Removal of color and turbidity in sugarcane juice treated by electrocoagulation with aluminum electrodes

Felipe Iwagaki Braga Ogando,Eduardo Simões,Claudio Lima De Aguiar,Taís Xastre

doi:10.1590/1981-6723.23620

Felipe Iwagaki Braga Ogando, Eduardo Simões + Show 2 more

Open Access

https://doi.org/10.1590/1981-6723.23620

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Abstract

Abstract The liming (Ca(OH)2 addition) and sulfitation (HSO3- addition) is the conventional treatment for purification of sugarcane juice (SCJ) in sugar cane mills to crystal sugar production. Although, the sulfite has been associated to human health problems, this industrial step kept untouchable or few studies have been made to change this scenery. This work aimed to evaluate the variables which influence the electrocoagulation performance on the SCJ purification as a sulfur-free crystal sugar process. A fractional factorial design with the surface response methodology was used to evaluate the influence of voltage, pH, soluble solids total (Brix), temperature and distance between the electrodes in the electrocoagulation process. The outputs were turbidity, juice color, sucrose contents (as pol%juice) and Reducing Sugars (RS). Residual aluminum was analyzed by voltammetry to control de aluminum releasing into the treated juice. The electrocoagulation reduced color and turbidity, in special at low pH (2.5), highest voltage (25 V) and minimal distance of electrode (1.0 cm). Although in this conditions, sucrose was converted into RS indicating partial hydrolysis. In this work, the most part of residual aluminum went to floated and precipitated phases (76.8% and 18.1%, respectively), whereas only 5.1% remained in the SCJ clarified. Electrocoagulation/electroflotation proved to be a potential technique as a substitute for sulfitation in SJC treatment, which ensures the production of safe food for humans.

Highlights

The crystal sugar manufacturing from sugarcane is divided into extraction and treatment of the sugarcane juice (SCJ); evaporation of clarified juice; crystallization, centrifugation, drying and bagging of the sucrose
Variations in factors voltage and distance led to greater amplitudes of ICUMSA color (Figure 3)
Higher voltage applied led to lower ICUMSA color, whereas distance between electrodes shorter led to greater ICUMSA color reduction

Summary

Introduction

The crystal sugar manufacturing from sugarcane is divided into extraction and treatment of the sugarcane juice (SCJ); evaporation of clarified juice; crystallization, centrifugation, drying and bagging of the sucrose (crystal sugar). The raw SCJ treatment is compound for sieving, sulfitation and liming of SCJ; heating and flashing to remove the gas; and decantation of impurities (non-sugars like proteins, waxes, colloids, etc.) from the SCJ This set of techniques aims: (I) to form flocs that suspend organic and inorganic impurities; (II) to promote conditions of temperature, pH and ion concentration that avoid sucrose loss by hydrolysis or Maillard reaction and/or caramelization; (III) to eliminate microorganisms that are harmful to the process and quality of sugar (Rein, 2007). Food and Agriculture Organization (FAO) of the United Nations defined an ingestion limit of 1 mg of aluminum per kg of body weight per week (Aguilar et al, 2008; Stahl et al, 2011)

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