Studies On The Preparation,Safety,Defecation Function And Weight Loss Of Banana Resistance Starch

Banana is one of the typical fruits in the tropical and subtropical areas.It has the rich nutritional value and physiological function.Banana has many physiologic functions,such as weight loss,defecation function,improvement for theimmunity,anticancer effect,antioxidative effect,protection againstcardiovascular disease,treating stomach ulcers and improvement for depression.These physiologic functions are related to resistant starch.Definition of resistant starch is the sum of starch and products of starch degradation not absorbed in the small intestine of healthy individuals.Production of banana is large.It is the fourth largest annual production,but their processing utilization coefficient is very low.So preparation of resistant starchfrom banana,which has many physiologic functions,is away to develop health food and functional food.In addition,the safety and mechanismfor weight loss,defecationfunction of banana resistant starch are still unclear.In this paper,green banana was used to produce banana resistant starch by the two steps combined enzyme hydrolysis.Theiroptimal parameters were optimized.Their safety was evaluated by animal experiment.Their physicochemical properties and rheological properties were analyzed to supply some parameters to industrial application for banana resistant starch.The animal models of constipation and obesity were established to evaluate weight loss and defecationfunction of banana resistant starch.Their mechanism was analyzed to provide scientific theoretical basis forindustrial application.The main resulats are as follows:1.Preparation of banana resistant starch by enzymic method and their technology optimizationThe processing technology of banana resistant starch prepared by a two-step hydrolysis was optimized.The optimization for the first step hydrolysis technology: the pectase to cellulose ratio was 1:2,the optimal dosage of enzyme was 0.27%,the reaction temperature was 45 °C,p H value was 5.7 and the reaction time was 50 min,the extract rate of RS was 73.02%.The optimization for the second step hydrolysis technology: the a-amylase to pullulanase ratio was 1:1,the optimal dosage of enzyme was 0.22%,the reaction temperature was 59 °C,pH value was 6.0 and the reaction time was 4.2 h.The extract rate of RS was 81.07%.2.The safety of banana resistant starchThe results of acute oral toxicity showed that LD50 of banana resistant starch to both female and male mice was more than 45 g/kg.It was classified as non-toxic.Results of thirty days feeding study indicated that prolong consumption of banana resistant starch had no damage effect on animal growth,hematopoietic function and liver and kidney function.It maximum non-effect dose was more than 50 g/kg.The results of Ames test indicated that revertant colony number is similar to spontaneous revertant colonies.No dose-effect relationship was observed.The mutation test in mice was negative.The results of the micronucleus rate and sperm malformation rate showed that banana resistant starch had no mutation and reproductive and developmental toxicity.3.The rheological propertiesof banana resistant starchThe degree of swelling and solubility of banana resistant starch increased with temperature.The light transmittance was inferior to corn starch.Their aging of paste was greater than corn starch and dependent on content.Iodine absorption curves showed that the maximum absorption peak of banana resistant starch was between 600 nm and 700 nm.Compared to amylase,little difference was observed.This indicated that banana resistant starch was rich in amylase and poor in amylopectin.The TPA showed that with the extension of cold storage time,the hardness of starch gel increased,springiness decreased and changes in resilience and cohesiveness were similar to springiness.4.The defecationfunction of banana resistant starchThe results showed that banana resistant starch had the function of moistening the intestines and freeing the stool.Banana resistant starch could induce decrease in SP in plasma and intestinal tissue of rats of model group.The dose-effect relationship was observed.This indicated that their mechanism of defecation function may be associated with increasement of the contents of SP in plasma and intestinal tissue.Different dosage of banana resistant starch could maintain the balance of intestinal flora and inhibit the growth of intestinal Enterococci and Enterobacteriaceae.It had little effect on the growth of rats and effective micoorganisms.5.The weight loss of banana resistant starch and their mechanismThe results of body weight of rats,rat body fat,blood indices indicated that banana resistant starch had the function of weight loss.Banana resistant starch could induce increase in the content of cholecystokinin and decrease in the content of Ghrelin and Gastrin.Thus,weight loss mechanism of banana resistant starch is by means of stimulating the secretion of gastrointestinal hormonesaffecting appetite,controlling food intake in rats,prolonging gastric emptying,achieve weight loss purposes.