Abstract
Oil from Madhuca longifolia seed kernel was extracted with 3 methods as Soxhlet extraction, pressing and the combined method (pressing + solvent extraction). Soxhlet extraction with n-Hexane gave the highest yield with 52.22±0.63%. The yield of pressing method was 25.95±0.82%. Combined method yielded 43.73±0.86%. Physico-chemical properties of extracted oil were determined and compared with coconut oil. Saponification value obtained was 182.79±1.49 mg KOH/g. Obtained iodine value was 56.28±0.69 g I2/100g. Determined peroxide value and acid value were 2.78±0.01 meq/kg and 3.55±0.03 mg KOH/g respectively. Melting point was recorded as 33.33±0.24 ºC. Smoke point, specific gravity and refractive index were 169.66±1.25 ºC, 0.9272±0.00 at 25 ºC and 1.4672±0.00 respectively. GC-MS analysis of fatty acid profile gave oleic (48.31%), stearic acid (24.50%) palmitic (19.12%) and linoleic (5.11%) as the major fatty acids. Several new fatty acid types that were not reported in the previous studies were identified. They are palmitoleic acid (C16:0), margaric acid (C17:0), nonadecylic acid (C19:0), cis-gondoic acid (C20:1), lignoceric acid (C24:0), and cerotic acid (C26:0). Another new fact discovered through this study was the considerably low amount of linoleic acid (5.11%) compared to the previous studies (9.4 to 15.4%). When M. longifolia seed oil and coconut oil (unrefined) were compared upon their radical scavenging activity (RSA) towards the stable 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical, M. longifolia seed oil exhibited bit weaker RSA than coconut oil. Taste, odor, mouth feel and organoleptic acceptability were tested with a sensory evaluation. Even though there was a little negative effect of M. longifolia seed oil on the taste of deep-fat fried French fries, other tested sensory attributes including odor, mouth feel and overall acceptability were acceptable. When foods prepared by stir frying method, there was no significant difference between two samples prepared with M. longifolia seed oil and coconut oil for all the tested sensory attributes.
