India is one of the largest producers of the fruits and vegetables in the world with population close to 1.2 billion. Fruits and vegetables are very important for healthy living because they contain beneficial nutrients (Bates and oberts, 2001). Onion (Allium cepa) is widely used both for flavoring and for the potential benefits of preventing and curing ailments (Rivlin, 2001). Onion is also recommended because of its good nutritive value (Shekhad, 1996). Since ancient times, onion has been used worldwide as seasoning, spices and herbal remedies (Ahmed, 1997). Onion is known to possess a vast variety of biological functions such as antimicrobial (Kim, 2002; Krest et al., 2000) anti thrombotic (Block et al., 1986), and antioxidant (Furhath, 1997; Prasad et al., 1996; Siems et al., 1996). Onion is a perishable crop and it cannot store safely in normal condition for a long time. Under storage, onion bulbs continuously loose water and dry matter, but more serious losses arise from, sprouting and rooting (Annymous, Pandey, 1994). Blanching is an important heat process in the preparation of vegetables destined for canning, freezing or drying. Primarily blanching is carried out to inactivate enzymes or to destroy enzyme substrate such as peroxides. In addition to destroying enzymes, blanching also brings the changes as the raw material by destroying the bacterial load and cellular gases are expelled. To overcome the post-harvest losses of onion