| Lacticaseibacillus casei Zhang and Bifidobacterium animalis subsp.lactis V9 are probiotics with good probiotic properties,independently developed in China,and fermented milk is one of the best carriers for probiotics.In this study,two strains of probiotics were applied to fermented camel milk as the research objects.The fermentation at 37°C was completed and the storage at 4°C for 21 days.During this period,multi-frequency diffusion spectroscopy was used to study the microrheological properties of the fermentation process in combination with the fermentation characteristics,acidity,viable bacterial count,viscosity,water retention and volatile flavor substances of the fermented camel milk samples during storage,and to analyze the textural properties of the fermented camel milk and the retention of IGF-1 activity in camel milk.This thesis presents a more systematic investigation of the use of Lacticaseibacillus casei Zhang and Bifidobacterium animalis subsp.lactis V9 in fermented camel milk.The specific conclusions are as follows:(1)In this study,four experimental groups were designed:commercial fermenters(control group),Lacticaseibacillus casei Zhang,Bifidobacterium animalis subsp.lactis V9and two strains of probiotics combined with commercial fermenters to ferment camel milk.All four groups of samples reached the end of fermentation in about 15h.During storage,the samples fermented with Lacticaseibacillus casei Zhang and Bifidobacterium animalis subsp.lactis V9 complex had suitable acidity,smooth and delicate texture,stable viable bacteria count,high hardness and high sensory evaluation score,which met the local fermented camel milk requirement index.In addition,the viable counts of Lacticaseibacillus casei Zhang and Bifidobacterium animalis subsp.lactis V9 were above 10~7 CFU/m L during storage,which could effectively ensure that probiotics exert their probiotic effects.(2)During the storage period,the IGF-1 activity retention rate of camel milk in the compound fermentation group of Lacticaseibacillus casei Zhang and Bifidobacterium animalis subsp.lactis V9 decreased by nearly 40%from 85.31%at the end of fermentation to 60.18%at the end of storage period;and The activity retention rate of fermented camel milk IGF-1 in the probiotic group was higher than that in the control group.(3)When stored for 21 days,the volatile flavor compounds of camel milk in the compound fermentation group of Lacticaseibacillus casei Zhang and Bifidobacterium animalis subsp.lactis V9 had higher similarity with the control group,and had more flavor than the original camel milk substance.In conclusion,adding probiotics Lacticaseibacillus casei Zhang and/or Bifidobacterium animalis subsp.lactis V9 to fermented camel milk can not only impart probiotic effects to fermented camel milk,but also improve texture properties,storage stability and sensory properties.The study provides a theoretical basis for the practical production and application of probiotic fermented camel milk. |
