When purified , tetramethylpyrazine is a colorless solid .
Tetramethylpyrazine , also known as ligustrazine , is a chemical compound found in natto and in fermented cocoa beans .
When purified , chemical compound is a colorless solid .
Tetramethylpyrazine , also known as ligustrazine , is a chemical compound found in natto and in fermented cocoa beans .