Commercial sheep flocks – fatty acid and fat-soluble antioxidant composition of milk and cheese related to changes in feeding management throughout lactation

Abstract

Fatty acids (FAs), tocopherols and retinoids were analysed in raw milk and cheese from six commercial sheep flocks monitored from early lactation in winter to late lactation in summer. In winter, animals received concentrate and forage indoors; in early spring, animals grazed part-time on cultivated or natural valley grasslands; and from mid spring on, animals were kept outdoors constantly on mountain natural pastures. Mountain grazing in late lactation significantly increased the amount of healthy desirable unsaturated FAs such as C18:1t11 (VA), C18:2c9t11 (RA), C18:2t11c13, C18:3c9c12c15 (ALA) and C20:5c5c8c11c14c17 (EPA), and those of α-tocopherol and α-tocotrienol of milk and cheese. Stepwise discriminant analysis was applied to classify cheese samples according to seasonal feeding management. The multivariate approach was able to discriminate beyond doubt mountain cheeses from those of indoor feeding and part-time valley grazing.

Fatty acids, vitamins and cholesterol content, and sensory properties of cheese made with milk from sheep fed rapeseed oilcake

“…Table 4 shows the FA composition of bulk milk and cheese from commercial or rapeseed concentrate feeding groups. As previous studies reported, cheese FA profile was quite similar to that of milk (Valdivielso et al, 2015b). Main FA in bulk milk and cheese were C16, C18:1 cis-9, C14, C10, C18, C4, and C6.…”

“…Tocopherols and carotenoids were simultaneously extracted from feed samples as previously described using 1-step solid-liquid phase (Valdivielso et al, 2015a). Tocopherols, retinoids, and cholesterol were simultaneously extracted from milk and cheese samples using the procedures described by Valdivielso et al (2015b). Tocopherols and retinoids extracted from the different samples were simultaneously separated by normal phase-HPLC on a Zorbax RX-SIL column (25 cm × 4.6 mm i.d.…”

“…The atherogenic index significantly (P ≤ 0.05) decreased in the milk and cheese from the rapeseed concentrate group compared with the values obtained :5 cis-5,cis-8,cis-11,cis-14,cis-17 1.352 ± 0.1644 1.324 ± 0.1342 1.571 ± 0.1541 1.308 ± 0.2401 C22:6 cis-4,cis-7,cis-10,cis-13,cis-16,cis- Means with different superscripts in the same row indicate statistically significant differences between a,b bulk milk from commercial and rapeseed concentrate groups and c,d cheese from commercial and rapeseed concentrate groups (P ≤ 0.05). , where UFA was the total content of UFA, tMUFA was the total content of trans MUFA (C18:1), VA was vaccenic acid (C18:1 trans-11), CLA was the total content of conjugated linoleic acid isomers, and RA was rumenic acid (C18:2 cis-9,trans-11) (Valdivielso et al, 2015b). in commercial concentrate one (from 3.44 to 2.32 and 3.92 to 2.65 for bulk milk and cheese, respectively).…”

“…No differences (P > 0.05) were found in the total and individual content of retinoids in bulk milk and cheese between the rapeseed and commercial concentrate groups. Due to the saponification reaction used for extracting tocols, carotenoids, and retinoids in the cheese samples (Valdivielso et al, 2015b), retinol was the retinoid compound detected in cheese whereas retinyl palmitate was found in milk. As mentioned for tocols, the total content of retinoids was lower in cheese than in milk (around 31 and 37% lower in the commercial and rapeseed concentrate groups, respectively; Table 3).…”

Changes in stable isotope ratios in PDO cheese related to the area of production and green forage availability. The case study of Pecorino Siciliano

“…On the other hand, the ability to trace the feeding system could represent a benefit for cheese arising from grass-fed lactating females. Indeed, when fresh herbage represents the basis of the daily ration, a high content of healthy desirable polyunsaturated fatty acids and antioxidant vitamins has been observed in cheese [23,24] and meat. [9] To our knowledge, this is the first study in which SIR analysis has been used to discriminate the area of production within an allowed PDO area.…”