Change of soybean oligosaccharides in the digestive tract.

Abstract

Soybean oligosaccharides(SOE) extracted from soybean whey serve as a growth-promoting agent for bifidobacteria.The effective components have been identified as the tri-and tetrasaccharide (SOR) fractions represented by raffinose (Raf) and stachyose (Sta). We therefore studied the digestibility of Raf and Sta. From the results of in vitro digestive experiments using the digestive enzymes, Raf and Sta were found to be almost indigestible.Raffinose and stachyose in the digestive tract of rats fed the conventional diet with 3.3% SOE were detected in the stomach and small intestine, but not in the large intestine or feces. Fecal excretion of Raf and Sta from germ-free mice was measured after one gastric intubation of SOR. Eighty to ninety percent of the Raf and Sta was recovered from the contents of the digestive tract and feces. These results suggest that Raf and Sta are neither degraded nor absorbed in the small intestine, but utilized efficiently by the microflora of the large intestine.

In Vitro Digestibility and Fermentation of Mannooligosaccharides from Coffee Mannan

“…One unit will liberate 1.0 mg of maltose from starch in 3 min at pH 6.0 at 37˚C. Digestion was started by adding 0.5 ml of ␣-amylase to 1ml of each substrate solution in a test tube and incubated at 37˚C for 4 h. Then the test tube was dipped into a boiling water bath for a few minutes to inactivate ␣-amylase (Kato et al, 1991). Oligosaccharides remaining after digestion were measured by high-performance liquid chromatography (HPLC).…”

Digestibility Characteristics of Isomaltooligosaccharides in Comparison with Several Saccharides Using the Rat Jejunum Loop Method

“…12,16) In particular, the activity of disaccharidases at the upper section of jejunum is considered to be highest. 17) In this study, the total length of a rat's small intestine was 90-110 cm, and the jejunum loop was the section of approximately 25 cm located below the duodenum. It is assumed that the jejunum loop in this experiment corresponds to the upper section of jejunum, where the disaccharidase activities must be highest.…”