Optimization of Preparation Technology of Cacao Extract and Analysis of Volatile Components From Different Regions

Abstract

Cocoa is an important tropical economic crop. Owing to its unique, rich, and fragrant flavour and significant nutritional value, it has become one of the three most popular beverages globally and has retained its popularity for a long time. Cocoa is an important raw material for chocolate and is also used as a spice in various desserts, baked goods, snacks and beverages. Although the aroma characteristics of cocoa are impacted by the place of its origin, not much research is available on such a crucial topic. The aim of this study was to optimise the cocoa extraction process and to investigate the compositional differences of cocoa extracts from different origins. Using Tanzanian cocoa as the raw material, the pretreatment process was optimised through an orthogonal experiment. The cocoa extract was obtained via heating under reflux and by using ethanol as a solvent. The extraction conditions were compared with those of other methods and solvents. The optimal extraction conditions (extraction liquid-to-solid ratio: 27 mL/g; extraction time: 4.8 h; and ethanol concentration: 77%) were determined by employing a response surface methodology experimental design. Under the optimal technological conditions, cocoa extracts of three origins, namely Tanzania, Ghana, and Ecuador, were extracted, and their volatile components were determined by GC–MS, to understand differences in these components. The study identified 46, 27 and 39 volatile components in the products of Tanzania, Ghana and Ecuador origin cocoa, respectively. The common volatile components were 2,3-butanediol, ethyl palmitate, phenylacetic acid, oleic acid, palmitic acid and theobromine. The volatile components in the cocoa extracts of different origins obtained using the same extraction method varied greatly. Differences in volatile components also result in differences in odour characteristics. The study results may provide a theoretical basis for adding aroma to cocoa extracts.