發(fā)布時間：2021-10-31 23:16

　　羊乳的凝乳能力差,加工酸奶后會導致酸奶乳清析出、干酪得率顯著降低。超聲處理是一種非熱加工技術(shù),廣泛應用于食品加工行業(yè)中,可有效起到殺菌、均質(zhì)、乳化、改性等作用。近年來,通過超聲加工技術(shù)改善羊乳凝乳能力成為研究熱點。本文開展了低強度（150-400 W）和高強度（2000-4000 W）超聲處理對羊乳理化、微生物及蛋白質(zhì)結(jié)構(gòu)的影響,研究了超聲對羊乳酶凝膠流變學特性和微觀結(jié)構(gòu)的影響,進一步評價了超聲處理對改善羊酸奶貨架期穩(wěn)定性及感官品質(zhì)。具體研究結(jié)果如下:研究了通過結(jié)合巴氏殺菌（72℃,15 s）和不同的超聲處理（150 W,200 W,300 W和400 W,10 min）對原料羊乳的理化和微生物的影響。經(jīng)過超聲處理的羊乳,其微生物數(shù)量、粘度、色差、脂肪球和酪蛋白膠束粒徑降低,但對膠體磷酸鈣和天然蛋白質(zhì)沒有任何影響。對酪蛋白膠束的結(jié)構(gòu)狀態(tài),pH值,鹽類平衡和色澤也沒有顯著影響。在20³0 kHz,12.1±0.89 W（超聲輸出功率800 W）的超聲條件下處理15³0 min,并測定了該處理對凝乳酶誘導凝膠的流變學特性和微觀結(jié)構(gòu)。與對照組（原料... 

【文章來源】：中國農(nóng)業(yè)科學院北京市

【文章頁數(shù)】：97 頁

【學位級別】：博士

【文章目錄】：
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



本文編號：3469048