Pectin methylesterase inhibitors for the preparation of fruit juices and derivatives

The invention concerns a proteic inhibitor of pectin methylesterase and the use thereof in the preparation of fruit and vegetable juice and yogurt. The inhibitor of pectin methylesterase (PMEI) could be successfully used to control PME activity in fruit and vegetable juices over a long storage. The employment of PMEI could allow lower thermal juice treatment inasmuch as thermal PME inactivation requires temperatures higher than those needed for pasteurisation. Such milder thermal treatment should result in better flavour quality and vitamin contents. Moreover, the inhibitor could be usefully employed in frozen product technology allowing the storage of frozen products at higher temperatures. Finally, PMEI could be employed in the production of pectins with higher polymerisation degree useful for increasing the viscosity of some food products. In fact, polygalacturonase (PG) is responsible of pectin degradation but is inactive against pectins with high methylation degree. PME inhibition is expected to also PG activity on pectic substrate.