Influence of white reference measurement and background on the color specification of orange juices by means of diffuse reflectance spectrophotometry

The color of citrus beverages, in general, is related to the consumers' perception of flavor, sweetness, and other characteristics related to the quality of these products, so it is important to develop suitable methods for accurately assessing this attribute. In this study, the color of 2 different kinds of orange juices (ultrafrozen orange juices and orange juices from concentrate) were measured using different white references in order to demonstrate the influence of white reference measurement on the color parameters obtained. The results of this work indicated that the election of a wrong white reference measurement can affect dramatically the accuracy of the objective specification of orange juice color. Thus, the application of analysis of variance (alpha = 0.01) revealed that, in most cases, the parameters obtained were significantly different. In terms of color differences, the change of the background for the same white reference affected the measurements less than the changes of white references for the same background. On the other hand, important chromatic differences between the 2 types of orange juices studied were found.