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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #334486
Title: Mechanism of removal of undesirable residual amylase, insoluble starch, and select colorants from refinery streams by powdered activated carbons

Author
item Lima, Isabel
item Eggleston, Gillian
item SARIR, E - Carboua International
item DONADO, C - Carboua International
item THOMPSON, J - Lsr Refinery, Llc
item St Cyr, Eldwin

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/2/2017
Publication Date: 6/22/2017
Citation: Lima, I.M., Eggleston, G., Sarir, E., Donado, C.A., Thompson, J., St Cyr, E.L. 2017. Mechanism of removal of undesirable residual amylase, insoluble starch, and select colorants from refinery streams by powdered activated carbons. In: Proceedings for the Advances in Sugar Crop Processing and Conversion Conference, March 15-18, 2016, New Orleans, Louisiana. p. 309-329.

Interpretive Summary: Refineries have been using both high and very high temperature stable amylases in their processes with had been developed for much harsher processing conditions. As a consequence, they appear in white, refined sugars and need to urgently be inactivated both at the sugar factories and refineries. Powdered activated carbon (PAC) has been shown to effectively residual amylases as well as impurities such as starch and various colorants from sugar syrups. Mechanisms for the performance of these powdered activated carbons in simultaneously removing multiple impurities with different physical characteristics were suggested to further improve the effective use of the PAC as well as their complementarity with the existing purification processes at the factory and refinery. Further studies are now warranted to investigate the use of high performance PAC as a tool to remove residual amylase, select colorants, and insoluble starch at the large-scale.

Technical Abstract: There is a need in the world-wide sugar industry to find a practical and economical solution to remove or inactivate residual alpha-amylases that are high temperature stable from factory or refinery streams. A survey of refineries that used amylase and had activated carbon systems for decolorization, revealed they did not have any customer complaints for residual amylase. Five commercial, high performance powdered activated carbons (PAC) were investigated for their ability to remove residual amylase as well as other impurities. Removal of the residual amylase protein by PAC was dependent on its surface area as well as mixing (retention) time. A select, high performance PAC (RFM-JH) with high surface area (1764 m2/g) performed the best and, because this PAC also had the largest particle size characteristics (mean particle size ~274 µm), it was also the easiest to filter after use. Activated carbon also had the additional benefit of removing color, and RFM-JH preferentially removed cane derived flavonoid and phenolic colorants at pH 9 over process formed color at pH 4, which is opposite of color removal by the refinery phosphatation-clarification process and thus complementary. The dose of RFM-JH was more critical than retention time with respect to color removal. RFM-JH also consistently removed undesirable insoluble starch from raw sugar syrups and refinery liquors. A tentative mechanism for the removal of impurities is provided. Further studies are now warranted to investigate the use of high performance PAC as a tool to remove residual amylase, select colorants, and insoluble starch at the large-scale.