Optimization of Extraction Conditions for Garlic Oleoresin and Changes in the Quality Characteristics of Oleoresin during Storage

This study was carried out to optimize the extraction conditions of oleoresin from garlic and to investigate its physicochemical changes during storage at . Ethanol was used as solvent for extraction of oleoresin from garlic. On the basis of yield and thiosulfinate contents, the optimum mixing ratio of garlic to ethanol, extraction temperature, time, and number of extraction repeats were found to be 1 to 2(w/v), , 3 hours, and three extraction repeats, respectively. The yield and thiosulfinate contents of garlic oleoresin under the above condition were 14.52% and , respectively. Five volatile sulfide compounds were identified by GC/MS of garlic oleoresin, i.e., diallyl disulfide, methyl allyl trisulfide, 3,4-dihydro-3-vinyl-1,2-dithiin, 2-vinyl-4H-1,3-dithiin and diallyl trisulfide. After 30 days of storage at , the thiosulfinate content of garlic oleoresin was , while there was no detectable amount of thiosulfinate in the oleoresin stored at . Brown color and turbidity increased significantly during the storage of garlic oleoresin at as compared to storage at , while relatively little change in acidity was observed in the oleoresin regardless of storage temperature.