Combined Fenton Oxidation and Chemical Coagulation for the Treatment of Melanoidin/Phenolic Acid Mixtures and Sugar Juice

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• 作者：Danny M. T. NguyenJohn P. Bartley ; William O. S. Doherty
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：February 15, 2017
• 年：2017
• 卷：56
• 期：6
• 页码：1385-1393
• 全文大小：329K
• ISSN：1520-5045

文摘

The use of SO₂ via the sulfitation process for the production of plantation white sugar is discouraged in many countries because of the health risks surrounding the consumption of contaminated sugar containing residual sulfur. Other current options based on the modification of crystallization schemes are not effective for removing certain colorants that are relatively difficult to remove for sugar refiners. This work evaluated the degradation and decoloration of mixtures containing a synthetic glucose-glycine melanoidin and three hydroxycinnamic acids (HCAs; caffeic, p-coumaric, and ferulic acids) present in sugar solutions and sugar cane factory juices by the Fenton and modified Fenton processes. The modified Fenton process [containing Al(III)] degraded the melanoidin and the HCAs by 69 and 53%, respectively, and resulted in 43% decolorization of the sugar solution. In the absence of Al(III), the Fenton process resulted in 63 and 47% degradation, respectively, but with only 24% decolorization. With factory juices, there were increases in color measured at pH 4.0 (≤45%) and pH 7.0 (≤21%). However, there were decreases in color at pH 9.0 (≤42%). Color measured at pH 4.0 suggests the presence of high-molecular weight colorants, while color at pH 9.0 is due the presence of natural colorants such as flavonoids and phenolics. A higher proportion of the color measured at pH 9.0 is more likely to be transferred to the sugar crystal than the other color species are, so a reduction in its proportion in the crystallizing solution may reduce raw sugar color.