The influence of fat on the deterioration of food aroma in model systems during storage

Storage studies (30 and 45°C) determining the stability of selected, aroma compounds (50 ppm) in the presence of simple microcrystalline cellulose (MCC) (with or without 5% vegetable oil and water activities of 0.11, 0.33, 0.53 and 0.76) were conducted. MCC was found to exhibit substantial aroma compound binding. Binding appeared to be strongly dependent on water activity with the binding being less at higher water activities and appeared to reach a maximum at an Aw of approximately 0.33. Aroma compounds varied greatly in terms of storage stability in the presence of our two model systems. Furfurylmercaptan, pyrrole, 1-methylpyrrole, 2,4-hexadienal and ethyl-2-mercaptoproprionate were found to be very unstable during storage (listed in decreasing order of loss). The inclusion of oil in the model systems invariably increased the stability of the aroma compounds studied although sometimes losses were so rapid that the effect was small. The degree of increase in stability in the presence of oil was dependent upon the aroma compound studied.