Kinetics of enzymatic degradation of apple pectin macromolecules as dependent upon the degree of esterification | Kinetika enzimske degradacije makromolekula pektinskih supstanci jabuke prema stepenu esterifikacije
2010
Nikolić, M., Agronomski fakultet, Čačak (Serbia) | Rakić, S., Poljoprivredni fakultet, Beograd - Zemun (Serbia) | Mojović, Lj., Tehnološko-metalurški fakultet, Beograd (Serbia) | Živković, M., Poljoprivredni fakultet, Beograd - Zemun (Serbia)
The objective of this study was to evaluate the kinetics of the enzymatic degradation of macromolecules pectin substances derived from apple cv. Budimka as dependent upon the degree of esterification and to optimize the process by the action of pectin lyase. The isolated pectin substances had a very high degree of esterification (DE 95%) and a high degree of polymerization (DP 134%) and contained 93% polygalacturonic acid. The observed decline in enzyme affinity was associated with a concurrent decrease in the degree of pectin esterification. At high pH values, the enzymatic activity decresed with decreasing degree of pectin esterification. At a pH below 5, a low rate of degradation was observed in the pectins with a degree of esterification of 95% and in those with a DE below 50%. At lowest pH values, maximum enzymatic activity was exhibited by pectin substances having a DE of approximately 82%. An increase in affinity occurring with decreasing pH was observed for all pectin substances, depending on the degree of esterification.
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