Encapsulation of alpha-tocopherol into zein nanoparticles

Authors: Kim, Sanghoon

Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2024
Publication Date: 8/19/2024
Citation: Kim, S. 2024. Encapsulation of alpha-tocopherol into zein nanoparticles. Food Research International. https://doi.org/10.3390/molecules29163911.
DOI: https://doi.org/10.3390/molecules29163911

Interpretive Summary: Vitamin E is one of the vitamins that do not dissolve in water. It consists of several forms, one of which is known as alpha-tocopherol. Compared to the other components, alpha-tocopherol is preferentially absorbed and stored in humans. In the body, it acts as an antioxidant, helping to protect cells from the damage caused by harmful particles known as free radicals. However, alpha-tocopherol breaks down upon exposure to ultraviolet (UV) light. To protect this beneficial chemical compound from the negative impacts arising from its surroundings, a protective covering (i.e., encapsulation) was made using a protein obtained from corn. The presented procedure offers the most simple and efficient encapsulation process which yields edible products. This research revealed that encapsulation with a corn protein effectively blocks UV light and prevents alpha-tocopherol from breaking down. This research advances the technique for the encapsulation of functional food ingredients, and scientists working in both the food industry and academia developing improved encapsulation technologies would benefit.

Technical Abstract: Vitamin E is a fat-soluble vitamin with several forms. Compared to the other components, a-tocopherol (TOC) is preferentially absorbed and accumulated in humans. In the body, it acts as an antioxidant, helping to protect cells from the damage caused by free radicals. It is an organic chemical compound that undergoes degradation upon irradiation with UV light. To protect this bioactive chemical compound from the negative impacts arising from its surroundings, encapsulation was carried out using zein as a shell material. Since TOC does not dissolve in the same solvent as zein, the commonly used process for the encapsulation with zein was modified to achieve desired phase-separation of TOC and its encapsulation into zein upon mixing the solutions. Due to the unique shape of the phase diagram of TOC in aqueous ethanol, the encapsulation efficiency was >99%. The size of encapsulated particles was ~300 nm or smaller and the thickness of the shell wall was ~30 nm. The presented procedure offers the most simple and efficient encapsulation process which yields edible products. The investigation of the irradiation effect of UV on TOC revealed that the encapsulation effectively blocks UV light and prevents TOC from being degraded.