Agar quality promotion prepared by desulfation with hydrogen peroxide.

The modified agars were prepared using H 2 O 2 in ethanol solution at appropriate pH conditions. Some interesting physical and chemical properties of modified agar were determined and characterized compared with those of raw agar, and the underlying mechanisms were preliminarily studied. Results showed that the maximum gel strength of the modified agar was 1068 g/cm2, which increased by 30.9% compared with that of raw agar (816 g/cm2), and the minimum sulfate content of the modified agar was 0.21%, which decreased by 73.4% compared with that of raw agar (0.79%). Moreover, the viscosity, molecular weight, gelling temperature and melting temperature all decreased, whereas the whiteness and transparency increased after modification. Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis indicated that the spatial structure of agar have changed after treated with H 2 O 2. Taken together, the results demonstrated that the desulfation of agar with H 2 O 2 is a promising approach with practical significance. Unlabelled Image • Sulfate content of agar significantly decreased after H 2 O 2 treatment. • Agar molecules exhibited an orderly structure and improved structural stability. • Viscosity of modified agar decreased, while gel strength slightly increased. [ABSTRACT FROM AUTHOR]