Effect Of Peanut Butter With Different Viscosity On Gastric Emptying And Its Mechanism

Gastric emptying is an important process of food digestion,which is affected by various factors such as food structure and complex gastrointestinal environment.Viscosity is a key part of food structure.Some studies have found that high-viscosity foods can slow down gastric emptying,enhance human satiety,and reduce dietary intake,thereby reducing the possibility of obesity.However,other studies have found that high-viscosity foods can promote or even have no effect on gastric emptying.Therefore,there is no unified conclusion on the effect of food viscosity on gastric emptying.Here,we constructed peanut butter with different viscosities as food models in this study.Firstly,we used ultrasound to detect the effect of peanut butter viscosity on gastric emptying and full-feeling in volunteers.Secondly,the structural degradation,nutrient release and gastric emptying differences of peanut butter with different viscosities were investigated using dynamic artificial gastric system(AGDS)and semi-dynamic(INFOGEST)models.Then,the differences in gastric emptying between the two digestion models were compared by measuring the changes in p H,particle size,rheology,microstructure,proteolysis,triglyceride,and total amino acid content of the emptied chyme.Finally,mice model was used to observe the changes in the physicochemical properties of chyme,to analyze postprandial blood glucose and the secretion of related gastrointestinal hormones and neurotransmitters,and the expression of genes related to Cajal interstitial cell proteins and ion channels were also detected.The results of the study were summarized as follows:(1)Human ultrasound studies have shown that high-viscosity peanut butter significantly affected gastric antrum contraction,inhibited gastric emptying,enhanced satiety,and delayed food intake within 60 min after a meal(p<0.05).Consistently,highest antral area was observed after ingestion of a high-viscosity meal compared to control and low-viscosity peanut butter.Meanwhile,the gastric emptying rate of the high viscosity group was significantly lower than that of the other two groups within 60 min after a meal,and the gastric antrum motility was stronger,indicating that the viscosity of peanut butter may affect the gastric emptying rate by affecting the gastric motility.(2)In vitro digestion showed that the gastric emptying rate of peanut butter with different viscosity was significantly different(p<0.05).Nearly 60% of the diet in the control group was emptied from the stomach to the duodenum through the pylorus within 60 min,while only 20%was found in the high-viscosity group.At the same time,the peanut butter in the high viscosity group was significantly different from the control group in p H value,physical stability,rheological properties,particle size distribution,SDS-PAGE and nutrient release in the small intestine(p<0.05).Smaller,more uniform droplets in the microstructure of AGDS chyme support viscosity and proteolytic,lipolytic results.AGDS,which provide strong mechanical shearing and milling forces,may be more efficient than semi-dynamic digestion in peanut butter digestion.Also,differences in gastric emptying can lead to differences in nutrient delivery in the small intestine.(3)Mice experiments showed that high-viscosity peanut butter significantly inhibited the gastric emptying rate of mice within 60 min of digestion,thereby affecting the rate of small intestinal propulsion(p<0.05).It can be seen that within 60 min of digestion,the protein hydrolysis and fat aggregation of the chyme of the mice in the high-viscosity group were slowed down,while the p H value and particle size had no significant changes.The postprandial blood glucose and related gastrointestinal hormone levels showed that the postprandial blood glucose,insulin and ghrelin in the high-viscosity group were limited,and the significantly lower than those in the control group(p<0.05).The secretion of CCK was accelerated,and its secretion level was significantly higher than that of the control group(p<0.05).The changes in the levels of the neurotransmitters including VIP and 5-HT in mice showed that high-viscosity peanut butter increased the serum levels of the excitatory neurotransmitter 5-HT and decreased the inhibitory neurotransmitter VIP(p<0.05).Meanwhile,the analysis of ICC gene level and protein fluorescence expression showed that the immunofluorescence intensity of ICCoriginating channel protein HCN1 decreased when high-viscosity peanut butter was digested for 30 min.Moreover,the expression levels of related characterization proteins HCN1,c-kit,CX43,and Trpm7 decreased(p<0.05),indicating that high-viscosity peanut butter indeed inhibited the secretion of ICC,restricted gastric antrum pacing activity,and delayed gastric emptying.In conclusion,high-viscosity peanut butter can enhance satiety by inhibiting the number of ICC and affecting the secretion of gastrointestinal hormones and neurotransmitters,limiting the mobility of the gastric antrum,leading to delayed emptying,and reducing the postprandial blood glucose peak.In addition,gastric emptying rate was found to be critical for the digestion and absorption of nutrients in the small intestine in in vitro digestion model and in vivo experiments in mice.This study could provide research ideas and scientific data support for designing novel foods with optimal viscosity properties to control the rate of food caloric intake or release,thereby ultimately reducing the risks associated with diseases such as obesity.