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Effects of Maturity at Harvest and Fermentation Conditions on Bioactive Compounds of Cocoa Beans

Dang, Yen K. T., Nguyen, Ha V. H.
Plant foods for human nutrition 2019 v.74 no.1 pp. 54-60
analysis of variance, antioxidant activity, bioactive compounds, caffeine, catechin, cocoa beans, cocoa powder, fermentation, fruits, harvesting, polygalacturonase, proanthocyanidins, theobromine
Cocoa beans and cocoa products contain considerable amounts of bioactive compounds. Harvesting cocoa fruit too early or too late may have effects on the phenolic and alkaloid concentrations of the cocoa powder. Fermentation, a primary processing used to transform cocoa beans to cocoa powder, may also influence the contents of bioactive compounds. In this study, proanthocyanidins, the major compounds in cocoa polyphenols, caffeine and theobromine of cocoa beans, were evaluated at different maturities at harvest, and with different fermentation durations, with and without the addition of a commercial enzyme, Pectinex® Ultra SP-L. The amounts of proanthocyanidins, caffeine and theobromine, and the antioxidant capacities of the unfermented cocoa beans increased as the fruits matured. The values ranged from 16.12–27.28 g catechin equivalents (CE)/100 g dry weight (DW); 99.66–173.61 mg/100 g DW; 556.39–948.84 mg/100 g DW; 23.23–26.32 mol Trolox equivalents (TE)/100 g DW, respectively. Prolonged fermentation with or without the addition of pectinase, from three to seven days, significantly reduced the amounts of these compounds present. Fermentation using the enzyme significantly reduced the proanthocyanidin content and antioxidant capacity of the cocoa powder, with the overall means decreasing from 8.93–4.93 g CE/100 g DW and from 15.81–12.95 g mol TE/100 g DW, respectively. Two-way ANOVA analyses showed that the proanthocyanidins, caffeine, theobromine contents and the antioxidant capacity of cocoa beans were strongly dependet to their stages of maturity, fermentation methods and fermentation duration.