第 39 回日本バイオレオロジー学会年会

プログラム・抄録集

GELATION OF MIXED KAPPA AND IOTA CARRAGEENAN SOLUTION
Lei Du，Bingjie Hu, ○Shingo Matsukawa*
東京海洋大学

大学院応用生命科学［〒108-8477

1. Introduction

東京都港区港南 4-5-7］

KC and IC rich phases could be observed regardless of

Carrageenans are sulfated polysaccharide, obtained

storing time. In addition, NMR results also gave muchfrom certain species of red seaweeds, and are widely

information on the micro-structure of the mixed system [4].

used in food, pharmaceutical, cosmetic industries. /-4．Discussion

carrageenangelation,It could be observed that KC and IC formed gel structure

meaning that two components form gel networks

independently in the mixture. Furthermore, solvent and ion

independently

mixtures[1-3]

undergotwo-step. In the present work[2]

, rheologicalredistribution between KC and IC solutions could occur only

and thermal properties of carrageenans were studied.

after long keeping times at temperatures far below theThe effect of gelation on water and ion distribution

transition temperatures of the KC.

between KC and IC phases was studied by forcing amacroscopic separation across a dialysis membrane.
2. Materials & Methods
Sodium-type -carrageenan (KC) and - carrageenan(IC) were supplied by MRC Polysaccharide Co. with further
dialysis. Carrageenan solutions with fixed KCl concentration
were stirred for 30 min at 90°C. After that, hot solutions weremixed another 15min at 90C to obtain mixtures. Rheologicalmeasurement at a frequency of 1 Hz and a strain of 1.0% wason a Hakke Mars II rheometer. And DSC measurements wereFig. 2. Schematic representation of water and cation between KC andIC rich phases during gelation.

carried out on a Setaram Micro-DSC VII. Water and ion

5．Conclusion

migration between KC and IC rich phases during gelation

Two step transition temperatures of mixture werewere detected by gravimetric analysis and ICP-AES,

almost same to that of individual KC and IC at the same

respectively.

condition. Furthermore, solvent and ion redistribution

3. Results

between KC and IC solutions could occur only after

Rheological and thermal properties of 2wt% mixed
carrageenan under 10mM KCl were studied (Fig. 1) andtwo-step gelation could be observed.

Fig. 1. Rheology (upper panel) and DSC (lower panel) for 2%
carrageenan with 10mM KCl with cooling rate of 0.5°C/min.

Furthermore, migration of cations between KC and IC
rich phases occurred after storing 10 hrs at 5C, withincreasing KC concentration and the content of K+ in KC richphase. At 15 and 20C, no obvious changes of cation between

long keeping times at temperatures far below thetransition temperatures of the KC.
Acknowledgement
The authors are thankful for the financial supports of a
Grant-in-Aid for Scientific Research (No. 26282017) fromthe Ministry of Education, Culture, Sports, Science andTechnology, Japan (MEC-SST).
References[1] Brenner T, Tuvikene R, Parker A, Matsukawa S,Nishinari K. Rheology and structure of mixed
kappa-carrageenan/iota-carrageenan
gels.
FoodHydrocolloids. 2014; 39: 272-279.
[2] Du L, Brenner T, Xie JL, Matsukawa S. A study onphase separation behavior in kappa/iota carrageenan
mixtures by micro DSC, rheological measurements andsimulating water and cations migration between phases.
Food Hydrocolloids. 2016; 55: 81-88.
[3] Parker A, Brigand G, Miniou C, Trespoey A, ValléeP. Rheology and fracture of mixed ι- and κ-carrageenan
gels: Two-step gelation. Carbohydrate Polymers. 1993;
20: 253-262.
[4] Hu BJ, Du L, Matsukawa S. NMR study on thenetwork structure of a mixed gel of kappa and iota
carrageenans. Carbohydrate Polymers. 2015. Underreview.