The authors, who published their findings in the Chemistry Central Journal said that their results indicate that cacao seeds provide nutritive value beyond that derived from their macronutrient composition and thus should be termed ‘super fruit’.
The fruit pulp of the Theobroma cacao pod that surrounds its seeds can be consumed; however the vast majority of people have only consumed the seed-derived portion of cacao in the form of cocoa powder or chocolate.
So the goal of the study, said the Hershey scientists, was to compare cocoa powder and chocolate, products representing the commonly eaten portion of the cacao fruit, with powders and juices from so-called “Super Fruits”.
Cocoa powder and chocolate were compared with powders derived from acai, blueberry, cranberry, and pomegranate, continued the authors, on measures of antioxidant activity, as measured by oxygen radical absorbance capacity (ORAC (μM TE/g)), total polyphenol content (TP (mg/g)), and total flavanol content (TF (mg/g)).
Method
To limit sampling error with each analysis method, each brand of fruit powder and product was prepared and analyzed in triplicate using chemical assays, said the team.
The materials selected, they explained, included commercially available fruit powders, natural (non-alkalized) cocoa, 100 per cent non blended fruit juices, natural cocoa beverage, solid dark chocolate (60-63 per cent cacao), and hot cocoa mix.
All powders were obtained via food ingredient suppliers, while the juices, solid dark chocolate, and hot cocoa mix were obtained at retail and analyzed in the form sold to consumers.
They said that a cocoa beverage was produced by combining 240 ml water, 25 g sugar, 1 g salt, and 12 g of natural cocoa powder and was designed to have a composition similar to that of the other fruit juices. 240 ml was considered a typical single serving of fruit juice or cocoa beverage, 40 g was considered a typical single serving of dark chocolate, and 28 g was considered a typical single serving of hot cocoa mix.
Results
The authors’ findings demonstrated that the antioxidant capacity of cocoa powder (634 ± 33 μMTE/g) was significantly greater than blueberry, cranberry, and pomegranate powder on a per gram basis.
They said that the total polyphenol content of cocoa powder (48.2 ± 2.1 mg/g) appeared to be greater than acai, blueberry, and cranberry powder; however these differences did not reach statistical significance, added the researchers.
And the Hershey team found that the total flavanol content (of cocoa powder (30.1 ± 2.8 mg/g) was significantly greater than all of the other fruit powders tested.
Analysis of fruit products demonstrated that the antioxidant capacity of dark chocolate (9911 ± 1079 μMTE/serving) was not significantly greater, on a per serving basis, than pomegranate juice but was greater than that of all other products tested. In contrast, hot cocoa mix had significantly less antioxidant capacity (1232 ± 159 μMTE/serving) than all of the other products tested, noted the team.
“The results of the current study demonstrate that cocoa powder has equivalent or significantly higher in vitro antioxidant activity, as measured by ORAC values, compared to the tested fruit powders.
Similarly, the TP content of cocoa powder was equivalent to that of the fruit powders and its TF content was significantly higher than that of all the fruit powders tested,” reported the Hershey scientists.
They also stress that the cocoa powders, cocoa beverages, and dark chocolate used in the study all contained natural (or non-alkalized) cocoa but that the hot cocoa mixes were made with alkalized cocoa.
The extent of polyphenol destruction, continue the researchers, is proportional to the degree of alkalization and change in the water extractable pH of the resulting powder antioxidant capacity and polyphenol content may be severely diminished in alkalized cocoa powder and products made with alkalized cocoa.
“Alkalinization is used to mellow the flavor of cocoa, however the process has been shown to destroy polyphenolic compounds and is likely responsible for the significant differences in ORAC, TP, and TC values observed between hot cocoa mix and the other cocoa products,” commented the team.
Source: Chemistry Central
Published online: doi:10.1186/1752-153X-5-5
Title: Cacao seeds are a “Super Fruit”: A comparative analysis of various fruit powders and products
Authors: S. J. Crozier, A G. Preston, W. J Hurst, M J. Payne, J Mann, L. Hainly, D. L. Miller