An attempt to minimize potassium sorbate concentration in sponge cakes by modified atmosphere packaging combination to prevent fungal spoilage Original Research Article

The combined effect of modified atmosphere packaging (MAP) and potassium sorbate (PS) on the preservation of a typical Spanish cake (sponge cake) was studied. A full factorial experiment design including other factors, such as water activity (aw) (0.80, 0.85 and 0.90) and pH (6 and 7.5) was applied. Eurotium amstelodami, E. herbariorum, E. repens and E. rubrum colony radii were measured daily for 28 days. All different combinations of PS concentration and MAP were more effective at pH 6 than at 7.5. As aw increased, the amount of PS or carbon dioxide (CO2) necessary to prevent or delay fungal growth increased. The antifungal activity of PS could be improved by packaging in a suitable modified atmosphere (MA). At pH 6, 0.1% of PS effectively prevented mould spoilage upto 28 days in the entire aw range, by combining with 50–70% CO2 level. On the other hand, 0.2% of PS in 30% N2:70% CO2 MA packages prevented spoilage of neutral cake analogues at all aw levels. Control air-packaged bags with 0.2% of PS showed visible growth after 6 days, at pH 6 and 0.90 aw. If no MAP was used, low aw was the main preservation factor.