Significance of the Nonvolatile Minor Compounds of the Neutral Lipid Fraction as Markers of the Origin of Dairy Products

Abstract

In the past few years several researchers have approached the problem of traceability of dairy products mainly by examining the volatile compounds that could be transferred from forage into milk and cheese. Our research focused on the study of the composition of the nonvolatile minor components of the neutral lipid fraction in mountain dairy products, obtained from animals feeding on pasture, and in milk and cheese samples produced from cows under intensive breeding, fed with concentrates and silages. Hydrocarbons were separated by silica gel column chromatography from the whole lipid matrix and analyzed by GC/MS. Among all the compounds detected, 1-phytene, 2-phytene, neophytadiene, and to a lesser extent the esters of phytol with C16 and C18 fatty acids seem to be promising tools for the recognition of the feeding system. The value of the sum of isoprenoid hydrocarbons (summation operator-hyd) of mountain dairy products (12.3-34.0 mg/kg) was always higher than that obtained from plain samples (1.3-6.4 mg/kg).

Hydrocarbon and Fatty Acid Composition of Cheese As Affected by the Pasture Vegetation Type

“…Among all of the compounds detected, linear and isoprenoid hydrocarbons and phytyl esters were taken into account, because in a preliminary work they had shown interesting correlations with the feeding. 11 Isoprenoid hydrocarbons are plant secondary metabolites, biosynthetically formed by condensation of isoprene units. Squalene, as well as phytol derivatives, such as 1-phytene, 2-phytene, phytane, and neophytadiene, are the main components of this class of compounds in milk fat.…”

“…Phytyl esters were previously identified. 11 The quantification of the compounds was performed by relating the peak abundance to that of squalane (internal standard), and the amount was expressed as milligrams per kilogram of fat.…”

“…7,9,10 A different approach to the traceability issue takes into account the nonvolatile hydrocarbon compounds present in the neutral lipid fraction of fat. In a previous paper 11 the suitability of both isoprenoid hydrocarbons and esters of isoprenoid alcohols for the discrimination between lowland and highland dairy products was shown. In particular, 1-phytene, 2-phytene, and neophytadiene seemed to be promising markers of the origin of dairy products.…”

Effect of time at pasture and herbage intake on profile of volatile organic compounds of dairy cow milk

“…Because diterpenoids in the milk were related to HI and the diet from mountain areas was richer in fresh herbage than in lowlands, Povolo et al . () proved that the sum of the contents of 1‐phytene, 2‐phytene and neophytadiene of milk and cheese from mountain areas was always higher than that obtained from farms under an intensive farming system. They proposed the value of this sum as a marker for the traceability of mountain dairy products.…”

“…Povolo et al . () reported that milk and cheese samples of mountain origin were characterized by higher amounts of molecules of 1‐phytene, neophytadiene, and 2‐phytene than those of plain origin because the diet in mountain areas was richer in fresh herbage than in lowlands. In our study, there was no significant difference in the relative intensity of 1‐phytene, 2‐phytene and neophytadiene in milk between NG and G4.…”