高静水压辅助果胶酶改性甘薯果胶及其对铅离子吸附能力的影响机制

发布时间：2021-05-26 18:50

　　甘薯（Ipomoea batatas.L）是世界第六大主要粮食作物,中国是世界上最大的甘薯生产国。甘薯淀粉生产过程中会产生大量薯渣,大部分薯渣作为废弃物直接丢弃,资源浪费和环境污染严重。薯渣中富含果胶,果胶除用作胶凝剂和增稠剂外,近年来作为新型高效生物吸附剂已吸引了人们的广泛关注。然而,作为具有高分子量和复杂结构的天然大分子聚合物,果胶的应用范围受到极大限制,需要对其进行改性,以改善其理化性质,扩大应用范围。因此,本研究采用高静水压和/或果胶酶处理对天然甘薯果胶进行改性,并研究改性处理对果胶结构、理化功能特性及Pb²⁺吸附能力的影响,并揭示其作用机制。该成果可为扩大甘薯果胶的利用提供理论支持。首先,研究了高静水压及果胶酶改性处理对甘薯果胶结构、理化特性及乳化活性的影响。结果显示,200MPa、15min、酶与底物浓度比为72 U/g时,甘薯果胶的分子量与酯化度最低。与单独高静压和果胶酶改性相比,高静压/果胶酶协同改性后果胶的分子量和酯化度最低,分别为0.05×10⁵ g/mol和18.16%;鼠李糖（16.73%）、半乳糖醛酸含量（757.3... 

【文章来源】：中国农业科学院北京市

【文章页数】：122 页

【学位级别】：博士

【文章目录】：
摘要
abstract
Abbreviations
CHAPTER 1 INTRODUCTION
    1.1 General Introduction
    1.2 Pectin
    1.3 Extraction methods of pectin
        1.3.1 Acid extraction
        1.3.2 Ultrasound assisted-extraction(UAE)
        1.3.3 Microwave-assisted extraction(MAE)
        1.3.4 Enzyme-assisted extraction(EAE)
        1.3.5 Subcritical water extraction(SWE)
    1.4 Modification methods of pectin
        1.4.1 Chemical modification of pectin
        1.4.2 Enzymatic modification of pectin
        1.4.3 Physical modification of pectin
    1.5 Functional properties of pectin
        1.5.1 Antioxidant,antitumor and anticancer activities
        1.5.2 Cholesterol lowering property
        1.5.3 Blood glucose lowering properties
        1.5.4 Prebiotic potential
        1.5.5 Heavy metal removal capacity
    1.6 Effect of heavy metals on environment and human health
        1.6.1 Effect of Pb on environment and human health
        1.6.2 Role of pectin in Pb biosorption
    1.7 Aim and content of research
        1.7.1.Aim
        1.7.2.Research content
        1.7.3.Technical road map
CHAPTER 2 EFFECT OF HHP ASSISTED PECTINASE MODIFICATION ON THE STRUCTURAL AND PHYSICOCHEMICAL PROPERTIES OF SWEET POTATO PECTIN
    2.1 Introduction
    2.2 Materials and methods
        2.2.1 Materials and reagents
        2.2.2 Preparation of pectin from sweet potato residue
        2.2.3 Preparation of modified sweet potato pectin
            2.2.3.1 Preparation of HHP– assisted pectinase treated sweet potato pectin
            2.2.3.2 Preparation of pectinase treated sweet potato pectin
            2.2.3.3 Preparation of HHP treated sweet potato pectin
        2.2.4 Proximate composition of sweet potato residue before and after enzymatic treatment
        2.2.5 Molecular mass distribution of pectin
        2.2.6 Degree of esterification(DE)and acetylation(DA)of pectin
        2.2.7 Degree of methoxylation(DM)of pectin
        2.2.8 Neutral sugars and uronic acids content of sweet potato pectin
        2.2.9 Analysis of Fourier transforms infrared spectroscopy(FTIR)
        2.2.10 H1Nuclear magnetic resonance spectroscopy(NMR)
        2.2.11 Morphological analysis of pectin
        2.2.12 Atomic force microscopy(AFM)
        2.2.13 Rheological properties of pectin
        2.2.14 Emulsifying properties of pectin
    2.3 Statistical Analysis
    2.4 Results and discussion
        2.4.1 Proximate composition of sweet potato residue before and after enzymatic treatment
        2.4.2 Molecular mass distribution and DE values of sweet potato pectin under single factor experiment
            2.4.2.1 Effect of different pressure on the Mw and DE values of swee potato pectin
            2.4.2.2 Effect of different time on the Mw and DE values of swee potato pectin
            2.4.2.3 Effect of different enzyme concentration on the Mw and DE values of swee potato pectin
        2.4.3 Molecular mass distribution,DE,DM,and DA values of sweet potato pectin under optimum conditions with different HHP and pectinase treatments
        2.4.4 Neutral sugars and uronic acids of sweet potato pectin samples
        2.4.5 FTIR analysis
        2.4.6 H~1 NMR analysis
        2.4.7 SEM analysis
        2.4.8 AFM analysis
        2.4.9 Rheological properties of sweet potato pectin samples
        2.4.10 Emulsifying properties of sweet potato pectin
    2.5 Conclusion
CHAPTER 3 EFFECT OF HIGH HYDROSTATIC PRESSURE-ASSISTED PECTINASE ON THE PB2+ADSORPTION CAPACITY OF PECTIN FROM SWEET POTATO RESIDUE
    3.1.Introduction
    3.2.Material and methods
        3.2.1 Materials and regents
        3.2.2 Pb~(2+) removal experiment
        3.2.3 Adsorption isotherms
        3.2.4 ζ -potential of pectin
        3.2.5 Characterization of samples before and after adsorption
        3.2.6 Statistical analysis
    3.3 Results and discussion
        3.3.1 Adsorption isotherms
        3.3.2 Effect of pH,pectin concentration and contact time on Pb~(2+) binding capacity
            3.3.2.1 Initial pH
            3.3.2.2 Pectin addition
            3.3.2.3 Time
            3.3.2.3 Temperature
        3.3.3 Adsorption potential for different metal ions
        3.3.4 FTIR Analysis
        3.3.5 H~1 NMR Analysis
        3.3.6 XPS analysis
        3.3.7 SEM- EDS Analysis
        3.3.8 AFM images
        3.3.9 Mechanism for enhanced Pb~(2+) removal by HHP assisted E pectin
    3.4 Hypothetical mechanism diagram
    3.5 Conclusion
CHAPTER 4 EFFECT OF IN VITRO GASTROINTESTINAL DIGESTION ON Pb~(2+) ADSORPTION CAPACITY OF SWEET POTATO PECTIN
    4.1 Introduction
    4.2 Material and methods
        4.2.1 Materials and regeants
        4.2.2 Preparation of natural and modified pectin from sweet potato residue
        4.2.3 Preparation of digestive fluids
        4.2.4 Pb~(2+) adsorption process of sweet potato pectin under stimulated gastrointestinal tract
        4.2.5 Characterization of samples before and after adsorption
        4.2.6 Statistical analysis
    4.3 Results and discussion
        4.3.1 Pb~(2+) adsorption process of sweet potato pectin under stimulated gastrointestinal tract
        4.3.2 FTIR analysis
        4.3.3 H~1 NMR analysis
        4.3.4 XPS analysis
        4.3.5 SEM analysis
        4.3.6 AFM analysis
    4.4 Conclusion
CHAPTER 5 OVERALL CONCLUSION AND RECOMMENDATION
    5.1 Conclusion
    5.2 Recommendations
BIBLIOGRAPHY
Acknowledgement
Resume


【参考文献】：
期刊论文
[1]超高压处理对甜菜果胶结构及乳化特性的影响[J]. 彭小燕,木泰华,孙红男,张苗,于明,何伟忠.  中国农业科学. 2015(07)
[2]改性甘薯果胶对癌细胞增殖的影响[J]. 张燕燕,木泰华,张苗.  中国农业科学. 2012(09)



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