Pyrazines in extruded malt

Green malt, partially dried, was processed by high‐temperature short‐time (HTST) extrusion cooking at three different temperatures. Volatile components of the product were analysed by gas chromatography (g.c.) using a headspace sampling technique, and identified by mass spectrometry (m.s.). The concentration of pyrazines increased when the temperature was increased from 130 to 160°C, but it fell at 190°C, probably as an effect of volatilisation. However, the influence of parameters such as water content, the milling of the raw material and its residence time in the extruder must also be taken into account. Extruded malt contained more total pyrazines than conventionally processed malt. 2‐Vinyl‐5‐methylpyrazine and 2‐vinyl‐6‐methylpyrazine were found only in extruded malt, especially at high processing temperature. The pyrazine content per colour unit was high, an observation which may lead to the production of a more flavourful beer of the lager‐type.