Evaluating different chain conformation of mannoproteins during encapsulation of grape seed extract

Modification of wine bitterness is subtle and complex. To investigate the mechanism underlying the differences in the initial bitter inhibition of grape seed extract (MOPC) by mannoproteins (MPs), the molecular interactions between MPs from different chain conformations and MOPC at different concentrations were analyzed using methylation, laser light scattering, rheological behavior analysis, and spectral techniques. The results indicated that MPs with linear hyperbranched structures at low concentrations (0.25 mg/mL) exhibit strong initial bitter inhibition, primarily due to the structural characteristics of the MPs-MOPC binary complexes. This included binding protein components to MOPC through electrostatic and hydrophobic interactions and encapsulating protein components and MOPC within a dense, strongly hydrophilic polysaccharide shell. These findings provide a theoretical basis for producing more efficient MPs by clarifying the key conformation and mechanism by which MPs inhibit wine bitterness.