Hexanal as a measure of rancidity in low fat foods

Abstract and Summary The concentration of n‐hexanal in low fat, dehydrated foods can be determined in 10 min by the gas chromatographic analysis of the vapors from a 15 g sample suspended in boiling water. With 4‐heptanone as an internal standard good day‐to‐day reproducibility was obtained and the results could be expressed as ppm hexanal in the sample. The onset of rancid odors was found to occur when the hexanal concentration increased to between 5 and 10 ppm. With an oat cereal good correlation between sensory evaluations and hexanal concentration between 0.3 and 5 ppm was obtained. The rate of hexanal increase at 55 and 45 C for a corn and a wheat cereal could be reliably projected to 37 and 21 C. Antioxidants applied to a wheat cereal reduced the rate of hexanal increase.