Influence of dietary grape pomace supplementation on chemical and sensory properties of ewes' cheese

The nutritional and sensorial properties of Pecorino cheese made from milk of ewes fed a diet formulated with grape pomace (GP), a winemaking by-product, were evaluated. Dietary inclusion of GP (GP+) did not influence cheese moisture or total lipid content; however, a significant reduction of C14:1 cis-9 was noted, assumed to be a dietary effect on stearoyl-CoA desaturase function. The amount of β-casein was increased in GP+ samples, but total and TCA soluble fraction nitrogen did not indicate any marked effect on the proteolytic processes. Analysis of volatile compounds showed lower relative percentages of aldehydes, ketones, esters and lactones in GP+ cheeses, indicating improved oxidative stability during ripening. There was a marked decrease of lightness and an increase of hardness, gumminess and resilience (Young's modulus) in the GP+ samples. Sensory analysis of 120-day ripened cheeses confirmed these findings, and highlighted an increase in odour intensity and saltiness.