RESTRICTED BOVINE SERUM-ALBUMIN DIFFUSION THROUGH THE PROTEIN NETWORKOF PASTA

Food digestion may be influenced by the diffusion processes that gover n the accessibility of substrates to enzymes, both within the intestin al lumen and within the food structure itself. The purpose of this stu dy was to determine the diffusion coefficient CD) of bovine serum albu min (BSA), which simulates or-amylase diffusional behavior, in the pas ta protein network. A diffusion cell consisting of two well-stirred co mpartments separated by a lasagne matrix was designed and used. Starch was enzymatically removed from the lasagne, and C-14-BSA was allowed to diffuse through the protein matrix for 26 h. The D obtained was sim ilar to 2-fold lower than the self-diffusion coefficient of BSA in fre e solvent. Protein network tortuosity, which increases path length dif fusion, was probably the main factor involved in this restricted diffu sion process. The presence of emulsified lipid, which is partly repres entative of the digestive environment, did not limit BA diffusion towa rd and within the pasta protein network.