Understanding oxidation of Hemp seed oil and improving its stability by encapsulation into protein microcapsules

Authors: Kim, Sanghoon; Hwang, Hong-Sik

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2024
Publication Date: 8/26/2024
Citation: Kim, S., Hwang, H. 2024. Understanding oxidation of Hemp seed oil and improving its stability by encapsulation into protein microcapsules. Journal of Food Science. https://doi.org/10.1111/1750-3841.17314.
DOI: https://doi.org/10.1111/1750-3841.17314

Interpretive Summary: Polyunsaturated fatty acids (PUFAs) are known to offer health benefits such as lowering of blood pressure, promotion of heart health, inflammation reduction, etc. As our body can't manufacture this type of fat, it is recommended to be supplied as supplementary foods. Hempseed oil is over 80% PUFAs, and is an exceptionally rich source of the two essential fatty acids, linoleic acid and linolenic acid, with the most desirable nutritional profile of lipids for human health. However, PUFAs in hempseed oil are highly susceptible to degradation during food processing, storage, and transportation, and thus causing the loss of its effectiveness. In this research, hempseed oil was encapsulated inside tiny particles to resolve this issue. The outer wall of this particle, which is made from of corn protein, prevented hempseed oil from direct contact with oxygen in the air. Consequently, the degradation of hempseed oil was delayed by a factor of 7-10 times. The technique developed during this research can be used for the stabilization of unstable functional food ingredients or drugs. Scientists working in both the food industry and academia to develop improved stabilization technologies would benefit.

Technical Abstract: Hemp seed oil (HSO) is an edible oil obtained by pressing hemp seeds. It is low in saturated fat and rich in polyunsaturated fatty acids (PUFAs) such as omega-6 fatty acids and omega-3 fatty acids. When they are in contact with oxygen in the air, PUFAs are easily degraded even at room temperature due to the multiple double bonds that facilitate the formation very reactive radicals when exposed to air. Unlike pure fatty acids, HSO contains antioxidants and shows an induction period when its degradation process was monitored with thermogravimetric analysis. As PUFAs are not degraded during this induction period, the stabilization effect of an antioxidant (tocopherol) was examined and compared with that of encapsulation, which isolates oil droplets from contact with oxygen in the air. Test results showed the encapsulation extended the induction period of HSO more effectively than intentionally-added tocopherol. This result suggests that any oil containing PUFAs can be effectively stabilized by encapsulation.