ABSTRACT

The present study evaluated the physicochemical and flavour profile of essential oils from grape and orange peels. The fruits were sourced from a local market in Umuahia. The peels were obtained from the fruits and processed into flour. Essential oils were extracted from the peel powder using solvent cold extraction technique with n-hexane, following a standardized protocol. Data obtained from analytical procedures were subjected to statistical analysis. The independent sample t-test at 95% confidence level was adopted. The obtained oils were evaluated for their yield, physicochemical properties and flavour profiles. Results showed that Grape peels had higher essential oil yield (11.50%) than orange peels (10.99%). Physicochemical analysis revealed that refractive index of grape peels and orange peels essential oils were 1.47 and 1.50, specific gravity of grape and orange peel essential oils are 0.84 and 0.85, Iodine values of the essential oil samples are 86.33 I2 g/100 g for grape peel essential oil and 77.3212 g/100 g for orange peel essential oil, saponification values of essential oils are 151.98 mg KOH/g for grape peel essential oil and 143.01 mg KOH/g for orange peel essential oil, grape peel essential oil had lower acid value of 8.17 mg KOH/g than the acid value oforange peel essential oil (24.94 mg KOH/g), The melting point ofthe essential oils are -83.38°C for grape oil and -72.51 °C for orange peel essential oil, boiling point are 220.08°C for grape peel essential oil and 177.58°C for orange peel essential oil. The flavour profile showed that grape peel essential oil recorded 62 volatile compounds, this amount to 88.22% of the total volatile oil composition while orange peel essential oil recorded 35 volatile components which represent 99.77% of the total volatile oil composition. Squalene was the most prominent flavour compound in grape peel essential oil with a concentration of 21.13% while limonene was the most abundant flavour component in orange peel essential oil with a concentration of40.01%. Conclusively, the essential oils of grape and orange peels possessed distinct chemical composition which will influence their food and non-food applications.