Profile of Bioactive Components of Cocoa (Theobroma cacao L.) By-Products from Ecuador and Evaluation of Their Antioxidant Activity

Abstract

The aim of the study was to determine the profile of bioactive compounds in cocoa residues (mucilage and bean shells), and to evaluate their antioxidant activity in two cocoa varieties, Nacional X Trinitario type (Fine Aroma) and the variety CCN-51. The extraction of phytonutrients from the residues was carried out selectively. The characterization and quantification of the total polyphenol content (TPC), and the total flavonoid content (TFC) were determined by UV–VIS spectrophotometry. High-performance liquid chromatography (HPLC) was used to determine the phenolic profile and methylxanthines. The antioxidant activity was evaluated by the methods of 2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) cation bleaching (ABTS), ferric-reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). The exudate mucilage samples from Nacional X Trinitario-type cocoa presented the highest content of TPC 105.08 mg gallic acid equivalents (GAE)/100 mL, TFC 36.80 mg catechin equivalents (CE)/100 mL, catechin (CAT) 35.44 mg/g, procyanidins (PCB2: 35.10; PCB1: 25.68; PCC1: 16.83 mg/L), epicatechin (EPI) 13.71 mg/L, caffeine (CAF) 0.90% and theobromine (TBR) 2.65%. In the cocoa bean shell, the variety CCN-51 presented a higher content of TPC (42.17 mg GAE/100 g) and TFC (20.57 mg CE/100 g). However, CAT (16.16 mg/g), CAF (0.35%) and TBR (1.28%) were higher in the Nacional X Trinitario cocoa type. The EPI presented no significant differences between the two samples studied (0.83 and 0.84 mg/g). The antioxidant activity values (ABTS, FRAP and ORAC methods) were higher in the samples of CCN-51 than in the Nacional X Trinitario type. The bean shell samples presented antioxidant values of 171.32, 192.22 and 56.87 mg Trolox equivalents (TE)/g, respectively, and the bean shell samples presented antioxidant values of 167.06, 160.06 and 52.53 mg TE/g, respectively. The antioxidant activity (ABTS, FRAP and ORAC) of the residues was correlated with the bioactive compounds of the mucilage and bean shells, showing a strong positive correlation (<0.99) with the procyanidins (B1, B2 and C1), EPI and CAT and a positive/moderate correlation (0.94) with methylxanthines.

Bioactives in Cocoa: Novel Findings, Health Benefits, and Extraction Techniques

“…This observation held true for both Nacional and Nacional × Trinitario cocoa varieties. Theobromine content peaked at 2.66 mg/100 mL in the mucilage of Nacional × Trinitario beans, with significant differences observed between theobromine and caffeine levels [46]. Theobromine and caffeine content varies depending on the fermentation process, with under-fermented beans generally exhibiting higher levels of both alkaloids compared to fermented beans [50].…”

“…A study by Llerena et al [46] investigated the bioactive compound profile and antioxidant activity in cocoa residues (mucilage and bean shells) of two varieties: Nacional x Trinitario (Fine Aroma) and CCN-51. The Nacional × Trinitario mucilage exhibited the highest concentrations of procyanidin B1, B2, C1, epicatechin, and catechin, with procyanidin B2 (3.52 mg/100 mL) and catechin (3.54 mg/100 mL) being the most abundant.…”

“…Consistent with previous research by Martinez et al [47] and Okiyama et al [48], flavan-3-ols (catechin, epicatechin, and procyanidins) were the dominant phenolic compounds identified, contributing to the bitter taste observed in cocoa derivatives and residues. Notably, unlike cocoa mucilage, cocoa bean shells possess a distinct phenolic profile compared to cocoa beans themselves [46]. Febrianto and Zhu's 2022 study [49] examined the chemical composition (methylxanthines, polyphenols, key odorant volatiles, and minerals) of 22 cocoa samples from various Indonesian regions.…”