Research On Development Of Low-Temperature Drinking Yogurt

In this paper,raw milk was used as raw material to study the influence of different production conditions on the quality of drinking yoghurt base material.Through the orthogonal experiment,the optimal process conditions were obtained,and better quality yoghurt base material was produced.On this basis,further study the influence of different stabilizers on the quality of drinking yoghurt formed by high-pressure homogenization.Finally,through the storage experiment of drinking yoghurt,study The quality change of yoghurt during storage,the best production technology and the best product shelf life were selected.The results of this paper are as follows:1.Single factor experiment was conducted to analyze the influence of different production conditions on the base material of low temperature drinking yoghourt?referring to yoghourt with storage temperature of 2-6??,and it was concluded that the water holding capacity and sense of yoghourt base material were relatively good under 95?/5min and 100?/15s sterilization processes;the water holding capacity and sense of yoghourt base material selected by fermentation strain M₅ were relatively good;the inoculation amount of fermentation strain was 100 DCU/T has better sense.2.By studying the sterilization conditions,the three-factor three-level orthogonal optimization experiment of fermenting bacteria and fermenting bacteria inoculum level,it is concluded that under the optimal fermentation temperature of 42°C,the order of influence of each experimental factor on the sensory score of yogurt is fermenting bacteria Species?B?>inoculation amount of fermenting strains?C?>sterilization conditions?A?,it is concluded that the optimized process conditions for the preparation of low-temperature drinking yogurt base materials are A₂B₁C₁,that is,the sterilization conditions are 95?/5 min,and the fermentation strains M₁,the inoculation volume is 100 DCU/T.3.By studying the effect of different stabilizers on the viscosity of low-temperature drinking yoghurt,the results showed that the viscosity of low-temperature drinking yoghurt increased with the increase of xanthan gum,decreased first and then increased with the increase of pectin,and increased with the increase of agar;by studying the effect of different stabilizers on the centrifugal sedimentation rate of low-temperature drinking yoghurt,the results showed that The results showed that the centrifugal precipitation rate of low temperature drinking yoghurt decreased first and then increased with the increase of xanthan gum,decreased first and then stabilized with the increase of pectin,and decreased first and then increased and then stabilized with the increase of agar.According to the experimental results and the expected requirements of low-temperature drinking yoghurt,pectin was selected as the stabilizer of low-temperature drinking yoghurt in this experiment,and the optimal addition was 0.3%.4.The effect of storage temperature and time on acidity of low temperature drinking yoghurt was studied.The results showed that storage temperature and time had significant effect on acidity.At the same time,with the extension of storage time,the acidity of yoghurt showed a rising trend,and the rising speed was faster in the first two weeks,and slower in the later period.The acidity of the product at week 3 is acceptable.5.By studying the effect of storage temperature and time of low-temperature drinking yoghurt on the content of coliform,mould,yeast,Lactobacillus,Lactobacillus and Streptococcus thermophilus in the product,the content of Lactobacillus,coliform,mould and yeast in the yoghurt is in line with the national food safety standard?GB 19302-2010?under the conditions of 4?,10?and15?respectively According to the relevant requirements of fermented milk,the number of lactic acid bacteria increased first and then decreased with the extension of storage time,and reached the peak value on the 7th day.Comparing the content of lactic acid bacteria in yoghourt with different storage temperature,it was found that the content of the active bacteria in the 15?storage sample was higher than4?and 10?in the early stage,and decreased rapidly in the later stage,significantly lower than 4?and 10?in the two groups.It is reasonable that low temperature drinking yoghurt should be preserved at about 4?and the shelf life should be considered for three weeks.