Optimizing vacuum drying process of polyphenols, flavanols and DPPH radical scavenging assay in pod husk and bean shell cocoa.

The objective of this study was to optimize different vacuum drying conditions for cocoa pod husk and cocoa bean shell in order to enhance these by-products for commercial applications. To carry out the optimization, the response surface methodology was applied using a Box-Behnken experimental design with 15 experiments for which different conditions of temperature (X1), drying time (X2) and vacuum pressure (X3) were established. The response variables were the content of total polyphenols, the content of flavanols and the radical scavenging activity evaluated in the extracts of the different experiments. Temperature (50-70 °C), drying time (3-12 h) and vacuum pressure (50-150 mbar) were considered as independent variables. The main factors affecting the response variables were temperature, followed by vacuum pressure. For the content of polyphenols, the optimal response values predicted for the cocoa pod husk was 11.17 mg GAE/g with a confidence limit (95%) of 9.05 to 13.28 mg GAE/g (optimal conditions: 65 °C, 8 h and 75 mbar), while for the cocoa bean shell cocoa was 29.61 mg GAE/g with a confidence limit (95%) of 26.95 to 32.26 mg GAE/g (optimal conditions: 50 °C, 5 h and 100 mbar). Therefore, results of this study suggest a high content of phenolic compounds obtained from these by-products that show relevance as functional ingredients for application in the food, nutraceutical, and cosmeceutical industries.

Microencapsulated betacyanin from colored organic quinoa (Chenopodium quinoa Willd.): optimization, physicochemical characterization and accelerated storage stability.

BACKGROUND: Betalains are presently gaining popularity as pigments for use as natural colorants and/or bioactive compounds in functional foods. Quinoa (Chenopodium quinoa Willd.) has been recognized as an extremely nutritious grain and has recently been found to be a novel and good betalain source. Microencapsulation has been studied as a protected-delivery procedure to stabilize betalains. There are no studies about microencapsulation of betacyanins extracted from quinoa using spray-drying technology. RESULTS: Optimal microencapsulation was obtained at a drying temperature of 165 °C, a rotameter air flow rate of 47 mm (940 L h-1 ) and 10% w/w maltodextrin, which produced good encapsulation yield (58.1%) and efficiency (100%). Optimized maltodextrin-betacyanin microcapsules (diameter 4.4 µm) have low moisture (1.64 ± 0.08%) and water activity (0.127 ± 0.006), a betacyanin content of 0.1995 ± 0.0017 g kg-1 and saponin content <0.080 mg kg-1 . The oxygen consumption rate by betacyanin was -4.373 × 10-5 bar min-1 at 80 °C and -6.67 × 10-5 bar min-1 at 90 °C, which was accompanied by fading of the color. CONCLUSION: Microencapsulated betacyanin was optimized by response surface methodology, and its stability was measured under accelerated conditions by oxygen consumption. Microencapsulations contain betacyanin and low saponin concentration, which might confer unique health-promoting properties. © 2018 Society of Chemical Industry.