The Research Of Comparison Of Fermentative Properties Of Industrial Baker’s Yeast

This paper has focused on the differences of the fermentative properties among fourkinds of baker’s yeast(Y normal yeast and M suger tolerant yeast). It provides a scientificbasis for the correct selection of yeast industry. we determined properties in fermentation ofthose yeast and the physical and chemical characteristics of dough. Compared and analyedfermentation performance of four yeast.Then we explored the application crafts of those yeastin bread industry and provide the basis for the industrial production of bread. Finally, weresearched the properties in fermentation of suger tolerant yeast to determined fermentationcrafts of each yeast to ensure the quality of bread.The sensuous, of all the four kinds of yeast had no obvious differences. All of themcould meet the national standards of edible yeast. The order of their colonies counts was Y-2＞Y-3＞Y-1＞Y-4. All the yeast could produce some protease and amylase, in which theenzyme active of Y-2was the highest.According the results of the rheological fermentation experiments, during3hfermentation, Y-3had the highest gas production with a high producing rate, while on theother hand the gas holdup of its’ dough was somehow bad. Y-4had a low gas producing ratebut a strong gas holdup capability. Both the gas production and gas holdup capabilities of Y-2were he best.The combination of intuitive method of dough by graduated cylinder and draininganalysis of various yeast fermentation power found that Y-2and Y-3showed higher yeastfermentation ability. Y-2and Y-3had a higher growth rate, more gas production, a largerdisulfide bond amount and a higher gluten index than the other two. Y-1had a higher enzymeactive during fermentation.The properties of steamed bread produced with those yeast would change when theadditive amount of them changed. With the increase of the yeast addition, the whiteness andspecific volume would rise, hardness would reduce, sensuous properties, However, itcouldn’t be excessive to prevent the product’s quality decreasing. The most proper additionof Y-1and Y-4was1.0-1.2%, Y-3was0.6-1.0%, Y-2was0.8-1.2%. They all had a bestperformance in terms of active, fermentation capability and product quality at35℃.Scanningelectron microscope SEM, Y-2andY-3steamed bread have uniform holes and larger aperture.Y-3steamed bread is not. Y-1holes though dense but small aperture.The experiments of suger tolerant yeast fermentation characteristics show that fermentation rate of dough could be increased with adding sugar and oil. If the addition ofexcess will inhibit fermentation performance. Adding sodium dehydroacetate in some degreecould promote the fermentation of dough. In our experiments, all the four kinds of yeastsperformed a best behavior with10%sugar addition and10%oil addition. M-3with a highsugar endurance could ferment well in high sugar environment, while the volume of doughfermented with M-4yeast’s oil endurance was lower.It had no significant differences in thequality of M-1yeast bread when add different amounts of margarine.Lastly, the endurance ofpreservative among all the kinds had no obvious difference.