食品科学 ›› 2025, Vol. 46 ›› Issue (10): 11-21.doi: 10.7506/spkx1002-6630-20240903-015

• 基础研究 • 上一篇    下一篇

季铵修饰壳聚糖气凝胶吸附焦糖色素的传质及密度泛函理论分析

李明星，黄齐齐，陆海勤，韦艳红，李文，李凯   

  1. （1.广西大学轻工与食品工程学院，广西 南宁 530004；2.广西民族大学化学化工学院，广西林产化学与工程重点实验室，广西 南宁 530008）
  • 出版日期:2025-05-25 发布日期:2025-05-07
  • 基金资助:
    国家自然科学基金青年科学基金项目（32001741）；国家自然科学基金地区科学基金项目（32160569）

Quaternary Ammonium-Modified Chitosan Aerogels for Adsorbing Caramel Pigments: Mass Transfer and Density Functional Theory Analysis

LI Mingxing, HUANG Qiqi, LU Haiqin, WEI Yanhong, LI Wen, LI Kai   

  1. (1. School of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China; 2. Guangxi Key Laboratory of Chemistry and Engineering of Forest Products, School of Chemistry and Chemical Engineering, Guangxi Minzu University, Nanning 530008, China)
  • Online:2025-05-25 Published:2025-05-07

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摘要： 本研究合成一种用于回溶糖浆脱色的季铵修饰壳聚糖气凝胶（quaternary ammonium-modified chitosan aerogel，QCSA）。以焦糖色素（回溶糖浆代表性色素）为吸附模型底物，考察QCSA吸附性能；采用新型Wen Li-Wei Wei吸附传质混合（Wen Li-Wei Wei adsorption mass transfer mixed，LWAM）唯象数学模型解析QCSA吸附焦糖色素传质机制；应用密度泛函理论（density functional theory，DFT）探究QCSA吸附焦糖色素微观相互作用机制。结果表明，在焦糖色素初始质量浓度60、80、100 mg/L条件下，QCSA平衡吸附量分别为198、263、308 mg/g，相应焦糖色素去除率分别为99.8%、98.2%、92.4%。LWAM唯象数学模型解析表明，吸附限速步骤由外扩散、内扩散及位点结合共同决定。DFT分析表明，QCSA吸附焦糖色素机制以静电相互作用主导，在—COO－/—COOH（焦糖色素）氧原子与—OH/—NH3＋（质子化QCSA）氢原子间产生氢键等弱相互作用，且焦糖色素分子为氢键受体。其中，O···H氢键发挥重要作用，其局部表面积占总氢键表面积的37.88%。综上，LWAM唯象数学模型可准确计算吸附过程任意时刻液膜、孔道及位点捕获量，为阐明吸附传质机制提供新视角。DFT分析有助于在原子水平上解析吸附体系中分子间相互作用，为优化吸附剂设计提供理论支持。

关键词: 回溶糖浆；焦糖色素；吸附；传质；机制

Abstract: In this study, a quaternary ammonium-modified chitosan aerogel (QCSA) was developed for the decolorization of remelt syrup. Caramel pigments (a representative pigment from remelt syrup) were used as the adsorption model substrate to study the adsorption performance of QCSA. A novel Wen Li-Wei Wei adsorption mass transfer mixed (LWAM) phenomenological mathematical model was used to analyze the mass transfer mechanism of QCSA adsorption of caramel pigments. Density functional theory (DFT) was used to investigate the microscopic interaction mechanism of QCSA adsorption of caramel pigments. The results showed that the equilibrium adsorption capacity of QCSA for caramel pigments at initial concentrations of 60, 80, and 100 mg/L were 198, 263, and 308 mg/g and the corresponding decolorization rates were 99.8%, 98.2%, and 92.4%, respectively. Analysis using the LWAM phenomenological mathematical model showed that the adsorption rate-limiting steps were jointly determined by external diffusion, internal diffusion, and site binding. The DFT analysis showed that the adsorption mechanism of caramels by QCSA was dominated by electrostatic interactions. Weak interactions, such as hydrogen bonds, occurred between the oxygen atoms of –COO–/–COOH (caramel pigment) and the hydrogen atoms of –OH/–NH3+ (protonated QCSA), with caramel pigment molecules serving as hydrogen bond acceptors. Among them, O···H H-bonds played a significant role, accounting for 37.88% of the total H-bond superficial area. In summary, the LWAM phenomenological mathematical model can accurately calculate the capture amounts of liquid films, pore channels, and sites at any time during the adsorption process, thereby providing a new perspective for elucidating the underlying mass transfer mechanism. DFT analysis facilitates the understanding of intermolecular interactions in adsorption systems at the atomic level, offering theoretical support for optimizing adsorbent design.

Key words: remelt syrup; caramel pigments; adsorption; mass transfer; mechanism

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