Optimization Studies on Ohmic-Assisted Extraction of Bioactive Compounds from Garlic

Abstract

Ohmic heating technique, a high-temperature short-time process (HTST), where heat is generated by controlling the electrical conductivity of the food components. In this study, garlic was extracted by ohmic heating technique at different voltage gradients (13.33 to 26.66 V/cm) for different extraction times (5, 7.5 and 10 min). Similarly, garlic was conventionally extracted in different heating rate (low, medium, high) for different extraction times (5, 7.5 and 10 min). The process parameters were optimized based on the physico-chemical analyses such as, total phenol content, DPPH radical scavenging activity and diallyl disulphide content by high performance liquid chromatography. Resulted data were compared with the data obtained from conventional extraction done at (35-82 ºC). Though there were no significant differences (p < 0.05) found in physico-chemical properties of garlic extract, while the samples treated with ohmic heating has significant levels of diallyl disulphide content. Diallyl disulphide content of about 67.1% was obtained in ohmic extract whereas only 33.8% was resulted by conventional extract.