composition is an important trait for the goat dairy industry because of its influence on cheese yield andthe organoleptic properties of dairy products (Chilliard et al., 2003). Goat milk is particularly rich insaturated fatty acids (SFA) whereas monounsaturated (MUFA) and polyunsaturated (PUFA) FA are lessabundant (Fontecha et al., 2000).The aim of this work was to provide new data to better understand theinfluence of polymorphism at casein loci on fatty acid profile in Girgentana goat milk.One hundred lactating Girgentana goats, homogeneous for milk production, days of lactation, body weightand diet were used. The procedure was developed using individual raw milk samples, collected in threedifferent stages of lactation: (October, February and June) from individuals with known genotypes at caseinloci. Were analyzed animals with A*A*, B*B*, A*B*, FF, A*F, B*F, A*E, EF, FN, NN and A*N genotypes(where A* indicates A, G, I, and H alleles while B* indicates B1, B2, B3, B4 and C alleles) at αs1‐casein; CC,AC, A0', AC', C0', CC', and C'C' genotypes at β‐casein; AA, AC, AF, CF, EF and FF genotypes at αs2‐casein; andAA, AB, AD, AN, BB, BD, BN, DD and D'G genotypes at κ‐casein. Milk samples were prepared following theRose‐Gottlieb’s method (1996) for FA extraction. For transesterification of the lipids KOH in methanol 2 Nwas used and thereafter the fatty acid methyl esters (FAMEs) were analyzed with a chromatographicmethod (Sağdiç et al., 2003).The determination of the fatty acid profile was performed by gaschromatography SHIMADZU GC‐2010 with flame ionization detector (GC‐FID). The FAMEs were injectedinto a capillary column (Zebron ZB‐WAX Plus 30m x 0:32 mm id, 0.2 mM film), identified according to theretention times and quantified by calibration curves. The results of fatty acid were expressed as g/100gtotal fat.Data set was analyzed using GLM procedures for repeated measure of SAS System v9.2.For almost all the fatty acid the environmental factors flock and month of sampling showed statisticallysignificant differences. Among all the fatty acids investigated only two showed statistically significantdifferences between genotypes for κ‐casein, in particular C18 (stearic acid) and C18:01 (oleic acid). For αs1‐, αs2‐ and β‐casein were not found statistically significant differences.The results showed that genetic polymorphisms at casein genes, in particular at κ‐casein, have importanteffects on goat milk fat and FA composition, especially for MUFA and PUFA, which are potentially involvedas positive factors in the health of human consumers.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2013|