Rapid determination of soluble solids content and acidity of Black currant ( Ribes nigrum L.) juice by mid-infrared spectroscopy performed in series

Abstract

Black currant juice quality is a prime importance for growers and industrials. Such quality relies on the empirical and destructive measurements of soluble solids content and acidity. These measurements are time consuming and expensive. The serial analysis of the Black currant juice quality could allow the valuation of the product for the producer and saving of time for the manufacturer. Our objective was to develop predictive models of soluble solids content and acidity based on the mid-infrared spectroscopy performed in series. We showed that infrared spectroscopy allowed determining efficiently the quality of Black currant juices and that such technique could be performed in series. Soluble solids content were determined with a R 2-value of 0.97 and an RMSECV of 1.14°Brix for a range of values comprised between 12.9°Brix and 16.42°Brix. Acidity content was determined with a R 2-value of 0.96 and an RMSECV of 2.61 g L −1 in a large range of values comprised between 14.87 g L −1 and 36.27 g L −1. These results allow asserting that the soluble solids content and the acidity of Black currant juice can be accurately determined by infrared spectroscopy. Furthermore, a large number of measures can be performed in series, what opens perspectives for a practical application.