Acidity and Antioxidant Activity of Cold Brew Coffee

Niny Z Rao,Megan Fuller

doi:10.1038/s41598-018-34392-w

Abstract

The acidity and antioxidant activity of cold brew coffee were investigated using light roast coffees from Brazil, two regions of Ethiopia, Columbia, Myanmar, and Mexico. The concentrations of three caffeoylquinic acid (CQA) isomers were also determined. Cold brew coffee chemistry was compared to that of hot brew coffee prepared with the same grind-to-coffee ratio. The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13. The hot brew coffees were found to have higher concentrations of total titratable acids, as well as higher antioxidant activity, than that of their cold brew counterparts. It was also noted that both the concentration of total titratable acids and antioxidant activity correlated poorly with total CQA concentration in hot brew coffee. This work suggests that the hot brew method tends to extract more non-deprotonated acids than the cold brew method. These acids may be responsible for the higher antioxidant activities observed in the hot brew coffee samples.

Highlights

Cold brew coffee is a popular phenomenon that has recently invigorated the coffee industry, in the warm summer months[1]
The results from the hot brew coffee analyses are shown in Tables 1 and 2
The 3-caffeoylquinic acid (CQA) and 4-CQA concentrations were the highest in the Ethiopian-Ardi samples, while Myanmar samples contained the lowest concentration of these two isomers

Summary

Introduction

Cold brew coffee is a popular phenomenon that has recently invigorated the coffee industry, in the warm summer months[1]. A recent population-based study of GERD patients (n = 317) and asymptomatic individuals (n = 182) found no association between GERD symptom frequency or severity and coffee consumption[10]. A substantial umbrella review of numerous meta-analyses found no consistent evidence of harmful associations between coffee consumption and diverse health outcomes, with the exception of issues related to pregnancy and risk of bone fractures in women[12]. Despite the growing popularity of cold brew coffee, very little research has been published on its chemical attributes, including pH and total antioxidant activity, and associated health effects. An exhaustive literature search returned only four peer-reviewed studies related to cold brew coffee[29,30,31,32]. None of these studies provided enough information to either support or refute the health claims about cold brew coffee made by commercial coffee vendors and cold brew enthusiasts

Methods

Results

Discussion

Conclusion