Dutch Process

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The Dutch process , dutching or alcali process , in German alkalizing or digesting , describes the treatment of broken cocoa kernels or cocoa mass with alkaline solutions (lyes) to change the color and improve the taste, as well as to obtain cocoa powder that is better dispersible and can be used in the Cocoa drink does not settle easily. The process is mainly used to produce cocoa powder. As a rule, it is not used in chocolate production , whereas most cocoa powder is alkalized today.

The process was invented in 1828 by the Dutchman Coenraad van Houten , from which the name Dutch Process or Dutching for short is derived.

effect

Untreated cocoa kernels are quite acidic (around pH 5.0-5.5), due to the fermentation that takes place immediately after the cocoa pods are harvested and is essential for the development of taste. The alkalization process increases the pH to around 6.6–7.0. Too high a pH value would impair the aroma, in particular there is a risk that the cocoa butter will saponify , which would lead to an unpleasant, soapy taste. This is why the cocoa is acidified after alkalization, if necessary, by adding edible acids such as acetic , tartaric or citric acid . The unpleasant, sour taste components of certain cocoa varieties are softened by the alkalization. Whether the change in taste as a result of the alkalization generally represents an improvement is subjective and may depend on whether the cocoa powder is ultimately used for drinking cocoa, for baking or for other purposes.

The change in color consists mainly of a significant darkening of the natural brown color. A variety of shades can be achieved by varying process parameters; generally speaking lead cooler roasting and lower caustic concentration to a reddish color, hotter roasting to a darker brown. To what extent alkalized cocoa powder actually settles less in the drink than untreated cocoa powder is not entirely clear. The occasional claim that alkalization would increase the solubility (in the physical sense) of cocoa powder in water or milk is in any case incorrect.

Procedure

The alkaline solutions used are aqueous solutions of 2.0-2.5% alkali metal or alkaline earth metal - carbonates , - hydroxides or - oxides (predominantly magnesium oxide , potassium hydroxide , ammonium hydroxide , but also potassium , sodium , calcium or ammonium carbonate , potassium bicarbonate , Sodium bicarbonate and others); the aqueous solutions are added at temperatures of up to 125 ° C. Alkalizing whole or broken cocoa beans is possible, but uncommon because the shell of the beans (removed later and not used) would absorb a large part of the lye. Instead, it is preferable to treat fragments of cocoa kernels before or after roasting or cocoa mass (in this case always after roasting) or the press cake , which is left after the cocoa butter has been pressed out of the cocoa mass and is then ground to a powder.

  • If cocoa kernel fragments are made alkaline, the process takes a relatively long time because the lye needs a certain time to penetrate into the fragments; the alkalization therefore does not have a uniform effect on the total amount of cocoa, because the outer areas of the fragments are more exposed to the action of the solution. Traditionally, the cocoa kernels are soaked in the alkalizing solution, left in tanks for 18–24 hours and finally dried. More modern, continuously operating systems combine soaking, drying and roasting and achieve soaking times of less than three hours, with treatment under pressure even only 30–60 minutes. These methods also have the advantage of a particularly low microbial load on the cocoa.
  • The alkalization of cocoa mass is usually carried out at an elevated temperature, which is accompanied by an acceleration of the process, for example under vacuum at temperatures of 80-90 ° C and constant kneading of the mass within about 30-40 minutes. Pure steam treatment can also be used.
  • The alkalization of cocoa press cakes takes place in heated drums under vacuum. At particularly high temperatures and caustic concentrations and longer exposure times, this process produces black cocoa, which is extremely alkaline (up to pH 8.5) and usually has a strong taste and is used for coloring.

Health aspects

The process reduces the antioxidants contained in cocoa. According to recent studies, however, it still contains a high concentration of polyphenols. With a light Dutch process, 40% of all antioxidants are retained, with an intensive one only 10%. Due to the high proportion, the antioxidants in cocoa are still at a high level. Cocoa powder naturally contains 34.6 mg of flavonoid antioxidants per gram of weight. This is one of the highest values ​​ever according to a study published in the Journal of Agricultural and Food Chemistry in 2008 . This study was carried out by the chocolate maker Hershey and the industrial research institute Brunswick Laboratories. Unsweetened cocoa powder is also one of the foods with the highest flavonol content on the USDA's list .

Web links

Individual evidence

  1. ↑ a b c Entry on Dutching. In: Römpp Online . Georg Thieme Verlag, accessed on April 24, 2015.
  2. ^ Hans-Dieter Belitz , Werner Grosch , Peter Schieberle : Textbook of food chemistry . 6th completely revised edition. Springer, Berlin / Heidelberg 2008, ISBN 978-3-540-73201-3 , p. 998 , doi : 10.1007 / 978-3-540-73202-0 .
  3. ^ A b c Stephen T. Beckett: The Science of Chocolate . 2nd Edition. Royal Society of Chemistry, Cambridge 2008, ISBN 978-0-85404-970-7 , Section 3.4.1: Alkalising (Dutching) , pp. 54-55 .
  4. ↑ a b c d e f Heinrich Fincke : Handbook of cocoa products . Ed .: Albrecht Fincke. 2nd Edition. 1965, III H .: "opening up" (alkalizing) the cocoa nibs or cocoa mass , p.  162-165 .
  5. ^ Heinrich Fincke : Handbook of cocoa products . Ed .: Albrecht Fincke. 2nd Edition. 1965, p.  60 ( limited preview in Google Book search).
  6. ^ A b c d Bernard W. Minifie: Chocolate, Cocoa, and Confectionery. Science and Technology . 3. Edition. Van Nostrand Reinhold, New York 1989, ISBN 978-94-011-7926-3 , Alkalization , pp. 61–67 ( limited preview in Google Book search).
  7. ↑ a b Press release on EurekAlert !, October 8, 2008.
  8. ↑ Seema Bhagwat, David B. Haytowitz, Joanne M. Holden: USDA Database for the Flavonoid Content of Selected Foods. (PDF; 988 kB) Release 3.1. May 2014, p. 116 , accessed on July 4, 2017 (English).
  9. ↑ Rosa M. Lamuela-Raventós, Cristina Andrés-Lacueva, J. Permanyer, María Izquierdo-Pulido: More Antioxidants in Cocoa . In: The Journal of Nutrition . tape 131 , no. 3 , 2001, p. 834-834 , PMID 11238767 .