Adding adulterants to coffee reduces bioactive compound levels and antioxidant activity

Abstract

The present study aimed to evaluate the effect of coffee adulteration on antioxidant activity in vitro. Coffee beverages were adulterated with different concentrations of coffee hulls, coffee straw, and corn (0%, 10%, 20%, 30%, 40%, 50%, and 100%) and tested separately. Each coffee beverage was prepared according to the same methods in all of the treatments. Phenolic compound, caffeine, trigonelline, and chlorogenic acid levels were determined in the beverages. Antioxidant activity in vitro was evaluated using the DPPH radical scavenging activity, reducing power, iron chelating activity, and lipoperoxidation inhibition methods. Phenolic compound, caffeine, and chlorogenic acid levels of the samples decreased with increasing adulterant concentration. Adding adulterant reduced the antioxidant capacity tested using all of the methods. The results show that adding coffee hulls, coffee straw, and corn affect the antioxidant capacity of the coffee beverages, reducing protection against oxidative stress.