A study on the gelation behavior of solutions of native gellan, deacylated gellan, and their mixture by water 1H T2 measurements. (November 2017)

• Record Type: Journal Article
• Authors: Hu, Bingjie; Lu, Yang; Zhao, Qiuhua; Matsukawa, Shingo
• Is Part Of: Food hydrocolloids. Volume 72(2017)
• Page Start: 47
• Page End: 51
• Publication Date: 2017-11
• Subjects: Gellan gum -- Gelation mechanism -- Molecular mobility -- Mixture -- Network structure -- Water 1H T2; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2017.05.011
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: The temperature dependence of water 1 H T2 for native gellan (NG), deacylated gellan (DG), and a mixed solution of NG and DG in the presence of various concentration of Ca 2+ were measured by NMR. The results showed that DG formed a network of aggregates more drastically and at lower temperature than NG. The water 1 H T2 of the mixture showed a two-step decrease during cooling but not during reheating, indicating that DG and NG separately formed aggregates during cooling and that both DG and NG disaggregated at similar temperatures during reheating. In spite of the two-step gelation process in the mixed solutions, the water signals decayed mono-exponentially at each temperature during cooling. This suggests that the network structure formed either an interpenetrating structure or a phase separated structure with the scale less than the diffusion distance of water within the 1 H T2 relaxation time where the water relaxation behaviors affected by DG and NG chains were averaged to show the mono-exponential decay. Graphical abstract: Highlights: Two step gelation in mixed gellan gum solutions were observed. The two step gelation was observed as change of water 1H T2. Change of gel network structure was discussed based on the 1H T2 change.