Effect of Microwave heating on physico-chemical and thermal behavior of blended fat
A blend of hydrogenated palm kernel oil and butter (3:2) was selected and exposed to microwave heating for 5, 10 and 15 min at low and high power settings. The treated samples were analyzed for physico-chemical properties viz. peroxide value (PV), color values, free fatty acid content (FFA), iodine value (IV) and C18:2/C16:0 ratio and subjected to “Differential Scanning Calorimetry” (DSC) to examine the correlation among thermal properties and the changes in their physico-chemical parameters. FFA, PV, and color value reflected a noticeable increase by 16.6%, 19.27% and 78.5%, respectively with the increase in microwave power and time setting where as IV and C18:2/C16:0 ratio reflected decline in their values by 19.27% and 21.5% respectively. The experimental data highlighted that DSC curve parameters like peak areas and peak height had significant and positive correlation at all the settings of microwave time and power with FFA, whereas significant and negative with IV. The data showed non-significant and positive correlation with PV at all the heating times and power settings of microwave. C18:2/C16:0 ratios reflected their negative and significant correlation with peak areas at high power setting whereas color value revealed a positive and significant correlation with peak B area at both power settings. The physico-chemical and thermal behavior reveales the blended fat stability during microwave heating operations.