Lipolytic volatile compounds in dairy products derived from cows fed with dried olive pomace

Abstract

The study was aimed at evaluating the effects of dietary supplementation with dried olive pomace in dairy cows on the development of lipolytic volatile compounds in raw milk and cheese. Twenty dairy cows, homogeneous for milk yield, parity and days in milk, were randomly assigned to a basal diet (CON) and a conventional diet integrated with dried olive pomace (DOP) as 10% of dry matter. After 60 days of treatment, raw bulk milk of CON and DOP groups was sampled and used to produce cheese that was sampled at 1, 7 and 30 days of ripening. Volatile compounds were analyzed by the SPME-GC/MS technique. Dietary treatment influenced C6, C8, C10 and C12 free fatty acids, the short-chain ethyl and methyl esters, many of ketones and γ- and δ-lactones in raw milk. Cheese showed main differences between groups after 7 days of aging. Levels of methyl decanoate and ethyl esters of even fatty acids from C4 to C14, as well as 2-heptanone, 6-dodecen-γ-lactone, octanal and some C9 secondary lipolytic catabolites such as 8-nonen-2-one, 2-nonanone and 2-nonenal were higher in DOP cheese. The γ-dodecalactone, δ-octalactone, 2-octenal and 1-hexanol were higher in the experimental cheese at 30 days of ripening. DOP dietary integration in feeding operations of dairy cows may modify the evolution of volatile compounds derived from lipolysis in milk and cheese toward moldy and peach notes. A sensory evaluation of these changes will be necessary to understand the consumer acceptability that represents an important feedback to drive dairy industry choices.