Characterisation of rheology and microstructures of κ-carrageenan in ethanol-water mixtures

Zhi Yang; Huijuan Yang; Hongshun Yang

doi:10.1016/j.foodres.2018.03.016

Characterisation of rheology and microstructures of κ-carrageenan in ethanol-water mixtures

Food Res Int. 2018 May:107:738-746. doi: 10.1016/j.foodres.2018.03.016. Epub 2018 Mar 7.

Authors

Zhi Yang¹, Huijuan Yang², Hongshun Yang³

Affiliations

¹ Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.
² Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore; Synergetic Innovative Centre of Food Safety and Nutrition, Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Jiangsu Innovative Centre of Meat Production and Processing, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, PR China.
³ Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China. Electronic address: chmynghs@nus.edu.sg.

PMID: 29580542
DOI: 10.1016/j.foodres.2018.03.016

Abstract

The effects of ethanol (up to 20 wt%) on the rheological properties and structural characteristics of κ-carrageenan gel were investigated by Field Emission Scanning Electron Microscopy (FESEM) and Small Angle X-ray Scattering (SAXS). Both the sol-gel and gel-sol transition temperatures shifted to higher degree (from 36.8 ± 0.5 to 52.5 ± 1.4 °C and from 51.2 ± 0.6 to 67.0 ± 0.5 °C, respectively) upon 20 wt% ethanol addition (P < 0.05). The critical relaxation exponent n and the critical gel strength S_g obtained from Winter-Chambon criterion decreased and increased, respectively as the ethanol concentration increased. The κ-carrageenan gel was formed due to the formation of fibrillar networks, and the fibrillar density increased upon ethanol addition via FESEM. Moreover, upon 20 wt% ethanol addition, the average radius of gyration of κ-carrageenan strand increased from 1.18 ± 0.03 of control to 1.55 ± 0.02 nm by SAXS. A mechanism underlying the effect of ethanol on the κ-carrageenan gelation was proposed based on coil to double helix transition followed by the helix aggregation.

Keywords: Network strength; Polysaccharide; Rheology; Small angle X-ray scattering; Sol-gel transition; Solvent quality.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbohydrate Conformation
Carrageenan / chemistry*
Elasticity
Ethanol / chemistry*
Gels
Microscopy, Electron, Scanning
Models, Molecular
Rheology
Scattering, Small Angle
Structure-Activity Relationship
Transition Temperature
Viscosity
Water / chemistry*
X-Ray Diffraction

Substances

Gels
Water
Ethanol
Carrageenan