This study aims to evaluate the effects of different cascara particle sizes and variations in the kombucha fermentation process on the bioactive compounds and antioxidant properties of cascara (Coffea arabica L.) kombucha. Cascara tea (CT), cascara tea with sugar (CS), and cascara kombucha (CK) were prepared using whole, coarsely ground, and finely ground cascara. A finer particle size enhanced color intensity and improved the extraction of bioactive compounds. CK prepared with finely ground cascara demonstrated the highest total phenolic content (TPC), total flavonoid content (TFC), and ferric reducing antioxidant power (FRAP). Fermentation influenced the profile of phenolic acids, leading to a decline in most compounds, except for vanillic acid in all CK samples, which increased during fermentation. Interestingly, apigenin levels increased, while quercetin levels decreased throughout fermentation. These findings highlight the role of fermentation, sugar addition, and particle size reduction in enhancing phenolic extraction and antioxidant potential in cascara-based beverages, particularly cascara kombucha.

Northeastern Thai ethnic foods are celebrated for their health benefits yet remain largely underexplored. This study assessed the antioxidant and cytotoxic properties of two ready-to-eat pastes—Jaew Hon (JH) and Gang Om (GO)—produced using laboratory (LAB) and industrial original equipment manufacturer (OEM) methods. Evaluations were conducted using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), and total flavonoid content (TFC) assays alongside the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for cytotoxicity. Physicochemical analyses revealed that JH OEM had the highest total dissolved solids (11.57°Brix) and water activity (0.91), while GO OEM exhibited the highest pH (5.28) and lightness (L* 31.43). Antioxidant results showed JH LAB outperformed in DPPH scavenging (96.25 mg AAE/100 g) and TPC (433.5 mg GAE/100 g), whereas GO OEM achieved the highest TFC (345.57 mg QE/100 g). Volatile compound profiling by Gas Chromatography–Mass Spectrometry (GC-MS) indicated distinct aroma profiles between LAB and OEM samples. Moreover, MTT assays revealed stronger cytotoxic effects for OEM products; specifically, GO OEM achieved 71.88% maximum inhibition and an IC50 of 276.10 µg/mL against HT-29 cells. Colony formation assays confirmed GO OEM’s significant antiproliferative activity, and gene expression analysis demonstrated upregulation of pro-apoptotic markers (Bax, Caspase-3) alongside downregulation of NF-κB p65, Cyclin D1, and MMP-9. Overall, these findings suggest that industrially produced GO and JH pastes hold promise as functional foods, integrating traditional culinary practices with modern production techniques. These findings lay the foundation for future research focused on uncovering bioactive mechanisms, optimizing processing methods, and confirming health benefits through in vivo studies.