Impact of roasting on the phenolic and volatile compounds in coffee beans

Abstract

Phenolic compounds present in coffee beans could generate flavor and bring benefits to health. This study aimed to evaluate the impacts of commercial roasting levels (light, medium, and dark) on phenolic content and antioxidant potential of Arabica coffee beans (Coffea arabica) comprehensively via antioxidant assays. The phenolic compounds in roasted samples were characterized via liquid chromatography–electrospray ionization quadrupole time‐of‐flight mass spectrometry (LC‐ESI‐QTOF‐MS/MS). Furthermore, the coffee volatile compounds were identified and semi‐quantified by headspace/gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS). Generally, for phenolic and antioxidant potential estimation, light roasted samples exhibited the highest TPC (free: 23.97 ± 0.60 mg GAE/g; bound: 19.32 ± 1.29 mg GAE/g), DPPH, and FRAP. The medium roasted beans performed the second high in all assays but the highest ABTS+ radicals scavenging capacity (free: 102.37 ± 8.10 mg TE/g; bound: 69.51 ± 4.20 mg TE/g). Totally, 23 phenolic compounds were tentatively characterized through LC‐ESI‐QTOF‐MS/MS, which is mainly adopted by 15 phenolic acid and 5 other polyphenols. The majority of phenolic compounds were detected in the medium roasted samples, followed by the light. Regarding GC‐MS, a total of 20 volatile compounds were identified and semi‐quantified which exhibited the highest in the dark followed by the medium. Overall, this study confirmed that phenolic compounds in coffee beans would be reduced with intensive roasting, whereas their antioxidant capacity could be maintained or improved. Commercial medium roasted coffee beans exhibit relatively better nutritional value and organoleptic properties. Our results could narrow down previous conflicts and be practical evidence for coffee manufacturing in food industries.

Integrating Metabolomics and Proteomics Technologies Provides Insights into the Flavor Precursor Changes at Different Maturity Stages of Arabica Coffee Cherries

“…The Maillard reaction was the main pathway for producing flavor during the roasting process, and amino acids and sugars are the most important precursors to the Maillard reaction [ 24 ]. However, different amino acids and sugars as precursors could generate different coffee flavors.…”

Influence of Saccharomyces boulardii inoculation on post‐harvest processing methods on the coffee quality

“…Chlorogenic acids were classified into a class of esters derived from hydroxycinnamic acids (phenols mainly include caffeic, ferulic, and p‐coumaric acids) and quininic acids with specific phenols. These compounds may affect the final cup quality of coffee; therefore, it is important to understand the phenolic acid content obtain in coffee (Doncea, 2010; Wu et al, 2022).…”

“…In roasted beans, the total phenolic content had generally lower values than in unroasted green beans. Studies indicated that as the roasting degree was higher, the total phenolic content will be lower as the phenolic compounds was highly thermal instable which compounds can be easily decomposed in high temperature of roasting (Wu et al, 2022). However, coffee beans with starter culture inoculated improved the total phenolic content, as reported by (Bressani et al, 2021)'s study.…”

Recent Research Advancements of Coffee Quality Detection: Targeted Analyses vs. Nontargeted Fingerprinting and Related Issues

“…Te main phenolic acid in cofee is chlorogenic acid (CGA) [91]. CGA can provide favor of bitter, sour, and astringent in cofee brewing, especially cafeoylquinic and feruloylquinic acids [92]. Feruloylquinic and cafeoylquinic acid also furnishes excellent functions of high antioxidant, antibacterial, antiviral, and chemopreventive capacity, which improve the nutritional value of brewing cofee [93].…”