The intestinal flora of the human body is closely related to health. Gut microbiota dysbiosis will lead to intestinal dysfunction and, consequently, a variety of intestinal diseases. In this study, subjects with different diseases were requested to take one of three microecological agents, stachyose, composite probiotics (CPb) and synbiotic MF-13. An Ion Torrent PGM^TM sequencing platform was used to analyze the structure of intestinal microflora and the contents of cholesterol and bile acid in the feces of the subjects were measured. Our aim was to investigate the regulatory effect of intervention with microecological agents on the intestinal microflora structure and lipid metabolism. The results showed that 1067 operational taxonomic units (OUT) were obtained from the fecal microbial samples from all subjects. The dominant bacteria were Firmicutes and Bacteroidetes, altogether accounting for 91.65%, and Bacteroidetes accounting for about 70.10% of the total number of sequences. Bacteroides and Prevotella were the dominant genera, accounting for 33.1% and 33.8% of the total sequences, respectively. At the phylum level, stachyose promoted the proliferation of Bacteroidetes, but inhibited the proliferation of Firmicutes. CPb had no significant effect on the abundance of each phylum, while MF-13 promoted the proliferation of Proteobacteria and Actinobacteria. Stachyose significantly decreased the abundance of Sutterella in subjects with constipation and insomnia, CPb significantly decreased the abundance of Sutterella in subjects with diarrhea, and MF-13 increased the abundance of Parabacteroides. The analysis of intestinal microflora diversity showed that Chao1 index significantly increased during the early period of MF-13 intervention, while there were no significant changes in other diversity indexes. Cluster analysis and non-metric multi-dimensional scaling (NMDS) analysis showed that microecological preparation intervention changed the intestinal microbiota structure in most of the samples, and the microflora structure of all populations showed an overlapping tendency. The intestinal microflora species that significantly differed between individuals were analyzed using Metastat statistics, and it was found that there was no significant change in the abundance of OTUs before and after intervention with each microecological agent, while there was a significant difference between individual subjects. MF-13 significantly promoted the fecal excretion of cholesterol and bile acids (P < 0.05). In conclusion, stachyose has an obvious influence on the intestinal microflora structure of volunteers, while CPb and MF-13 do not. However, MF-13 can increase the intestinal excretion of cholesterol and bile acid, which is beneficial to the metabolism of intestinal cholesterol, but the durability of this effect is poor.

This study explored the impact of ultra-high pressure jet (UHPJ) treatment on the quality of fresh skimmed milk. After UHPJ treatment at pressures ranging from 100 to 300 MPa, the changes in the color, odor and overall flavor of skimmed milk were detected by using electronic eye, electronic nose and sensory evaluation. The results showed that the main color number of skimmed milk was white 4095, constituting 46.80%-53.83%. A total of 42 volatile flavor components such as esters, ketones, and aldehydes were detected by electronic nose. The majority of the flavor components exhibited milky, fruity, roasted, and grassy aromas. Principal component analysis (PCA) revealed that the flavor of samples treated at 300 MPa differed greatly from that of other treated samples. Sensory evaluation indicated that among the flavor attributes evaluated, milky aroma and sweetness were prominent, and there were considerable differences between different samples in terms of sweetness, peptone-like, rusty, burnt and bland flavors. Samples treated at 250 and 300 MPa generated sulfide compounds such as dimethyl sulfide that significantly enhanced the burnt and peptone-like flavors of skimmed milk. In conclusion, UHPJ treatment with 200 MPa can better retain the flavor components in skimmed milk and consequently maintain the flavor of raw milk.