DefinePK

Abstract

Carotenoids are one among valuable nutrients in oil palm fruit. The facts carotenoids are vulnerable to heat were indicated by lower carotenoids concentration in palm oil after sterilization process. Sterilization of oil palm usually conducted at temperature above 150oC at which carotenoids degraded from 4000 ppm to 700 ppm. To retain carotenoids, sterilization of oil palm fruit should be conducted at low temperature. Microwave irradiation offers flexibility in arranging heat level and irradiation time for sterilization process as compared to thermal sterilization. This study aims to evaluate combination of time and temperature for microwave sterilization and develop safety margin that deactivate lipase and at the same time retain carotenoids. To determine safety margin for carotenoids content, an analysis on relationship between D-value and temperature was conducted for lipase inactivation process and carotenoids degradation. The D-values of lipase were determined from lipase inactivation at various power levels, sample’s size of oil palm fruit and irradiation time. Microwave oven that connected with thermocouple, data logger and computer was used to determine D-value. The safety margin for this process was developed from D-value curve of both lipase and carotenoids. Areas under intersection between two curves represent combination of time and temperature for irradiation process. This time and temperature combination at the intersection points offering maximum and minimum level of carotenoids content in palm oil product. It was concluded that sterilization of oil palm fruits by microwave irradiation may occur at low temperature (below 60oC) and require longer irradiation time (more than 20 min). This microwave sterilization process can deactivate lipase and also retain carotenoids in palm oil.