Impact of high-voltage electric discharge treatment on cocoa shell phenolic components and methylxanthines

Cocoa shell is one of the by‐products obtained in chocolate industry which was considered as waste for a very long time. Recently, the presence of high‐valuable bioactive components in cocoa shell was recognized, and research on the pallet of food products enriched with cocoa shell is increasing. The most abundant bioactive components of untreated cocoa shell (UCS) are theobromine (3.906 ± 0.070 mg/g), caffeine (0.646 ± 0.055 mg/g), and (+)‐catechin (0.290 ± 0.005 mg/g), followed by gallic acid (0.147 ± 0.041 mg/g) and (−)‐epicatechin (0.165 ± 0.099 mg/g). Furthermore, the impact of concentration (1.5 and 3% of cocoa shell in water), high‐voltage electric discharge (HVED) treatment (40 and 80 Hz), and treatment time (15, 30, and 45 min, respectively) on bioactive compounds content was evaluated. Statistically significant differences between treatment conditions were obtained. Generally, water‐HVED treatment at 40 Hz has lower impact on bioactive components than water, and water‐HVED at 80 Hz, therefore, can have a significant effect on future treatments of materials rich in bioactive compounds. PRACTICAL APPLICATIONS: HVED is an innovative nonthermal processing technique that has mechanical and electrical effect on the product resulting with lower costs and increase of functional properties. This study has shown that HVED causes lower decrease of phenolics and methylxanthines in cocoa shell which can have a significant effect on future treatments of materials rich in bioactive compounds. Because it is not recorded in scientific literature that HVED treatment was used on cocoa shell so far, it will help in future research and applications of cocoa shell in the food industry.