Sensory properties of meat and dairy products are affected by the forages consumed by the animals

Abstract

The nature of forages ingested by ruminants is one of the factors of variation of sensory properties of dairy products and meats. Recently, the effect of this factor was underlined, particularly for the PDO products. For these products, animal feeding is one of the elements that link the product to the ’terroir’.

Grass conservation as silage does not seem to affect cheese sensory properties when the silage is done properly, except for the colour which tends to be more yellow when the animals are fed silage. Contrarily when the animals graze grass, the cheeses have a more intense colour, flavour and odour, compared to winter rations based on hay and silage. The botanical composition of grass has an effect on cheese sensory properties. The most important differences regard texture, mainly in cooked type cheeses when cows graze in pastures with a great biodiversity.

These sensory differences can be due to milk constituents coming directly from animal food. This is the case of carotenoids, responsible for the yellow colour of dairy products, and abundant in green forages. The differences can also be due to milk constituents that the animal produces which are different with different feeds. This is the case of the plasmin content of milk or fat composition that can affect cheese texture.

Meat from animals grazing grass is darker and tougher than meat from animals given concentrates. This effect can be partially linked to the ultimate pH (for the colour), to the age at slaughter (generally higher for animals grazing grass), to the carcass fatness and to the intramuscular fat content (higher for animals given concentrates). Grass feeding also affects meat flavour. This effect is probably linked to an increase of skatole and its interaction with branched chain fatty acids. Also animals grazing grass have a higher proportion of linolenic acid in their fat. Some products of oxidation of linolenic acid are responsible for the pastoral flavour of meat.