Water activity and Hunter colour values of beef patties extended with Samh (Mesembryanthemum forsskalei Hochst) flour

Ground beef patties with or without 3.5% soy protein concentrate (SP), 10 and 20% Samh (Mesembryanthemum forsskalei Hochst) flour (SF) were packaged in foam trays, over-wrapped with polyvinyl chloride (PVC) film and displayed refrigerated at 3±1°C in a retail case for 0, 2 and 5 days. At the end of each displaying period, different raw patty characteristics were studied. Initially, i.e. day 0 of display, ash content of the patties increased significantly (P < 0.05) with the extension of the beef patties with SP or SF. On the other hand, moisture content and water activity (aw) decreased (P<0.05) as a result of the addition of SP or SF to the beef patties. SF was more effective in reducing aw than SP. Hunter colour a* value and saturation index (SI) decreased with the incorporation of SP or SF in the beef patties; however, Hunter colour L* and b* values showed no or minimal changes with such incorporation of SP or SF. Saturation index (SI) and hue angle decreased and increased, respectively, with the extension of the beef patties with SF or SP. Irrespective of the treatments, most of the parameters mentioned above were significantly (P<0.05) affected by the display period.