Rapid hexanal analysis: A key tool in food product development

Oxidized lipids have a characteristic rancid smell for which the human nose is very sensitive. Controlling this smell is crucial in the development of all fatty foods. With the current desire to move to more unsaturated fats and the parallel interest in reducing the use of anti-oxidants, this becomes increasingly difficult. Although the rancid smell of oxidized lipids can be caused by many compounds, for the most widely used lipids hexanal is one of the main causative molecules. Hexanal development over time usually follows an exponential curve. In the incubation period hexanal levels are low, whereas after an onset point they increase rapidly. The extent to which this onset point is delayed is an important measure for the efficacy of an antioxidant, or for the protective properties of a novel packaging material.

Here we describe a very fast GC-MS method that allows measuring hexanal levels in various food systems within 2 minutes. Additionally, a model system for studying natural anti-oxidants consisting of salt and sunflower oil as a mimic of dry powdered soups or sauces is proposed. The application of the new fast GC-MS strategy to assess lipid-oxidation deceleration factors of novel, natural anti-oxidants is demonstrated. Other applications using the rapid GC-MS hexanal method in e.g. comparing packaging materials will be discussed as well.