| Resistant starch means " One type of starch and degradation products which can not be absorbed in small intestine of healthy body." It can be divided into four types:RSI, RS2, RS3, RS4. RS has many physiological effects like dietary fiber such as weight control, prevention of intestinal diseases, lower blood glucose and serum lipids, improved vitamin and mineral absorption. Compared with dietary fiber, RS has become the central issue because of the good processing properties. It can be added into different kinds of foods.Different types of RS have different effects on intestinal conditions and serum lipids because of different fermentation patterns. There are few dates about RS on human intestinal functions and comparing with different types of RS on physiological effects in domestic study. Studies abroad are only about RS2and comparing with RS2and RS3. Comparing with RS2, RS3and RS4are lack of dates.Retrograded Starch was prepared with the high-amylose corn starch by aotuclaving-cooling cycles and aotuclaving-cooling cycles combined with acids hydrolysis technology which could offer dates for industrial production. Rats were fed on different types of resistant starch to study the effects of RS on fermentation patterns, intestine and serum lipids. This study provides theoretical basis on the fermentation of colon and mechanism of intestinal health. The main conclusions of the research are as follows:1. Study on the preparation technology of retrograded starch with the high-amylose corn starch. The best preparation parameters using aotuclaving-cooling cycles: concentration of HylonⅦ starch solution is30%, temperature of starch solution is125℃, time of aotuclaving is45min, times of aotuclaving-cooling cycles are2. The yield of RS is about33.63%. The best processing conditions using aotuclaving-cooling cycles combined with acids hydrolysis technology are30%starch solution were aotuclaved at125℃for45min, hydrolyzed with0.15mol/L citric acid at room temperature for12hours after2times of aotuclaving-cooling cycles. The yield of RS3is about39.27%.2. SD rats which contain half male and half female were chosen as experimental animal. Different types of resistant starch were added into the feeds with10%. The types of resistant starch are HylonVll which contains53%of RS2, retrograded starch which contains39%of RS3and NOVELOSE2480which contains80%of RS4. During the experiment, Rats had free diets and water. The experiment was last for30days, testing various physiological indicators:(1) Weight and demands of the rats which from three experimental groups were lower than the control group and the RS4group is more significant. Describe satiety of RS4is the most intense and RS4is the best for weight control. The food efficiency in rats of three experimental groups was significant lower than the control group and there are no significant differences among the experimental groups. Describe that digestibilitise of RS are lower than the common corn starch and among the different types of RS are the same.(2) The intestinal tissue of rats. Weight and area of the ceacal wall in rats of three experimental groups were higher than the control group and there are no significant differences among the experimental groups. Describe that RS could supply the energy which making the ceacal wall thicker and heavier. Rats intestinal wall structures. Three different types of RS have damages on the structures of intestinal villi and the shape of intestine.(3) The intestinal condition of rats. The wet weight and moisture of caecal contents in rats of three experimental groups were higher than the control group and the RS2is the best in defecation. The pH of three experimental groups was lower than the control group and the group of RS3is the most significant.(4) The metabolites of rats. The free ammonia concentration of caecal contents in rats of three experimental groups was lower than the control group and the group of RS3is the most significant. The concentration of acetate, propionate, n-butyrate, iso-butyrate and total SCFAs of three experimental groups were higher than the control group. RS2was significant in increasing the concentration of acetate while RS3was significant in increasing the concentration of propionate, n-butyrate, iso-butyrate. Tracked and detected the indicators in the feaces of three experimental groups during the experiment. The patterns of pH, free ammonia and SCFAs concentration are the same. Each index was changed rapidly during the first10days and after15days became mild. RS3is the best regulator in intestinal metabolites. It can lower the concentration of bad metabolites and higher the concentration of good metabolites.(5) The serum lipids in rats. The AI and concentration of TG and TC of three experimental groups were lower than the control group. RS3was significant in reducing the concentration of TG while RS4was significant in reducing AI and the concentration of TC. Describe that RS4have superiority in regulating the serum lipids. 3、The results in vitro fermentation of RS2, RS3, RS4were the same as in vivo: SCFAs were primary produced in12h. The concentration of acetate, propionate, butyrate and total SCFAs were significant higher than the control group. The most significant increase is the concentration of butyrate. The pH and the concentration of free ammonia in fermentation was first declined and then increased. Growth of Lactobacillus and Bifidobacterium were significant and growth of Enterobacter was inhibited in the later period. All the indicators showed that the fermented speed of three different types of RS are RS4>RS2>RS3and RS3is the best in regulating intestinal metabolites and flora. |
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