Hot water extraction and artificial simulated gastrointestinal digestion of wheat germ polysaccharide.

The conditions of wheat germ polysaccharide extraction were determined using the water extraction method. The gastric and intestinal digestion of wheat germ polysaccharide was analyzed in vitro. According to a single factor experiment and response surface experiment, the optimal extraction conditions of wheat germ polysaccharide were the following: liquid-solid ratio, 5:1 mL/g; extraction temperature, 69 °C; repetition of the extracting procedure, 3 times; extraction time, 44 min. Under such conditions, wheat germ polysaccharide yield was 8.89% ± 0.002%. In the in vitro gastrointestinal experiment, wheat germ polysaccharide was digested and the content of reducing sugar increased during the digestion period, indicating that this increase might be due to the breakdown of glycosidic bonds in the wheat germ polysaccharide. Furthermore, no monosaccharide was detected, demonstrating that the gastrointestinal digestion did not cause free monosaccharide released. These results show some preliminary characteristics of the wheat germ polysaccharide in vitro digestion, providing a theoretical basis for further understanding wheat germ polysaccharide properties.