Recent Progress in Technologies for Enzymatic Peeling of Fruit

Abstract

Enzymatic peeling of fruit and vegetables is considered superior to conventional peeling methods in terms of minimizing product damage and indeed is expected to improve them. This technology was first proposed for the peeling of citrus fruit and numerous studies on its practical use have been conducted. However, its application to non-citrus fruit and vegetables remains limited. A novel process, including heat treatment prior to enzymatic treatment, is proposed to peel persimmon fruit. Heat treatment induces fine and even cracks on the fruit surface of certain persimmon cultivars, which act as channels via which enzyme solution can enter the peel tissue. Another function of the heat treatment is to inactivate polygalacturonase-inhibiting protein (PGIP), which is inherent in persimmon fruit. Inactivation of PGIP improves the efficiency of enzymatic peeling with exogenous polygalacturonase. Chemical pre-treatments with a food-grade emulsifier solution and a weak basic solution also enhance the permeability of enzyme solution into the peel tissue. These physical and chemical treatments are useful for applying enzymatic peeling to various persimmon cultivars. In future, enzymatic peeling technology is expected to be applied to various agricultural crops as the technology is further refined.