Clarification and Stability Enhancement of Pear Juice using Loose Nanofiltrationb

Abstract

This research explored the possible application of loose Nanofiltration (NF) to enhance 19 stability and shelf life of pear juices. The results obtained from loose Nanofiltration of sulfite pre-treated (SPT) and sulphite un-treated pear juices (SUT) showed similar patterns of decline in flux rate and increase in volume concentration ratio (VCR) over time. The treated juice (loose NF permeate) showed a significant (P < 0.05) increase in lightness (L*), improvement from brownish tinge to clear light greenish tinge (a*) and an improvement in overall colour difference (ΔEab) values. Additionally, loose NF permeates from SPT and SUT were much clearer than the control as indicated by 87-91% improvement in percent adsorption. Loose NF permeates compared to control showed only a minor increase in the absorbance values when tested for stability at 80°C. Such changes in the permeate characteristics indicated significant improvement juice quality. The retentate from loose NF revealed high sugar content (17-18°Brix), was dark brown in colour and contained more organic acids.