Study On Preparation Of The Set Tartary Buckwheat Yogurt And Its Modulation On The Intestinal Flora

The set tartary buckwheat yogurt combines nutritional value,peculiar flavor and health care value of both the yogurt and tartary buckwheat.In this work,based on the single factor experiments and the response surface method,the fermentation process of the set tartary buckwheat yogurt was optimized.Then,the quality of this yogurt was evaluated using high performance liquid chromatograph(HPLC)and gas chromatograph-mass spectrometer(GC-MS).Furthermore,the effect of this yogurt on the intestinal flora in mice was investigated based on the analytical methods of fluorescent quantitative PCR and pate count.These detailed results were shown as follows:1.By the acclimation of the strains of Streptococcus thermophiles GIM1.83,Lactobacillus bulgaricus GIM1.155 and lactobacillus plantarum ST-III.The mixed strain obtained had an obviously stronger fermentative capability,which resulted in a shorter coagulating time of 1h,a more enhanced total acidity by 5%,a higher viable count by 35%.The best mixed strain ratio was 1:1:2.2.Based on the single factor experiments,the fermentation process of the set tartary buckwheat yogurt production process was optimized using the response surface designed method,and then the best technological parameters were obtained.Based on the deployment by the addition of the suitable sweetener and stabilizer,the final production formula of the set tartary buckwheat yogurt was shown as follows:the addition of tartary buckwheat pulp 30%,inoculum amount 4%,fermentation temperature 40?,fermentation time 8h,guar gum 0.15%,CMC-Na 0.2%,sorbitol 2%,and aspartame 0.04%.3.On the basis of the analyzed results of the set tartary buckwheat yogurt,the total viable count was up to 2.98×109 CFU/mL,the total acidity up to 88.61 T and the flavonoids content up to 18mg/100g.Compared to the ordinary yogurt,the set tartary buckwheat yogurt contained a higher content of the total amino acids by45.14%,where the content of the essential amino-acids acids by40.7%.4.The volatile aromatic components in this yogurt were analyzed by two type methods,the electronic nose and the headspace solid-phase microextraction GC/MS.From the results,the obvious difference of volatile aromatic components between the set tartary buckwheat yogurt and the ordinary yogurt was found.Specifically,the content of ethanol,one of the main flavor substances,in the set tartary buckwheat yogurt was 3.25 times than that in the ordinary yogurt.At the same time,the tartary buckwheat yogurt also contained the long chain fatty acids,such as myristoleic acid,palmitic acid and arachidic acid,and the special aromatic heterocyclic compounds.5.From the oxidation resistance results of the tartary buckwheat yogurt,the DPPH radical scavenging capacity and ABTS radical scavenging capacity were up to 5.023?molTrolox/g DW and 1.012?molTrolox/g DW,respectively.6.The mice intestinal flora experiment results showed that compared with the mice fed by the typical yogurt,the amount of lactobacillus and bifidobacterium in the mice fed by tartary buckwheat yogurt increased significantly.On the contrast,the amount of E.coli decreased sharply.The results were in well agreement with that from qPCR.Moreover,the tartary buckwheat yogurt also could accelerate the amount of Clostridium tender from 107.11 to 108.02 copies/g and decrease the bacteroid amount.After the experiment,the short chain fatty acid content in the the tartary buckwheat yogurt groups increased significantly.