Changes in the chemical and physical characteristics of cow’s milk butter during storage: Effects of temperature and addition of salt

Abstract

The effect of storage at 4°C or 12°C on cow‘s milk butter manufactured without or with salt (2.1%) was examined. Storage of the butter for 9 months scarcely affected the fatty acid contents, and only the amounts of C18:3 n–3, C20:5 n–3 and C22:2 n–6 decreased significantly in the total lipid fraction. The total amount of free fatty acids increased significantly during storage (from 136–167 to 360–575mg/100g of fat), and both the addition of salt and the higher storage temperature enhanced the release of fatty acids from lipids. The free fatty acid contents (360–575mg/100g of fat) and the values of the parameters indicating lipolysis (acidity value: 1.89–2.18mg KOH/g of fat; degree of acidity: 0.95–1.09% oleic acid) at the end of the storage period indicate that butter undergoes very slight lipolysis. The values of parameters indicating fat oxidation (peroxide value and TBA value) increased significantly during storage (from 0.38–0.39 to 0.90–3.75meq. O2/kg of fat, and from 0.084–0.1 to 0.093–0.220mg malondialdehyde/kg, respectively), and both the addition of salt and the increase in storage temperature had enhancing effects on the oxidative processes. The b* values increased significantly during storage, while a* and L* values decreased. In conclusion, cow’s milk butter was hardly modified during refrigerated storage, while both the addition of salt and the increase in storage temperature increased lipolytic and oxidative changes.