Investigating fouling and cleaning during the filtration of Gum Arabic

Gum Arabic is a dried exudation obtained from various species of Acacia trees. Around 500 species of Acacia are known, however only a few are commercially important. Acacia Senegal is mainly used in the food industry, particularly in confectionary which accounts for about 60 % of the world consumption. It also finds uses in flavourings and pharmaceutical preparations as a building and emulsifying agent.

The industrial processing of gum uses large quantities of water and energy. The application of synthetic membrane filters offers the possibility of reducing the carbon footprint of this important industrial process. The filtration of chemically and rheologically complex food products such as gum inevitably leads to fouling; historically this has limited the application of membranes industrially. The surface science of gum adhesion and removal processes are being investigated using real feeds, to gain an understanding of the current limitations of the application of membrane technology in processing this product. Our goal is to change industrial practice in the factory.

In this paper we report the use of polymeric and ceramic ultra and microfiltration membranes to treat a waste stream containing ca 1wt% gum. The effect of operating conditions (temperature, pH, flow rate and transmembrane pressure) upon the permeate flux and the transmission of gum species is reported. Gum fouling mechanisms are described. Chemical and hydraulic protocols to effectively regenerate the membrane have also been developed.

Fouled bag filters from an industrial gum processing plant have also been obtained. Cleaning protocols have been developed and optimised for these filters, to reduce the consumption of these items industrially.