Rapid Assessment of Vitamin A Activity through Objective Color Measurements for the Quality Control of Orange Juices with Diverse Carotenoid Profiles

The evaluation of the vitamin A activity of foods is important for the establishment of Dietary Reference Intakes and food composition databases, food labeling, etc. Regarding orange juice, probably the most accepted fruit product in much of the world, the vitamin A labeling has been reported to be defective and misleading, which revealed the inadequacy of the quality control system. In this study, the color and the vitamin A activity (in terms of retinol activity equivalents) of diverse orange juices were evaluated as well as the correlations existing between them. Correlation coefficients above 0.9 were found for some color parameters considered jointly and individually, so appropriate equations to assess the vitamin A activity of the samples from them were obtained. The results of the analysis of variance (p < 0.05) revealed that there were no differences between the data derived from the chromatographic analyses and those calculated from the color parameters, thereby validating the assessment of the vitamin A activity of the juices through objective measurements of color, whose advantages (rapidity, versatility, nondestructiveness, portability, etc.) make of it a powerful tool for quality control purposes in the food industry.

Keywords: Analysis of variance (ANOVA); carotenoids; CIELAB; food labeling; multiple regression; objective measurement of color; orange juice; provitamin A; quality control; retinol activity equivalents (RAE); vitamin A