Physicochemical Properties and Antioxidant Activities of Commercial Cold Brew Coffees in the Suwon Region

This study investigated the physicochemical characteristics and antioxidant activities of commercially available cold brew coffee products in the Suwon region using multivariate statistical analyses, including principal component analysis (PCA) and hierarchical cluster analysis (HCA). PCA identified two principal components (PC1 and PC2), which together accounted for 86.28% of the total variance. PC1 was positively associated with soluble solids (r= +0.938), total acidity (r= +0.923), total polyphenol content (r= +0.877), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (r= +0.638). In contrast, it was negatively correlated with lightness (L*, r= —0.974), redness (a*, r= —0.985), yellowness (b*, r= —0.974), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity (r= —0.737). PC2 was primarily characterized by pH (r= —0.932), indicating that acidity-related attributes were a secondary source of variation among the products. HCA classified the 11 commercial samples into three distinct groups according to their physicochemical and antioxidant characteristics. Group A (Samples 5 and 10) consisted of light-colored coffees with relatively mild acidity. Group B (Samples 1, 2, 3, 4, 6, 7, 9, and 11) represented the largest cluster and was further subdivided into three subgroups: a light-colored, mildly acidic subgroup (Sample 7); an acidity-deficient subgroup (Samples 4 and 11); and a highly concentrated, dark-colored subgroup with pronounced or buffered acidity (Samples 1, 2, 3, 6, and 9). Group C comprised only Sample 8, which exhibited the highest concentration and acidity, consistent with its isolated position in the PCA score plot. These findings demonstrate that the combined application of PCA and HCA provides an effective approach for classifying commercial cold brew coffee products based on their physicochemical and antioxidant properties. This classification framework may serve as a useful tool for quality evaluation, product standardization, and the development of consumer-oriented cold brew coffee products.