Proteolytic volatile compounds in milk and cheese of cows fed dried olive pomace supplementation

The aim of the study was to evaluate the effect of dietary inclusion dried olive pomace (DOP) on proteolytic volatile compounds in raw milk and milk cheese. Two groups of lactating cows (20 animals in each) randomly assigned to isoenergetic and isoproteic treatments provided as mixed ration (CON) and as CON with addition of 2 kg of DOP/day/animal (EXP). DOP partially replaced maize silage, alfalfa hay, sunflower and wheat. 60 days of feeding, raw bulk milk was collected, sampled, pasteurised used to produce cheese that was sampled at days 1, 7 and 30 of maturation. were analysed by solid phase microextraction (SPME) coupled gas chromatography-mass spectrometry (GC-MS) and data were expressed the relative peak area. In raw milk the phenyl-acetaldehyde and 2-phenylethyl alcohol, the only detected phenylalanine catabolites, were increased dietary treatment by 61.9 and 235%, respectively (P < 0.01). In CON EXP cheeses the compounds derived from phenylalanine, leucine and methionine were present being generally higher in EXP cheese during time. In particular, among the volatile compounds, the contents of which higher, were: the phenylacetaldehyde – 32.6% and 34% higher at days 7 30 (P < 0.01 and P < 0.05, respectively); the 2-phenylethyl alcohol – 229% at day 7 (P < 0.001), the 3-methyl-1-butanol – 299% and 59.1% higher days 7 and 30 (P < 0.001 and P < 0.05, respectively), the isoamyl butyrate – 58.2% higher at day 30 (P < 0.05) and the isoamyl isopentanoate – 290% and 60.1% higher at days 7 and 30 (P < 0.01 and P < 0.05, respectively). Dietary addition may affect aroma of dairy products, however the sensory evaluation test is needed to complete the feedback supporting industry choices.