title: Seasonal variation in conjugated linoleic acid and vaccenic acid in milk fat of sheep and its transfer to cheese and ricotta.
abstract: The seasonal variation in conjugated linoleic acid (CLA) and vaccenic acid (VA) concentrations in sheep dairy products and the extent of their transfer from milk fat to cheese and ricotta fat were investigated. Samples were collected from 2 sheep milk processing plants in North Sardinia (Italy) every 2 wk from March through June. Concentrations of fatty acids (FA) in fresh cheese and ricotta fat were primarily dependent on the fatty acid content of the unprocessed raw milk. The content of c9,t11-CLA averaged 1.73, 1.69, and 1.75 mg/100 mg of FA methyl esters (FAME), respectively, for milk, cheese, and ricotta, and differed significantly between cheese and ricotta. The content of VA averaged 3.40, 3.33, and 3.43 mg/100 mg of FAME, respectively for milk, cheese, and ricotta. The FA composition of dairy products was markedly affected by period of sampling: the mean c9,t11-CLA and VA concentration decreased from March (2.20 and 4.52 mg/100 mg of FAME) to June (1.14 and 1.76 mg/100 mg of FAME) in all dairy products. No differences in c9,t11-CLA and VA concentration of dairy products were observed between the 2 dairy companies obtaining milk from the same geographical origin. The seasonal changes in CLA and VA in milk fat were probably related to changes in pasture quality.
authors.affiliation: Dipartimento di Scienze Zootecniche, Università degli Studi di Sassari, Via Enrico De Nicola 9, 07100 Sassari, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Nudda
authors.forename: M A
authors.initials: MA
authors.lastname: McGuire
authors.forename: G
authors.initials: G
authors.lastname: Battacone
authors.forename: G
authors.initials: G
authors.lastname: Pulina
mesh_terms: D000818:Animals; D002611:Cheese / Q000032:analysis*; D005260:Female; D005511:Food Handling / Q000379:methods; D007774:Lactation / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D009829:Oleic Acids / Q000032:analysis*; D006109:Poaceae / Q000737:chemistry; D012621:Seasons; D012756:Sheep / Q000502:physiology
chemical_list: D044243:Linoleic Acids, Conjugated; D009829:Oleic Acids; C050413:11-octadecenoic acid