Influence of temperature and pH on the antigen-binding capacity of immunoglobulin G in cheese whey derived from hyper-immune milk

Characterization of Bovine Serum Albumin and (-)-Epigallocatechin Gallate/3,4- O-Dicaffeoylquinic Acid/Tannic Acid Layer by Layer Assembled Microcapsule for Protecting Immunoglobulin G in Stomach Digestion and Release in Small Intestinal Tract

The protein-polyphenol layer by layer (LbL) assembled polymer composite microcapsule is a considerable delivery system that can be used to improve the bioactive stability and effectiveness of natural compounds in various applications. In the present study, three kinds of polyphenols were loaded in the sequence of (-)-epigallocatechin gallate (EGCG), 3,4- O-dicaffeoylquinic acid (3,4-diCQA), and tannin acid (TA) to prepare a BSA-polyphenol LbL membrane. The composition of IgG-(BSA-EGCG/3,4-diCQA/TA) _n microcapsules and their stability and releasing ability in the gastrointestinal tract were evaluated. In addition, by binding of these three kinds of polyphenols to BSA, the thermal denaturation temperature and ordered secondary structure of the BSA-polyphenol microcapsules were increased, and the time of scavenging activity on 2,2'-azinobis(3-ethylbenzothiazolin-6-sulfonic acid) free radicals was significantly prolonged. These findings suggest that (BSA-EGCG/3,4-diCQA/TA) _n microcapsules can not only protect IgG in food processing and stomach digestion but also release it in the small intestinal tract for bioactive delivery.

Hyperimmunised bovine milk and whey: influence of pH and enzymatic treatments on the antigen-binding capacity of immunoglobulin G

BACKGROUND

Hyperimmunised bovine milk and whey (whole and defatted) were submitted at 37°C to different pH values (between 1 and 10) and enzymes (pepsin, trypsin and chymotrypsin) at their optimum pH and the IgG immunoactivity against Campylobacter jejuni was measured by means of ELISA assays.

RESULTS

The kinetic antigen-binding capacity (ABC) losses follow a hyperbolic-type equation. The ABC of IgG is strongly reduced at low pH (1 and 2) and the effect is lower at alkaline pH (8 and 10). The presence of pepsin (at their optimum pH of 2) almost completely reduced the IgG ABC after 2 h of treatment. The ABCs are higher in whole products (milk and whey). The influence of trypsin and quimotrypsin on the ABCs is moderate (ABC losses lower that 25%).

CONCLUSIONS

The ABC of IgG obtained from hyperimmunised bovine defatted milk and whey is largely reduced in conditions similar to those found in the human digestive tract. Only whole milk can maintain around 40% of their initial ABC. IgG encapsulation or other methods to protect the immunoglobulin activities could be an alternative to use these type of products in final foods formulae.