学位论文 > 优秀研究生学位论文题录展示

超高压对甘薯蛋白物化及功能特性的研究

作　者: Nasir Mehmood Khan
导　师: 木泰华
学　校: 中国农业科学院
专　业: 农产品质量与食物安全
关键词: 甘薯蛋白高静水压结构修饰理化性质 pH值乳化流变
分类号: TQ914.1
类　型: 博士论文
年　份: 2013年
下　载: 20次
引　用: 0次
阅　读: 论文下载

内容摘要

在中国,甘薯淀粉加工过程中会产生大量的废水,从废水中回收蛋白质既能实现经济效益,又能解决环境污染问题,因此越来越受到广泛的关注。甘薯蛋白(SPP)是甘薯淀粉加工后废水的主要成分,甘薯蛋白极富营养价值,它的氨基酸组成均衡、功能性质良好。研究表明SPP可作为功能性添加剂应用于食品产品的开发。为此,利用超高压技术对SPP进行适当结构修饰可增强SPP的功能性质,扩大其在食品行业的应用范围。本文研究了超高压处理(HHP)对不同浓度2%、4%和6%的SPP理化性质和乳化特性的影响。当压力从200MPa上升到600MPa时,SPP的疏水性、变性焓和溶解性会产生明显的改变(P<0.05)。当压力为400MPa时,SPP-2和SPP-6的乳化活性指数(EAI)升高；而在压力为600MPa时,所有SPP的乳化活性都显著下降(P<0.05)。当压力大于200MPa时,SPP-2和SPP-6的乳化稳定性显著下降,而SPP-4的乳化稳定性增加(P<0.05)。随着压力的升高,相比于SPP-4和SPP-6,SPP-2乳化剂的粘度急剧下降。Sporamin A和Sporamin B均被加压SPP乳化剂较好的吸收。这些结果显示HHP处理可以改变SPP的理化特性和乳化特性。本文还探讨了pH在3,7,8三个水平时HHP对SPP乳化剂理化性质的影响。在不同pH值条件下经过HPP处理后,不同乳化剂乳化活性指数(EAI)和乳化稳定性(ESI)都显著升高(P<0.05)。当压力从200MPa上升到600MPa时,油滴尺寸明显降低,而体积较小油滴的分布频率明显提升；pH为3、7、8的乳化体系中界面蛋白浓度也明显升高。在非还原条件下,pH为7的由SDS-PAGE组成的乳化体系中产生了由二硫键连接的高分子量聚合物。600MPa的超高压降低了流动指数,导致所有SPP乳化剂的水相粘度升高。pH为3和7时,经过和不经过HHP处理,SPP乳化剂都会剪切变释,而pH为8的乳化剂受到200MPa和400MPa的高压处理时则显示出牛顿流体的特性。结果表明,HHP处理所得的稳定乳化剂在食品行业中有广泛的应用前景。表面疏水性在pH为3时显著升高,而在pH为6和9时下降(P<0.05)。随着压力的增大,pH为6时乳化剂的EAI明显上升；在pH为6和9时乳化剂的ESI明显更高(P<0.05)。当pH为3和6的乳化剂经超高压处理时,会使体积较小油滴的分布频率升高,而油滴尺寸则明显下降。在pH为6和9时,经HHP处理的SPP乳化剂的粘度升高,但所有利用HHP处理的SPP乳化剂产品的假塑性均未改变。结果显示HHP能够改变SPP的结构使其具有更好的乳化性能,从而扩大其在食品行业的应用范围。相比于SPP凝胶模型,瓜尔胶中存在的SPP经HHP处理后乳化稳定性提高,乳化率降低,粘度明显提高。另外,GMS则对SPP的乳化能力产生负面影响,对乳化剂的稳定性、乳化率和粘度均产生不良影响。结果表明,HHP是改良瓜尔胶中SPP乳化能力的可靠方法。

全文目录

摘要  5-7
Abstract  7-16
1. INTRODUCTION  16-34
  1.1 Sweet potato protein  17-18
    1.1.1 Structure of sweet potato protein  17-18
  1.2 Protein as an emulsifier  18-19
  1.3 Introduction to emulsion  19-21
  1.4 Industrial Applications of Emulsions  21-22
  1.5 Emulsion characterizations  22-24
  1.6 Modification of protein structure for enhancing of proteinemulsifying efficiency  24-25
  1.7 Limitation of heat, chemical and enzymatic modiifcation ofprotein structure  25-26
  1.8 High hydrostatic pressure (HHP) for modification proteinstructure  26-29
  1.9 Emulsifying properties of protein with high hydrostaticpressure treatment (HHP)  29-30
  1.10 Progress in HHP treatment for protein modification  30
  1.11 Progress in emulsifying properties of sweet potato proteinresearch  30-31
  1.12 Aim and content of the research  31-34
2 EFFECTS OF HIGH HYDROSTATIC PRESSURE ON PHYSCOCHEMICAL AND EMULSIFYINGPROPERTIES OF SWEET POTATO PROTEIN  34-55
  2.1 Abstract  34-35
  2.2 Introduction  35-36
  2.3 Materials and Methods  36-40
    2.3.1 Materials  36
    2.3.2 Preparation of SPP  36
    2.3.3 HHP processing  36
    2.3.4 Free sulphydryl(SH)content  36-37
    2.3.5 Surface hydrophobicity(H_o)  37
    2.3.6 Sodium dodecyl sulphate polyacrylamide gel electrophoresis(SDS-PAGE)  37
    2.3.7 Differential scanning calorimetry(DSC)  37
    2.3.8 Protein solubility  37-38
    2.3.9 Emulsion preparation  38-40
      2.3.9.1 Emulsifying activity and stability indices  38
      2.3.9.2 Droplet size  38-39
      2.3.9.3 Emulsion microscopy  39
      2.3.9.4 Rheological properties  39
      2.3.9.5 Protein composition of the interfacial film  39-40
    2.3.10 Statistical Analysis  40
  2.4 Results and Discussion  40-54
    2.4.1 Free sulphydryl (SH) content  40-41
    2.4.2 Surface hydrophobicity(H_o)  41-42
    2.4.3 Electrophoresis  42-43
    2.4.4 DSC characteristics  43-46
    2.4.5 Solubility  46-47
    2.4.6 EAI and ESI  47-54
  2.5 Conclusions  54-55
3 THE EFFECTS OF PH AND HIGH HYDROSTATIC PRESSURE ON PHYSCICOCHEMICALPROPERTIES OF A SWEET POTATO PROTEIN EMULSION  55-72
  3.1 Abstract  55-56
  3.2 Introduction  56-57
  3.3. Materials and Methods  57-61
    3.3.1 Materials  57
    3.3.2 Preparation of SPP  57
    3.3.3 Emulsion preparation  57
    3.3.4 HHP treatment  57-58
    3.3.5 Determination of the emulsifying activity index and the emulsifyingstability index  58
    3.3.6 Measurements of droplet size and distribution  58-59
    3.3.7 Emulsion microscopy  59
    3.3.8 Interfacial protein concentration  59
    3.3.9 Interfacial protein composition  59-60
    3.3.10 Rheological measurement  60
    3.3.11 Statistical analyses  60-61
  3.4 Results and Discussion  61-71
  3.5 Conclusions  71-72
4 EMULSIFYING PROPERTIES OF SWEET POTATO PROTEIN:INFLUENCE OF PH AND HIGHHYDROSTATIC PRESSURE TREATMENT  72-90
  4.1 Abstract  72-73
  4.2 Introduction  73-74
  4.3 Materials and Methods  74-77
    4.3.1. Materials  74
    4.3.2 Preparation of SPP  74
    4.3.3 HHP processing  74
    4.3.4 Circular dichroism (CD)  74-75
    4.3.5 Hydrophobicity (丑o)  75
    4.3.6 Emulsion preparation  75
    4.3.7 Emulsiyfing activity and stability indices  75
    4.3.8 Measurement of droplet size and distirbution  75-76
    4.3.9 Emulsion microscopy  76
    4.3.10 Rheological properties  76
    4.3.11 Statistical analysis  76-77
  4.4 Results and Discussion  77-90
5 EFFECTS OF HIGH HYDROSTATIC PRESSURE ON EMULSIFYING PROPERTIES OF SWEETPOTATO PROTEIN IN MODEL PROTEIN-HYDROCOLLOIDS SYSTEM  90-104
  5.1 Introduction  90-91
  5.2. Materials and Methods  91-93
    5.2.1 Materials  91
    5.2.2 Preparation of SPP  91
    5.2.3 SPP-hydrocolloid Model  91
    5.2.4. HHP processing  91
    5.2.5 Emulsion preparation  91
    5.2.6 Emulsiyfing activity (EAI) and stability indices (ESI)  91-92
    5.2.7 Determination of emulsion stability against creaming  92
    5.2.8 Rheological measurement  92-93
    5.2.9 Statistical analyses  93
  5.3 Results and Discussion  93-104
    5.3.1 EAI & ESI  93-95
    5.3.2 Creaming stabilities of SPP-hydrocolloids model  95-99
    5.3.3 Rheology of SPP-hydrocolloids model  99-103
    5.3.4 Conclusions  103-104
6 CONCLUSION AND RECOMMENDATION  104-108
  6.1 Conclusion  104-107
  6.2 Recommendation  107-108
REFERENCES  108-117
APPENDIX  117-123
ACKNOWLEDGEMENTS  123-124
RESUME  124-125
PUBLICATIONS  125

超高压对甘薯蛋白物化及功能特性的研究

内容摘要

全文目录

相似论文