De-branching of starch molecules enhanced the complexation with chitosan and its potential utilization for delivering hydrophobic compounds

Abstract

The current study aimed to prepare the complexes between debranched-waxy corn starch and chitosan polymers (DBS-CS), and then investigated their corresponding structural characteristics, rheological property and potent application in Pickering emulsion. The results indicated that the existence of chitosan significantly inhibited starch short-range molecular rearrangement for all DBS-CS samples, which was manipulated by both debranching treatment and chitosan content. Interestingly, this is the first study to reveal that the outstanding peak at 1.8 ppm in 1H NMR spectrum for sample DBS-CS was gradually shifted towards a lower-field region following an increased chitosan content. Moreover, the debranching treatment shifted the crystallinity pattern from A-type to B-type and the relative crystallinity of DBS-CS decreased gradually with the increased content of CS. All samples had a pseudoplastic fluid and shear-thinning behavior with an enhanced shear resistance following the complexation. The DBS-CS was applied in a Pickering emulsion for showing a greater emulsifying stability and a lower gel strength than native NS-CS prepared emulsion. Importantly, the encapsulation ability of curcumin in the DBS-CS emulsion was significantly improved, followed by an increase of 15.45% for its corresponding bioavailability compared to the control. Therefore, this study might highlight a potential carrier for delivering the bioactive substances in a green pattern.