Alcachofa En Atmosferas Modificadas

WFL Publisher
Science and Technology Food, Agriculture & Environment Vol.1(2) : 130-133. 2003

www.world-food.net

The storage of globe artichokes under modified atmospheres
Alexios A. Alexopoulos, Konstantinos A. Akoumianakis and Harold C. Passam*
Agricultural University of Athens, Laboratory of Vegetable Production, 75, Iera Odos, 118 55 Athens, Greece. *e-mail: passam@aua.gr
Received11 January 2003, accepted 23 April 2003.

Abstract
Globe artichokes (Cynara scolymus L. cv. Argous), 5.5-7.5 cm and 7.6-10.0 cm in diameter, were harvested from a commercial plantation in southern Greece over two seasons and stored for up to 28 days at 2+0.5 and 10+1.0oC. Artichokes that were not enclosed in plastic lost 24-52% and 48-51% weight within two weeks of storage at 2oC and 10oCrespectively, and so were unmarketable. By contrast, artichokes that were stored in polystyrene boxes covered with cling film, perforated polyethylene or clear polystyrene lost less than 3% weight (at 2oC) and 6% (at 10oC) over the same period, and 2.5-5.5% and 5.411.1% respectively after 4 weeks. Colour retention of the outer bracts was also improved by enclosure in plastic. The CO2 concentrationwithin the packages was low at 2oC, being 0.4-1.9% for cling film and less than 0.4% for the other two plastics, compared with 1.9-3.2% and 0.1-1.1% respectively at 10oC. Colour and CO2 concentration were not affected by artichoke diameter, although the rate of weight loss was lower in large heads. Enclosed artichokes stored at 10oC were only 20-40% acceptable after 14 days and not at all after 28days, whereas those stored at 2oC were 60-100% acceptable for market even after 28 days, cling film being slightly preferable to polyethylene and polystyrene. Key words: Globe artichoke, Cynara scolymus, modified atmospheres, storage.

Introduction Globe artichokes (Cynara scolymus L.) are a highly perishable commodity, characterized by rapid rates of respiration and water loss1. In Greece, theinflorescences are usually harvested together with 20-30 cm of the inflorescence stalk, tied in bundles and marketed within 1-2 days2. Alternatively, the inflorescence stalk is excised and the heads stored at 0-3oC and 90-95% r.h.3. Controlled atmospheres containing increased CO2 and reduced O2 levels have been reported to increase storage life3-5, but because CO2 concentrations of higher than 2%cause blackening of the bracts6, Kader7 concluded that controlled atmosphere storage is of no commercial value for this crop. Vegetable retailing via supermarkets frequently entails pre-packaging in plastic covered trays or containers in which the respiration of the produce results in a modification of the storage atmosphere. Because of their high rate of respiration1, artichokes will rapidly changethe composition of a closed atmosphere, resulting in high concentrations of CO2, with a concomitant danger of decay6. Consequently, it may be surmised that for satisfactory storage of artichokes in enclosed packages, the covering membrane should have a high permeability to CO2. In the present paper, we examine the suitability of three types of plastic for artichoke storage. Materials and MethodsThe experiments were carried out over two years using artichokes cv. Argous harvested from a commercial plantation in the county of Argolidas in southern Greece on 22-4-2001 (year 1) and 16-4-2002 (year 2). The artichokes were transported to the Agricultural University of Athens on the day of harvest and the experiments started the following day. The inflorescences (heads) were excised from thestalks, divided into two lots according to diameter (5.5-7.5 cm and 7.6-10.0 cm) and placed singly in clear, polystyrene boxes (10.5 x 8.5 x 10.5 cm) covered with: (1) cling film (stretch polyethylene film, 12 µm in thickness), (2) perforated polyethylene (20 µm thickness, with 20 per130

forations 100 cm2), (3) 120 µm-thick polystyrene, or (4) left uncovered (air control). Each treatment...