Impact of Convectional and Superheated-Steam Roasting on the Physicochemical and Microstructural Properties of Cocoa Butter Extracted from Cocoa Beans

摘要

Cocoa beans were subjected to roasting using convectional and superheated-steam roasting methods. The influence of the roasting methods on the physicochemical properties (the content of free fatty acids, peroxide and p-Anisidine, the fatty acid and triglyceride compositions and the thermal behavior) and the microstructure of the raw and roasted cocoa butter extracted from cocoa beans were examined. The results exhibited significantly (P < 0.05) higher free fatty acid, peroxide and p-Anisidine levels in conventionally roasted samples than in raw and superheated-steam roasted samples. The conventional roasting method degraded the fatty acids significantly, specifically the unsaturated fatty acids, compared to the superheated-steam roasting method. The important triglycerides, namely, POP (palmitic-oleic-palmitic) and POS (palmitic-oleic-stearic) were present at significantly higher levels in superheated-steam roasted samples than in conventionally roasted samples. In addition, conventionally roasted samples liquefied faster than did superheated-steam-roasted and raw samples. Superheated-steam-roasted samples exhibited finer and clearer crystals than did conventionally roasted and raw samples.