Developing a PLS model for determination of total phenolic content in aged cachaças

The aging of cachaça in wooden casks is an important step in the production process of this beverage because in addition to the improvement of properties, it also increases its market value greatly. According to the Brazilian legislation in order to prove that this drink was aged, the presence of phenolic compounds must be detected and the most commonly method used for this is the Folin-Ciocalteu method which demands expenditure of time and reagents. Thus, this paper aims to propose a direct method for determination of total phenolic content using UV-Vis spectra of diluted aged cachaça and the multivariate calibration method PLS (partial least squares). Satisfactory results were obtained in the concentration range from 0.73 to 82.34 mg GAE L− 1 (mg-equivalent of gallic acid per liter) providing root mean square error of prediction of 4.11 mg GAE L− 1. The method was validated through the estimation of figures of merit such as trueness, precision, sensitivity, analytical sensitivity, bias, relative prediction deviation and range error ratio. Then the proposed method was considered adequate for the rapid determination of total phenolic content in aged cachaça and could be an alternative for routine analysis.