Total phenolics and antioxidant capacity of cocoa pulp: processing and storage study

Cocoa pulp, the white mucilage that surrounds cocoa beans, is the main substrate in cocoa bean fermentation and is rich in macro- and micronutrients. Yet, the presence of phenolics and their antioxidant activity in cocoa pulp has not been explored. The objectives of this study were to quantify the total phenolics of cocoa pulp by using Folin-Ciocalteu assay and antioxidant activity by using Oxygen Radical Absorption Capacity (ORAC) assay as well as Cellular Antioxidant Activity (CAA) assay. The effect of single and double pasteurization was investigated to better understand the potential health value and subsequently promote the utilization of cocoa pulp. Eight weeks storage studies at 4ºC, 25ºC, and 37ºC were also performed to monitor the stability of phenolics, ORAC values, and color of pasteurized cocoa pulp. Single and double pasteurization decreased phenolics content of the cocoa pulp by 25% and 38%, respectively, when compared to unpasteurized pulp (103.76±4.79 mg GAE/100 g pulp). The ORAC values were not significantly different between unpasteurized (1871±58 μmol TE/100 g pulp), single (1835±41 μmol TE/100 g pulp), and double pasteurized (1681±157 μmol TE/100 g pulp) pulp. There was a significant increase in the CAA values (EC50) of double pasteurized pulp (59.76±9.26 μmol QE/100g pulp) as compared to unpasteurized pulp (23.71±3.12 μmol QE/100 g pulp). Thus, there was a weak negative correlation between ORAC and CAA values in quantifying the antioxidant activity of cocoa pulp. Overall color differences (ΔE*) relative to unpasteurized pulp were not significantly different between single (11.50±6.64) and double pasteurized pulp (14.96±8.64). Throughout the eight week storage studies, single and double pasteurized pulp showed very little change in the phenolics content and the ORAC values at 4ºC and 25ºC. However, at 37°C, up to 50% relative loss in phenolics content and 40% relative loss in the ORAC values were observed in single pasteurized pulp; whereas double pasteurization resulted in lesser relative loss. Both single and double pasteurized pulp showed the lowest lightness (L*) values when stored at 37ºC, as well as the lowest hue angle and chroma values when stored at 4ºC, suggesting less color changes at lower storage temperature.M.S.Includes bibliographical referencesby Vidya Endraiyan