The objective of this study was to evaluate the fatty acid (FA) profile, nutritional quality and oxidative stability (OE) indexes of butter obtained from milk of cows fed sugar cane-based diets containing increasing levels of sunflower oil (SO): 0 (Control); 1.5; 3.0 and 4.5% of diet DM. The butter FA profile was analyzed by gas chromatography and OE was determined using the Rancimat® equipment (model 743) operated at 120ºC and air flow of 20 L/h. The concentrations of rumenic acid (cis-9 trans-11 CLA), vaccenic acid (trans-11 C18:1) and oleic acid (cis-9 C18:1) in butter fat were increased by 867, 687 and 148%, respectively, as the dietary SO level increased from 0 to 4.5%. In contrast, the concentrations of medium chain saturated FA were linearly reduced (P<0.05) in butter fat from cows fed increasing levels of SO. Regarding the butter nutritional quality, a linear decrease (P<0.0001) in atherogenicity and thrombogenicity indexes and a linear increase (P<0.0001) in the hypocholesterolemic/ hypercholesterolemic ratio were observed compared to control, 1.5, 3.0 and 4.5% SO, respectively. Consistent with the increased (P<0.0001) concentration of mono and polyunsaturated FA, the OE of butter fat was linearly reduced (P<0.0001) as the dietary SO level increased. It was concluded that diet supplementation with SO improved the nutritional quality of butter fat of Holstein x Gir dairy cows as a result of positive changes in milk FA profile. However, these changes in milk FA composition were accompanied by a reduction in the SO of butter, which in turn is associated with a shorter shelf life.
fatty acid; CLA; oxidative rancidity; dairy product; human health
