Antioxidant status and odor profile in milk from silage or alfalfa-fed cows

ROSSETTI, L; LANGMAN, L; G. GRIGIONI; BIOLATTO A; SANCHO A,; COMERON, E; DESCALZO, A

Melbourn Australia

Congreso; IDF/DIAA Functional Dairy Foods 2009; 2009

Dairy Association of Australia

In order to determine feeding differences on natural antioxidant vitamin delivery, two contrasting diets: alfalfa (ALF) and sorghum silage (SS) were analysed. Diets showed different profiles for fat-soluble vitamins. ALF was higher in a-tocopherol, b-carotene, and retinol than SS diet. On the contrary, silage diet was higher in ã- and ä- tocopherol due to the soy expeller contribution in these isomers. ALF diet favored higher milk production and protein yield in comparison to SS, whereas fat content was the opposite (P< 0.01). Composition of diets was partially reflected in milk. ALF diet favored the incorporation of a-tocopherol, retinol, b-carotene and vitamin D3 into raw milk. Meanwhile, a less abundant isomer of vitamin E, g-tocopherol, was significantly higher in SS than in ALF milk and ä-tocopherol was not detected. In addition, ALF diet also promoted higher antioxidant activity. Ferric reduction antioxidant power (FRAP) was significantly higher in ALF than in SS milk, however oxidation determined by thiobarbituric acid reactive substances (TBARS) was similar for both types of milk. Also no differences in ascorbic acid concentration were detected in either types of milk. ALF or SS milk were clearly separated (100%) by their antioxidant status and odor profiles as a function of feeding into SS and ALF groups when biochemical variables and sensor LY2/gCTI were analyzed together. Two linear Fischer’s discriminant functions were defined according to dietary treatments using b-carotene and sensor LY2/gCTI. The success rate of correct classification of each sample was of 100% either for the original cases or after cross-validation (P<0.0001). The use of an electronic nose proved to be a useful instrumental method to discriminate the odor profile of milk samples with different antioxidant status.