Allium roseum leaves were subjected to thin layer convective drying at three temperatures (40, 50 and 60C) and two air velocities (1.0 and 1.5m/s). The effects of the drying conditions on drying characteristics, color, phenolic compounds and antioxidant properties of A. roseum leaves were assessed. Convective drying induces a considerable moisture removal from fresh leaves (more than 96%) and requires 7 and 28h at 60 and 40C, respectively. Fresh A. roseum leaves have a water activity higher than 0.9, which had been reduced after drying to a value of about 0.5. Drying resulted in color modifications and drastic declines in total polyphenol content (between 60 and 69%), total flavonoid content (between 17 and 29%) and radical-scavenging capacity (between 72 and 88%). Drying temperature showed a significant effect on drying rate, moisture loss, water activity, total polyphenol content, total flavonoid content and radical-scavenging activity of A. roseum leaves. Allium roseum, also known as rosy garlic, and called in Tunisia "Lazoul," is a spontaneous plant that grows in the southern part of the country during the rainy years. Local indigenous communities traditionally use Lazoul leaves as a condiment in various meals. The specific taste attributed to these leaves is highly appreciated, but moreover their therapeutic properties, due to antibacterial, antifungal and antioxidant activities, are now well known. However, the short vegetative presence of Lazoul limits its availability and renders it rare. Traditional food prepared with fresh A. roseum leaves tend to disappear, and thus, preparation of such foods, which has been inherited from one generation to the other within a traditional knowledge, is now threatened. Drying may be a solution for A. roseum preservation throughout the year. Moreover, bringing small-scale technologies to local people may revitalize biodiversity and protect traditional food from disappearance. © 2013 Wiley Periodicals, Inc.
