Modified atmosphere packaging of minimally processed avocado cv. ‘Booth 7’

Abstract

SummaryAvocado fruits were washed with 200 µg l–1 active chlorine, partially ripened to a firmness of about 12.5 ± 0.6 kg cm–2, and sliced. Fruit slices were dipped in 1.0 mg l–1 citric acid and 200 µg l–1 ascorbic acid maintained at 4°–6°C for 2 min, dried with tissue paper and packaged in 0.05 mm or 0.075 mm-thick low density polyethylene (LDPE) at a 1:1 surface area to product weight ratio (cm2 g–1). Sodium chloride (1 g) sealed in 0.075 mm-thick poly-coated paper pouches was included in the packages for moisture absorption. In-package O2 and CO2 concentrations, as well as the ethanol and acetaldehyde concentrations, firmness and lightness (L value) of the tissue slices were measured during storage for 10 d. The sensory attributes of the modified atmosphere (MA)-packaged slices were compared with fresh fruit slices. In-package O2 concentrations fell from 14.1% to 6.3% and CO2 concentrations rose from 4.7% to 4.9%. Ethanol concentrations increased from 9.0 to 32.1 µg g–1 and acetaldehyde from 1.1 to 3.8 µg g–1 during storage from day-1 to day-10 in the 0.05 mm-thick LDPE with sodium chloride moisture absorbers. In-package concentrations of O2 fell from 10.8% to 3.8% and CO2 rose from 3.8% to 8.1%, while ethanol concentrations increased from 10.0 to 40.4 µg g–1 and acetaldehyde from 1.3 to 4.7 µg g–1 during storage from day-1 to day-10 in the 0.075 mm-thick LDPE with sodium chloride moisture absorbers. The L value and sensory attributes of avocado slices packaged in 0.05 mm-thick LDPE, with moisture absorbers, were not significantly different from fresh slices, indicating the effectiveness of these MA conditions. Regardless of packaging conditions, avocado slices reached the firmness values of 5.8–6.3 kg cm–2 required for the ‘table-ripe’ stage on day-10 in storage. Therefore, packaging of ‘Booth 7’ avocado slices in 0.05 mm-thick LDPE with sodium chloride as a moisture absorber resulted in a storage-life of 10 d at 8°C and 90 ± 2% RH.