Phenolics and methylxanthines profile of cocoa shell and the effect of cold plasma treatment on their content

Cocoa shell, a by-product of cocoa industry, is valuable source of dietary fibers, phenolics, methylxanthines and vitamins. Recently, the presence of high-valuable bioactive components in cocoa shell was recognised and the pallet of food products enriched with cocoa shell is increasing. The most abundand bioactive components of cocoa shell are methylxanthines (theobromine and caffeine) and flavanols (catechins, epicatechins and procyanidins). Cold plasma treatment is often used for decontamination of products but also effects food constituents. The aim of this study was to determine bioactive components profile of cocoa shell and evaluate the effect of cold plasma treatment of their composition and content. Qualitative and quantitative determination of 6 phenolic components (gallic acid, caffeic acid, p-coumaric acid, (+)-catechin, (-)-epicatechin and (-)-epicatechin gallate) and 2 methylxanthines (theobromine and caffeine) was performed by chromatographic method with absorbance detection while total phenolic content was determined by Folin-Ciocalteu method. The results showed that theobromine, caffeine and (+)-catechine are major bioactive components of cocoa shell followed by gallic acid and (-)-epicatechin. Although water extraction decreased bioactive components content compared to untreated cocoa shell, the decrease was lower when cold plasma treatment was applied.