Knoflook en verwarming?*

Uit een Argentijns-Amerikaanse studie blijkt dat ook bij verwarming knoflook nog zijn goede eigenschappen kan behouden mits aan bepaalde voorwaarden wordt voldaan. Normaal verliest knoflook al bij verwarming een paar minuten, veel van zijn goede eigenschappen. Door nu 10 minuten voor het koken de knoflook fijn te maken en de knoflook niet langer dan 10 minuten te laten koken blijven bijna alle goede eigenschappen behouden. Langer dan 10 minuten koken doet veel goede eigenschappen verdwijnen. In de magnetron blijken de goede eigenschappen hoe dan ook verloren te gaan.

Door het fijn maken komt een enzym, alliinase vrij dat de in de knoflook aanwezige alliine omzet tot het gezonde bestanddeel allicine. Deze stof geeft ook de specifieke knoflookgeur. Door verwarming lijkt de activiteit van het enzym alliinase stop gezet te worden.

"Effect of Cooking on Garlic (Allium sativum L.) Antiplatelet Activity and Thiosulfinates Content"
CONTACT:
Claudio R. Galmarini, Ph.D.
INTA-EEA La Consulta and CONICET
Mendoza, Argentina

Effect of Cooking on Garlic (Allium sativum L.) Antiplatelet Activity and Thiosulfinates Content

Pablo F. Cavagnaro, Alejandra Camargo, Claudio R. Galmarini,* and Philipp W. Simon

INTA - EEA La Consulta and CONICET, INTA, EEA La Consulta CC8, San Carlos, Mendoza (5567), Argentina, Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Almirante Brown 500, Chacras de Coria, Mendoza M 5528 AHB, Argentina, and USDA-ARS Vegetable Crops Research Unit and Department of Horticulture, University of Wisconsin, 1575 Linden Drive, Madison, Wisconsin 53706

Funding provided by Project INTA-BID 12908, PICT-O 12902.

Abstract:

The raw form of garlic and some of its preparations are widely recognized as antiplatelet agents that may contribute to the prevention of cardiovascular disease. Herein, we examined the in-vitro antiaggregatory activity (IVAA) of human blood platelets induced by extracts of garlic samples that were previously heated (in the form of crushed versus uncrushed cloves) using different cooking methods and intensities. The concentrations of allicin and pyruvate, two predictors of antiplatelet strength, were also monitored. Oven-heating at 200 C or immersing in boiling water for 3 min or less did not affect the ability of garlic to inhibit platelet aggregation (as compared to raw garlic), whereas heating for 6 min completely suppressed IVAA in uncrushed, but not in previously crushed, samples. The latter samples had reduced, yet significant, antiplatelet activity. Prolonged incubation (more than 10 min) at these temperatures completely suppressed IVAA. Microwaved garlic had no effect on platelet aggregation. However, increasing the concentration of garlic juice in the aggregation reaction had a positive IVAA dose response in crushed, but not in uncrushed, microwaved samples. The addition of raw garlic juice to microwaved uncrushed garlic restored a full complement of antiplatelet activity that was completely lost without the garlic addition. Garlic-induced IVAA was always associated with allicin and pyruvate levels. Our results suggest that (1) allicin and thiosulfinates are responsible for the IVAA response, (2) crushing garlic before moderate cooking can reduce the loss of activity, and (3) the partial loss of antithrombotic effect in crushed-cooked garlic may be compensated by increasing the amount consumed. (Maart 2007) (Opm. Meer over knoflook.)