| Flatulence associated with the large consumption of sweet potatoes is the major factorthat limits the use of sweet potato as a staple food. Accumulation of intestinal gas could resultin discomfort, cramps, abdominal pain, diarrhea, etc. The primary goals of this study were to(1)determine the composition the soluble sugars in sweet potatoes；(2) to investigatedifferences on rates of hydrogen production, the total quantity and time of hydrogen producedbetween sweet potato and soybean；（3）to assess the flatulence potential of sweet potatoincluding soluble sugars and starch contents,as well as to investigate the effects of differentprocessing method, such as cooking in boiling water, superfine grinding or microwaving, onflatulence production in rats.Composition of the soluble sugars extracted with80%ethanol from raw and processedsweet potato tubers were analyzed by HPLC.The main component of flatus is hydrogen whichhas been found to be related to total flatus gas volumes. Hydrogen produced by rats is apredictive bioassay for flatulence in man. in man. In the present paper a modified Gumbmanand Williams′s method for collecting and measuring the hydrogen production in thelaboratory rat was developed.The major sugars in raw roots were sucrose, glucose, and fructose. The major sugars inprocessed roots(baked, steamed, microwaved, boiled, pressure cooked) were maltose, sucrose,glucose, and fructose. All kinds of the processes enhanced the amylase activity and resulted inmajor conversion of starch to reducing sugars; a slight change in amount of non-reducingsugars occurred upon processing. Large differences in sugars existed within the differentsweet potato varieties. The major sugars sucrose, glucose, and fructose were found in rawroots.Raffinose and its higher oligomers were not found in any of the varieties, which were inagreement with the most of earlier papers. The extent of hydrogen production by raw(cooked)sweet potato and raw(cooked) soybean was investigated with this new method. Three distinctphases existed for hydrogen produced by rat—a slow rat of hydrogen production at initialstage, followed by a rapid rate of accumulation at intermediate stage, the accumulation ofhydrogen became constant with a slow rate at the final stage. but for different samples, thetime and rates of hydrogen production on each the stage were different. The total quantity ofhydrogen produced between sweet potato and soybean were different too.Raw sweet potatoand soybean flatulence time were different, Soybean was slightly larger than the sweet potatoon time of hydrogen produced. The fraction of sweet potato which was extracted by water didnot contain soluble sugars, but the resulted in higher hydrogen than raw sweet potatoes.Thesoluble sugars seemed not to be the flatulence-produce factors in sweet potato. The flatusinduced by sweet potatoes was caused by a different components than flatulence caused bythe consumption of legume crops. A positive significant correlation coefficient of0.9356wasfound between the content of sweet potato starch and the flatus production by rats. Superfinesweet potatoes could reduce hydrogen to some extent. Cooking sweet potatoes was anefficient method to reduce the production of hydrogen, but there still had a longer total time ofhydrogen production compared to the control diet.Raffinose and its higher oligomers were not found in the sweet potatoes，content ofreducing sugars increased after heat treating. Soybean was slightly larger than the sweet potato on time of hydrogen produced. The starch appeared to be the major contributor toflatulence; Heat treating was an efficient method for reducing the gas-formation induced bysweet potato. |
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