Influência dos processamentos das folhas do café (Coffea arabica) para chás: Compostos bioativos, propriedades funcionais e resíduos de praguicidas

Abstract

Coffee leaves produced in the southern region of Minas Gerais can be exploited in a sustainable way, aiming at the development of a beverage that integrates regionality and health. Thus, the objective of this study was to develop different types of tea from leaves from the sprouting of organic and conventional coffee plants and to characterize them in terms of total flavonoids, total phenolics and antioxidant potential (ABTS and DPPH). The presence and levels of pesticide residues in the obtained infusions were also evaluated. To this end, the processes used in Camellia sinensis (green, yellow and oolong tea) were adapted to coffee leaves, in addition to solid-state fermentation (FES) with the addition of different starter cultures [(i) Lactobacilli acidophilus LA-5®, Bifidobacterium BB-12® and Streptococcus thermophilus; (ii) Saccharomyces cerevisiae; and (iii) the mixture of the above]. Fermentation kinetics were monitored for 240 h, at 0, 48, 96, 144 and 240 h intervals, to determine the optimal point considering the levels of bioactives and antioxidant potential, which were determined by spectrophotometry. The multi-residue method by means of HPLC-MS/MS was used to detect triazole and organophosphate pesticides. The flavonoid contents varied between 3.78 ± 0.03 and 12.55 ± 0.20 EC mg.g-1, phenolics between 16.83 ± 0.06 and 18.52 ± 0.04 EAG mg.g- 1 and antioxidant potential (ABTS) between 49.76±0.76 and 84.35 µmol.g-1 and (DPPH) between 47.66 ± 0.24 and 62.84 ± 0.18 µmol.g-1 of sheet processed on dry basis. Coffee leaves from conventional cultivation and processed similarly to yellow tea showed the highest levels of bioactives and antioxidant potential (p≤0.05). In general, the fermented teas showed the highest values at the end of 48 h, with the control group having the highest levels of phenolics and total flavonoids, decreasing sharply after this period, while the added S. cerevisiae had the highest antioxidant potential. The infusions obtained from coffee leaves from conventional plantations, with pesticide management, showed triazoles and organophosphates at levels that could compromise human health. Future research involving the period of pesticide application is necessary in order to ensure the safe consumption of coffee leaf teas from conventional crops.