[Preparation and physicochemical properties of double aldehyde starch microcapsules loaded with tea polyphenols].

Objective: To achieve high-value and functional applications of Mongolian oak starch resources.

Methods: Dialdehyde Mongolian oak starch was prepared by modifying Mongolian oak starch with NaIO_4, using the degree of aldehyde substitution as an indicator to study the oxidation conditions. The dialdehyde Mongolian oak starch was then combined with gum arabic to create a composite wall material for encapsulating tea polyphenols, and the reaction conditions were optimized through PB tests and response surface analysis to investigate the encapsulation efficiency and sustained release properties of the polyphenols.

Results: When the oxidation temperature was 35℃, oxidation time was 3 hours, and the oxidation pH was 2, a nearly linear relationship was observed between the degree of double aldehyde substitution and the amount of oxidizing agent when the molar ratio of NaIO_4 to Mongolian oak starch was less than 0.65. The optimal preparation conditions for the microcapsules were a degree of aldehyde substitution of 65%, a core-to-wall ratio of 1∶3.5, a wall material ratio of 1∶1, a solid-to-liquid ratio of 1∶40, encapsulation time of 4.0 hours, encapsulation temperature of 50℃, and an emulsifier dosage of 4 wt%. Under these conditions, the encapsulation efficiency of the microcapsules reached 90.856%.

Conclusion: The microcapsules containing double aldehyde Mongolian oak starch wall material can selectively dissolve in intestinal environments and release tea polyphenols, achieving targeted release and demonstrating selective sustained-release effects.