Characterized Polysaccharides from Green Tea Inhibited Starch Hydrolysis and Glucose Intestinal Uptake by Inducing Microstructural Changes of Wheat Starch

Abstract

The purpose of the current study was to investigate the effect of green tea ethanol extract (GTE) and polysaccharide fractions from green tea (PFGs) on the hydrolysis of wheat starch, microstructural changes, and intestinal transport of glucose. The amount of resistant starch (RS) was significantly lowered in the water-soluble polysaccharide (WSP), water-soluble polysaccharide-pectinase (WSP-P), and water-insoluble polysaccharide-alkali soluble (WISP-Alk-Soluble; p < 0.05). The microstructures of gelatinized wheat starch granules with WSP, WSP-P, and WISP-Alk-Soluble were spherical with small cracks. The amount of intestinal transported glucose from digested wheat starch was 2.12–3.50 times lower than the control group. The results from the current study suggest that water- and alkali-soluble PFGs could be potential ingredients to lower starch hydrolysis as well as to control the postprandial blood glucose level when foods that contain starch are consumed.

Effect of Characterized Green Tea Extraction Methods and Formulations on Enzymatic Starch Hydrolysis and Intestinal Glucose Transport

“…It was also found that polysaccharides inhibited both α-amylase activity and starch hydrolysis . Our group previously found that water-soluble polysaccharides inhibited starch digestion by changing the microstructure of starch granules, inducing an increase of the RS content . Recently, it was shown that wheat starch granules surrounded by polysaccharides with intermolecular bonding such as O-H resulted in a disruption of the interaction between wheat starch and α-amylase .…”

“…47 Our group previously found that water-soluble polysaccharides inhibited starch digestion by changing the microstructure of starch granules, inducing an increase of the RS content. 20 Recently, it was shown that wheat starch granules surrounded by polysaccharides with intermolecular bonding such as O-H resulted in a disruption of the interaction between wheat starch and α-amylase. 19 To clarify the possibility of the structural interaction between wheat starch and GTEs or CATEPLUS, the current study further examined microstructural changes of enzymatically hydrolyzed wheat starch.…”

“…Polysaccharides obtained from green tea processing were proven to have a hypoglycemic effect. ,,, For instance, starch granules were surrounded by cordyceps polysaccharides, which would interrupt the interaction between leached amylose from wheat starch and digestive enzymes . Recently, our group characterized various polysaccharide fractions from green tea and then found that water-soluble polysaccharides (WSP) remarkably inhibited glucose absorption followed by changes in the microstructure of starch . In addition to catechins and polysaccharides, flavonol extracts obtained via the enzyme treatment of green tea contained quercetin, myricetin, and kaempferol, which are known to have biological functions such as inhibition activities of α-glucosidase. − In addition, several studies noted that dietary flavonol monoglucosides competitively inhibited glucose transport through the intestinal Na + -dependent glucose transporter (SGLT1) .…”

Effects of Freeze–Thaw Pretreatment Combined with Hot Air on Snake Gourd (Trichosanthes anguina L.)

“…Structure Characterization of Ethanol (TG1) and Water (TG2) Extraction 2.4.1. Preparation of TG1 and TG2 TG1 and TG2 were prepared according to the report [23] with a minor modification. First, 10 g of snake gourd powder was extracted twice with ethanol (1:15, w/v) at 75 • C for 1 h. After centrifugating (6000 rpm, 15 min), the supernatant was collected, condensed and lyophilized to give TG1.…”