How ruminant diet changes cheese aroma: a review of pasture, plant by-products and mineral supplements, their effects on volatile compounds, and the limits imposed by cheesemaking, ripening and sensory perception.
Main question: How does the diet of milk-producing cows, sheep and goats alter the volatile compounds that develop in cheese, and through which biochemical pathways? This 2020 review brings together evidence on pasture, conserved forage, plant by-products and trace-element supplementation.
Diet can influence aroma by changing milk composition and the substrates available during ripening, as well as microbial and enzyme activity. The review follows the breakdown of fat and protein, alongside lactose, lactate and citrate metabolism, into acids, aldehydes, lactones, ketones, alcohols and esters. Some plant-derived compounds may also reach milk more directly.
The reported effects are specific to the feeding treatment and cheese. Grape pomace and liquorice supplementation reduced selected short-chain fatty acids in some trials, while zinc supplementation increased butanoic and hexanoic acids in certain dairy products. Zinc and selenium were associated with increased concentrations of particular lactones in Caciotta; zinc also increased several lactones and ethyl esters in ripened Caciocavallo. Proposed explanations involving bacterial autolysis and lipase activity remain hypotheses.
Pasture composition can change the volatile profile. Ragusano made from milk of cows receiving native pasture alongside a total mixed ration contained eight aroma-active compounds absent from the comparison cheese. In a Montasio study, different alpine pastures altered ketones, phenolic compounds and terpenes, but the sensory differences detected by the tasting panel were slight.
Cheesemaking can modify or remove dietary effects. In one olive-pomace trial, differences in free fatty acids, esters and ketones measured in raw milk disappeared after pasteurisation and cheesemaking. Starter cultures and ripening conditions therefore matter alongside the feed itself.
The central finding is that feeding strategy can alter cheese aroma chemistry, but the evidence does not establish a universal route from a particular feed to a predictable flavour. Compound concentrations alone do not demonstrate improved taste or consumer preference. The authors call for better understanding of direct feed-to-milk transfer, interactions with the cheese matrix and the combined sensory effects of volatile compounds.
Source: Ianni, A.; Bennato, F.; Martino, C.; Grotta, L.; Martino, G. (2020). Molecules, 25(3), 461. DOI: 10.3390/molecules25030461. Published 22 January 2020.
The attached article is reproduced unchanged under the Creative Commons Attribution 4.0 licence (CC BY 4.0). The text above is a summary of the review. Original article: https://doi.org/10.3390/molecules25030461. Licence: https://creativecommons.org/licenses/by/4.0/.