NaCl浓度和pH对甘薯蛋白肽乳化特性的影响  

Effects of NaCl Concentration and pH Value on the Emulsifying Properties of Sweet Potato Peptides

作　　者：崔珊珊[1,2] 木泰华[1] 孙红男[1] 张苗[1] 陈井旺[1] 

机构地区：[1]中国农业科学院农产品加工研究所/农业部农产品加工综合性重点实验室,北京100193 [2]新疆农业大学食品科学与药学学院,乌鲁木齐830091

出　　处：《中国农业科学》2016年第9期1778-1786,共9页Scientia Agricultura Sinica

基　　金：国家自然科学基金(31371878)

摘　　要：【目的】明确不同Na Cl浓度和p H对甘薯蛋白肽乳化特性的影响,为甘薯蛋白肽在食品工业中的应用提供理论依据。【方法】测定不同Na Cl浓度(0.2、0.4、0.6、0.8和1.0 mol·L^(-1))和不同p H(3、5、7和9)条件下,甘薯蛋白肽乳化液的显微结构、乳化颗粒平均粒径(d4,3)、乳化活性、乳化稳定性、流变学性质和甘薯蛋白肽的表面疏水活性。【结果】与未添加Na Cl的相比,添加浓度为0.2 mol·L^(-1)的Na Cl时,甘薯蛋白肽乳化液的d4,3由54.19μm增大至59.70μm;乳化活性指数由86.29 m^2·g^(-1)显著降低为56.35 m^2·g^(-1)(P<0.05);乳化稳定性指数由14.84 min降为13.19 min。然而,随着Na Cl浓度的增大,甘薯蛋白肽乳化颗粒均一程度降低,d4,3进一步由0.2 mol·L-1时的59.70μm增加至69.72μm;而乳化活性由56.35 m^2·g^(-1)逐渐降低至32.32 m^2·g^(-1),乳化稳定性呈先升高后降低的趋势,在0.4 m^2·g^(-1)时达最大值,为15.55 min;初始表观黏度增大,并有剪切变稀现象发生;表面疏水活性降低。此外,随着p H增加,乳化颗粒均一程度升高,d4,3由pH 3时的64.45μm减小至p H 9时的51.21μm;而乳化活性由pH 3时的3.99 m^2·g^(-1)升高至p H 9时的120.47 m^2·g^(-1),乳化稳定性呈先降低后升高的变化趋势,p H 3时其最佳值为29.13 min;初始表观黏度降低,并有剪切变稀现象发生;表面疏水活性升高。【结论】甘薯蛋白肽的乳化特性与Na Cl浓度和p H密切相关,添加≥0.2 mol·L^(-1) Na Cl降低了甘薯蛋白肽的乳化活性和稳定性,而增加p H可有效提高甘薯蛋白肽的乳化活性。【Objective】 The study aims to clear the effects of different Na Cl concentrations and p H values on the emulsifying properties of sweet potato peptides and provide a theoretical basis for the application of sweet potato peptides in the food industry. 【Method】Microstructure, average particle size（d4,3）, emulsifying activity, emulsifying stability, rheological property of emulsion and hydrophobicity of sweet potato peptides with different Na Cl concentrations（0.2, 0.4, 0.6, 0.8 and 1.0 mol·L^-1） and different p H values（3, 5, 7 and 9） were measured. 【Result】Compared with the sweet potato peptide emulsion without Na Cl, when 0.2 mol·L^-1Na Cl was added into the sweet potato peptide emulsion, d4,3 was increased from 54.19 μm to 59.70 μm, the emulsifying activity index was decreased significantly from 86.29 m^2·g^-1 to 56.35 m^2·g^-1（P〈0.05）, and the emulsion stability index was decreased from 14.84 min to 13.19 min. However, with the increase of Na Cl concentration, the uniformity of sweet potato peptide emulsion was decreased, d4,3 was further increased from 59.70 μm to 69.72 μm, the emulsifying activity was decreased from 56.35 m^2·g^-1 to 32.32 m^2·g^-1, emulsifying stability was firstly increased and then decreased, reached a maximum of 15.55 min at 0.04 mol·L^-1, the initial apparent viscosity was increased and exhibited shear-thinning phenomenon, and surface hydrophobicity activity was decreased. In addition, with the increase of p H value, the uniformity of emulsion was increased, d4,3 was decreased from 64.45 μm at p H 3 to 51.21 μm at p H 9, the emulsifying activity was increased from 3.99 m^2·g^-1 at p H 3 to 120.47 m^2·g^-1 at p H 9, the emulsifying stability was firstly increased and then decreased, reached a maximum of 29.13 min at p H 3, initial apparent viscosity was reduced and exhibited shear-thinning phenomenon, and the activity of surface hydrophobicity was increased. 【Conclusion】 Emulsifying properties of sweet potato peptides are closely related to

关 键 词：甘薯蛋白肽 NACL PH 乳化特性 

分 类 号：S531[农业科学—作物学]