热超声对山羊乳理化及凝胶特性的影响规律研究

发布时间：2021-10-31 23:16

　　羊乳的凝乳能力差,加工酸奶后会导致酸奶乳清析出、干酪得率显著降低。超声处理是一种非热加工技术,广泛应用于食品加工行业中,可有效起到杀菌、均质、乳化、改性等作用。近年来,通过超声加工技术改善羊乳凝乳能力成为研究热点。本文开展了低强度（150-400 W）和高强度（2000-4000 W）超声处理对羊乳理化、微生物及蛋白质结构的影响,研究了超声对羊乳酶凝胶流变学特性和微观结构的影响,进一步评价了超声处理对改善羊酸奶货架期稳定性及感官品质。具体研究结果如下:研究了通过结合巴氏杀菌（72℃,15 s）和不同的超声处理（150 W,200 W,300 W和400 W,10 min）对原料羊乳的理化和微生物的影响。经过超声处理的羊乳,其微生物数量、粘度、色差、脂肪球和酪蛋白胶束粒径降低,但对胶体磷酸钙和天然蛋白质没有任何影响。对酪蛋白胶束的结构状态,pH值,盐类平衡和色泽也没有显著影响。在20³0 kHz,12.1±0.89 W（超声输出功率800 W）的超声条件下处理15³0 min,并测定了该处理对凝乳酶诱导凝胶的流变学特性和微观结构。与对照组（原料... 

【文章来源】：中国农业科学院北京市

【文章页数】：97 页

【学位级别】：博士

【文章目录】：
摘要
Abstract
Abbreviations
Chapter1:Background and objectives
    1.1 Introduction
    1.2 Composition of goat milk
        1.2.1 Proteins
        1.2.2 Lipids
        1.2.3 Minerals and vitamins
    1.3 Ultrasound processing technique
        1.3.1 Effects of ultrasound on the casein micelles
        1.3.2 Effect of sonication(ultrasound)on whey protein
        1.3.3 Effect of sonication on fat globules
        1.3.4 Effect of sonication on coagulation
        1.3.5 Effect of sonication on minerals
        1.3.6 Effect of sonication on shelf life
    1.4 The Main Problems of This Research
    1.5 Objectives of Research
    1.6 Research contents
Chapter2:Effect of thermosonication process on physicochemical properties and microbial load of goat’s milk(Published I)
    2.1 Introduction
    2.2 Material and methods
        2.2.1 Sample preparation
        2.2.2 Thermosonication treatment of goat milk(TSGM)
        2.2.3 Microbiological analysis
        2.2.4 p H-measurements
        2.2.5 Soluble calcium and phosphorus analyses
        2.2.6 Viscosity
        2.2.7 Turbidity
        2.2.8 Particle size measurements
        2.2.9 Protein contents
        2.2.10 Gel electrophoresis
        2.2.11 Color measurement
        2.2.12 Statistical analysis
    2.3 Results and Discussion
        2.3.1 Microbiological analysis
        2.3.2 p H-measurements
        2.3.3 Size distribution
        2.3.4 Turbidity
        2.3.5 Soluble calcium and phosphorus analyses
        2.3.6 Colour
        2.3.7 Protein content
        2.3.8 Viscosity
        2.3.9 SDS-PAGE analysis
    2.4 Conclusion
Chapter3:Ultrasound improves the rheological properties and microstructure of rennet-induced gel from goat milk(Published II)
    3.1 Introduction
    3.2 Materials and methods
        3.2.1 Goat milk sample
        3.2.2 Ultrasonic(US)treatment
        3.2.3 Particle size and surface charge
        3.2.4 Transmission electron microscope(TEM)
        3.2.5 Fluorescence spectroscopy
        3.2.6 Fourier transform infrared(FTIR)analysis
        3.2.7 Gel preparation
        3.2.8 Rheological properties
        3.2.9 Microstructure
        3.2.10 Statistical analysis
    3.3 Results and discussion
        3.3.1 Particle size and surface charge
        3.3.2 Transmission electron microscope(TEM)
        3.3.3 Fluorescence spectroscopy
        3.3.4 Fourier transform infrared(FTIR)analysis
        3.3.5 Rheological properties
        3.3.6 Microstructure
    3.4 Conclusions
Chapter4:Microstructure and texture of the set yoghurt from thermosonication andhomogenization goat milk
    4.1 Introduction
    4.2 Materials and methods
        4.2.1 Milk samples
        4.2.2 Homogenization and thermosonication treatment
        4.2.3 Fluorescence spectroscopy
        4.2.4 Fourier transform infrared(FTIR)analysis
        4.2.5 Gel electrophoresis(SDS–PAGE)
        4.2.6 Manufacture of yoghurt
        4.2.7 Texture profile analysis(TPA)
        4.2.8 Water holding capacity(WHC%)
        4.2.9 Scanning electron microscopy(SEM)
        4.2.10 Statistical analysis
    4.3 Results and discussion
        4.3.1 Chemical composition and temperature during thermosonication process
        4.3.2 Fluorescence spectroscopy
        4.3.3 Fourier transform infrared(FTIR)analysis
        4.3.4 SDS page
        4.3.5 Texture profile analysis(TPA)
        4.3.6 Water holding capacity(WHC%)
        4.3.7 Microstructure by SEM
    4.4 Conclusions
Chapter5:Physicochemical and rheological properties of stirred yoghurt during storage inducedfrom high intensity thermosonicated goat milk
    5.1 Introduction
    5.2 Materials and methods
        5.2.1 Samples
        5.2.2 Homogenization and thermosonication treatment
        5.2.3 Particle size measurements
        5.2.4 The p H,soluble calcium and phosphorus analyses
        5.2.5 Yoghurt preparation
        5.2.6 Rheological properties
        5.2.7 Syneresis
        5.2.8 Titratable acidity and p H values
        5.2.9 Confocal scanning laser microscopy(CSLM)
        5.2.10 Color measurements
        5.2.11 Sensory evaluation
        5.2.12 Electronic nose
        5.2.13 Statistical analysis
    5.3 Results and discussion
        5.3.1 Particle size measurements
        5.3.2 The p H,soluble calcium and phosphorus analyses
        5.3.3 Rheological properties
        5.3.4 Syneresis
        5.3.5 Titratable acidity and p H values
        5.3.6 Confocal scanning laser microscopy(CSLM)
        5.3.7 Color measurements
        5.3.8 Electronic nose
        5.3.9 Sensory evaluation
    5.4 Conclusion
CHAPTER6
    6.1 Conclusions
    6.2 Recommendations for future research
    6.3 PUBLICATIONS
References
Acknowledgement
Resume



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