Research concerning physicochemical changes and freshness indicators of milk fat during storage

Abstract

Physicochemical characteristics and freshness indicators of cow butter during refrigeration (2 ... 4oC) and freezing (-15 ...- 18oC) storage were studied. Alteration (hydrolysis and oxidation) of food is responsible for the degradation of sensory quality, nutritional value and even formation of toxic substances such as peroxides, requiring intimate knowledge of the process and consequently taking appropriate measures to avoid losses that can be registered. Changes in freshness parameters and alterative processes installation, when butter becomes improper for consumption were also studied, inducing fatty acid content, acidity, peroxide value (PV), iodine value (IV) and the presence of epyhidrinic aldehyde. There was an increase of titrable acidity during storage; butter hydrolysis was installed after 15 days under refrigeration and after one month under freezing conditions. Hydrolysis processes are installed more quickly in terms of refrigeration and freezing than oxidative processes, being intensified by a higher water content in product and by hydrolytic enzymes presence. Results showed that butter was resistant to oxidation, advanced oxidation being installed after 6 months in chilled butter and after 9 months in frozen butter.