Antioxidant activity of Osage orange extract in soybean oil and fish oil during storage

Authors: Hwang, Hong-Sik; Moser, Jill; Tisserat, Brent; Harry O Kuru, Rogers; Berhow, Mark; Liu, Sean

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2020
Publication Date: 12/15/2020
Citation: Hwang, H-S., Winkler-Moser, J.K., Tisserat, B., Harry-O'kuru, R.E., Berhow, M.A., Liu, S.X. 2020. Antioxidant activity of Osage orange extract in soybean oil and fish oil during storage. Journal of the American Oil Chemists' Society. 98(1):73-87. https://doi.org/10.1002/aocs.12458.
DOI: https://doi.org/10.1002/aocs.12458

Interpretive Summary: Edible oils such as vegetable oils and omega-3 oils and oil-containing food products generally require antioxidants to prevent oxidation during manufacturing, transportation and storage. Synthetic antioxidants are strong antioxidants and have been used for over 60 years to prevent oil oxidation. However, several studies reported that the synthetic antioxidants might be toxic and could cause liver problems and cancer. Therefore, the food industry is looking for natural antioxidants that can replace synthetic antioxidants. Previously, a few studies reported that Osage orange fruit extract had potential as a natural antioxidant for edible oils. However, the previous studies were conducted very briefly, for example, using only one analytical method and no systematic study has been conducted. In this study, we conducted a systematic study to have better understanding on the antioxidant activity of Osage orange fruit extract and to evaluate the potential as a natural antioxidant for edible oils and related food products. First, we found that hexane was a more efficient solvent to extract Osage orange fruit than other solvents. The amounts of major antioxidants in this extract were higher than previously reported extracts. The antioxidant activity of the extract was examined in soybean oil and fish oil during storage at 25 and 40 °C. Four analytical methods were used to evaluate oil oxidation, which provided thorough information on the activity. The antioxidant activity of the extract was similar to a synthetic antioxidant and apparently stronger than commercial natural antioxidants, rosemary extract and mixed tocopherols in soybean oil. In fish oil, the extract had higher activity than all other antioxidants compared in this study including a synthetic antioxidant. Although it should be further tested for safety before the actual use, this study shows that Osage orange extract can be developed as an antioxidant for edible oils after further studies on the safety.

Technical Abstract: The food industry is seeking natural antioxidants for edible oils that have comparable activity to synthetic counterparts. In this study, Osage orange extract (OOE) rich in osajin (42.9%) and pomiferin (30.0%) was obtained after hexane extraction of the fruit, and its antioxidant activity was examined in stripped soybean oil (SBO) and fish oil (FO), in which antioxidants and polar compounds were removed. The antioxidant activity of OOE was compared with commercial natural antioxidants (i.e., rosemary extract and mixed tocopherols) and a synthetic antioxidant,butylated hydroxytoluene (BHT), during storage at 25 and 40 deg. C. Its activity was similar to 0.02% BHT in SBO and was similar or slightly stronger than 0.02% BHT in FO. When OOE was studied at 0.05, 0.1, and 0.2%, there was a weak dose–response in SBO but a stronger dose–response in FO. Headspace volatile analysis using solid phase microextraction (SPME) combined with GC-MS indicated that 0.01% OOE was very effective in preventing the formation of volatile oxidation products in both oils. Although it should be further tested for safety before actual use, this study shows that OOE can be developed as an antioxidant for edible oils.