食品科学 ›› 2019, Vol. 40 ›› Issue (6): 35-40.doi: 10.7506/spkx1002-6630-20180327-365

• 食品化学 • 上一篇    下一篇

pH值对低酯果胶/酪蛋白酸钠复合体系流变及结构特性的影响

彭媛媛1,2,王昱圭1,2,汤雪纤1,2,赵 欣3,张甫生1,2,郑 炯1,2,*   

  1. 1.西南大学食品科学学院,重庆 400715;2.食品科学与工程国家级实验教学示范中心(西南大学),重庆 400715;3.重庆第二师范学院,重庆市功能性食品协同创新中心,重庆 400067
  • 出版日期:2019-03-25 发布日期:2019-04-02
  • 基金资助:
    中央高校基本科研业务费专项(SWU20161702001);重庆市功能性食品协同创新中心项目(167001);国家级大学生创新创业训练计划项目(201710635036)

Effect of pH Value on Rheological and Structural Properties ofL ow Methoxyl Pectin/Sodium Caseinate Composite System

PENG Yuanyuan1,2, WANG Yugui1,2, TANG Xueqian1,2, ZHAO Xin3, ZHANG Fusheng1,2, ZHENG Jiong1,2,*   

  1. 1. College of Food Science, Southwest University, Chongqing 400715, China; 2. National Demonstration Center for Experimental Food Science and Engineering Education (Southwest University), Chongqing 400715, China; 3. Chongqing Collaborative Innovation Center for Functional Food, Chongqing University of Education, Chongqing 400067, China
  • Online:2019-03-25 Published:2019-04-02

摘要: 为研究pH值对低酯果胶/酪蛋白酸钠复合体系流变及结构特性的影响,分别在不同酸性条件下(pH 3.0、3.5、4.0、4.5、5.0、5.5)对复合体系的静态剪切及动态黏弹流变特性、Zeta电位、粒径、浊度、微观结构进行测定。结果表明:复合体系流变特性呈两段式变化,在pH 3.0~4.0时,随pH值的增大,复合体系流体指数n和tanδ均增大,稠度系数K减少;在pH 4.5~5.5时,体系n和tanδ骤减后继续增加,且增加程度更大,K骤增后继续减少。复合体系Zeta电位值随着pH值的增大而降低。Zeta电位值在pH 3.0~4.0时为正,在pH 4.5~5.5时为负。复合体系粒径和浊度值均随着pH值的增大呈先增大后减小的趋势,在pH 4.5时达到最大。随着pH值的降低,复合体系微观结构由杂乱变得细密。在pH 3.0~4.0时,体系以低酯果胶附着在酪蛋白表面结构为主;在pH 4.5~5.5时,体系中低酯果胶的网状结构更明显。因此,pH值的变化会改变复合体系的流变及结构特性,从而影响体系的稳定性。

关键词: 低酯果胶, 酪蛋白酸钠, pH值, 流变特性, 微观结构

Abstract: We studied the effect of pH on the rheological and structural properties of low methoxyl pectin/sodium caseinate composite system. At different acidic pH values (3.0, 3.5, 4.0, 4.5, 5.0, 5.5), static shear and dynamic viscoelastic rheological properties, zeta potential, particle size, turbidity, and microstructure were measured. The results showed that the rheological properties of the composite system changed in two stages. Fluid index n and tanδ increased whereas consistency coefficient K decreased with the increase of pH from 3.0 to 4.0. As the pH increased from 4.5 to 5.5, n and tanδ decreased rapidly and then increased to a level higher than the initial one while K increased steeply and then decreased. Zeta potential decreased with increasing pH; it was positive at pH 3.0 to 4.0 but was negative at pH 4.5 to 5.5. Particle size and turbidity increased to a maximum at pH 4.5 and then decreased with the increase of pH. As the pH value decreased, the microstructure of the composite system changed from a disordered state into a dense one. At pH 3.0–4.0, the structure of the casein surface was dominated by low methoxyl pectin, and the network structure of low methoxyl pectin was more obvious at pH 4.5–5.5. Therefore, changes in pH can cause changes in the rheological and structural properties of the composite system, thereby affect the stability of the system.

Key words: low methoxyl pectin, sodium caseinate, pH, rheological properties, microstructure

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