Researchers from the University of Georgia, Athens report that annatto tocotrienol – mainly composed of delta-tocotrienol – was more effective than palm-based tocopherol-tocotrienol mixtures and alpha-tocopherol in inhibiting lipid peroxidation in menhaden fish oil and structured lipid-based infant formula emulsion.
“In our study, annatto tocotrienol-rich fractions [TRF] was found to be more effective than palm TRF and alpha-tocopherol in inhibiting lipid oxidation in menhaden fish oil and structured-lipid based infant formula emulsion at 0.02% and 0.05%,” they wrote in Food Chemistry.
Adding alpha-tocopherol did not alter the antioxidant activity of the annatto extract in the tested foods, they added.
Vitamin E is a family of eight separate but related molecules: four tocopherols (alpha, beta, gamma, delta) and four tocotrienols (alpha, beta, gamma, delta). While alpha-tocopherol is found in most multivitamins and is supplemented in foods, a growing base of evidence suggests that this popular vitamin E interferes with the uptake and function of tocotrienols. Tocotrienols are derived from three major sources, including rice, palm and annatto. Annatto is the only tocopherol-free source of tocotrienols.
The current study used the DeltaGold annatto tocotrienol ingredient supplied by American River Nutrition, and typically contains about 90% delta- and 10% gamma-tocotrienol. In addition, palm tocotrienol containing 23% alpha-tocopherol was used.
Commenting on the research, Dr Barrie Tan, president of American River Nutrition Inc. said that this was a great first step in addressing stability issues of the healthful application of omega-3s in food systems.
“Tocotrienol is a new generation of vitamin E, shown here as a powerful infant formula emulsion protectant,” he added.
American River Nutrition recently was awarded a letter of no objection for the company’s DeltaGold vitamin E tocotrienol ingredient by the US Food and Drug Administration for its GRAS application.
Lipid oxidation of foods is a major concern, particularly for polyunsaturated fatty acids and antioxidants like vitamin E tocopherol are typically used to prevent this spoilage.
Long Zou and Casimir Akoh compared annatto tocotrienol with tocotrienols from palm, alpha-tocopherol, delta-tocotrienol and delta-tocopherol in fish oil and infant formula for 28 days. Concentrations of the study compounds used ranged from 0.02% to 0.05%.
The results showed that, in fish oil, alpha-tocopherol increased hydroperoxide formation, while palm tocotrienol acted as a prooxidant, and no effect was seen with annatto tocotrienol on primary oxidation products.
All compounds exhibited significant antioxidant activity against secondary oxidation products after 14 days, but alpha-tocopherol and palm tocotrienol had significantly higher prooxidant activity than annatto tocotrienol after 21 days, said the researchers.
In the experiments using infant formula oil-in-water emulsion, the data indicated that annatto tocotrienol and delta-tocotrienol fared significantly better in decreasing hydroperoxide formation compared to alpha-tocopherol, palm tocotrienol, and delta-tocopherol. Indeed, after 28 days, delta-tocotrienol and annatto tocotrienol at 0.05% still showed an antioxidant effect, as opposed to a prooxidant effect noted for both concentrations of alpha-tocopherol, palm tocotrienol, and delta-tocopherol.
“From food application’s point of view, since the antioxidant ability of annatto TRF alone or alpha-tocopherol/annatto TRF mixture is better than that of alpha-tocopherol, one may use annatto TRF to fully or partially replace alpha-tocopherol as an antioxidant in food formulations, especially in oil-in-water emulsion systems,” wrote the researchers. “However, more research is required to confirm this hypothesis.”
Source: Food Chemistry
Volume 168, Pages 504-511, doi: 10.1016/j.foodchem.2014.07.098
“Antioxidant activities of annatto and palm tocotrienol-rich fractions in fish oil and structured lipid-based infant formula emulsion”
Authors: Zou L, Akoh CC