Uitrasonic Enzymatic Extraction Of Yeast β-glucan And Its Application In Synbiotics

Yeastβ-glucan is a functional polysaccharide that can regulate immunity,improve intestinal micro ecosystem and promote animal growth.The extraction and purification process of yeastβ-glucan will affect its physical and chemical properties and its development in the field of functional food.The extraction efficiency ofβ-glucan is low.In view of this,based on the research at home and abroad,baker’s yeast was used as raw material and extracted by ultrasonic-double enzyme methodβ-glucan.And yeastβ-glucan was analyzed physicochemical properties of and its application in the preparation of synbiotics.The main results are as follows:（1）The selection of baker’s yeastβ-glucan extraction method.Baker’s yeastβ-glucan was extracted by ultrasonic method,ultrasonic yeast wall breaking enzyme method and ultrasonic double enzyme method.Through FT-IR spectrum and Congo red test,the finished products of the three extraction methods may existβLinked glycosidic bond.In contrast,the ultrasonic double enzyme method was used to extractβ-glucan that has a higher content of 57.83%（w/w）and a larger average particle size of 2607.0 nm.At the same time,it has higher degree of porous agglomeration,so it is determined to extract yeastβ-glucan.The extraction method ofβ-glucan was ultrasonic double enzyme method.（2）The optimization of technological conditions of ultrasonic double enzyme extraction of baker’s yeastβ-glucan.Taking ultrasonic power,ultrasonic time,hydrolysis time of yeast wall breaking enzyme,the concentration of yeast wall breaking enzyme,and hydrolysis time of yeast extraction enzyme as factors,the total solid yield（g）and protein extraction amount（μg）as indicators.The extraction process was optimized by single factor and orthogonal test.The optimized extraction conditions were as follows:ultrasonic power 325 W,ultrasonic time 40 min,yeast wall breaking enzyme concentration 0.50%（w/v）,yeast wall breaking enzyme extraction time 90 min,and yeast extraction enzyme extraction time 60 min.（3）The properties of yeastβ-glucan and its application in the preparation of synbiotics.The NMR chemical shifts at 103.52 ppm（C1）and 86.68 ppm（C3）,and the FT-IR spectra at 888 cm^-1βconfiguration C-H peak indicates thatβ-glucan has aβglycosidic bond.The growth performance and viable bacteria number of the synbiotics that prepared from yeastβ-glucan were the best when the mass ratio of Lactobacillus plantarum:β-glucan and Lactobacillus acidophilus:β-glucan was 2:1（w/w）and 3:2（w/w）.The number of viable cells of Lactobacillus plantarum and Lactobacillus acidophilus could reach 10¹²CFU/m L and 10¹³ CFU/m L respectively after 4 hours of digestion ofβ-glucan-Lactobacillus plantarum synbiotics andβ-glucan-Lactobacillus acidophilus synbiotics in simulated gastric juice.The protective effect ofβ-glucan on Lactobacillus acidophilus is better than that of Lactobacillus plantarum.It is preliminarily speculated that it is synbiotics prepared byβ-glucan extracted by ultrasonic-double enzyme method have the properties of promoting the growth of probiotics and anti digestion.