Effect of drying methods on anti-oxidative potential of garlic (Allium sativum L.)

Abstract

The effects of drying methods and conditions on quality parameters and medicinal properties of garlic (Allium sativum L.) were studied by performing various drying methods including freeze-(FD), vacuum-(VD), and oven-(OD) drying at various drying temperatures (20, 50 and 60°C). Dried garlic obtained from vacuumand oven-drying at a higher drying temperature resulted in a higher optical index and b∗value (high b∗values indicate yellow color) but a lower moisture content, water activity, and L∗value (high L values indicate a lighter color). In addition, dried garlic showed inhibition of α-amylase and a-glucosidase ranging from 42.70 to 61.84 and 41.91 to 73.38%, respectively. Freeze dried garlic showed the highest inhibition of α-amylase while oven-dried garlic exhibited the highest inhibition of a-glucosidase. A strongly significant correlation between b∗value and antioxidant activity and enzyme inhibitory activity of garlic was observed. Furthermore, oven-drying of garlic produced better acceptable quality characteristics and better conservation of bioactive compounds compared to vacuum- and freeze-drying.