Restricted Bovine Serum Albumin Diffusion through the Protein Network of Pasta

Food digestion may be influenced by the diffusion processes that govern the accessibility of substrates to enzymes, both within the intestinal lumen and within the food structure itself. The purpose of this study was to determine the diffusion coefficient ( D ) of bovine serum albumin (BSA), which simulates α-amylase diffusional behavior, in the pasta protein network. A diffusion cell consisting of two well-stirred compartments separated by a lasagne matrix was designed and used. Starch was enzymatically removed from the lasagne, and 14 C-BSA was allowed to diffuse through the protein matrix for 26 h. The D obtained was ∼2-fold lower than the self-diffusion coefficient of BSA in free solvent. Protein network tortuosity, which increases path length diffusion, was probably the main factor involved in this restricted diffusion process. The presence of emulsified lipid, which is partly representative of the digestive environment, did not limit BSA diffusion toward and within the pasta protein network.