Application of nanoemulsion technology for development of novel functional foods with essential oils encapsulation: A review

The demand for shelf-stable and nutritious food products is increasing day by day and consumers are ready to pay a higher price for such food products. Some artificial preservatives and antioxidant agents, such as butyrate hydroxanisole (BHA), tertiary butyl hydroquinone (TBHQ), and butyrate hydroxytoluene (BHT), have been widely used for food preservation, but these are harmful for human health and can cause DNA mutation and carcinogenesis. Now-a-days, the latest researches focus on compounds of natural origin as preservatives of novels that can help in the extension of food shelf life without harmful effects on human health. Spices and aromatic herbs with medicinal value have been traditionally applied in phytotherapy due to the presence of a variety of activities of their secondary biomolecules, particularly carminative, antiviral, antimicrobial, spasmolytic, hepatoprotective, anticarcinogenic, etc. Essential oils and extracts from these herbs have bio-preservation actions and a lot of research has been done for the use of these essential oils and extracts in the food sector. Essential oils are aromatic metabolites derived from plants, such as grasses, buds, flowers, leaves, roots, stems, bark, resins, and its secretions, which have excellent antioxidant and antimicrobial properties. Therefore, essential oils from these traditional herbs and spices have excellent potential in the food industries, but have some limitations in its direct incorporation. Due to their hydrophobic nature, they are unstable in aqueous medium, which poses more challenges for incorporating it into food due to the interaction of essential oil with protein and fat that may reduce its antioxidant and antimicrobial potential. In addition, strong taste with a high concentration for effective microbial inhibition would exceed organoleptic levels of acceptance. Therefore, one of the ways to overcome these deficiencies is to encapsulate essential oils before incorporating them into food matrices. Encapsulation provides isolation, penetration, protection, or controlled release of reactive substances from the surrounding matter. Nanoemulsion delivery systems are known to use a low concentration of essential oils to increase their functionality in food.