Study On The Growth Properties Of Lactic Acid Bacteira In Oat Substrate

In the development of probiotic foods, non-dairy probiotic fermented food has become animportant trend, because cereal-based food products, comparing to conventional fermenteddairy foods, offer benefits including high dietary fiber, low fat and lactose intolerance. Oatcereal is one of full nutritional value of food. Natural enzyme from malt could hydrolyze oatpolysaccharides to oligosaccharides, which may be more effective nutrition promotion for thegrowth of lactic acid bacteria.Oat-based substrate hydrolyzed by malted barley was studied for the capability to developsymbiotic cereal fermented products. In this substrate, selected strains could grow fast and arewith long preservation stability and good favor. The reason for malt and oat β-glucaninfluence the growth of tested strains was also investigated.The results show that oats paste could be used for the growth of probiotic. The averagegrowth logarithmic viable count of seven tested strains is1.766during10h fermentation. Oatsubstrate with added barley malt can obviously promote the growth of lactic acid bacteria.STab. phase of Lactobacillus helveticus extent from6h to10h, and viable count increasefrom1.28×10~8cfu/ml to2.29×10~8cfu/ml. L. helveticus with highest final living bacteriumand pleasure fermentation flavor number shows great commercial development potential. Thelive bacteria count of L. helveticus fell from7.17to8.36when was preserved in4℃refrigerator for21d, that still meets probiotic food requirements.To promote L. helveticus growth, the pretreatment condition of oats substrate with addedmalted barley was optimized: oat grain content7%, malt flour1%, hydrolysis for30min at60℃, inoculation quantity is1:1000.Malt contains rich nutrients and variety of endogenous enzymes. The effect of barley malt onpromoting L. helveticus growth has two reasons. The result suggested the facilitation of maltwas mainly from supplying small molecular hydrolysate of malt supplemented oat substratenutritional deficiencies, rather than malt endogenous enzyme on nutrient hydrolysis of oat.Oat substrates were hydrolyzed by thermosTab. α-amylase and β-glucanase could not improvegrowth of L. helveticus, but facilitation from glucoamylase was predominant but notsignificant. It had been proved that in small molecular carbon source, glucose has notsignificant effect, but sugar and maltose have inhibition effect on the growth of L. helveticus.For nitrogen sources, milk, the best growth matrix for lactic acid bacteria, has positive effect,but casein completely hydrolysis couldn’t promote the growth of test strain. β-glucan is a kindof dietary fiber and prebiotics. Oligosaccharides could be as effective bacteria growthenhancer. But under experimental condition, The proper hydrolysis of oat β-glucan into low molecular weight oligosaccharide had no obvious effect in promoting test strain.Formulation and process was optimized to develop non-dairy product with good taste, flavorand nutrition. Optimal parameters from orthogonal experiment were: milk powder4%,sucrose3%, fermentation time10h. Proper amount of jujube or carrot adding could improvethe sensory quality of products.