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Tag : Biomarkers

Biomarkers for onion storage

The aim of onion bulb storage is to meet consumer demand for extended availability of onions whilst maintaining product quality. The principal biological factors leading to onion bulb deterioration are respiration, resumption of growth and pathogen attack. In onion bulbs a dormant period, when sprouting and rooting can not be induced, is followed by a period of internal changes that prepare the bulb for breaking of dormancy and subsequent growth. Out of storage, the bulb then proceeds towards flowering and seed production. Sprouting occurs when the leaf primordia that are produced in stored onion bulbs develop green leaves, rather than scale leaves, which elongate and eventually protrude from the neck of the bulb. The growth rate of the sprout inside the bulb varies according to cultivar and storage regime, and is a major factor in determining the storage life of onions. Temperature has a profound effect on the dormancy period and storage life of onion bulbs. In general, sprouting is inhibited both by low and by high temperatures, and encouraged at intermediate temperatures. Cultivars respond differentially to temperature. Typically, the optimum temperature range for sprouting in dry storage is 10-20ºC. Moisture loss is greater at temperature ranges <10ºC and >27ºC.... Read more