CORRELATING THE STRUCTURE AND VISCOSITIES OF DIFFERENT PECTIN FIBERS TO IN VIVO HUMAN SATIETY AND IN VITRO GASTRIC DIGESTION VISCOSITIES USING A NOVEL IN VITRO GASTRIC DIGESTION METHOD

• Main Author: Logan, Kirstyn
• Other Authors: Goff, Douglas H.
• Language: en
• Published: 2013
• Subjects: pectin; fiber; fibre; satiety; satiation
• Online Access: http://hdl.handle.net/10214/7746

The effects of a simulated in vitro digestion model on the viscosity of solutions comprised of high methoxyl, low methoxyl, and low methoxyl amidated pectins were examined in conjunction with a human satiety study with healthy men (n=10) and women (n=15). Participants attended 8 morning sessions with a washout period of one week after a 12 h overnight fast. Self reported measurements were taken for the satiety parameters of hunger, fullness, satisfaction and prospective food intake using 100 mm VAS scales at predetermined time intervals over the course of 3 h. Orange juice solutions of each type of fibre were formulated to be either low viscosity (LV, 0.039±0.007 Pa•s) or high viscosity (HV, 0.14±0.035 Pa•s). The apparent viscosities of an in vitro digestion model simulating the gastric and duodenal phases in the presence of hydrolytic enzymes and bile salts were reported at 10 s-1 and 50 s-1. All pectin types showed varying apparent viscosities during the gastric phases, but showed considerable reductions in viscosity after the final phase. The low-methoxyl low and high viscosity pectin beverages were associated with the greatest effect on human subjective ratings of satiety, and high methoxyl low and high viscosity pectin beverages inconsistently exerting effects on satiety. Thus, some types of pectin are able to increase perception of satiety in humans. However, there was not a strong correlation between apparent viscosity of in vitro digestive fluids and total mean AUC for satiety related questions. Thus, fiber-induced satiety cannot be explained in full by digestate viscosity alone. === NSERC