Processing Methon Of Freeze-drying Fermented Oat Solid Drink

Oats contain high levels of protein,unsaturated lipids,vitamins,antioxidants,phenols,and also have different types of dietary fiber which have strong health functions,but so far,the development and utilization of the oats resources of our country compared with developed countries still lag behind a lot,.For a long time,oat products in the domestic and foreign markets are mainly processed food.oat does not contain wet gluten,so flour can not form a dough,which is the technical problems of oat deep processing.Sweet glutinous rice is a long-established folk snack which fermented by sweet koji.It can greatly improve the oats palatability and retain nutrients.However,Because it is a folk fermentation liquid product,the uncontrollable fermentation strain,preservation and transportation are main factors that restrict its further promotion.As a source of glutinous rice,Shaanxi is rich in fermenting bacteria.Choosing five kinds of popular commercial glutinous rice wine starter from different regions of Shaanxi,using enzyme activity as evaluation index,the excellent glutinous rice wine was screened.The mold and the yeast in the glutinous rice wine starter was iso-lated and purified.Then through multiple screening,We get a kind of mold and a yeast.Then oat was used as raw material for Tianpei(sweet fermented grain),and the physicochemical properties(total sugar,total acid,pH,alcohol content)and active components(?-glucan,flavonoids,polyphenols)were determined before and after fermentat-ion.In order to retain the taste of fermented grains to the maximum extent and facil-itate the practical edible transportation,the advantages and disadvantages of various drying methods were compared.Finally,it was proposed to make fermented grains freeze-dried in vacuum.In order to maintain the shape of fermented grains after freeze-drying,the relationship between freeze-drying temperature,the amount of added sucrose and the morphology of freeze-dried grains was explored.The results of the study are as following:(1)When the ratio of yeast to mold is 1:9,the enzyme activity of the mixed koji peaks.4Q is identified as Aspergillus niger and J2 is identified as Cyberlindnera fabianii.pure Aspergillus Qu was made and then was mixed with different proportion of yeast to make fortified Qu.The results showed that the optimum complex proportion of fortified Qu:inoculum 1%(including Aspergillus 4Q 0.9% and yeast J2 0.1%).Compared with the commercial Daqu,the saccharification power and liquefaction powerofthe fortified Qu were 768.6 U/g and 734.3 U/g,respectively.(2)In terms of physicochemical properties,the total acid total sugar content continued to increase,the pH continued to decrease during the whole fermentation process.In terms of active ingredients the flavonoid content decreased slightly,the ?-glucan content remained unchanged,and the polyphenol content increased significantly.the content of ?-glucan in oat was 2.12 g /100 g,and there was no significant change with the extension of fermentation time.The initial polyphenol content of oat was 24.21mg/100 g,and the polyphenol content showed an increasing trend with the fermentation time.After 36 hours,the polyphenol content tended to be stable,and at 60 hours,the polyphenol content was up to 49.38 mg /100 g.And the flavonoid content decreased from 25.48 mg/100 g to 18.78 mg/100 g.(3)The results show that the minimum temperature and maximum temperature of pre-freezing are respectively-50 °C and 30 °C.The surface is relatively dry and the sugar bubbles are less.At the same time,rehydration time is also moderate.When the amount of sucrose is 2 g/100 g,It is a suitable amount of sucrose addition.The above results show that the mold and the yeast isolated from the representative glutinous rice stalks in Shaanxi has good production performance.After fermentation,oats can retain the original nutritional value to a large extent,and finally a new type of functional food was provided which can preserve and transport more easily.It provides a new way of thinking for the development of oat products and industrial production.