Interactions between /Ractoglobulin and Pectins during in Vitro Gastric Hydrolysis

摘要

This paper deals with the influence of different levels of three pectins,low-methylated pectin (LMP),high-methylated pectin (HMP),and low-methylated and amidated pectin (LMA),on the in vitro gastric hydrolysis of beta-lactoglobulin (beta-Ig).Proteolysis by pepsin consisted of a 2-h progressive reduction of pH.A turbidity measurement of beta-Ig-pectin mixtures was carried out during the proteolysis.The influence of pectins on pepsin enzymatic activity was also evaluated.beta-Lg was resistant to peptic digestion.The presence of each of the three pectins at a concentration of 50 wt % increased the N release at all pH values considered,despite a significant inhibition of the pepsin enzymatic activity with the pectins.The turbidity of beta-lg solutions during proteolysis was reduced by the addition of pectins,because of the formation of electrostatic complexes between this protein and pectins.The increase of N release could be a false positive result due to the difficulty of precipitating protein by trichloroacetic acid because of the formation of electrostatic complexes demonstrated by the decrease of turbidity.