Determination of antioxidant and antimicrobial properties of zein-casein encapsulated spearmint essential oil

Microencapsulation is a useful and often preferred process to preserve by providing the component stability of the essential oils and to prevent or/and increase bioactivity properties. Characteristic features such as microencapsulation efficiency, microencapsule stability and protection of core are shaped with selected core and coat materials. In this research, the efficiency, antioxidant, antimicrobial, surface and size properties and release period based on empty and essential (volatile) spearmint (Mentha spicata) oil microcapsules which are obtained via zein and zein/casein complexes and prepared with liquid-liquid dispersion and lyophilization techniques are identified. In the study, average 1% essential oil is obtained from spearmint plant with the help of the clevenger apparatus technique. The GC-MS technique is used for determining the components of the spearmint essential oils and their amounts (%). Among 24 detected components, the major one is carvone (45.53%). While the encapsulation efficiency of 13% zein-casein formulation was 54.66%±3.76% which is the highest encapsulating retention success among the different concentrations (1%, 3%, 5%, 7%, 9%, 11%, 13%, and 15%) of zein-casein microcapsules, the encapsulation efficiency value of microcapsules obtained by using only zein was 46.84%±0.22%. When investigated microcapsules were by SEM, it was observed that the structure of capsule was supported by casein particles. In addition to that, in the release rate test, release of the spearmint essential oil from microcapsules was determined as 64.27% in microcapsules obtained by using only zein. The release rate of the microcapsules zein-casein was determined as 37.86%. Antioxidative activity of zein-casein-mint microcapsules is found to be superior to the essential oil and zein-mint microcapsules. The study shows us that the antimicrobial capacity of mint essential oil in free-from is higher than the one in microencapsule form. KEYWORDS: Microencapsulation, zein, casein, Mentha spicata, essential (volatile) oil, antioxidant, antimicrobial