Onion cultivars differ in pungency and bulb quality changes during storage

Pungency and bulb quality changes during storage mere evaluated using onion (Allium cepa L.) cultivars representing different storage abilities, pungency, and soluble solids content, Bulbs were harvested from greenhouse-grown plants, cured, and stored for 3 or 6 months at 5 +/- 3 degrees C, 80% +/- 5% relative humidity (0.8 to 1.1 kPa vapor pressure deficit). Prior to storage, and after each month of storage, bulbs were evaluated for pungency by measuring enzymatically formed pyruvic acid (EPY), soluble solids content (SSC), percent loss in mass (%ML), and loss of dormancy. Pungency differed among cultivars prior to and during storage. Among short-day (SD) cultivars, EPY either decreased or increased linearly with increased storage duration. Among intermediate (ID)- and long-day (LD) cultivars, EPY decreased linearly or quadratically during storage. Short-day cultivar SSC increased, then decreased quadratically during storage, while ID and LD cultivar SSC decreased linearly over time, Percent loss in mass increased linearly during storage among all cultivars, although SD cultivars exhibited greater %ML than did ID or LD cultivars.