Effect of curing methods, packages and gamma irradiation on the quality of volatile garlic oil during storage

The values of V.R.S. as a measurement of pungency, were decreased gradually during storage especially in un-irradiated cloves treatments. Chinese garlic had higher values than Egyptian cultivar after 3,6 months. But after 9 months the pungency of Egyptian was higher than that of Chinese garlic. Irradiation decreased the V.R.S. after 3 and 6 months, but after 9 months the irradiated samples contained more V.R.S. than the unirradiated ones. No effect was observed for type of packages or curing methods. Gas chromatographic profiles, at harvest, proved that 35, 32 peaks were found in the volatile oil of Egyptian and Chinese cultivars, respectively. The identified compounds were dimethyl disulphide, diallyl disulphide, methyl allyl disulphide and dimethyl trisulphide. These compounds were found in either Egyptian or Chinese garlic. Besides, the dimethyl sulphide was detected in Chinese garlic. All tested treatments, i.e. cultivar, irradiation, curing methods and storage period, affected the percent and number of the identified constituents or unidentified compounds. Dimethyl sulphide and allyl sulphide were absent in the Egyptian Cultivar at harvest, but they were found during storage. Allyl sulphide was found in Chinese garlic only at end of storage period