Microencapsulation of Litsea cubeba Essential Oil in β-Cyclodextrin Using Paste and Co-Precipitation Methods

Abstract

Microencapsulation of Litsea cubeba essential oil (LCEO) with β-cyclodextrin (BCD) was carried out using the paste and co-precipitation methods at various oil concentrations and ratios of LCEO to BCD adapted from a central composite design to determine the effect of these factors on the microencapsulation efficiency, microencapsulation yield, surface oil and recovery of the finished product. In addition, the effect of different levels of water activity and temperature on the oxidative stability of the powder was investigated. Treatment 4 using the paste method with 90% LCEO and a ratio of LCEO to BCD of 15:85 was found to be more efficient compared to samples produced by the co-precipitation method. This condition provided an oil loading of 102 mg.g-1 of powder, 74.7% microencapsulation yield, 71.9% microencapsulation efficiency, 94.8% recovery of LCEO powder and surface oil with 4.08 mg.g-1 of powder. Statistical analysis indicated that the temperature and water activity had significant effects on the peroxide value. Moreover, there was an interaction between these two factors. The LCEO powder had higher oxidative stability with the lowest peroxide value of 4.9 meq.kg-1 when it was stored at 10 °C and a water activity of 0.53 whilst the accelerated conditions of 50 °C and a water activity of 0.64 resulted in the highest peroxide value (13.6 meq.kg-1) and lower oxidative stability. It was notable that except for the samples stored at a water activity of 0.64 and temperatures of 30 and 50 °C, the other samples did not exceed the limit for the peroxide value of 10 meq.kg-1 which is the acceptable limit for edible vegetable oils.