Effect of pre-cooling on the postharvest of parsley leaves

Author: Virgínia S. Álvares, Fernando L. Finger ^*, Raul C. de A. Santos, Jacson R. da Silva Negreiros and Vicente W. D. Casali

Received 9 January 2007, accepted 7 April 2007.

Abstract

The objective of this work was to determine the effects of a hydrocooling procedure, followed by storage at 5^oC, on the shelf life of parsley cv. Graúda Portuguesa leaves. Bunches of parsley leaves were pre-cooled for fifteen minutes in a water and ice mixture kept at 5^oC. During this period of pre- cooling, close to 43% of the initial field heat was removed from the leaves. After the pre-cooling treatment, the leaf bunches were placed at 5^oC for 7 days. A control treatment was made up of bunches of parsley leaves that were also stored at 5^oC for 7 days without being pre-cooled. The hydrocooling procedure reduced the loss of fresh weight from the leaves in the first twelve hours of storage and maintained the relative water content (RWC) at a high level even after seven days of storage at 5^oC. Visual wilting of leaves was observed when approximately 10% of the initial fresh weight was lost, which was achieved 30 hours after harvest for the control and 42 hours for the pre-cooled bunches. During storage, no significant alterations of the leaf chlorophyll, total soluble sugar and non-reducing sugars or starch contents were detected. However, the reducing sugars content increased at a rate of 2.62 g kg^-1 leaf dry weight per day, corresponding to a 4.1-fold increase in 144 hours. Based on the data, we recommend pre-cooling as an efficient method to retard the beginning of wilt for stored parsley leaves.

Key words: Petroselinum crispum, weight loss, relative water content, chlorophyll, carbohydrates.