Effect of Heating and of Short Exposure to Sunlight on Carotenoids Content of Crude Palm Oil

Abstract

This study was done to evaluate the effect of short exposure to sunlight and of heating on crude palm oil (CPO) quality particularly on its carotenoids content. Firstly, CPO was exposed to sunlight for 14 hrs. Then, samples were collected and kept at 4°C for analysis of carotenoids content, free fatty acid (FFA) and peroxide value (PV). Secondly, CPO was heated at 50°C, 120°C, 200°C or 400°C for 30 min, 60 min or 120 min and samples were cooled down and kept at 4°C until analysis of carotenoids content, FFA and PV. Finally, we studied the effect of heating of CPO in the food matrix (maize cake). Thus, maize cake was steamed on gas stove (100 ± 5°C) during exactly 1, 2, 3 or 4h and kept at 4°C until analysis of moisture and carotenoids contents. The results showed that short exposure to sunlight did not significantly affect carotenoids content, FFA and PV of CPO. However, heating accelerated the formation of peroxides and degradation of carotenoids. Destruction of carotenoids increased with both temperature and duration of exposure to heat. FFA did not significantly change during heating. Likewise, during heating of CPO in the food matrix, carotenoids content decreased significantly with cooking time. These results suggest that short exposure to sunlight does not have a significant effect on carotenoids content of CPO. But, its heating (directly or in the food matrix) results in significant degradation of carotenoids.

Phytonutrient content and oil quality of selected edible oils upon twelve months storage

“…The outcome postulated that major contribution of the degradation of carotenoid in PPMO is temperature instead of light at temperature not more than 35°C. The finding is in good agreement with Fabrice, reported that significant carotenoid degradation caused by temperature applied to crude palm oil (Fabrice Fabien et al, 2014). Schroeder and Johnson (1995) also reported that carotenoids are vulnerable to enzymatic or nonenzymatic oxidation where rate and extent of oxidation depend on the structure of carotenoid, the presence of prooxidants and antioxidants, high temperature, light exposure, oxygen availability, enzyme types and metals.…”

“…Both typical and optimum-case conditions exhibited similar retention percentage, approximately 82% and similar t 1/2 whereas worst-case condition showed significantly low retention percentage and t 1/2 (Tables 2 and 3 and Supplementary Table 2). The outcome postulated that major contribution of the degradation of carotenoid in PPMO is temperature instead of light at temperature not more than 35 C. The finding is in good agreement with Fabrice, reported that significant carotenoid degradation caused by temperature applied to crude palm oil (Fabrice Fabien et al, 2014). Schroeder and Johnson (1995) also n.d. 0.1 ± 0.0 0.1 ± 0.1 0.1 ± 0.0 0.1 ± 0.1 C16:0 33.3 ± 2.0 34.8 ± 0.8 34.2 ± 0.4 36.0 ± 1.1* 39.9 ± 0.4 41.7 ± 0.1* 41.2 ± 0.8 43.0 ± 1.7* 15.8 ± 1.3 15.1 ± 0.4 14.3 ± 0.6 16.9 ± 1.0 7.8 ± 0.5 7.8 ± 0.2 6.6 ± 0.4 8.7 ± 1.3 C16:1 0.4 ± 0.0 0.4 ± 0.0 0.5 ± 0.2 0.4 ± 0.1 0.3 ± 0.1 0.5 ± 0.0 0.4 ± 0.0 0.5 ± 0.1 1.4 ± 0.0 1.3 ± 0.0 1.3 ± 0.1 1.4 ± 0.1 0.2 ± 0.2 0.9 ± 0.1 0.1 ± 0.0 1.5 ± 0.1 C18:0 3.6 ± 0.3 3.4 ± 0.2 3.4 ± 0.1 3.1 ± 0.4 4.2 ± 0.1 4.1 ± 0.0 4.3 ± 0.1 3.9 ± 0.3 n.d.…”

Assessing the Effects of Sunlight on the Photooxidation of Tropical Oils with Experimental and Computational Approaches

“…This is due to the high viscosity, high melting points, and the high levels of SFA present in TO, owing to which these oils solidify readily under ambient conditions within a short time. Marketers or vendors address this challenge by exposing the oils to sunlight to liquefy the solidified oils and maintain the liquid or semi‐solid forms (Ngono Ngane Annie, 2014), which increases marketability and consumer acceptance. While these practices are suitable from the marketing and economics outlook, from a scientific perspective, they pose risks to the stability of the oils by oxidation or related decomposition and are inappropriate (Maszewska et al, 2018; Oh et al, 2014).…”

Assessing the effects of Sunlight on the Photooxidation of Tropical Oils

“…This is due to the high viscosity, high melting points, and the saturated fatty acids present in TOs, owing to which, these oils solidify readily under ambient conditions within a short time. Marketers or vendors address this challenge by exposing the oils to sunlight for liquefying the solidified oils and maintaining the liquid or semi-solid forms (Ngono Ngane Annie, 2014), which increases the marketability and consumer acceptance. While these practices are suitable from the marketing and economics outlook, from a scientific perspective, they pose risks to the stability of the oils by oxidation or the related decomposition and are inappropriate (Maszewska et al, 2018& Oh et al, 2014.…”