Abstract
Purpose
The purpose of this study is to evaluate the effect of the addition of dried lemongrass leaves (DLGL) powder, at different levels, on phenolics content, antioxidant activities, consumer acceptance and the inhibition of lipid peroxidation of roasted coffee (RC).
Design/methodology/approach
DLGL powder was incorporated at the levels of 0%, 2.5%, 5.0%, 7.5% and 10% of RC weight. The total flavonoids (TF), total phenolics (TP) and antioxidant activity measured using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reducing power assay of RC, DLGL and binary mixture of them determined. The oxidative indices of coffee oil samples during storage were investigated. In addition, the sensory characteristics of RC fortified with different levels of DLGL powder were evaluated.
Findings
The TP content of DLGL powder was 1,100.32 mg/100 g DWb, nearly 1.2 times higher than found in RC beans. The TF content of RC enriched with 2.5%, 5.0%, 7.5% and 10% DLGL were found to be around 1.05, 1.10, 1.15 and 1.20 times higher than that in the control coffee samples. RC supplemented with various levels of DLGL powder showed higher DPPH radical scavenging and reducing power activities. At the end of the storage period (six months), the acid, peroxide, P-Anisidine and total oxidation value values of RC supplemented with 10% DLGL powder were about 1.94, 2.52, 2.60 and 2.59 times as low as in the control sample without any addition of DLGL powder, respectively. RC containing 2.5% and 5.0% DLGL powder had significantly (p < 0.05) the highest sensory scores. Consequently, the addition of DLGL in coffee at up to a 5% ratio may have potential health benefits.
Practical implications
RC containing 2.5% and 5.0% DLGL powder had significantly (p = 0.05) the highest sensory scores.
Originality/value
Consequently, the addition of DLGL in coffee at up to a 5% ratio may have potential health benefits.