Study of the Influence of Some Compounds on the Prediction Equations of Total Phenolic Content and Antioxidant Capacity by Colorimetric Parameters

The prediction of such bioactive compounds using colorimetry is a promising, nondestructive, low-cost, and rapid alternative; however, the mathematical models are affected by the compounds present in the food, depending also on the methodology used for the analysis. In this sense, this work aimed to evaluate which compounds present in red fruits can affect the prediction of total phenolics and antioxidant capacity, using colorimetric parameters. The quantities of substances with potential impact previously found in these fruits were studied using the Plackett-Burman design. The results showed that anthocyanins, ascorbic acid, and tartaric acid influenced the colorimetric parameters, thus making these compounds impact the achievement of the equations. For the quantification of total phenolics, ascorbic acid was the only compound with a significant effect and also had an impact on the other methodologies of antioxidant capacity. The variations caused by ascorbic acid in the absorption coefficient and refractive index were also evaluated and it was concluded that the interference of this compound occurs by interactions with anthocyanins.