Effect of Roasting Time and Temperature on the Generation of Nonvolatile (Polyhydroxyalkyl)pyrazine Compounds in Peanuts, As Determined by High-Performance Liquid Chromatography

A high-performance liquid chromatographic (HPLC) method was used for the determination of (polyhydroxyalkyl)pyrazine (PHAP) compounds in peanuts roasted to different levels as part of a 3×3 time/temperature study. The content of volatile alkylpyrazine compounds generated at each point was determined by headspace gas chromatography−mass spectrometry (GC−MS) and compared to the PHAP content. In general, results showed that the levels of both PHAP and alkylpyrazine compounds increased with both time and temperature, reaching a maximum at the longest roast time and highest temperature. Formation rates for both types of compounds showed a strong dependence on temperature, giving linear Arrhenius plots with similar slopes. There was no indication that the PHAP compounds formed during roasting decomposed to form alkylpyrazines. Keywords: Roast peanuts; (polyhydroxyalkyl)pyrazines; alkylpyrazines; LC-MS; flavor generation; headspace GC−MS