Influence of roasting conditions on fatty acid composition and oxidative changes of cocoa butter extracted from cocoa bean of Forastero variety cultivated in Togo

Abstract

Cocoa butter is responsible for physico-chemical, rheological and sensory properties of chocolates. Forastero cocoa beans are rich in cocoa butter. Roasting of cocoa beans is an essential step of their processing, giving rise to many desirable transformations. On the other hand, it causes changes in certain valuable ingredients including also cocoa butter. This article studies the influence of roasting conditions, i.e. temperature, humidity and flow velocity of roasting air, on the fatty acid composition, peroxide value and content of conjugated dienes and trienes in cocoa butter extracted from cocoa beans. Generally, in most cases roasting did not increase the peroxide value. In the constant conditions due to obtained results of PV, CD and CT values it is recommended to roast cocoa beans at the temperature of 150°C, 1m/s air velocity and 5% relative humidity. In the variable conditions lower values of PV, CD and CT were achieved when cocoa beans were roasted in variants with changing temperature from 150°C to 135°C or with changing air velocity from 1 to 0.5m/s. Generally, the roasting process substantially did not change the content of each fatty acid, regardless of the applied conditions.