14B-19

J. LI¹, H. Li², 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: GC is a common approach for analysis of volatile compounds, but it is difficult to extract and concentrate the volatile aldehydes and acids for GC analysis. The extract of potato chip by organic solvent will mainly contain high boiling point components, such as lipid, which will interfere with GC analysis. Headspace solid phase microextraction could be used to extract volatile compounds directly for GC analysis.

OBJECTIVES: Our study is to utilize SPME and GC to analyze the low molecular weight aldehydes and fatty acids in two different kinds of potato chips, plant oil fried potato chip and olestra fried potato chip. The storage of potato chip varied from 0 week to 8 weeks at the elevated temperature of 40 ^oC.

METHODS: Fresh potato chip were put into 40^oC oven for 0-8 weeks and then moved to a freezer until analysis. 30.0 gram of potato chip sample was grandered and put into a bottle. The SPME was used to extract the headspace volatiles. The extraction condition was at 60 ^oC for 60 minutes. GC-MS and GC were used for qualification and quantification purpose.

RESULTS: Seven aldehydes and four fatty acids were identified by GC-MS as propionaldehyde, isobutyraldehyde, butyraldehyde, isovaleraldehyde, 2-methylbutyraldehyde, valeraldehyde, hexanal, acetic acid, propionic acid, butyric acid, and valeric acid. In classical potato chip, hexanal reach the maximum level at fifth week to 62 ppm, while other aldehyde content did not change much and the maximum concentration were less than 8 ppm. In olestra potato chip, the aldehyde concentrations were much lower than corresponding values in classic potato chip.

SIGNIFICANCE: Our results indicate that SPME could be a very convenient and fast method for the analysis of trace volatile compounds in lipid containing foods like potato chip.