Multiple enzyme-assisted clarification process of fruit juice
Author(s)
Cerreti, Martina
Date Issued
June 6, 2017
Type
Doctoral Thesis
Abstract
The aim of this PhD thesis research project was to create a new approach to conventional clarification processing of fruit juice, using tailored enzymatic treatment in free and/or immobilized form. The first part of the work provided new insight into the individual and interactive effects of pectinase, protease, or multiple (pectinase-protease) treatments on juice turbidity and on haze formation. A significant and synergic effect of the combined use of pectinase, Klerzyme 150 DSM and protease, papain from Papaia latex, was demonstrated. Excellent results in terms of turbidity levels (during cold storage at 4 °C for 14 days) and potential haze formation in juice were obtained. Moreover, in the second part of the research, the optimum conditions of the clarification process were achieved using response surface methodology. The recommended enzymatic treatment conditions were: temperature 25-30 °C for 100-110 min using 0.22-0.25% (v/v) of protease-pectinase complex enzyme amount (the ratio of protease : pectinase was 1:2).
In the last part of this PhD project the use of PVA gel in the form of LentiKats®, a biocompatible and non-toxic enzymatic carrier, to immobilize pectinases was investigated. A biocatalyst, Panzym YieldMash, a polygalacturonase, showed the possibility of practical application in juice. Indeed, the efficient depolymerisation of apple pectin was performed. The immobilized polygalacturonic enzyme was capable of producing an 80% reduction in turbidity in a pectin solution compared to 95% as found with the soluble enzyme. The value could be considered acceptable for the application of this immobilized system in fruit juice processing, as well as considering that the same percentage of turbidity reduction was observed in the following two cycles.
Additional information
Dottorato di ricerca in Scienze, tecnologie e biotecnologie per la sostenibilità
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