Influence of propagation method and storage conditions on fructo-oligosaccharide degradation in onions (Allium cepa L.)

Abstract

Onions (Allium cepa L.), grown from seeds and sets were stored in two separate warehouses for 5 months, either under forced air ventilation or cold temperature conditions. Storage carbohydrates including fructo-oligosaccharides (FOS) were quantitated monthly by anion exchange chromatography with pulsed amperometric detection. Set grown onions cv. ‘Sturon’ exhibited highest FOS concentrations after harvest (71.0 ± 19.9 g/L), surpassing those of their seed grown counterparts (43.0 ± 2.7 g/L). Although FOS degraded in both set and seed grown onions during storage, their concentrations remained higher in set grown onions throughout 5 months of storage. However, differences in retention between the levels of storage carbohydrates in cold stored onions and those of onions stored under forced ventilation were insignificant. In brief, while the studied storage conditions were widely irrelevant, propagation method and cultivar selection were found to be of utmost importance for the retention of storage carbohydrates during long-term storage.