Comparison of Different Extraction Methods for Carotenoid Analysis in Maize Flour

Health benefits of carotenoids embedded in maize kernel have been shown with numerous studies. Different methods are utilized for the analysis of carotenoids that are fat-soluble compounds of maize kernel. It is thought that extraction procedure is the key element resulting in variation among different methods. This study was carried out to determine the effects of three different extraction methods on the results of analyses performed to quantify carotenoid contents in maize. 150 different maize genotypes were used as plant material in the study. Soxhlet (hot extraction), cold (solvent) extraction, and direct extraction methods were used as the extraction treatments. The oil samples extracted with these methods were analyzed with UV-Spectrophotometer, at a wavelength of 450 nm for the estimation of carotenoids. The means from the extraction methods were compared by Kruskal-Wallis test and the relationships among the analysis results were investigated with simple linear regression analysis. The oil samples extracted with Soxhlet method yielded higher values for carotenoids as compared to the other methods. According to the regression analysis, there was a linear and highly significant relation for oil ratio between Soxhlet and cold extraction results. For carotenoids, the regression coefficients among the three methods came out to be rather low. These results indicate that the values acquired from the analyses on oil samples obtained with different extraction methods do not provide operational interchangeability in carotenoid analyses