and PL were slowly increased,but linoleic increased at first and then decreased.It showed a relationship to growth and decline between the oleic acid and linoleic acid in content,so that the change curves of average content appeared a geometric graph of mirror symmetry.（4） The best support materials proportion of oat oils microencapsulation was:Arabic gum:dextrin:corn-syrup 3:3:4,the addition of 30%oat oil of support materials,the emulsification temperature 40℃,the amount of emulsifier 1%.This technological process could get a more stable emulsification.The optimization spray drying technological condition of oat oils microencapsulation was:entering air temperature 180℃, homogening pressure 30MPa,air outlet temperature 82℃.