Premium
Concentrations of Volatile 4‐Alkyl‐Branched Fatty Acids in Sheep and Goat Milk and Dairy Products
Author(s) -
Kaffarnik Stefanie,
Kayademir Yasemin,
Heid Carolina,
Vetter Walter
Publication year - 2014
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12673
Subject(s) - flavor , food science , chemistry , sheep milk , milk fat , context (archaeology) , fatty acid , biology , biochemistry , paleontology , linseed oil
Goat and sheep milk and dairy products thereof are characterized by a strong and unique flavor. In this context, the volatile minor fatty acid 4‐ethyloctanoic acid plays a prominent role along with 4‐methyloctanoic acid when both are present in free form. Using a novel GC/MS method in the selected ion‐monitoring mode, previously developed for sheep subcutaneous adipose tissue, we were able to analyze the total concentrations of these flavor‐relevant minor fatty acids as methyl esters in goat and sheep milk as well as in their products. Differences between the concentrations and ratios of 4‐methyloctanoic acid and 4‐ethyloctanoic acid in goat milk ( n = 4), goat cheese ( n = 4), sheep milk ( n = 2), and sheep cheese ( n = 4) were observed. Goat milk and cheese resulted in higher concentrations for both fatty acids (190 to 480 μg/g milk fat) and smaller 4‐Me‐8:0 to 4‐Et‐8:0 ratios (1.4 to 2.7) compared to sheep milk and cheese (78 to 220 μg/g milk fat; 4‐Me‐8:0 to 4‐Et‐8:0 ratio: 15 to 42). In all samples, the concentration of 4‐Me‐8:0 exceeded the one of 4‐Et‐8:0. However, due to its lower flavor threshold value the contribution of 4‐Et‐8:0 to the flavor was generally >76%. The calculated flavor values were >1400 for goat milk and cheeses and >200 for sheep milk and cheeses. In goat milk and its products, only a proportion of <0.1% 4‐alkyl‐branched fatty acids present in free form in the goat milk and <0.5% in the sheep samples would be sufficient to generate the characteristic goaty flavor. Parameters that promote or prevent the release of 4‐Me‐8:0, and especially 4‐Et‐8:0, will be decisive for the flavor in the resulting dairy product.