ANTIMICROBIAL EFFECT OF ORANGE JUICE, PEEL AND IT’S ESSENTIAL OIL ON THE SHELF LIFE OF CAKE

Abstract

The objective of this work was to study the effect of orange juice, peel and it’s essential oil as antimicrobial agent, on the shelf life of cake when stored at room temperature and at 4oC for 4 weeks. Sensory evaluation of different cup cake types produced from wheat flour containing different levels of orange peel and essential oil showed that there are non significant differences in taste and flavour between treatments (control with orange), orange peels 2.5% + orange juice, orange essential oil 0.3% + orange juice and control. The cake made with mixture of 0.3% orange essential oil + orange juice gave products of low pH (7.16), but cake with a mixture of orange juice and orange peel 2.5% plus milk gave the lowest aw (0.88).           All pathogens were not detected in all samples stored at 4 oC, while small numbers of Staph aureus and B. cereus were detected upon 21 days of storage at 30 oC. The inhibition zones against strains of Asp. Niger sp. flavus, sp parasitius, sp ocfiracus, Fuarium moriliforme and pencillum spp , showed that orange oil had the highest inhibitory effect all tested followed by the effect of orange peels, then orange juice. Generally it could be clearly all additives had considerable effects on the growth inhibition of all fungal tested strains, while, essential orange oil had the most inhibitory effect causing undetected cells in some strains from As. sp . and Pencillium spp.