Stable Isotope Characterization of Milk Components and Whey Ethanol

Abstract

A multi-isotopic study of several components of milk has been carried out on commercial samples and on milk produced in feeding experiments involving different kinds of diets originating from C(3) or C(4) photosynthetic metabolisms and exhibiting a relatively wide range of isotope ratios. The dispersion of the carbon, hydrogen, and nitrogen isotope parameters of dried matter and of the lactose, protein, and lipid components has been estimated. In addition, the carbohydrates were represented by the site specific isotope ratios (SNIF-NMR) of ethanol resulting from standardized fermentation of lactose. The rates of response of the isotopic parameters to changes in the feeding materials is slower for the minor components, proteins, and lipids than for lactose and ethanol. For similar diets, the nonexchangeable sites of lactose and the methyl site of ethanol, in particular, are relatively enriched in deuterium in the case of polygastric animals, cow, goat, and ewe, as compared to the monogastric species, sow and mare, and woman. From an analytical point of view, the carbon and hydrogen parameters of ethanol provide efficient criteria for identifying a whey origin with respect to other agricultural and fossil sources.

H, C, N and O stable isotope characteristics of alpine forage, milk and cheese

“…1b) (Martinelli, Victoria, Trivellin, Devol, & Richey, 1992;Yoneyama, Yamada, Kojima, & Yazaki, 1984), in agreement with values reported in the literature (Knobbe et al, 2006;Martinelli et al, 1992;Steele, Bonish, Daniel, & Ohara, 1983 Camin et al, 2004Camin et al, , 2008Knobbe et al, 2006;Masud et al, 1999;Steele & Daniel, 1978 (Camin et al, 2008;Knobbe et al, 2006). Casein d 15 N between 2.5& and 4.2& confirmed the maximum limit of 4& for mountain dairy products.…”

“…The d 13 C values in casein were 2.9 (AE0.3)& and 4.2 (AE0.4)& higher than in forage for AV and MDS respectively. In the literature, an increase in the value of d 13 C passing from the diet to the animal product in the range of 1e4& is reported for milk from grass-fed cows, while maize feeding results in a decrease of up to À4& (Camin et al, 2004(Camin et al, , 2008Knobbe et al, 2006;Masud et al, 1999;Metges et al, 1990;Minson et al, 1975). The increase in MDS d 13 C could be related both to isotope fractionation during feed protein conversion into animal and milk protein, and to maize supplementation, which is known to have a significantly higher 13 C content (À12 to À14&).…”

“…C isotope ratio (expressed as d 13 C) of milk and cheese components is related to the quantity of maize, which is an important constituent of cows' diet in many countries, especially in intensive breeding systems, but is often also used for energy supplementation in other dairy systems. Maize is a C4 plant with higher (Camin et al, 2004(Camin et al, , 2008Crittenden et al, 2007;Knobbe et al, 2006;Kornexl et al, 1997;Masud, Vallet, & Martin, 1999;Metges et al, 1990;Minson, Ludlow, & Troughton, 1975;Molkentin, 2009;Molkentin & Giesemann, 2007;Sacco et al, 2009). Each 10% increase in maize content in the diet corresponds to a 0.7e1.0& increase in the d 13 C of casein and a d 13 C maximum threshold value of À23.5& is suggested for milk casein, above which the presence of maize in the diet cannot be excluded (Camin et al, 2008).…”

Determinação da origem biossintética de ácido acético através da técnica "Site Specific Natural Isotopic Fractionation Studied by Nuclear Magnetic Resonance (SNIF-NMR)"

“…Essa adição não se configura necessariamente em uma fraude, uma vez que é permitida dependendo das condições climáticas para uma determinada safra 2 . A técnica SNIF-NMR também tem sido utilizada para averiguar a adição de açúcares não declarados em outros produtos além do vinho 3,4 , como por ex., em sucos de frutas 5-7 , mel 8 , tequila, entre outros [10][11][12][13][14] . Sua aplicação consiste nas medidas conjuntas de ressonância magnética nuclear e de espectrometria de massas, sendo que a primeira determina a relação isotópica H da metila do etanol, produzido a partir do processo de fermentação do suco, e comparada com a de outros produtos.…”

“…, entre outros [10][11][12][13][14] . Sua aplicação consiste nas medidas conjuntas de ressonância magnética nuclear e de espectrometria de massas, sendo que a primeira determina a relação isotópica H da metila do etanol, produzido a partir do processo de fermentação do suco, e comparada com a de outros produtos.…”