Extraction comparison and characterization of garlic oleoresins; a potential functional ingredient

Oleoresins are major coloring and flavoring components of herbs and spices. Among spices, garlic is a major spice used widely in cuisines and other food formulations all around the world. Garlic oleoresins have a promising future as functional ingredient in food industries. Apart from conventional extraction methods, by using modern extraction techniques, a higher yield of oleoresins can be achieved without affecting their phytochemicals, antioxidants and other characteristics. In present research, 5 different extraction methods were used for extraction and characterization comparison. After cleaning, garlic bulbs were converted to powder and moisture was optimized to 12% prior to extraction. Among conventional extraction, different solvents were used and petroleum ether with the highest extraction efficiency was used for extraction comparison with other extraction methods. The highest extraction of garlic oleoresins (6.06%) was observed against solvent extraction. In case of phytochemicals, antioxidants and volatiles and non-volatiles characterization, extract obtained through supercritical fluid extraction (SCFE) was found best as compare to other extracts. SCF extract was further subjected to Fourier transformed infrared (FTIR) for structural analysis and gas chromatography with flame ionization detector (GC-FID) for fatty acids’ profiling. Different functional groups and total 13 fatty acids were detected in various concentrations (0.80–50.50%) in SCF extracted garlic oleoresins. All the data obtained was analyzed statistically. It was concluded that although SCF yielded slight lower quantity of garlic oleoresins (4.28%) but it was found most economical (due to chemicals and solvents free method) and best in terms of characterization and purity.