基于木质素/多酚修饰的菠萝皮渣纤维素纳米晶稳定Pickering乳液机制及功能调控

Pineapple as a typical tropical agricultural product in China, is rich in deep processing but easy to produce a large amount of peel. Based on the extensive coexistence of lignin, polyphenol and cellulose in foods as well as their interactions, this project uses pineapple peel as raw material to fabricate lignin/polyphenol modified pineapple peel cellulose nanocrystals (CNCs) and construct Pickering emulsion. The main research contents are as follows: 1. The lignin-modified CNCs are obtained by regulating pineapple peel lignin removal and hydrolysis conditions, and the lignin/polyphenol modified CNCs are obtained by blending with a typical polyphenol (tannic acid) solution. The modification mechanism of CNCs can be revealed by the modification parameters and structural characterizations analysis; 2. By constructing modified CNCs-stabilized Pickering emulsion, the correlations between lignin/polyphenol modification and emulsion structure/stability are clarified. The emulsion stabilization mechanism is revealed by establishing the correlations between the interface microstructure and rheological properties of emulsion; 3. The emulsion functional properties are regulated by lignin/polyphenol modified CNCs, and the corresponding structure-activity and dose-effect relationships between the structure/function of the emulsion are revealed. This project has great significances and practical values for developing plant components self-modified CNCs and structure/function regulation of Pickering emulsion, improving stabilization mechanism of CNCs based emulsion, and innovating the high value utilization of agricultural products processing wastes.

菠萝是我国典型农产品，加工形式丰富但易产生大量皮渣。本项目以其皮渣为原料，基于木质素-多酚-纤维素在食品中的广泛共存及相互作用现象，制备木质素/多酚修饰的菠萝皮渣纤维素纳米晶（CNCs）并构建Pickering乳液。主要研究内容：一、调控菠萝皮渣去木质素和水解条件获得木质素修饰CNCs，并与典型多酚（单宁酸）作用制备木质素/多酚修饰CNCs，基于修饰参数和结构特征分析揭示修饰机制；二、构建Pickering乳液，阐明木质素/多酚修饰CNCs与乳液结构/稳定性的相关性，建立乳液界面微结构和流变学特性的构效关系，揭示CNCs稳定乳液机制；三、通过木质素/多酚修饰CNCs调控乳液功能性质，揭示乳液结构/功能之间的构效、量效规律。本项目对于发展植物组分自修饰CNCs及其稳定的Pickering乳液结构/功能调控，完善CNCs稳定乳液机制，创新农产品加工废弃物的高值化途径，具有重要意义和实际价值。

项目基于植物细胞壁组织中纤维素-木质素-多酚紧密结合现象，提出通过控制果蔬皮渣去木质素程度和多酚调控改善纳米纤维素稳定Pickering乳液性能。基于植物组分（木质素、多酚）自调控的纳米纤维素绿色改性，不仅能够提高果蔬皮渣利用率，还能作为膳食纤维和多酚营养组分满足乳液营养需要。研究结果具有普遍性，能够为果蔬皮渣的高值化利用提供思路和理论指导。项目系统研究了纳米纤维素的分离制备技术，通过硫酸水解、球磨介质调控、TEMPO氧化等体系实现对典型果蔬皮渣（柠檬、菠萝皮渣）中的纳米纤维素的分离提取研究，构建了纳米纤维素的可控制备工艺。通过对纳米纤维素形貌和结构调控、纳米纤维素组分和与多酚、蛋白等协同手段稳定Pickering乳液进行了研究，重点解析了木质素/多酚对纤维素纳米晶结构和稳定Pickering乳液机制，分析了不同类型纳米纤维素及其与不同组分（多酚、蛋白）协同稳定Pickering性能和机制，解决了纳米纤维素界面失稳的瓶颈问题，明确了纳米纤维素Pickering乳液的稳定性、结构和性能的调控机制，建立了纳米纤维素结构—Pickering乳液特性——乳液应用与构效关系的相关机制和调控规律。项目有助于纳米纤维素在食品级Pickering乳液中的应用，目前已在乳液膜、调味料、酸奶、肉糜等产品中开展了应用研究。