Lipid Changes During Braised Pork Stew And Its Effect On The Intestinal Flora Of Rats

Braised pork is rich in fat and protein,and its main processing technology is to cook it for a long time under low heat.The fat in braised pork is a typical stewed pork fat(stewed pork fat,the same below).It is generally believed that excessive intake of saturated fatty acids in braised pork may cause cardiovascular and cerebrovascular diseases.However,it is reported that the long-term intake of braised pork benefits for the health of the elderly and the reason may be stewing changes the composition of fatty acids in braised pork.Dietary fat can slow down the rate at which food passes through the gastrointestinal tract to increase the digestibility of nutrients such as fats and proteins,and play a role in the balance of the intestinal microbiota.Different fatty acids also have different effects on the intestinal microflora of the body.At present,the research on the quality change and its effect on the physiological function of stewed pork stew is very limited.On this basis,the non-fat group was used as a blank group,and refined lard,fish oil,and soybean oil were used as control groups to study the influence of stewed pork fat intake on rat basal physiological indicators and intestinal microflora,to provide the basis for the healthy and nutritious cooking and eating of braised pork.The specific research content and results are as follows:1.Study on the quality change of braised pork in the process of stewingIn order to explore the influence of the stewing process on the main nutritional components and quality,the basic nutrition,texture quality,fatty acid composition and sensory quality of braised pork at different time(60 min,90 min,120 min,150 min)were determined.The study found that the moisture content in the sample decreased with the stew time,the fat content decreased significantly(p<0.05),and the protein content increased significantly(p<0.05).After a long period of stewing,the hardness,chewiness,and shearing power of the braised pork showed a downward trend,and the elasticity showed an upward trend,and the color became golden red and bright.The TBARS value of the broiled meat increased significantly to 0.95 mg MDA/kg,and the value gradually decreased to 0.28 mg MDA/kg with the extension of the simmering time.After a long period of stewing,the total saturated fatty acids of braised meat showed a downward trend,and the monounsaturated fatty acids showed an overall upward trend.Compared with the raw meat,the ratio of unsaturated fatty acids and saturated fatty acids in stewed meat increased from 1.45 to 1.55.The results of the study show that:long time simmering can improve the nutrition and food quality of braised pork,and combined with sensory evaluation and fatty acid composition to determine the best stewing time is 120 min.2.Effect of stewed pork fat on growth and blood parameters in ratsThe fat-free group was used as a blank group,and refined lard,fish oil,and soybean oil were used as control groups to study the effects of stewed pork fat on general growth,blood glucose,blood lipid,and intestinal morphology of growing rats.The results showed that the intake and type of dietary fat had no significant effect on body weight in rats with equal intake of nutrient and energy(p>0.05).Compared with the refined lard group,stewed pork fat can reduce the content of fasting blood glucose(GLU),cholesterol(TC),triglyceride(TG)and low density lipoprotein(LDL-C)in rats to a certain extent,and increase the content of high density lipoprotein(HDL-C).The atherosclerosis index(AI)of the refined lard group was 4.19 significantly higher than that of the other groups(p<0.05),and the liver index was also higher than other groups.Compared with the fat-free group,the contents of TC and TG in the liver and feces of the homozygous diet group containing dietary fat were higher.The villus height of homozygous diet group containing dietary fat as significantly higher than that of the fat-free diet group(p<0.05).The villus height of duodenum and jejunum in the stewed pork fat group was significantly higher than that in the fat-free group(p<0.05).The ratio of villus height and crypt depth in the stewed pork fat group was higher than that in the other groups.The results showed that compared with fat-free diet,stewed pork fat will improve fasting blood glucose and blood lipid levels,but it can improve the intestinal absorption of nutrients.Compared with the refined lard group,stewed pork fat can reduce the body's fasting blood glucose and blood lipid levels to a certain extent,and can improve the intestinal absorption of nutrients.3.Effect of stewed pork fat on intestinal microflora in ratsIllumina HiSeq sequencing technology was used to detect the intestinal microflora of rats in the fat-free group,experimental group,refined lard group,fish oil group,and soybean oil group,to observe the diversity of intestinal microbial diversity of dietary fat.12 phyla,37 families,and 73 genus species were detected from five groups of samples.Compared with the homozygous diet group containing dietary fat,the Bacteroidetes abundance in the fat-free group decreased,the Firmicutes abundance increased,and the ratio of the Firmicutes/Bacteroidetes increased.In the homozygous diet group containing dietary fat,the ratio of Firmicutes/Bacteroides in the fish oil group was the lowest,and the ratio in the experimental group and soybean oil group was lower than that in the refined lard group.The results showed that the fat-free diet will increase the risk of obesity to some extent.Stewed pork fat,soybean oil and fish oil can reduce the risk of obesity to a certain extent compared with refined lard;compared with other dietary fat groups,stewed pork fat will increase the abundance of Bacteroidaceae in rats.In addition,dietary fat addition and species will affect the distribution of intestinal microflora in rats to some extent.In summary,stewing can improve the food quality and nutritional quality of pork.Compared with refined lard,stewed pork fat can reduce blood glucose and lipid levels in the body.Compared with the non-fat diet,stewed pork fat can not only improve the digestion and absorption capacity of the intestine,but also improve the intestinal flora constitutes a proportion.