Impact of pretreatment‐assisted enzymatic extraction on recovery, physicochemical and rheological properties of oil from Labeo rohita head

Abstract

AbstractEffects of pretreatments, namely heating (HT), microwave (MW), and ultrasound (US) followed by the enzymatic extraction on extraction yield, fatty acid profile (FAP), oxidative stability, and rheological properties of oil from Labeo rohita head (LRH) were investigated. MW and US pretreatments showed higher oil recoveries ranged from 68.45 to 69.75% and 58.74 to 67.48%, respectively, as compared to untreated LRH. US pretreatment enhanced the content of monounsaturated fatty acid and polyunsaturated fatty acid of LRH oil. Furthermore, MW pretreatment reduced the stability of LRH oil, while US pretreatment did not affect the oxidative stability of LRH oil as evidenced by differential scanning calorimetry analysis and peroxide value, anisidine value, thiobarbituric acid‐reactive substances, and free fatty acid values. Besides, all oils behaved as Newtonian fluids. US extracted oil has shown both the lowest apparent viscosity and sensitivity to temperature change (Ea = 29.74 kJ/mol). Therefore, MW or US‐assisted enzymatic extraction of LRH oil could be a good alternative to conventional enzymatic extraction.Practical applicationsMicrowave (MW) and ultrasound (US) pretreatments improved the extraction yield of oil significantly from Labeo rohita head (fish byproduct) compared to conventional enzymatic extraction. The oil extracted by US pretreatment was found to have a high content in unsaturated fatty acids and higher oxidative stability over enzymatic extracted oil. Thus, the results revealed that the MW or US‐assisted enzymatic extraction was a promising method for the improvement of the extraction yield of Labeo rohita head oil with high quality.