Stability and antioxidant activity of annatto (Bixa orellana L.) tocotrienols during frying and in fried tortilla chips

Authors: Moser, Jill; BAKOTA, ERICA - Harris County Institute Of Forensic Sciences; Hwang, Hong-Sik

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2017
Publication Date: 1/16/2018
Citation: Winkler-Moser, J.K., Bakota, E.L., Hwang, H.-S. 2018. Stability and antioxidant activity of annatto (Bixa orellana L.) tocotrienols during frying and in fried tortilla chips. Journal of Food Science. 83(2):266-274.

Interpretive Summary: Tocotrienols are antioxidant lipids related to vitamin E that are believed to have a number of beneficial biological activities, including cholesterol lowering, cardioprotective, anti-cancer, and neuroprotective. Tocotrienols are less prevalent in the diet than other members of the Vitamin E family, so in order to enhance their content in food, there is a need to identify tocotrienol sources and determine the effect of food processing on their stability. Therefore, tocotrienols from annatto, a commonly used food extract, were added to sunflower oil used for frying tortilla chips, and the effects on the frying oil stability, chip flavor, and content of tocotrienols in the chips were evaluated. In addition, tortilla chips were bagged and stored under accelerated oxidation conditions (50 °C), and the effect of the tocotrienols on the shelf life of the tortilla chips, as determined by headspace hexanal and sensory analysis, were evaluated. The results of the studies showed that the annatto tocotrienols had no effect on the stability of the frying oil or on the flavor of the fresh tortilla chips. Analysis of the chips indicated that tocotrienols were absorbed in proportion with the frying oil. After storing the tortilla chips at 50 °C for three weeks, the chips fried with annatto tocotrienols had lower scores for off-flavors and had lower levels of headspace hexanal, which is an indicator of lipid oxidation. These study demonstrated that tocotrienols from annatto could successfully be incorporated into frying oil and fried foods, and that they had the added benefit of improving the shelf stability of the tortilla chips through their antioxidant activity.

Technical Abstract: Annatto tocotrienols (AnT3), which contain ~90% delta-tocotrienol (delta-T3), were added to mid-oleic sunflower oil used for frying tortilla chips over three days. The objectives were to evaluate their stability during frying and activity as antioxidants in frying oil and in tortilla chips during storage. AnT3 did not significantly affect the stability of the oil during frying or the sensory profiles of freshly fried chips. The naturally present alpha-tocopherol (alpha-T) in the oil degraded at a lower rate in the presence of AnT3, resulting in significantly higher alpha-T by the end of the frying study. Levels of tocopherols and tocotrienols in the chips mirrored oil levels. AnT3 did not affect the sensory profile of the chips after one week of storage at 50 °C, but after three weeks of storage, the control chips had higher levels of painty and rancid flavors compared to chips with AnT3. Headspace hexanal was also significantly higher in the control chips compared to the chips with AnT3 after three weeks of storage.