Stabilization And Controlled Release Mechanism Of Nutrients Nanocarriers Prepared With Synergistic Food Polysaccharides-Protien Complex

Polysaccharide and protein, the most common biopolymers involved in food systems, play important roles in the stability, textural properties, rheological behavior, processability and favor of food. The exploitation of polysaccharide-protein interactions offers opportunities for the design of new food with different structures and functional properties, and for the improvement of the existing food on their properties as well. The preparation of microcapsules with polysaccharides-protien complex has become a key method for the design of functional food.The polysaccharide-protein interaction varies, depending on the feature of the materials and the environmental conditions. Understanding the nature of the materials and the key parameters is thus essential for the rational formulation of the polysaccharide-protein complex. The proteins with nature cavity structure, i.e., whey protein and ferritin, were selected as wall material to complex with different food polysaccharides with alternative features, in order to obtain microcapsules with stabilization and controlled release properties. All the results are as followed:1Effect of temperature on the stability of pectin solutions:Heated at100℃, the pectin solution went through a dramatic disaggregation and degradation at first, followed by a peculiar raise at a specific time, normally around70min. It was conjectured that intermediates with relative aggregated structure were generated through re-organization and re-association process of disaggregated pectin chains formed at the first stage. This obvious and peculiar raise is more pronounced at higher concentrations with each esterification degree studied. The aggregated intermediate was mainly stabilized through hydrogen bonds. Freezing-thawing cycle treatments would destroy these hydrogen-bonding mediated structures and eliminate the effect. This phenomenon might relate to unbranched or multiple-branching microstructure of different polysaccharides.2Effect of ionic strength on the stabitlity of whey protein:The stability of whey protein solution was decreased by serious protein aggregation and gelation caused by excess free calcium ions. If the calcium ions were pre-encapsulated and their activity was pre-limited, the calcium content could be doubled without significant effects on the stability of whey protein. The controlled release property of calcium was also improved.3The pectin-whey protein interactions under incompatible conditions:At pH7.4, the presence of negatively charged pectin could induce depletion aggregation in whey protein solution, and promote phase separation. The double emulsified microcapsules prepared with the complex showed protective and controlled release properties for the vitamin.4The polysaccharide-whey protein interactions under compatible conditions:The polysaccharide-whey protein complex prepared through electrostatic attraction was employed as the wall material of emulsified microcapsules. The complex significantly exhibited excellent protective effects and controlled release properties on vitamin E. The microcapsules formed by pectin-protein as wall material showed more resistance against enzymatic attacks because of the formation of compact aggregates promoted by electrostatic effects.5The stability of alginate-ferritin composite nanoparticles:The alginate-ferritin composite nanoparticles were prepared successfully in this study. Compared to ferritin solutions, alginate-holo/apo ferritin composite particles both showed higher stability, and no obvious aggregation domains were observed over the studied pH spectrum of3-10and NaCl concentration of0-1.0mol/L. The alginate provided a protective effect to ferritin molecules, which prevented the formation of protein aggregates induced by isoelectric point and high ionic strength.