Alterações físicas e químicas em cebolas armazenadas sob refrigeração

Storage under low temperatures, immediately after the harvest, is the most used technique to extend the shelf life of different fresh produce. The present work was carried out with the objective of assessing physical and chemical alterations in onions stored under refrigeration. Onions (Allium cepa L.) cultivars 'Beta Cristal' and 'Optima' were harvested at Embrapa Vegetables experimental fields, were cured and taken to the Food Science and Technology Lab where bulbs were selected and stored at 5±1°C and 85±5% relative humidity for 60 days. Every 10 days bulbs wee assessed for dry matter, mass loss (%), brightness, firmness, titratable acidity, soluble solids and pungency. It was observed during the storage period for both cultivars an increase in weight loss, a reduction in the content of soluble solids and titratable acidity. There was a significant variation in bulbs brightness during storage. After 60 days, onions from both cultivars presented higher brightness comparing to the beginning of the experiments. There was a significant increase in firmness for 'Optima' bulbs. At the end of the experiment, pungency was 6 and 5 times higher in 'Beta Cristal' and 'Optima' cultivars, respectively, when compared to the values observed in the beginning of the experiment.