Various studies have shown that food structure has an impact on digestion kinetics. We focus here on the effects of gastric and intestinal enzymes (in-vitro digestion) on two canola seed storage proteins, napin and cruciferin. To monitor structure effect we conducted experiments on gels of these proteins at different pHs, yielding different structures and elastic modulus. What is new is to get information on the mechanisms at the lowest scales, using imaging and radiation scattering at large facilities: Synchrotron fluorescence microscopy, X-Ray scattering, at SOLEIL synchrotron, and Small-Angle Neutron Scattering, at Laboratoire Léon Brillouin reactor. We can identify the mechanisms at each step and in two distinct scale ranges, observed simultaneously, the one of the individual protein scale and the one of the structure connectivity:
* during gelation individual canola proteins are not deeply modified in comparison with their state in solution ; larger scale gel heterogeneity appears due to connectivity or aggregation
* in the gastric step (up to 40 min):
a) at short scale (large q) we see that the proteins disintegration is much slowed down in gels than in solutions, particularly in the gastric phase;
b) at larger scales (low q), we see that the gel structure is also self-resistant to the action of the enzyme (pepsin).
* in the intestinal step, such kinetics differences hold until major disintegration after no more than 15 min.
Dr.Alexandros Koutsioumpas
Dr. Christian Franz