A novel approach to the determination of the pyruvate and acetate distribution in xanthan
A novel approach to the determination of the pyruvate and acetate distribution in xanthan
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DOI：
10.1016/j.foodhyd.2014.08.014
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发表时间：
2015-02-01
影响因子：
10.7
通讯作者：
Foster, T. J.
中科院分区：
文献类型：
--
作者：
Abbaszadeh, A.;Lad, M.;Foster, T. J.
本工作演示了黄原胶的有序无序转变的物理性质，如转变温度和模量，和乙酸和丙酮酸含量之间的定量关系。模型已被构建，反映简单的线性依赖性的转变温度和对数的模量对乙酸，丙酮酸，黄原胶和盐的浓度。黄原胶中的双相转换检测使用差示扫描量热法（DSC）提出，以反映在每个阶段中含有不同的乙酸和丙酮酸水平的阶段。在这些阶段中的相应的乙酸盐和丙酮酸盐的含量进行了估计。C-13交叉极化魔角旋转（CPMAS）核磁共振测量进一步表明，在溶液中测量的官能团的分布反映在固体粉末中的环境分布中。这可以采取沿单个链的沿着异质性（链内异质性）或单个链中的均一但不同水平的官能团（链间异质性）的形式。链内建议或“块状”分布的支持是由样品提供的，这些样品已被报道显示出不同的转变温度，尽管具有明显相同的总乙酸盐和丙酮酸盐含量。这归因于转变温度的值沿单个链是不同的沿着。(C)2014爱思唯尔有限公司版权所有。
The present work demonstrates a quantitative relation between the physical properties of the order disorder transition in xanthan, such as transition temperature and modulus, and the acetate and pyruvate content. Models have been constructed which reflect simple linear dependence of transition temperature and the logarithm of the modulus on acetate, pyruvate, xanthan and salt concentration. Biphasic transitions in xanthan detected using Differential Scanning Calorimetry (DSC) are proposed to reflect phases containing different acetate and pyruvate levels in each phase. The respective acetate and pyruvate contents in these phases have been estimated. C-13 Cross Polarisation Magic Angle Spinning (CPMAS) Nuclear Magnetic Resonance measurements further suggest that the distribution of functional groups measured in solution is reflected in a distribution of environments in solid powders. This could take the form of heterogeneity along an individual chain (intra-chain heterogeneity) or uniform but different levels of functional groups in individual chains (inter-chain heterogeneity). Support for the intra-chain proposal or "blocky" distribution is provided by samples which have been reported to exhibit different transition temperatures despite having apparently the same overall acetate and pyruvate content. This is ascribed to the values of transition temperature being different along an individual chain. (C) 2014 Elsevier Ltd. All rights reserved.