Effect of ultraviolet irradiation on the shelf life and chemical composition of cold brew coffee

Abstract

Cold brew coffee is a beverage prepared at low temperatures, usually consumed immediately after preparation or after a short storage period due to its short shelf life. Different technologies are required to increase the shelf life without affecting its sensory and functional properties. In this work, the effect of ultraviolet light (UV-C) treatment on the shelf life of cold brew coffee was studied. The physicochemical characteristics, polyphenolic content by Folin–Ciocalteu method, chlorogenic acids contents by RP-HPLC analysis, and selected volatile compounds by HS-SPME and GC–MS were studied for 28 days, at 4°C and 18°C storage temperatures. Applying UV-C to selected samples stored at 4°C extended the microbiological shelf life from up to 14 days compared to less than 7 days for samples without treatment. The samples treated with UV-C presented total polyphenol content around 1.6 times higher than the controls and chlorogenic acid content around 1.4 times higher than controls on day 14. No significant differences were observed in most of the volatile compositions among the different samples. Thus, UV-C technology is a promising non-thermal alternative to extend the shelf life of cold-brewed coffee. © 2024 Institution of Chemical Engineers (IChemE)