Effect of Carbon Dioxide on Anthocyanins, Phenylalanine Ammonia Lyase and Glucosyltransferase in the Arils of Stored Pomegranates

Abstract

`Wonderful' Pomegranates (Punica granatum L.) were placed in jars ventilated continuously with air or air enriched with 10 or 20 kPa CO₂ at 10 °C for 6 weeks. Samples were taken initially and after 1, 2, 4, and 6 weeks, and postharvest quality attributes were measured. The arils of the pomegranates stored in air were deeper red than the initial controls and than those stored in CO₂-enriched atmospheres. This increased color was associated with increased anthocyanin concentration. Arils from fruit stored in air enriched with 10 kPa CO₂ had a lower anthocyanin concentration than air-stored fruit, and atmospheres enriched with 20 kPa CO₂ had even lower levels, possibly from suppressed anthocyanin biosynthesis. Anthocyanin concentration correlated well with the activity of phenylalanine ammonia lyase but not with glucosyltransferase activity. Moderate CO₂ atmospheres (10 kPa) prolong the storage life and maintain quality of pomegranates, including adequate red color intensity of the arils.