Thermal degradation of agar: Mechanism and toxicity of products

Food Chemistry
Qian-Qian OuyangPu-Wang Li

Abstract

The mechanism of the thermal degradation and the toxicity of the thermal degradation products of agar were studied using TG/DTA, Fourier-transform infrared spectroscopy and pyrolysis gas chromatography/mass spectrometry. It was found that the thermal degradation of agar is a single-step reaction, the thermal degradation temperature (T0, Tp, Tf) increases with increasing gel strength (P) and the influence of P on the thermal degradation rate is modest. The thermal degradation of agar is an exothermic reaction, and the activation energy of the reaction increases with increasing P. In the thermal degradation, agar is first decomposed into 3,6-anhydropyran galactopyranose and galactopyranose, then 3,6-anhydropyran galactopyranose, and finally furyl hydroxymethyl ketone, through loop opening, dehydration and hydrogen transfer. Galactopyranose follows three degradation pathways, and its final degradation products are 3,4-atrosan, d-allose, furfural and 5-(hydroxymethyl)-2-furancarboxaldehyde. Of the degradation products, furyl hydroxymethyl ketone, furfural, and 5-(hydroxymethyl)-2-furancarboxaldehyde show some toxicity to humans.

Citations

Sep 11, 2018·Critical Reviews in Biotechnology·Ilekuttige Priyan Shanura FernandoYou-Jin Jeon
May 30, 2020·International Journal of Biological Macromolecules·Osman DumanSibel Tunç
Jul 21, 2021·Bioengineered·Yu-Chen LiaoJo-Shu Chang
Apr 21, 2020·ACS Omega·Anastasia NenashkinaEkaterina V Skorb

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