Mathematical quantification of total carotenoids in Sioma® oil using color coordinates and multiple linear regression during deep-frying simulations

Abstract

Sioma® is a variety of red palm oil produced in Ecuador; it is mainly unsaturated, has no flavor, odor, nor cholesterol, and it is GMO-free and free of trans fatty acids. The main objectives of this study were: (a) to study changes in fatty acids, color coordinates, total carotenoids and carotenoid composition during deep-frying simulations; (b) to develop a mathematical model that allows quantification of total carotenoids (antioxidant compounds) using routine color measurements. Two different deep-frying temperatures were assayed 180 and 240 °C. The main fatty acids and carotenoids found in this oil were: (a) oleic, palmitic, and linoleic acids, and (b) α-, β-, and δ-carotenes. During these deep-frying simulations, Sioma® oil became lighter and more yellowish (L* and b* values increased) and more greenish (a* values decreased); these changes were more evident for higher temperatures. At 180 °C, total carotenoids decreased linearly, from almost 500 mg L−1, at a rate of 5 mg /kg1 min−1; however, at 240 °C the degradation of carotenoids was almost complete after 40 min. Finally, the mathematical models developed using multiple linear regressions allowed an easy and fast quantification of total carotenoids using color measurements.