文献类型：期刊文献

英文题名：Gelation mechanism and network structure of mixed kappa carrageenan/lambda carrageenan gels studied by macroscopic and microscopic observation methods

作者：Geonzon, Lester C.[1];Zhuang, Xinye[2];Santoya, Amos M.[3];Bacabac, Rommel G.[3];Xie, Jingli[2];Matsukawa, Shingo[1]

机构：[1]Tokyo Univ Marine Sci & Technol, Dept Food Sci & Technol, Minato Ku, 4-5-7 Konan, Tokyo 1088477, Japan;[2]East China Univ Sci & Technol, Dept Food Sci & Technol, 130 Meilong Rd, Shanghai 200237, Peoples R China;[3]Univ San Carlos, Dept Phys, Med Biophys Grp, Cebu 6000, Philippines

年份：2020

卷号：105

外文期刊名：FOOD HYDROCOLLOIDS

收录：;EI(收录号：20233214513779);WOS:【SCI-EXPANDED(收录号:WOS:000540693200012)】；

基金：The authors thank Prof. Toru Suzuki for a fruitful discussion about the fluorescence microscopy results. This work was supported by JSPS KAKENHI Grand Number JP18H00962. Rommel G. Bacabac was funded by the Philippine Council for Industry, Engineering and Emerging Technology Research and Development-Department of Science and Technology (PCIEERD-DOST) project no. 04310 and received logistic support from the USC Research office and Department of Physics.

语种：英文

外文关键词：Carrageenan mixture; Gelation mechanism; Particle tracking; Phase transition; Bimodal distribution

摘要：Dynamic rheology and particle tracking experiments were carried out to investigate the gelation mechanism and network structure of mixed kappa-carrageenan (KC) and lambda-carrageenan (LC) gels on the macroscopic and microscopic levels. Mixtures of KC and LC (total carrageenan concentration = 1.5%, K+ concentration = 15 mM) were prepared at different mixing ratios. The storage modulus (G') was highest for pure KC and decreased monotonously with decreasing KC content. The mean square displacement (MSD) of probe particles was used to characterize the network on cooling and after one day of storage. On cooling, a single step decrease in the ensemble-averaged MSD was observed, in agreement with the rheological measurements. Time-averaged MSD values of individual particles showed a large distribution after one day in storage, especially for gels with low content of KC. This heterogeneity reflects microstructural heterogeneity, suggesting phase separation into KC-rich and LC-rich domains. Individual particle MSD values showed a bimodal distribution. The MSD could be described as a power-law, MSD similar to tau(alpha), with tau the lag time. The exponent alpha also showed a bimodal distribution. These findings suggest that two groups of probe particles with distinctly different mobilities are present in the mixed gels with particles of higher and lower mobilities present in the LC-rich and KC-rich phases. Based on the rheological results, as well as the particle tracking experiments, we propose that mixtures of KC and LC separate into a continuous phase and a non-continuous filler phase, with the continuous phase being made up of the more concentrated carrageenan. When the concentrations of the two carrageenans are roughly equal, we suggest that a bicontinuous phase-separated network is formed.