Study On Flavor And Antioxidation Of Germinated Selenium Enriched Rough Millet And Its Fermented Beverage By Lactic Acid Bacteria

Germinated selenium rich rough milletis a high quality raw material of whole grain food,This paper takes rough millet as a research object to explore the effects of germination,selenium enrichment and fermentation on the flavor and antioxidant activity of rough millet.The optimum mix proportion of the strains was determined by p H value,number of living bacteria and sensory quality.The optimum conditions for the Lactobacillus fermentative strain were selected by single factor and orthogonal test.Finally,the fermented beverage of Lactobacillus fermentative rich rough millet was prepared by adding apple and hawthorn juice as needed.The purpose of this study is to produce high quality rough millet products to provide the direction for the rational utilization of whole grain brown rice resources.The main results are as follows:(1)The content of protein,fat,flavone,polyphenol,glutathion and antioxidant activity in the uncoated rough millet were higher than that of millet.Germination and selenium enriched treatment showed significant effects on the physical and chemical indexes and antioxidant activities of rough millet.The protein content of germinated selenium rich brown rice was 43.8%,fat content decreased 28.4%,flavonoid content increased 3.29times,polyphenol content increased 3.15 times,and the content of glutathion increased by1.38 times,and the four antioxidant capacity indexes increased 17.54%,19.08%,20.92 and25.10%respectively.(2)The non shelled rough millet beverage showed bitter taste,stronger astringency and saltier taste than that of millet beverage.Germination made the astringency,bitter aftertaste,fresh taste,richness and saltiness of rough millet drink weaken to different degrees,and the aftertaste of astringency did not change.After selenium enrichment,the aftertaste of rough millet beverage was enhanced,and the fresh,rich and salty taste had no obvious change.Rough millet beverage contains more aromatic compounds,nitrogen oxides and hydrocarbons than millet drinks.The aromatic compounds,nitrogen oxides and hydrocarbons of brown rice beverage increased after germination.Selenium enriched can reduce the aromatic compounds,nitrogen oxides and hydrocarbons of brown rice beverage.(3)The optimal ratio of Lactobacillus plant and Lactobacillus rhamnosus was determined to be 4:6 by p H value and live number.The best ratio of germination of Lactobacillus selenite rich rough millet beverage was 1:12,sucrose added 3%,inoculation2%,fermentation time 10 h.(4)With the increase of fermentation time,the bitter taste,bitter aftertaste,astringency and abundance of the rough millet beverage with selenium sprouting gradually decreased,among which the bitter taste decreased obviously,the acid and salty taste gradually increased.The fresh taste showed the trend of rising firstly and then decreaed,and the astringency aftertaste had did not change.With the increase of fermentation time,nitrogen oxide,ammonia,olefin and aromatic compounds in rough millet beverage with selenium rich germination increased gradually.Hydrogen,alcohols,alkanes(methane,etc.)and some aromatic compounds showed a tendency to decrease gradually.23 volatile flavor substances were detected in the fermented beverage of Lactobacillus selenite rich brown rice.The concentration of characteristic flavor substances 1-octene-3-alcohol,acetoin,nonic acid and heptanic acid increased significantly.(5)DPPH free radical scavenging rate,O2~-·scavenging ability,·OH removal ability and reduction capacity of germinated selenium rich brown rice beverage all showed an upward trend after fermentation.Which increased.1.47%,1.18%,2.24%,4.32%,respectively(6)The taste of fermented beverage with Lactobacillus of functional germination and selenium rich rough millet was weaker than that before adding.Astringency,saltiness and freshness are enhanced.The acidity,bitterness,astringency and richness have no obvious changes.The odor contains more aromatic compounds,nitrogen oxides,hydrocarbons,alcohols and some aromatic compounds than before addition.The characteristic flavor substances such as phenylacetaldehyde,2-hexene aldehyde(E,nonaldehyde,n-hexanol,pyrazine,3-ethyl-2,5-dimethylacetate,butyl acetate,2-methyl-1-butanol acetate,3-(methyl thiol)propyl acetate were detected in the fermented beverage of functional selenium rich rough millet Lactobacillus due to the addition of apple and hawthorn juice.The flavor of rough millet beverage was improved.(7)The protein content of the fermented beverage of Lactobacillus sp.was 0.717(g/100m L),the fat content(0.121g/100m L),the four antioxidant activity indexes of the four kinds of the beverage were increased after adding apple and hawthorn,the rising degree was 11.6%,4.37%,9.42%and 3.82%,respectively.The product health index meets the international requirements,and the expected shelf life is 15 d.