Resin polarity and pore architecture govern selective enrichment of antioxidant flavonoids from cocoa (
Theobroma cacao
L.) rind: a macroporous adso
Nur Jalilah Ahmad, Badrul Hisyam Zainudin, Mohamad Shazeli Che Zain Abstract
BACKGROUND
Cocoa ( Theobroma cacao L.) rind is an underutilized agro‐industrial by‐product with potential as a source of valuable flavonoids. However, its complex chemical composition presents challenges for producing polyphenol‐enriched extracts with enhanced antioxidant activity. This study evaluated the potential of macroporous adsorption resins for the selective enrichment of cocoa rind flavonoids.
RESULTS
Eight resins were screened, and selected resins were further evaluated for adsorption kinetics, equilibrium isotherms, thermodynamics, fixed‐bed performance, desorption efficiency, reusability, metabolite profiles, and antioxidant activity. Amberlite XAD‐7HP achieved the highest enrichment efficiency, increasing total phenolic content from 79.10 to 314.00 mg gallic acid equivalents (GAE) g −1 extract, representing a 3.97‐fold increase, and total flavonoid content by approximately 1.49‐fold. Adsorption followed pseudo‐second‐order kinetics and the Freundlich isotherm, while thermodynamic analysis indicated a spontaneous and exothermic process. Although XAD‐7HP provided the highest enrichment, SP207 demonstrated greater operational stability during repeated adsorption–desorption cycles. Untargeted liquid chromatography–mass spectrometry profiling revealed resin‐dependent metabolite distributions, with XAD‐7HP selectively enriching flavonol glycosides and other flavonoid‐related compounds. The enriched XAD‐7HP extract also exhibited the strongest 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging activity, with the IC 50 decreasing from 194.78 to 38.84 μg mL −1 , corresponding to an approximately 80.1% reduction compared with the crude extract.
CONCLUSION
Macroporous adsorption resin technology is a promising approach for valorizing cocoa rind by producing polyphenol‐enriched extracts with enhanced antioxidant activity. Amberlite XAD‐7HP demonstrated superior enrichment performance, whereas SP207 offered greater operational stability during repeated use. These findings support further investigation into resin‐based enrichment as a strategy for developing value‐added ingredients from cocoa rind. © 2026 Society of Chemical Industry.