Variation for health-enhancing compounds and traits in onion (Allium cepa L.) germplasm

INSANI, M. E.; CAVAGNARO, P. F.; SALOMON, V. M.; LANGMAN, L.; SANCE, M.; PAZOS, A.; CARRARI, F. O.; FILIPPINI, O. ; VIGNERA, L.; GALMARINI, C. R.

Food and Nutrition Sciences

Scientific Research Publishing

Lugar: Wuhan; Año: 2016 vol. 7 p. 577 - 591

2157-944X

Consumption of onion has been associated with reduced incidence of chronic diseases. Phenolic,organosulfur and carbohydrate compounds present are largely responsible for these effects. Thisstudy examined compositional variation for health-enhancing compounds in a genetically diversecollection of onion cultivars. Total antioxidant activity and aroma profiles were characterized.Significant variation in bulb concentration for total and individual phenolic compounds, thiosulfinates,carbohydrates, and total and soluble solids was found. The range of variation was particularlylarge (>50-fold difference between the cultivars with the highest and lowest content) forfructo-oligosaccharides (FOS) and the polyphenols quercetin, epigallocatechin gallate and epicatechingallate. Amino acid profiles varied significantly as well with substantial variation (~10 fold)observed in both total and essential amino acids. Total antioxidant activity was positively correlatedwith polyphenols content, and quercetin in particular (r = 0.83), suggesting a major contributionfrom phenolic compounds to onion antioxidant properties. Significant positive correlationwas also found between solids and thiosulfinates content (r = 0.74) and between solids and FOS (r= 0.81), suggesting a dilution/concentration effect for organosulfur compounds and FOS in onionbulbs. The present study revealed broad variation for health-enhancing compounds content in onion germplasm, which can be exploited in breeding programs aiming at increasing onion nutraceuticalvalue.