Use of unusual storage temperatures to improve the amino acid profile of potatoes for novel flavoring applications

Abstract

To investigate the potential of potato culls as a source of novel flavorings, free amino acid profiles of juice from tubers stored at 0°C, 12°C or 24°C were analysed by gas chromatography/mass spectrometry after separation on cation exchange resin and derivatization with N-methyl- t-butyl-dimethyl-silyl-trifluoroacetamide. Juices were also incubated for 42 h with or without a commercial protease for comparison. Storage at all three temperatures increased glutamine concentration. The relative percentages of asparagine and glutamine decreased while several other amino acids increased in the juice of potatoes stored at 0°C and 24°C. Small shifts in free amino acid profile, increasing alanine, valine, aspartic acid, asparagine and arginine levels, were obtained by incubating juice from potatoes stored at 0°C without added protease while the protease produced substantial increases but with emphasis on leucine and isoleucine and phenylalanine, which increased bitterness. Since storage alone increased the concentration of single amino acids such as alanine, methionine and phenylalanine by several fold, it may be the preferred means of improving potato culls for novel flavor applications where bitterness must be minimized.