Authors: Isabella Kleman *, Anna Karin Rosberg, Paul Becher, Oleksiy Guzhva, Lars Mogren
Onion ( Allium cepa L.) is an important crop that is cultivated and consumed all over the world. It is the second most produced horticultural vegetable crop (after tomato) based on weight. In order to be available year-round in Sweden, onions must be stored for several months during the cold part of the year, when no fresh onions can be harvested. Dry onion bulbs are well suited for storage, as long as they remain dormant. However, dormancy break resulting in early sprouting is a common quality problem during storage, reducing the amount of high quality bulbs. Before visible sprouting, changes in the bulb chemical composition take place, including relocation of oligosaccharides and breakdown of larger sugar molecules into smaller units that are then used as energy during the sprouting process. In this project we used a handheld reflectometer to measure levels of mono- and disaccharides and calcium in onion bulbs throughout the storage period in order to identify early stages of sprouting. The method has potential to be used on site in onion storage facilities to help aid decision-making reducing the amount of onion waste.