Influence of different coffee brewing methods on the biochemical composition of fruit juice and coffee drink

A fruit juice and coffee drink is an interesting combination that provides the necessary bioactive compounds and caffeine for the whole day. The coffee brewing method changes not only the amount of caffeine but also the taste of fruit juice and coffee drink. The least bitter taste is felt in cold brewed coffee, making it an ideal ingredient for a fruit juice and coffee drink. The aim of this study was to evaluate the influence of preparing technologies for creating an innovative fruit juice and coffee drink with a high content of bioactive compounds. Four different types of medium-roasted “Lofbergs” coffee beans were compared, as well as two brewing techniques: French press (hot coffee) and cold-brew. Concentration of vitamin C, pH, soluble solids content, titratable acids, total phenol content, DPPH antiradical activity, and sensory analyses were determined for all prepared samples. Concentration of vitamin C in juice with coffee was from 10.36 to 22.60 mg•100 gE−1, and the highest vitamin C concentration was preserved in the pasteurised juice and coffee drink with cold-brew coffee preparation technique. Concentration of soluble solids was from 12.3 to 12.6%, titratable acids from 0.79 to 0.87%, pH from 2.68 to 2.88, total phenols from 54.31 to 129.26 mg•100 gE−1, and the highest total phenol concentration was obtained in the pasteurised fruit and coffee drink with smooth and sweet coffee beans prepared using the cold-brew technique. DPPH antiradical activity was from 126.24 to 177.89 mg•100 g−1 in the tested samples, and the highest DPPH antiradical activity was detected in the pasteurised fruit and coffee drink with sweet and nutty coffee beans prepared with cold-brew technique. The best sensory profile was for coffee and juice drinks with “Lofbergs” medium roast fruity and velvety Rwanda coffee beans and “Lofbergs” medium roast prepared with cold-brew technology.