Preparation and Production of Nano Capsules of Aloe vera Gel Containing Ziziphora tenuior L. Essential Oil

Introduction Fruits and vegetables are perishable due to high humidity and biological activity after harvesting (breathing, transpiration and biochemical activities). Covering fruits with antimicrobial compounds, while being edible and safe for consumers, is an effective solution to prevent the spoilage of fruits and increase their shelf life. In developing countries, packaging, storage and transportation technologies for these products have not been developed yet. One of the cheap and high-performance methods to increase the shelf life of fruit and maintain its quality during the storage period is to use a coating on the fruit. The purpose of coating application is to reduce water loss, slow aging, polish and better marketing. In addition to improving quality, coating can protect the fruit from pathogens and contamination. Edible coatings create a thin layer on the surface of the food that are effective and eco-friendly alternatives and maintain the firmness of fresh fruits and vegetables. The main components of edible coatings are natural polysaccharides, including starch, cellulose, pectin, alginates and chitosan. These coatings apply by spraying, immersion or rubbing. The use of essential oils and other extracts of medicinal plants has been evaluated in the development of edible coatings. Adding Ziziphora tenuior L. essential oil to food has been considered as an antioxidant and antimicrobial compound. Directly use of essential oils for fruits and vegetable shelf life has some limitations due to low solubility in water, high vapor pressure and physical and chemical instability. One of the ways to reduce these limitations is the nanoencapsulation of essential oil as. Applications of nano technology to the development of edible coatings (included various nanosystems, including polymeric nanoparticles, nanoemulsions), efforts to control the release of essential oils. Aloe vera gel, which is extracted from the inner parts of the leaves, is clear, odorless, completely healthy and environmentally friendly and can replace the coverings used after harvesting fruits. This is a polysaccharide gel, it dissolves easily in water and has advantages such as preserving the aromatic substances inside the fruit, covering the wound and cuts and it is possible to add substances such as vitamins and essential oils to this gel. Due to the antibacterial properties of aloe vera, adding aloe vera gel to edible coatings can increase the antibacterial properties of this biodegradable coating. On the other hand, using nano technology can increase the efficiency, consistency and better quality of food coatings. Materials and Methods The aim of the present study was to prepare and produce an oral coating of nanoecapsule containing Ziziphora tenuior L. essential oil. The components of the nanocapsule of Aloe vera gel was water, toewin and Ziziphora tenuior L. essential oil. Fresh Aloe vera leaves were used to prepare gel. Zeta-average diameter, particle size distribution, scattering index (PDI) and zeta potential (particle surface charge) were measured. Transmission electron microscopy (TEM) imaging was used to evaluate the morphology of the nanocapsule. The stability of produced nanocapsule was evaluated by measuring the particle size changes for 3 months. Results and Discussion 21 compounds were identified in the essential oil of Ziziphora tenuior. The main and important constituents of Ziziphora tenuior L. essential oil were Pulegone, Menthofuran and 1,8-Cineole. The results showed that the particle size of nanocapsule containing essential oil was 84.46 nm and zeta potential was -16.02 mV. The results of transmission electron microscope (TEM) photos showed that the size of the particles is less than 200 nanometers and the shape of the particles is almost spherical. The outer surface of the capsules is completely smooth and uniform. Stability studies of particle size and zeta potential for 3 months showed that nanocapsule containing essential oils had good stability. In this formulation, the zeta potential was about -16 mV, which is due to the non-ionic parts of the surfactant on the surface of the nanocapsule, which contributes to the repulsion force and caused the stability of the size of the nanocapsules. In order to determine the amount of essential oil in the nanocapsule, spectrophotometric method was used. The percentage of essential oil in nanocapsule was 83.25%. Conclusion Nanoencapsulation of essential is one of the ways to reduce the limitations of essential oil aplication. In the present study, a nancapsule with natural and biodegradable materials (Aloe vera gel) containing Ziziphora tenuior L. essential oil was prepared and the results showed that Ziziphora tenuior L. essential oil was successfully encapsulated in Aloe vera gel. In general, the results of the present study showed that the nanocapsule of Aloe vera gel is a suitable carrier for Ziziphora tenuior L. essential oil and can be used as an oral coating to preserve fruits and vegetables.