陈青,马慧婷,陆海霞,姚兰英.低酰基结冷胶/酪蛋白酸钠复合体系液-固转变流变学表征[J].农业机械学报,2017,48(8):322-327.
CHEN Qing,MA Huiting,LU Haixia,YAO Lanying.Rheological Characterization on Liquid-Solid Transition of Low Acyl Gellan/Sodium Caseinate Mixtures[J].Transactions of the Chinese Society for Agricultural Machinery,2017,48(8):322-327.
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低酰基结冷胶/酪蛋白酸钠复合体系液-固转变流变学表征   [下载全文]
Rheological Characterization on Liquid-Solid Transition of Low Acyl Gellan/Sodium Caseinate Mixtures   [Download Pdf][in English]
投稿时间:2016-12-16  
DOI:10.6041/j.issn.1000-1298.2017.08.038
中文关键词:  结冷胶  酪蛋白酸钠  液-固转变  流变学
基金项目:国家自然科学基金项目(51103131)、食品科学与工程浙江省重中之重一级学科开放基金项目(JYTSP20142091)和浙江大学高分子合成与功能构造教育部重点实验室项目(2015MSF002)
作者单位
陈青 浙江工商大学 
马慧婷 浙江工商大学 
陆海霞 浙江工商大学 
姚兰英 浙江工商大学 
中文摘要:采用流变学方法研究了低酰基结冷胶(LA)和酪蛋白酸钠(SC)复合体系的液-固转变,对比了储能模量、损耗模量交点法和Winter准则,并利用非等温动力学模型研究了LA/SC复合体系的结构变化。结果表明,Winter准则更适用于表征LA/SC复合体系的液-固转变。对于LA/SC复合体系而言,酪蛋白酸钠存在一个临界质量浓度0.005g/mL,当体系内酪蛋白酸钠质量浓度低于该临界值时,酪蛋白的添加对凝胶温度影响不大,但当酪蛋白酸钠质量浓度超过该临界值时,酪蛋白酸钠的添加会显著地降低复合体系的凝胶温度。复合体系的松弛指数随着酪蛋白浓度的升高呈先增大后降低的变化趋势,而分形维数则随着酪蛋白浓度的升高呈先减小后增大的变化趋势。非等温动力学研究结果表明,复合体系的凝胶可以分为2个阶段。
CHEN Qing  MA Huiting  LU Haixia  YAO Lanying
Zhejiang Gongshang University,Zhejiang Gongshang University,Zhejiang Gongshang University and Zhejiang Gongshang University
Key Words:gellan gum  sodium caseinate  liquid-solid transition  rheology
Abstract:The liquid-solid transition of low acyl gellan (LA) and sodium caseinate (SC) mixtures were investigated by using rheological measurements. The liquid-solid transition temperatures were determined from two criteria: the crossover of storage modulus G′ and loss modulus G″, and the Winter’s criterion. The results showed that the Winter’s criterion was more suitable to determine the sol-gel transition temperature. For LA/SC mixtures, there was a critical SC concentration (0.005g/mL ratio of mass to volume). The concentration of sodium caseinate almost had no influence on the gelation temperature of LA/SC mixtures at or below concentration of 0.005g/mL. While above 0.005g/mL, the gelation temperatures of LA/SC mixtures were decreased linearly with the increase of SC concentration. The relaxation critical exponent n can be determined by the Winter’s criterion. There was no universal n for the gelation in LA/SC mixed solutions, indicating that this gelation belonged to the cross-linking of existing macromolecules. And n increased with the increase of SC concentration until SC concentration reached a critical level, after which further increase in SC concentration resulted in a reduction of n. The fractal dimension df was calculated from n without the screened hydrodynamic interaction or the excluded volume effect and the trend of the change of the df was opposite to that of n. Using a non-isothermal kinetics model, active energy (Ea) during gelation was calculated. However, a discontinuity was observed in the activation energy plots. Based on this, two gelation mechanisms were presumed-association of low acyl gellan gum and sodium caseinate molecules and aggregation of polymer strands.

Transactions of the Chinese Society for Agriculture Machinery (CSAM), in charged of China Association for Science and Technology (CAST), sponsored by CSAM and Chinese Academy of Agricultural Mechanization Science(CAAMS), started publication in 1957. It is the earliest interdisciplinary journal in Chinese which combines agricultural and engineering. It always closely grasps the development direction of agriculture engineering disciplines and the published papers represent the highest academic level of agriculture engineering in China. Currently, nearly 8,000 papers have been already published. There are around 3,000 papers contributed to the journal each year, but only around 600 of them will be accepted. Transactions of CSAM focuses on a wide range of agricultural machinery, irrigation, electronics, robotics, agro-products engineering, biological energy, agricultural structures and environment and more. Subjects in Transactions of the CSAM have been embodied by many internationally well-known index systems, such as: EI Compendex, CA, CSA, etc.

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