Allium Thiosulfinates: Chemistry, Biological Properties and their Potential Utilization in Food Preservation

Onion (Allium cepa L.), garlic (Allium sativum L.) and other edible Allium are among the oldest cultivated plants, and are used for multiple purposes. They are a rich source of several phytonutrients, and recognized to have significant and wide biological activities. These biological activities are related to the thiosulfinates, volatile sulfur compounds which are responsible for the pungency of these vegetables. The thiosulfinates or alkane(ene) thial-S-oxide are formed by the action of the enzyme alliinase (E.C. 4.4.1.4) from their respective S-alk(en)yl cysteine sulfoxides. However, depending on the Allium species, and under differing conditions, thiosulfinates can decompose to form additional sulfur constituents, including diallyl, methyl allyl, and diethyl mono-, di-, tri-, tetra-, penta-, and hexasulfides, vinyldithiins, and (E)and (Z)-ajoene. With increasing interest into the utilization of natural biologically active compounds and the development of specific packaging, mainly active packaging, the thiosulfinates aroused much interest for the improvement of shelf-life and safety of perishable foods, and their potency as food preservatives and substitutes for chemicals. This review examines the nature and the biological activities of Allium thiosulfinates and their potential values as food preservatives in food preservation and shelflife extension. _____________________________________________________________________________________________________________