Real-time monitoring of peptic and tryptic digestions of immunoglobulin G and the impact of dietary hydrocolloids on digestion

Abstract

Immunoglobulin G (IgG) exhibits potent antiviral, antibacterial, and immunological activities. The digestion process and bioavailability of IgG are often a concern. Dietary hydrocolloids are crucial for regulating healthy digestion and the bioavailability of protein as functional components. Understanding the effects of dietary hydrocolloids on the digestive kinetics of IgG is requisite. Herein, the pepsin and trypsin digestion of IgG was investigated using ordered porous layer interferometry (OPLI). The real-time variation in the interference spectral shift reflected by OPLI can be converted into changes in the optical thickness (OT) to obtain a degradation kinetics curve. The impact of dietary hydrocolloids, including alginic acid sodium salt (ALG), polydextrose (PD), and konjac glucomannan (KG), on IgG degradation was evaluated using OPLI. The results demonstrated that ALG significantly inhibited the degradation of IgG by pepsin under acidic conditions, whereas the addition of PD increased the Michaelis–Menten constant for IgG degradation by trypsin. Notably, this dependence is not based on the hydrocolloid viscosity, but relies more on the electrical properties. The study enhances our understanding of how hydrocolloids affect IgG digestion and could provide valuable insights into preserving IgG activity and facilitating the development of oral drugs or health products related to IgG.