Production And Application Of Lactic Acid From Fermented Wheat Bran By Lactobacillus Casei WT-8

ABSTRACTLactobacillus casei WT-8 was chosen as a strain for fermentation in this paper,and take the wheat bran as raw material,through optimization of culture conditions of strain, fermentation medium and conditions of wheat bran,increasing the lactic acid production for the purpose,and the starter prepared from fermentation liquid of wheat bran,which baked the nutritional bread,to enhance the economic value-added of wheat bran is of great realistic significance.Through the single-factor experiment,the optimal growth conditions and inoculum volume of seed were as followed:the strain in the seed culture medium grew faster at growth temperature 38℃,intitial pH 6.5,and at inoculum volume 10%,lactic acid production 15g/L at the fermentation medium of wheat bran.The fermentation medium of wheat bran was optimized by the single-factor experiment and orthogonal experiment,the optima enzyme preparations additive of 50mL fermentation liquid of wheat bran was as followed:addition of a-amylase was 15×10^-3g, addition of neutral protease was 3×10^-3g,addition of acid protease 1×10^-3g,addition of cellulase was 10×10^-3g.At the optimal process conditions for 60h,lactic acid production reached up to 32g/L.Further optimize fermentation conditions,which on the basis of the optimal fermentation medium of wheat bran,by the single-factor experiment and orthogonal experiment,the optimal fermentation conditions were as followed:ferment temperature 38℃,addition of soybean power 3.5%,initial pH 6,sugar content 12°Bx,neutralizer was CaCO₃.At the optimal conditions for 60h,lactic acid production reached up to 48 g/L.Through taking the optimized wheat bran powder to prepare starter,and adding these to the nutrition bread production,results are as followed:mixed 90g of fermentation liquid with 300g flour to ferment for 48h in natural condition,sour dough which pH for 3.4 optimal to add to the dough for fermentation,the sensory evaluation and preservation periods of sourdough bread were better than bread which has no sour dough.