Characterization of honey ultrafiltration process

Abstract

Ultrafiltration is a treatment used to transform raw honey into a material suitable for food processing. But the operating conditions required for the efficient ultrafiltration of honey have not been obtained. The effects of dilution of honey with water, molecular weight cut-off of ultrafiltration membrane, feed flow velocity and applied pressure on the performance of ultrafiltration were examined. At the same feed flow velocity and applied pressure, the permeation rate of sugar increased with temperature and dilution of honey. The water activity of honey increased with dilution, and when the sugar concentration of honey is greater than 35.5%, the water activity is less than 0.94 ; such conditions inhibit multiplication of microorganisms. The flux of the ultrafiltration membranes with a molecular weight cut-off below 30 000 slightly changed by alterations in the variety of honey and the pH of honey solutions, indicating that these membranes are suitable for industrial use. The optimum conditions needed for ultrafiltration were also examined in terms of energy efficiency. Less energy was needed at lower flux. The combination of feed flow velocity and applied pressure minimizing the required energy for ultrafiltration can be determined at each flux.