Conching is the processing step in which chocolate is subjected to long-term heat treatment, mechanical forces and addition of fat and emulsifiers. It is a mixing and heating treatment that is conducted to produce liquid chocolate (all solid particles are coated with fat), evaporate volatile acids, achieve a proper viscosity, remove excess moisture, and develop a desirable color. There is an important relationship between the chocolate flavour and the type of conching process.
Chocolate conching is known to be one of the key quality driving steps in chocolate manufacturing, which is still very time-consuming and energy-intensive. The initial dry conching phase is very important to decrease moisture and to improve rheology.
Milk fat in SFC (sprayed full cream) is released during conching at conditions with high lactose crystallization (high temperature or low water remove by closed lid). Fat release in chocolate with RFC (roller dried full cream) is only slightly affected by conching conditions.
In the initial stage of conching, volatile polyphenols are lost due to evaporation, together withwater and short-chain fatty acids. It has been established that the content of volatile polyphenolsis reduced by 80% in this process.
Complexes between polyphenols, amino acids, peptides, and proteins are formed during this process. This is one of the reasons why conching affects chocolate flavor and reduces astringency.
Although the aroma concentration is overall clearly declining during conching, chocolate with high conching time is perceived as richer in chocolate flavor. It is concluded that improving texture properties enable a more balanced flavor perception.
Process of conching in chocolate production
