Oxidative stability of snack and cereal products in relation to moisture sorption

A collection of snack and cereal products including peanuts, pork scratchings, a mixture of rolled oat and wheat from muesli and oatmeal have been characterized in terms of the relationship between storage humidity and stability against lipid oxidation. The products were stored above various saturated salt solutions in an atmosphere corresponding to ambient air. The development of free radicals, hexanal and water content was monitored during the storage. For oatmeal, muesli-mixture and pork scratchings an optimal humidity existed at which the oxidation rate constant was minimal. Furthermore, the humidity was concluded to be an important packaging parameter for oatmeal and muesli as a large difference between minimal and maximal oxidation rate constant was observed. The optimal humidity with respect to oxidative stability did not coincide with the BET-monolayer value. The radical content was very dependent of the relative humidity as an increased humidity resulted in decreased radical content.