Development Of A Self-servcie Yogurt Product

DIY means do it yourself.It refers to that someone makes something by his own.After the conception established,the related product is popular among the young consumers soon.Furthermore,the DIY yogurt has been commercialized in New Zealand and Japan.This research is focusing on the core technology of DIY yogurt production,and forming the system of the DIY yogurt production technology.It also provides technical support for the DIY yogurt industrialization of our country.The following three steps are the main parts.Beginning with five strains of lactic acid bacteria in animal products laboratory?L1?L2 ? L3 ? S1 ? S2?.Firstly,the researcher preliminarily detected the characteristics of producing viscidity and the growth curve?acid yield curve under the same circumstance.Based on this,the relative heat resistant strains were screened out in the individual by thermal stimulation method.Finally,yogurt was fermented by the heat resistant strains,then detecting the acidity,water-holding power,the quantity of living bacteria,which ultimately determined L2,S1 as the test strains.The researcher analyzed the effect of the amount of live bacteria by different inlet air temperature?feed speed?bacteria wall ratio?protecting carrier volume?skim milk powder?.On the basis of single factor,the researcher determined the optimum process conditions by comprehensive analysis of response surface method.Optimizational results are as follows:?the vacuum degree-0.05 ^-0.06 Mpa?the best process conditions: 79? as inlet air temperature,727mL/h as feed rate,1:4.55 as bacteria wall ratio,9.80% as protecting carrier quantity?skim milk powder?.The quantity of living bacterium is 2.81 x 10⁸ cfu/g.DIY yogurt was made of sugar,milk powder mixed with starter culture which was screened and microcapsuled and the product also included nutrition label design and vacuum packing.According to the accelerated shelf life experiment?ASLT?[1],the researcher has detected storage period at 35??45? and extrapolated that normal temperature storage shelf life was 32 days by Q₁₀ method.