Polysaccharide-Peptides-Based Microgels: Characterization, In Vitro Digestibility, and Rheological Behavior of their Suspensions

Coating layers and the use of fillers can alter the microgel's functional performance such as texture modifiers or delivery systems. The present research evaluates how the rheological properties of gellan-collagen peptides microgels suspensions and digestibility behavior can be modulated by the addition of a coating layer and by the use of starch (filler agent). Gellan-collagen peptides microgels were successfully produced through atomization process. Starch addition decreased anthocyanin retention (~ 1%) for non-coated particles, and for all formulations caused peptides loss (~ 32%), besides increasing the polydispersity of the microgels (> SPAN value). Gellan coating, on the other hand, caused anthocyanin loss (~ 2.5%) for non-starch microgels, produced more uniform particle sizes (< SPAN) and decreased collagen peptides adsorption in 72%. Rheology data demonstrated that microgels without both coating and starch did not influence the relative viscosity of suspensions (ƞ rel ) independently of concentration, within the range evaluated (2.5% – 15%). Moreover, the addition of starch in coated microgels led to a synergistic effect on the increase of ƞ rel, indicating that these microgels can exert greater influence on the viscosity of the product to which they are applied. Regarding the in vitro digestibility, although no particle disintegration was observed for any formulation before the intestinal phase, a distinguished degrading behavior occurred during this last stage, where coated particles added with starch exhibited the least degraded structure. Our work shows the potential of gellan-collagen peptides microgels for application in foods with high moisture content and to act as carriers of drugs and bioactive compounds for protection and controlled release applications.