Effects of Dietary Supplements of DHA-enriched Micro Algae Diet on Physical and Technological Properties of Dairy Cow Milk Fat

Abstract

This study examined the effect of dietary supplementation of DHA-enriched micro algae diet on physical and technological properties of dairy milk fat in terms of the dynamic crystallization and melting behaviour. Two dairy cows were subjected to feeding regime of DHA-enriched micro algae diet and control diet. The experiment was carried out during 21-d to determine the normal (control) and DHA-enriched micro algae diet modified milk fat that were taken for further analysis. The melting and crystallization behaviour of the milk fat from the cows fed control and DHA-enriched micro algae diets was studied using differential scanning calorimetry (DSC), Q1000 (TA Instruments, New Castle, DE, United States). DHA-enriched micro algae supplementation strongly affected the melting and crystallization properties of milk fat. Generally, the onset temperature (°C) of milk fat crystallization was significantly lower in DHA-enriched milk fat as compared to the control. The quantity of heat released by fat crystallization expressed as J/g (peak area) was significantly lower in enriched milk fat. DHA-enriched milk fat also had a lower peak maximum temperature as compared to control in all samples investigated. All melting curves displayed two peaks (lower melting and higher melting peaks) and for melting peaks, DHA-enriched milk fat melted at significantly lower temperature as compared to the control indicating an increase in the degree of unsaturation of milk fat. Melting offset temperature was significantly lower for DHA-enriched milk fat as compared to the control. It can be concluded that from the results of this study, micro algae supplementation significantly altered the milk fat composition and positively affected melting and crystallization behaviour of milk fat.