Formation of Strecker aldehydes and pyrazines in a fried potato model system

Sugars and amino acids were removed from potato slices by soaking in water and ethanol. They were then infused with various combinations of sugars (gl ucose and/or fructose) and amino acids (asparagine, glutamine, leucine, iso leucine, phenylalanine, and/or methionine) and fried. Volatile compounds we re trapped onto Tenax prior to gas chromatography-mass spectrometry. Relati ve amounts of compounds (relative to the internal standard) and relative yi elds (per mole of amino acid infused into the slices) were determined. Amou nts of 10 pyrazines, 4 Strecker aldehydes, and 4 other compounds were monit ored. Relative amounts and relative yields of compounds varied according to the composition of the system. For the single amino acid-glucose systems, leucine gave the highest relative amount and relative yield of its Strecker aldehyde. Asparagine and phenylalanine gave the highest total relative amo unt and total relative Yield, respectively, of pyrazines. In the system con taining all of the amino acids and glucose, the relative amount of 3-methyl butanal was higher, whereas the amounts of the other monitored Strecker ald ehydes were lower. Most of the relative amounts of individual pyrazines wer e lower compared to the glucose-asparagine system, whereas the total relati ve yield of pyrazines was lower, compared to all of the single amino acid-g lucose mixtures. Addition of fructose to the mixed amino acid-glucose model system generated Strecker aldehydes and pyrazines in ratios that were more similar to those of untreated potato chips than to those from the same sys tem but without fructose. Both the sugars and the amino acids present in po tato are crucial to the development of flavor compounds in fried potato sli ces.