Hay or silage? How the forage preservation method changes the volatile compounds and sensory properties of...

The aim of this study was to determine the effect of the forage preservation method (silage vs. hay) on volatile compounds and sensory properties of a traditional Caciocavallo cheese during ripening. A brown-midrib sudangrass hybrid was cultivated on a 7-ha field and at harvesting it was half ensiled in plastic silo bags and half dried to hay. Forty-four lactating cows were equally allotted into 2 groups fed a isonitrogenous and isoenergetic total mixed ration containing as the sole forage either sorghum hay (H group) or sorghum silage (S group). Milk from the 2 groups was used to produce 3 batches/diet of Caciocavallo ripened for 30, 60, and 90 d. Milk yield and composition as well as cheese chemical and fatty acid composition were not markedly affected by the diet treatment and ripening time. By contrast, ripening induced increased levels of the appearance attribute "yellowness," along with the "overall flavor," the odor/flavor attributes "butter" and "hay," the "salty," "bitter," and "umami" tastes, and the texture attribute "oiliness," whereas the appearance attribute "uniformity" and the texture attribute "elasticity" were reduced. The silage-based diet induced higher perceived intensities of several attributes such as "yellowness"; "overall flavor"; "butter"; "grass" and "hay" odor/flavors; "salty," "bitter," and "umami" tastes; and "tenderness" and "oiliness" textures. In S cheese we also observed higher amounts of ketones and fatty acids. Conversely, H cheese showed the terpene α-pinene, which was not detected in S cheese, and a higher intensity of the appearance attribute "uniformity." These differences allowed the trained panel to discriminate the products, determined an increased consumer liking for 90-d ripened cheese, and tended to increase consumer liking for hay cheese.