(Bio)processing as Tool to Tailor Cereal Flavour

摘要

Wholegrain products are regarded beneficial for health by reducing the risk of several chronic diseases. Certain cereal types have a typical flavour, which in some cases is not regarded attractive enough for consumers. The flavour of native, untreatedgrain is mild and bland. Generally, the cereal flavour forms during processing, especially in heat treatments. By applying different bioprocessing techniques the flavour and texture of the products may be adjusted into desired direction. Volatile and non-volatile compounds influence the perceived flavour directly or indirectly as flavour components or flavour precursors. Descriptive profiling is used to form a general view of the sensory characteristics in the product. To understand the chemistry behind the flavour, statistical multivariate techniques are used to relate sensory characteristics and chemical compounds. In this work the impact of germination, milling fractionation, sourdough technology and enzymatic treatments on cereal flavour formationand characteristics will be discussed. Germination-drying process was found to adjust effectively the perceived flavour and increase the flavour stability of oat. Sourdough fermentation increased the perceived sourness and flavour intensity, and the following heat-treatment induced the appearance of flavours and compounds originating from Maillard reaction. The fractions of rye kernel have their characteristic flavour: between the mild tasting endospermic part and the bitter tasting outermost bran fraction, a rye-like flavour without any obvious bitterness was observed. This fraction contains significant amounts of bioactive compounds, such as alkylresorcinols, lignans and phenolic acids. Enzymes were also investigated as tools to modify rye flour. As a result of protease treatment the intensive, bitter flavour of rye was increased indicating that certain small peptides and concomitantly released phenolic compounds had a role in the bitter flavour.