14B-18

J. LI¹, H. Li², N. Zhu¹, and C. T. Ho¹. (1) Food Science, Rutgers University, 27 Marvin Lane, Piscataway, NJ 08854, (2) Chemistry Department, Beijing Normal University, Beijing, 100875, China

JUSTIFICATION: Volatile aldehydes are important Maillard reaction intermediates in potato chip. Among them, hexanal is the characteristic lipid oxidation product, which is key factor for the off flavor in most lipid rich foods. Due to the high volatile and reactive characteristics of low molecular weight aldehydes, it is difficult to extract and analysis those compounds from foods. The reaction between cysteamine and carbonyl group containing compounds will quantitatively produce thiazolidines at neutral pH and relatively low temperature. This could be a breakthrough for the analysis of volatile aldehydes from oil containing foods like potato chip.

OBJECTIVES: Our research work is to utilize the quantitative reactions between cysteamine and aldehydes to quantify the aldehyde contents in potato chips through out the storage time.

METHODS: After storage, potato chip was reacted with cysteamine at optimized reaction conditions. The reaction product was extracted by LN distillation with methylene chloride. GC-MS and GC were used to identify and quantify the thiazolidine formed during the cysteamine reaction. Standards of thiazolidines were synthesized as the reference for GC-MS and GC analysis.

RESULTS: The most significant aldehyde compounds identified in potato chip are formaldehyde, acetaldehyde, propionaldehyde, isobutyraldehyde, butyraldehyde, isovaleraldehyde, 2-methylbutyraldehyde, valeraldehyde hexanal, heptanal and 3-methylthiopropionaldehyde. The concentration of hexanal, the representative lipid oxidation product, was much higher in the classic potato chip than in the olestra potato chip that contained less fat. Different aldehyde exhibited different changing trend during the storage time. Each of them had similar trend in classic potato chip comparing to olestra potato chip, except for hexanal.

SIGNIFICANCE: The reaction of cysteamine with aldehyde was successfully utilized in the analysis of aldehydes in potato chip. The interesting finding of the aldehyde trend during the storage may indicate their correlation and their reaction mechanism.