Antioxidant activity of the essential oil of Citrus limon before and after its encapsulation in amorphous SiO2
Louiza HIMED, Salah MERNIZ, Rebeca MONTEAGUDO-OLIVAN, Malika BARKAT, Joaquín CORONAS
In recent years, the consumer demand for natural ingredients has resulted in sustained growth in the global market of essential oils. Indeed, essential oils are considered today as a product "trend" to the general public, which in particular raises considerable appeal from the agro-food sector. However, this application sector has to face many disadvantages related to the variability of their composition, and their volatility and storage instability.
The objective of this work was to extract the essential oil of Citrus limon, determine its chemical composition, evaluate its antioxidant activity and see the effect of its encapsulation on such activity. The cold pressing of the lemon peel yielded 1.24±0.07% of the essential oil. This oil was characterized by a composition rich in limonene (67.1%) followed by α-pinene (11.0%) and α-terpinene (8.0%).The antioxidant
activity of the oil expressed by the antiradical power DPPH and by the reducing power CUPRAC gave rise to results comparable to that of the standards. The encapsulation of this oil in silica did not modify its antioxidant activity. The thermogravimetric analysis showed a weak thermal estabilization of the encapsulated oil compared to the free oil. FTIR-ATR showed that the encapsulation did not alter the composition of the oil.