title: Effect of processing and cooking conditions on onion (Allium cepa L.) induced antiplatelet activity and thiosulfinate content.
abstract: Allium  vegetables serve as sources of antiplatelet agents that may contribute to the prevention of cardiovascular disease. However, onion and garlic, the major  Allium  species, are usually cooked before consumption. Here, we examined the effect of cooking on onion in vitro antiplatelet activity (IVAA). Two different cooking systems (convection oven and microwaves) and several time-temperature variables were tested on whole bulbs, quarters of bulbs, and completely crushed bulbs, monitoring the degradation of sulfur antiplatelet compounds (e.g., thiosulfinates) by analysis of pyruvate levels. Although heating was, in general, detrimental for onion IVAA, the extent of this effect varied greatly, from unaffected antiplatelet activity (AA) (i.e., similar to raw onion) to a complete lost of activity, depending upon the manner in which onions were prepared prior to heating, the cooking method, and the intensity of the heat treatment. "Whole", "quarters", and "crushed" onions lost their IVAA after 30, 20, and 10 min of oven heating, respectively. The longer retainment of AA in intact bulbs was attributed to a later alliinase inactivation. Proaggregatory effects observed in samples subjected to the most intense oven and microwave heat treatments suggest that extensively cooked onions may stimulate rather than inhibit platelet aggregation. The efficacy of  Allium  species as antiplatelet agents, as affected by preparation and cooking conditions, is discussed.
authors.affiliation: Instituto Nacional de Tecnología Agropecuaria (INTA), EEA La Consulta CC8, San Carlos, Mendoza 5567, Argentina. pablocavagnaro@hotmail.com
authors.forename: Pablo F
authors.initials: PF
authors.lastname: Cavagnaro
authors.forename: Claudio R
authors.initials: CR
authors.lastname: Galmarini
mesh_terms: D000328:Adult; D005260:Female; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D019697:Onions / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D013441:Sulfinic Acids / Q000032:analysis*; D013997:Time Factors
chemical_list: D010936:Plant Extracts; D010975:Platelet Aggregation Inhibitors; D013441:Sulfinic Acids; C100040:thiosulfinic acids