The effect of gel structure on the kinetics of simulated gastrointestinal digestion of bovine β-lactoglobulin

The structure and properties of protein gels depend on the conditions under which they are formed. Here, we assessed the susceptibility of protein to simulated gastro-duodenal digestion of weak gels with contrasting structures, produced from either purified bovine beta-lactoglobulin (beta-Lg) or whey protein isolate (WPI) at pH ranging from 2.5 to 6.5 and using different heating regimes. Gels formed close to the isoelectric point proved to be very resistant to simulated gastric digestion, with more than 85% of beta-Lg remaining and in the simulated duodenal phase of digestion. The sample heated to 85 degrees C was most resistant with over 40% remaining. In the WPI sample heated to 85 degrees C, more than 20% of the original beta-Lg content remained undigested after simulated gastro-duodenal proteolysis. These results suggest that firm particulate gels can persist longer in the Cl tract and may be useful in inducing satiety and thus provide another weapon in the fight against obesity. (C) 2012 Elsevier Ltd. All rights reserved.