Microencapsulation of essential oil of pimento [Pimenta dioica (L) Merr.] by chitosan/k-carrageenan complex coacervation method

The encapsulation of the Pimenta dioica (P. dioica) essential oil in chitosan and chitosan/k-carrageenan microspheres was investigated. The P. dioica essential oil was extracted from P. dioica (L) Merr. berries by means of supercritical CO2. 23 components, among which eugenol (68.06%), methyl eugenol (9.37%), were identified through GC analysis. The study of the antioxidant activity revealed that the IC50 (DPPH) value for the P. dioica essential oil is significantly lower (p≤0.05) than the value of the butylated hydroxytoluene (BHT) and of the ascorbic acid (AAc). The microspheres containing P. dioica essential oil were prepared through the extrusion of the oil-in-water (O/W) emulsions using as wall material the chitosan and the chitosan/k-carrageenan in different mass ratios. Chitosan microspheres present a high swelling degree than the chitosan/k-carrageenan microspheres (p<0.05). The release kinetics of the P. dioica essential oil presented a case II transport mechanism (zero order release kinetics) for chitosan/k-carrageenan microspheres (1:1 mass ratio) and a non-Fickian release mechanism for chitosan/k-carrageenan microspheres (1:0, 3:1 and 2:1). The morphology of the microspheres, the efficiency of the encapsulation and the antimicrobial activity of the P. dioica essential oil crude and microencapsulated essential oil were studied. Microencapsulated P. dioica essential oil exhibited antimicrobial activity against Candida utilis, Bacillus cereus and Bacillus subtilis.Nowadays, more and more consumers prefer foods able to equally satisfy the nutritional requirements, the pleasure to eat and the health security. Therefore, it is noticeable the tendency of using natural additives and ingredients for food preparation. This paper presents mechanisms for loading and releasing P. dioica essential oil involved in the preparation of chitosan and chitosan/k-carrageenan microspheres. Our study suggests that P. dioica essential oil encapsulated in chitosan and chitosan/k-carrageenan microspheres can be used in the meat industry to increase the functionality of meat products.