High pressure-temperature effects on enzymatic activity

Abstract

Initially exploited in chemistry and physics, high-pressure technology has gained importance in various fields. Flavonoids, namely naringin and naringenin, from citrus, are functional chemicals with important properties in the fields of healthcare, food and agriculture. Naringin, the principal bitter flavonone glycoside and the primary bitter component in grapefruit juice, can be hydrolysed by naringinase into tasteless naringenin. The temperature of 303 K was ideal for maximizing the activity of the naringinase at 160 MPa when compared to atmospheric pressure. The pressure had a positive effect on the reaction rate, with a value of - 15.0 1.8 cm(3) mol(-1) for the activation volume. Kinetic parameters, k(m) and V-max for naringinase were evaluated, the maximum initial rate at 160 MPa (V-max = 2.7 mM min(-1)) was higher than that at atmospheric pressure (V-max = 0.06 mM min(-1)). This is a promising result for future application of enzymatic hydrolysis of naringin at high pressure, in the citrus juice industry. @ 2006 Elsevier Ltd. All rights reserved.