Regional Differences in Onion Bulb Quality and Nutrient Content, and the Correlation Between Bulb Characteristics and Storage Loss

Many onion growers and researchers assert that differences in soil type, agricultural practices,weather, and duration of prolonged onion cultivation in a particular field could affect onionbulb quality. This study evaluates the bulb quality of onions grown in different regions anddetermines the correlations between bulb characteristics and postharvest loss during cold andambient storage. Soil and onion bulbs were collected from fields in six onion growing regionsin Korea, during the growing season of 2011-2012. The fresh weight, dry matter content, andcarbon (C), sulfur and magnesium contents of the onion bulbs were significantly affectedby the location in which they were grown. Bulbs grown in Muan had the greatest number ofscales, thinnest scale thickness, and the highest total soluble solids (TSS) and total flavonoids(TF). Bulbs originating from Jecheon had the lowest pyruvic acid (PA), total phenolics and TF. Storage loss of bulbs from the different regions was similar in refrigerated storage, but differedin ambient temperature storage. Bulb fresh weight was positively correlated with scale thickness(r = 0.617) and cold storage loss (CSL; r = 0.398). Dry matter content was positively correlatedwith C (r = 0.958) and TF (r = 0.256) contents, while it was negatively correlated with CSL (r= -0.424). CSL was primarily affected by the fresh weight, as well as the dry matter, C, and PAcontents of the bulbs, while ambient storage loss was primarily influenced by the amount ofTSS. KCI Citation Count: 3