079: Microencapsulation With Casein and Pectin Enhances the Antioxidant Activity of Anthocyanins and Their Storage Ability

Introduction

In the food industry, anthocyanins (ACN) have received much attention for their superior antioxidant activity and health benefits. However, their sensitivity to environmental factors and low stability limit their application in functional foods. ACN interact with proteins via hydrophobic interactions because of the high affinity between ACN and proteins. Subsequently, the ACN-loaded proteins are cross-linked with polysaccharides via electrostatic interactions to form gelatinous polymers, which are ultimately turned into powder through spray drying. By utilizing this property, microcapsules with high encapsulation rate and controllable release can be prepared to achieve protective loading of ACN in complex food substrates and enhance their antioxidant capacity.

Methods

In this study, we investigated the structure-stability relationship between casein and anthocyanins (ACN) using computational calculations and experimental methods, including UV-vis Spectrophotometry, Fluorescence Quenching, and Molecular Dynamics Simulations. Additionally, the ACN-loaded proteins were cross-linked with pectin to obtain microencapsule particles. Finally, these microencapsulations (ACN-loaded microcapsules) were collected after spray drying. The particle size distribution, chemical structure, and surface morphology of the microcapsule system were comprehensively characterized using Zetasizer Nano-ZS, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Furthermore, we thoroughly evaluated the antioxidant capacity and storage stability of ACN-loaded microcapsules. Finally, by establishing in vitro digestion model, these ACN-loaded microcapsules were used to assess the preservation of ACN stability and bioactivity.

Results

Our studies demonstrated that ACN-loaded proteins showed that ACN formed stronger interactions with the protein through hydrophobic interactions. ACN-loaded microcapsules were prepared by spray drying and exhibited high encapsulation efficiency and drug loading. Stability tests showed that the ACN-loaded microcapsules had enhanced pH stability and storage stability. Antioxidant assays revealed that, compared to free anthocyanins and ACN-loaded proteins, the ACN-loaded microcapsules exhibited stronger antioxidant activity. Additionally, in vitro digestion experiments showed that the ACN-loaded microcapsules demonstrated stronger retention of anthocyanins during both the gastric and intestinal phases, reducing degradation.

Significance

This study offers a practical approach to enhance the stability and bioactivity of anthocyanins, making them more suitable for use in functional foods. The encapsulation technique could support the development of novel food products with improved antioxidant properties and longer shelf life.

Authors: Fangfang Li, Zipei Zhang