Effects of Tea Polyphenols on Emulsification of Olive Oil in a Small Intestine Model System

Abstract

Tea catechins have been shown to reduce plasma cholesterol and suppress hypertriacylglycerolemia by reducing triglyceride absorption. However, the mechanism is not yet clear. One of the possible mechanisms is that tea polyphenols may modify dietary fat emulsification in the gastrointestinal tract. The digestive enzyme (lipase) acts on specific emulsion interface properties (droplet size and surface area). Therefore, changes in these properties may modify emulsification and lead to changes in dietary fat digestion and absorption. In this study, the effect of both green and black tea on the changes of emulsification was examined by measuring the droplet size and the surface area. A model emulsion system containing olive oil, phosphatidylcholine (PC), and bile salt was developed to simulate small intestinal conditions. Initial changes in droplet size (from 1.4 to 52.8 microm and from 1.4 to 25.9 microm) of the emulsion were observed in the presence of 1.04 mg/mL and 0.10 mg/mL of total catechins prepared from green and black tea, respectively. Both teas caused similar changes on the emulsion properties; however, black tea was more effective than green tea. The underlying mechanisms of actions of tea polyphenols are discussed.

Bioavailability of procyanidin dimers and trimers and matrix food effects in in vitro and in vivo models

“…Different studies have been carried out into the interaction between polyphenols and a food matrix such as milk (23,24) , olive oil (25) or sugar (26) . The evidence suggests that variations in polyphenol absorption also occur due to * Corresponding author: Dr Maria-José Motilva, fax þ34 973 702596, email motilva@tecal.udl.es Abbreviations: GSPE, grape seed procyanidin extract; IN, fraction found inside dialysis solution; OUT, fraction found outside dialysis solution; PC, procyanidins.…”

“…Different studies have been carried out into the interaction between polyphenols and a food matrix such as milk (23,24) , olive oil (25) or sugar (26) . The evidence suggests that variations in polyphenol absorption also occur due to interactions between polyphenols and other food components.…”

Effects of Dietary Fish Oil and Apple Polyphenol on the Concentration Serum Lipids and Excretion of Fecal Bile Acids in Rats

“…Furthermore, green tea extract (32) and oolong tea polyphenols (33) are known to have lipase inhibitory activity. Shishikura et al (34) have reported the possibility that lipid absorption is suppressed by minimal ingestion of polyphenols. Sugiyama et al (18) also suggest that the small intestine inhibits absorption, which leads to the increased production of fecal bile acid.…”

The Inhibitory Effects of Anthocyanin-Rich Sunrouge Tea on Pancreatic Lipase Activity

“…According to Wang et al, the increasing of lipase inhibitory activity with catechins depended on the ratio of catechins to lipase and reach to the limit at the constant level 15 . Furthermore, lipase activity was also influenced by the emulsion particle size, which was determined by a number of factors such as mineral and emulsifier levels 21 . Therefore, the EEX-mediated inhibition of lipase might be suppressed by the catechin:lipase ratio and the level of emulsification.…”