不同凝胶化程度马铃薯淀粉的体外发酵特性研究

Studies on the Characteristics of Potato Starch with Different Gelatinization Degrees in Vitro Fermentation

虽然天然B型晶体结构的淀粉是一种2型抗性淀粉,但是绝大多数在食用前都要经过不同程度的热加工,导致其酶抗性显著下降。在一定的条件下,即使是易被酶水解的淀粉也有可能会逃脱小肠的消化进入结肠而被微生物利用,然而易消化淀粉进入结肠中对肠道菌群和人体健康的影响还未被关注。本研究通过精准控制水分含量和加热温度制备出不同凝胶化程度(DG)的马铃薯淀粉样品,通过体外粪便发酵试验明确其产气量、短链脂肪酸产量、肠道菌群组成等发酵特性。试验结果表明:在发酵前半阶段(0~12 h),产气量从低凝胶化程度淀粉样品(DG16)的9.8 mL增加到高凝胶化程度淀粉样品(DG100)的14 mL,乙酸和丙酸的产量也随着凝胶化程度的增加而逐渐增加,高凝胶化淀粉样品(DG100)的乙酸(67.26 mmol/L)和丙酸产量(61.19 mmol/L)显著高于低凝胶化淀粉样品(DG16,乙酸41.29 mmol/L,丙酸21.27 mmol/L);中、低凝胶化程度的马铃薯淀粉组(DG16、DG49)在发酵结束时具有最高的丁酸产量,这与发酵过程中罗斯氏菌属、毛螺菌科和布劳特氏菌属等菌群的增殖有关;中、高凝胶化程度淀粉组(DG49、DG65和DG76)在发酵结束时促进了巨单胞菌属的增殖,产生较高的乙酸和丙酸。结论:能够促进丁酸菌增殖及具有良好丁酸生成能力的低、中凝胶化程度的马铃薯淀粉(DG16、DG49)具有改善结肠健康的功能。

Although starch with natural B-type crystal structure is a typical type 2 resistant starch,most of them have to undergo varying degrees of thermal processing before consumption,resulting in a significant decrease in enzymatic resistance.Under certain conditions,even the digestible starch could escape digestion in the small intestine and enter the colon to be utilized by microbiota,which,however,has rarely been reported.The present study prepared a series of potato starch samples with different gelatinization degrees(DG)and investigated the fermentability by human fecal microbiota in an in vitro batch system.Gas production increased from 9.8 mL of gelatinized starch with low DG(DG 16)to 14 mL of gelatinized starch with high DG(DG100)during the first half of fermentation(0-12 h),and the acetate and propionate production also gradually increased with increasing DG.For instance,the yields of acetate(67.26 mmol/L)and propionate(61.19 mmol/L)of high gelatinized starch sample(DG100)were significantly higher than those of low gelatinized starch sample(DG16,41.29 mmol/L of acetate,21.27 mmol/L of propionate).Compared with other groups,gelatinized starch groups with low and medium DG(DG16,DG49)exhibited the higher butyrate yields at the end of fermentation.Moreover,Roseburia,Lachnospiraceae and Blautia were promoted by gelatinized starches with low and medium DG.Compared with other groups,gelatinized starch groups with medium and high DG(DG49,DG65 and DG76)promoted the proliferation of Megamonas,and generated higher levels of acetate and propionate.The proliferation of butyrate-producing bacterial and higher production of butyrate by gelatinized potato starch with low and medium DG(DG 16 and DG49)suggested that these starches could potentially improve the colon health function.