Integrated Analysis of Commercial Coffee Samples from Saudi Arabia: Evaluation of Elemental Composition, Phytochemicals, Antioxidant Activity, and Statistical Profiling

Abstract

This study aimed to evaluate the phytochemical composition, antioxidant activity, elemental content, and chemometric classification of 21 coffee samples sourced from various retail outlets in Jazan, Saudi Arabia. The samples represent a range of geographical origins and roasting levels. Each sample was ground independently and freshly prepared prior to the analysis. Total phenolic content(TPC) was determined using the Folin-Ciocalteu method, while antioxidant activity was assessed using the DPPH radical scavenging assay. Elemental analysis was conducted using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and volatile compound profiling was performed using gas chromatography-mass spectrometry (GC-MS). Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) are classified as chemometric techniques and are used to evaluate multidimensional datasets. The caffeine content ranged from 18.48% to 62.48%. TPC values were between 52.0 and 69.0 mg GAE/mL, and DPPH antioxidant activity ranged from 39.0% to 75.5%. Among the elements detected, manganese (Mn) had the highest average concentration (1769.43 ± 683.41 ppb), followed by copper (Cu: 806.38 ± 257.93 ppb) and zinc (Zn: 523.71 ± 340.80 ppb). Toxic elements such as arsenic (As), beryllium (Be), chromium (Cr), and antimony (Sb) were not detected. PCA and HCA successfully classified the samples based on their elemental and phytochemical profiles. GC-MS identified volatile compounds including fatty acid esters, aromatic hydrocarbons, and steroid derivatives unique to specific samples. Notably, strong correlations among Cu, Zn, Cd, and Pb suggested co-accumulation patterns. This study provides an integrated assessment of the chemical composition of commercial coffee products, complemented by nutritional and health evaluations, and illustrates the strategic use of chemometric techniques for distinguishing or classifying coffee samples.

Keywords: Food safety; Free radical scavenging; LC–MS/MS; Polyphenols; Sample classification; Trace elements.