Impact of Alkalization on the Antioxidant and Flavanol Content of Commercial Cocoa Powders

Abstract

Cocoa is a food ingredient that is important for the contribution of flavor to foods but is also associated with potential health benefits. The chemistry thought to be responsible for its cardiovascular health benefits is the flavanol (flavan-3-ol) antioxidants. Evidence from the literature indicates that natural cocoas are high in flavanols, but when the cocoa is processed with alkali, also known as Dutch processing or Dutching, the flavanols are substantially reduced. This paper provides a survey of the physical and chemical composition of representative natural cocoas and lightly, medium, and heavily alkalized cocoas. As part of the survey, both brown/black and red/brown alkali-processed cocoas were measured. Natural cocoa powders have an extractable pH of 5.3-5.8. Alkalized cocoa powders were grouped into lightly treated (pH 6.50-7.20), medium-treated (pH 7.21-7.60), and heavily treated (pH 7.61 and higher). The natural, nonalkalized powders had the highest ORAC and total polyphenols and flavanols (including procyanidins). These chemical measurements showed a linear decrease as the extractable pH of the cocoa powder increased. Likewise, the flavanol monomers, oligomers, and polymers all showed a linear decrease with increasing pH of the final cocoa powder. When brown/black cocoa powders were compared to red cocoa powders, similar decreases in flavanols were observed with increased alkalization. The average total flavanol contents were 34.6 +/- 6.8 mg/g for the natural cocoas, 13.8 +/- 7.3 mg/g for the lightly processed cocoas, 7.8 +/- 4.0 mg/g for the medium processed cocoas, and 3.9 +/- 1.8 mg/g for the heavily processed cocoa powders. The observed linear and predictable impact of alkalization on flavanol content is discussed with respect to other reports in the literature as well as what implications it may have on diet and food manufacturing.

Removal of Pb (II) From Contaminated Water by Bagasse Adsorbent Modified with Dithizone

“…A total of 30 g fine particles of bagasse was poured in 500 mL KOH solution (10 %) and stirred for one night. Addition of KOH solution to bagasse particles facilitated the elimination of colorants, organic acids, lipids and proteins in the cellulosic structure of bagasse, and mostly important alkalized the surface of particles (27,28). The alkalized particles were then washed with sufficient water until pH 7 in the eluate solution was achieved.…”

Oligomeric Cocoa Procyanidins Possess Enhanced Bioactivity Compared to Monomeric and Polymeric Cocoa Procyanidins for Preventing the Development of Obesity, Insulin Resistance, and Impaired Glucose Tolerance during High-Fat Feeding

“…Miller et al demonstrated a steady decrease in flavanol content with increasing pH in cocoa powder 43 . As a result, Dutched chocolate typically exhibits low total flavanol content 11,43 . A recent study demonstrated that Dutching decreases C and EC levels in cocoa powder by 38% and 67% respectively 6 .…”

Effect of storage temperature on the decay of catechins and procyanidins in dark chocolate

“…doi: 10.17221/265/2016-CJFS Cocoa powder and baking chocolates are the cocoa products with the highest amount of non-fat cocoa solids, followed by dark chocolate which contains around 20-29.5% non-fat solids and is derived from cocoa liquor (Miller et al 2008). In recent years, several studies have documented the beneficial effects of dark chocolate on human health.…”