Study On Processing Of Xylitol Yogurt

Xylitol yogurt is made from high quality raw milk by xylitol instead of sucrose and a certain proportion of lactic acid bacteria and other fermented strains after fermentation.Xylitol yogurt has good quality,taste and nutritional value.It is beneficial to the health and absorption of trace elements in human intestinal tract.It is loved by many consumers and shows a rapid development trend.This paper aims to explore the xylitol yoghurt fermentation process and the influence of heat treatment on the quality of yogurt and the change of product quality in the process of storage,processing conditions,put forward the reasonable heat treatment conditions and storage conditions,provide data support for the development of xylitol yoghurt products and product marketing.(1)Study on the processing technology of xylitol yogurt: choosing milk as the main raw material,xylitol as the main sweetener,adding Lactobacillus bulgaricus and Streptococcus thermophilus as fermentation strains to produce xylitol yogurt.By investigating the amount of xylitol,the proportion of inoculation,the amount of fermenting agent,the fermentation temperature and the fermentation time,the wood sugar yogurt was produced.The influence of sugar alcohol and yogurt on acidity,color and sensory evaluation was optimized,and the best technology of xylitol yogurt fermentation was optimized by response surface methodology.The results showed that the best fermentation technology of xylitol yogurt was 5% xylitol,0.4% inoculant,41 fermentation temperature and 8 h fermentation time.Under this condition,the yoghurt fermented is uniform,sweet and sour,soft and delicate,and stable in tissue condition.(2)The effect of treatment temperature on the storage characteristics of xylitol yogurt.The effects of different processing temperature on sensory characteristics,acidity and water holding capacity of yogurt during storage were studied.The results showed that the yogurt obtained after heating at 85 C for 5 min had better sensory evaluation and color.It had high water holding capacity during storage and maintained good stability and quality characteristics during storage.(3)Xylitol yogurt flavor components analysis: using headspace solid phase microextraction(SPME)combined with GC/MS analysis technology,the volatile flavor compounds of xylitol yogurt were qualitatively and quantitatively analyzed,and compared with the control yogurt.The results show that the volatile compounds identified in yogurt including alkanes,ketones,aldehydes,acids,alcohols,esters,lactones and aromatic substances of 8;most of the compounds in which the relative content of total acids,8(in total 29.74%),7 kinds of ketones,aldehydes(in total 28.04%)6(in total 12.16%),5 kinds of alkanes(in total 8.60%),5 lactones(in total 7.57%),4(a total of 9.98% alcohol content),4 kinds of esters(content 6.18%),aromatic substances(4 in total 2.32%).