Effect of Different Drying Techniques on the Quality of Garlic: A Comparative Study
The demand for spices and extracts is growing all over the world, although the spices are exported in a variety of forms in the international spice trade, about 80-85% are sold in the whole ungrounded state. The rest are marketed as ground spices or in mixes and as spice essential oils and oleoresins. Dehydrated garlic as spice is of considerable importance in world trade. The quality of dehydrated product is affected by number of factors and is dependent on the quality of raw material used, method of preparation, processing treatments and drying conditions. The freeze drying applied to the manufacturing of certain foods can result in economically unprofitable products. The difficulties encountered in the heat transfer can be avoided by combining other dehydration methods. The garlic cloves for maximum possible Moisture Loss (ML) and retention of volatile oils (VOR) with minimum changes in sensory quality scores (SQS maximum 20) were subjected to hot air drying (13.3% mL, 17.1/20 SQS, 60% VOR, at 60°C for 3 h), Fluidized Bed Drying (FBD) (17.1% mL, 14.2/20 SQS, 65% VOR at 55°C for 2 h), microwave heating (9.75 mL, 16.9/20 SQS , 75% VOR for 14 sec) and freeze drying treatment (58.8% mL, 19.3/20 SOS, 98.7% VOR). By analyzing their effect on the loss of moisture, volatile oil retention and sensory quality, it could be concluded that Freeze drying operation could be combined with fluidized bed drying to get a product with desirable quality attributes and maximum moisture removal at minimum processing cost.