Instability of low‑moisture carrageenans as affected by water vapor sorption at moderate storage temperatures

The scientific article was published in 10th January 2020
SN Applied Sciences, (2020) 2:243, (Springer Nature Switzerland AG)

The authors are:
Margus Friedenthal, Agricultural Research Centre
Kairit Eha, Department of Chemistry and Biotechnology, Tallinn University of Technology (TTU)
Aleksei Kaleda, Center of Food and Fermentation Technologies
Natalja Part, Center of Food and Fermentation Technologies
Katrin Laos, Department of Chemistry and Biotechnology, Tallinn University of Technology (TTU)

Abstract

Isothermal microcalorimetry was used to study the exothermic heat flow caused by the absorption of water into carrageenans and a furcellaran, leading to their thermodynamic instability under moderate storage conditions (35 °C, τ = 12 h), where τ is the reaction time (h).

The net heats evolved by furcellaran, ι-carrageenan, κ-carrageenan, and a mixture of κ/λ-carrageenan were 43.5 J/g, 45.9 J/g, 31.6 J/g, and 28.1 J/g, respectively. The pronounced exothermic behavior of furcellaran was attributed to the enthalpic association of water molecules with the thermally degraded carbohydrate matrix.

The responses of a heat treatment of carrageenans at 55 °C, 85 °C, and 105 °C for 15 min on exothermic heat Q (J/g) at different water activities (aw = 0.26, 0.51, 0.76, and 1.0) were measured. The dependence of the net recorded heat Q on water activity can be satisfactorily approximated by the equation Q = a[1 − (1 − aw)b], where a and b are the coefficients found by the nonlinear least-squares method. It was concluded that carrageenans affected by excessive heat treatment should be preferably stored with limited water access.

Keywords Carrageenan · Instability · Water sorption · Isothermal microcalorimetry

The scientific article "Instability of low‑moisture carrageenans as affected by water vapor sorption at moderate storage temperatuures" (PDF, 1.3 MB)