Physicochemical Properties And Rheological Analysis Of ?-Glucan And Arabinoxylan In The Oat

With the improvement of people's living standards,the population who suffered from high blood sugar,high blood pressure,high cholesterol and other diseases is increasing.Since oats are rich in protein,minerals,vitamins and dietary fiber,they are known as one of the best cereal foods.?-glucan and arabinoxylan are important dietary fibers in oats,which are good for lowering blood sugar,lowering blood cholesterol,laxative,preventing colon cancer,enhancing immunity and others.They have been widely focused.To improve the economic value of oats,it's necessary to prepare high-purity of?-glucan and arabinoxylan comprehensively.The main contents of this article are as follows:1.?-glucan and arabinoxylan in oats were prepared.For raw material,shelling oat was milled into flour and bran.Crude?-glucan and arabinoxylan were obtained by water extraction and alkaline extraction from flour and bran respectively and their physical and chemical properties were analyzed.The results were as follows:the contents of neutral sugars,?-glucans,uronic acid,protein and starch in crude?-glucan were 73.05%,60.10%,7.00%,4.27%,1.08%.The contents of neutral sugars,?-glucans,uronic acid,protein and starch in crude arabinoxylan were 35.23%,1.77%,6.22%,10.75%,0.37%respectively.Main monosaccharide in the crude?-glucan was glucose of which content was 60.83%,and main monosaccharides in the crude arabinoxylan were arabinose and xylose whose contents were 13.72%and 22.16%.The main solid shape of crude?-glucan was flaky and the main solid shape of the crude arabinoxylan was filamentous and flaky.2.?-glucan and arabinoxylan in oats were purified.Their physical and chemical properties were analyzed.Crude?-glucan was separated into two fractions(OG-1 and OG-2)whose molecular weights were different confirmed by gel column.The?-glucan content of OG-1 was almost zero,whereas the?-glucan content of OG-2was up to 70.40%.By measuring the monosaccharide composition,the results showed that the monosaccharide in OG-2 was only glucose of which content was67.06%.OG-2 contained?-D-glucopyranose rings and its molecules were linked together by?-glycosidic bond.Therefore,we think OG-2 is purified?-glucan.Its molecular weight was 1.50×10~3and its structure was mainly flaky by electron microscope.Crude arabinoxylan was preliminary purified to obtain relatively pure purified sample AX by Sevag method.The contents of neutral sugars,uronic acid,protein,starch,?-glucan in AX were 63.43%,9.07%,6.10%,0.42%and 0.48%successively.The main monosaccharides in AX were arabinose and xylose of which contents were 27.33%and 40.31%.Its molecular weight was 3.04×10~5by HPSEC.It is?-D-xylan.Its apparent viscosity increased as its concentration increased,but its viscosity was still below 0.1 Pa·s even when the concentration reached to 2.0%.Its main structure was filamentous.3.The effects of oat?-glucan on rheological properties of some common carbohydrates were preliminary explored,including polysaccharides from the seeds of Plantago asiatica L,citrus pectin(APC 186,APC 200),xanthan,CMC(high,medium and low viscosity).The results suggested that when concentration of?-glucan increased,the apparent viscosity of 0.5%polysaccharides in the seeds of Plantago asiatica L increased gradually;the apparent viscosity of 0.5%CMC-H,2.0%CMC-M,4.0%CMC-L decreased gradually;the apparent viscosity of 2.0%citrus pectin APC 186,2.0%citrus pectin APC 200,0.25%xanthan were almost unchanged.