Temperature-dependent studies on the total phenolics, flavonoids, antioxidant activities, and sugar content in six onion varieties.

Heating effect on total phenol, flavonoids, antioxidant activity, and sugar content of six onion varieties has been quantitatively investigated to explore the effect of different temperatures. The onion varieties comprised one red-skinned variety, two white-skinned varieties, and three yellow-skinned varieties. The heating temperature was scanned at 80°C, 100°C, 120°C, and 150°C for 30 minutes each, and quantitative analysis was performed relative to the powdered onion at ambient temperature.

Quantitative analysis of flavonoids, sugars, phenylalanine and tryptophan in onion scales during storage under ambient conditions.

A comprehensive quantitative analysis of flavonoids, sugars, phenylalanine, and tryptophan have been carried out in different onion scales during storage at ambient temperature (20-23 °C) and relative humidity (60-80 %). Depending on the length of storage, dry matter content and composition shows variation inside the onion bulbs. Inner sprouts were observed on longitudinally cut bulbs after 2 months and visible sprouts appeared after 5 months of storage.

Evaluation of total phenolics, flavonoids and antioxidant activity of 18 Korean onion cultivars: a comparative study.

Background: Onion is undoubtedly one of the major sources of flavonoids. However, there exists a varietal difference in composition, concentration and beneficial activities of onion, on the basis of cultivars, day length sensitivity/ripening and types. To characterise such differences, 18 onion cultivars from Korean were evaluated for their total phenolics, flavonoids and antioxidant activity.

Identification of two novel inactive DFR-A alleles responsible for failure to produce anthocyanin and development of a simple PCR-based molecular marker for bulb color selection in onion (Allium cepa L.).

Two novel inactive alleles of Dihydroflavonol 4-reductase-A (DFR-A) were identified in yellow onion (Allium cepa L.) cultivars and breeding lines from Korea and Japan. Unlike the previously reported inactive yellow DFR-A allele, designated as DFR-A ( TRN ) , in which the 3' portion of the coding sequences was deleted, an allele containing a premature stop codon, DFR-A ( PS ) , was isolated from the majority of cultivars.

Identification of a novel chimeric gene, orf725, and its use in development of a molecular marker for distinguishing among three cytoplasm types in onion (Allium cepa L.).

A novel chimeric gene with a 5' end containing the nearly complete sequence of the coxI gene and a 3' end showing homology with chive orfA501 was isolated by genome walking from two cytoplasm types: CMS-S and CMS-T, both of which induce male-sterility in onion (Allium cepa L.). In addition, the normal active and variant inactive coxI genes were also isolated from onions containing the normal and CMS-S cytoplasms, respectively.