The effect of different pre-treatments prior to garlic drying on the quality of produced garlic powder

Drying due to the adverse physical and chemical changes is one of the most difficult processes in the food industry, especially to produce garlic powder. In this study, in order to avoid the Maillard reaction, garlics were pretreated by 0.5% sodium metabisulfite, 10% NaCl and citric acid (up to pH = 4) solutions. For this purpose, first, fresh garlic, after preparation according to the usual industrial method, was immersed in the pretreatment solution for 2 minutes at room temperature. The treated garlic was dried using cabinet method at 80 °C and 90 °C to achieve 5.2% water content, and then stored for 60 days at room temperature to evaluation of some quality characteristics including moisture content, vitamin C content, browning level, flavonoid content and pH. Based on the obtained results, moisture content did not change significantly in all treatments during storage. Control sample (without pretreatment) had had the highest off color and browning. Flavonoid and vitamin C contents were reduced in pretreated samples due to their solubility in water. Generally, based on the obtained results, garlic powder produced by pretreatments had lighter color than control sample which could increase their market acceptance and pretreatment with salt had highest effect in the production of garlic powder with a suitable color.