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Open Access Research

Steam-cooking rapidly destroys and reverses onion-induced antiplatelet activity

Emilie A Hansen1, John D Folts2 and Irwin L Goldman3*

Author Affiliations

1 Department of Health Professions, Metropolitan State University of Denver, Denver, CO, USA

2 Department of Medicine, Cardiology Section, H6/379 CSC, University of Wisconsin-Madison, Madison, WI, 53702, USA

3 Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA

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Nutrition Journal 2012, 11:76  doi:10.1186/1475-2891-11-76

Published: 20 September 2012

Abstract

Background

Foods in the diet that can aid in the prevention of diseases are of major interest. Onions are key ingredients in many cuisines around the world and moreover, onion demand has trended higher over the past three decades. An important pharmacological aspect of onion is the ability to inhibit platelet aggregation. Raw onions inhibit platelet aggregation; however, when onions are boiled or heated, antiplatelet activity may be abolished.

Methods

Onion quarters were steamed for 0, 1, 3, 6, 10, and 15 min. The in vitro antiplatelet activity of a yellow hybrid storage onion was examined at these times on the blood of 12 human subjects using in vitro whole blood aggregometry.

Results

Contrary to findings reported for boiling, antiplatelet activity was destroyed between 3 and 6 min of steaming, and at 10 min of steaming, cooked onions stimulated platelet activity. Extracts from cooked onion had the potential to reverse the inhibitory effect on blood platelets by 25%. Responses were consistent across all donors. Total polyphenolic concentration and soluble solids were not affected by steaming time.

Conclusions

The potential value of cooked onion preparations may result in destruction or reversal of antiplatelet activity, without affecting the polyphenolic concentration.

Keywords:
Onion; Platelets; Antiplatelet; Cooking; Polyphenols