The Effect of Controlled Atmosphere Packaging on Overall Quality of 'Wonderful' Pomegranate

The cold storage of fruits is a key step to guarantee the product quality. However, temperatures below 5°C could cause chilling injury, decay, browning, husk pitting and discoloration of pomegranates. Controlled atmosphere could reduce pomegranate physiological disorders and pathogen growth. Therefore, the objective of this work was the assessment of different controlled atmosphere conditions on pomegranate overall quality under cold storage during 70 days. 'Wonderful" pomegranates (Vicuña, Coquimbo, Chile) were processed at 8±1 ºC, washed with sodium hypochlorite (200 mg L^-1 x 3 min) and then placed in 20 L sealed plastic containers connected to a gas panel mixer by 6 mm plastic hoses. 10 fruits were placed in each container where 5 %O₂-5 %CO₂ and 5 %O₂-10 %CO₂ gaseous combinations were applied at 0 or 5 °C.  Gas concentrations were measured with a portable gas analyzer. Respiratory rate, weight loss, color, chilling injury (%), total soluble solids, titritable acidity and decay (%) were determined. Pomegranates stored at 0 °C showed lower respiratory rates than those stored at 5 °C with values ranging from 4-5.6 mgCO₂ kg^-1h^-1 and 4-8 mg CO₂kg^-1h^-1, respectively. The pomegranate husk color was not affected (p³0,05)  by the different atmospheres and storage temperatures with values of lightness (L), saturation (C) and tone (Hab) of 42-56 , 40-54 and 27-41, respectively. The greater weight losses were observed in fruits stored in atmosphere of 5% CO₂ -10% O₂. Fruit stored at 0 °C showed chilling injury from day 30+2, which was higher in 5% O₂-10% CO₂ treatment, with 100% of the fruit with moderate damage. In pomegranates stored at 5 °C damage was observed at 60+2 days in atmosphere of 5% O₂- 10% CO₂, with 100% of fruit with slight damage. Controlled atmosphere caused a significant reduction on fruit decay due to an inhibition on mold growth mainly observed in 5% O₂-5% CO₂ atmosphere.  Results showed the feasibility of this technology to extend the shelf life of pomegranates.