Effects of UV light on the physic-chemical properties of yerba-mate

Abstract

Purpose – The aim of this paper is to evaluate the effects of ultraviolet (UV) light on the color, secondary metabolites and sensory acceptance of processed yerba-mate. Design/methodology/approach – Samples were exposed to UV light for 72 hours. The colorimetric coordinates (L*, a* and b*) were analyzed every 6 hours, while secondary metabolites and sensory acceptance were assessed at the beginning and at the end of the experiment. Methylxanthines and phenolic compounds were quantified by ultra performance liquid chromatography photodiode array detectors and vegetable pigments by UV/visible spectrophotometry. Findings – Decreases in methylxanthines, rutin and isomers of chlorogenic acids were found, along with an increase in isomers of dicaffeoylquinic acids. The product showed less sensory acceptance compared to the control. These results show that UV light treatment of yerba-mate accelerates the maturation process. Practical implications – UV light can be used in yerba-mate maturation with a reduction time and can ensure microbiological safety with small changes in its phytochemical profile. Originality/value – This paper is the first report of a novel strategy to investigate the yerba-mate maturation using UV light.