Effect of alkalization on the Maillard reaction products formed in cocoa during roasting

- Alkaline treated cocoa had higher concentrations of α-dicarbonyl compounds.
- 3-Deoxyglucosone, glucosone, diacetyl decreased after roasting.
- Less 5-hydroxymethylfurfural and methylglyoxal formed in alkaline-treated cocoa.
- Lysine modification and degradation of fructoselysine increased during roasting.
- Carboxymethyllysine was higher in alkaline-treated cocoa.

Cocoa beans are used in vast variety of food products whether as raw or after alkaline treatment. In this study, cocoa beans were treated with sodium carbonate or water and then roasted together with non-treated cocoa beans. To understand the effect of alkalization on Maillard reaction during cocoa roasting, changes in the concentrations of certain Maillard reaction compounds were determined. Additionally, changes in the concentrations of sugars and modification of lysine were also monitored. Alkaline treatment favored the degradation of sugars in cocoa together with roasting. The concentration of α-dicarbonyl compounds was higher in alkaline treated cocoa compared to water-immersed and non-treated cocoa. Roasting process substantially decreased the concentrations of 3-deoxyglucosone (3-DG), glucosone, glyoxal and diacetyl in alkaline treated cocoa. The concentrations of methylglyoxal and 5-hydroxymethylfurfural (HMF) increased in cocoa samples after roasting although this increase was less in alkaline treated cocoa compared to the other treatments. Most of the lysine was modified within 30 min and fructoselysine, measured as furosine, gradually degraded independent of the treatments, but depending on temperature. N-ε-Carboxymethyllysine (CML) was doubled in alkaline treated cocoa although it did not change depending on the roasting.