Lipid oxidation and vitamin D3 degradation in simulated whole milk powder as influenced by processing and storage.

Vitamin D3 levels are known to sometimes decline in fortified products, which could be due to its degradation, although the exact mechanism is unknown. In this study, the influence of processing and storage conditions on lipid oxidation and vitamin D3 degradation were studied. Simulated whole milk powders with and without heat treatment were stored for 12 months at two different storage temperatures (20 °C and 40 °C).

Identification of Vitamin D3 Oxidation Products Using High-Resolution and Tandem Mass Spectrometry.

In a successful fortification program, the stability of micronutrients added to the food is one of the most important factors. The added vitamin D3 is known to sometimes decline during storage of fortified milks, and oxidation through fatty acid lipoxidation could be suspected as the likely cause. Identification of vitamin D3 oxidation products (VDOPs) in natural foods is a challenge due to the low amount of their contents and their possible transformation to other compounds during analysis.

Degradation studies of cholecalciferol (vitamin D3) using HPLC-DAD, UHPLC-MS/MS and chemical derivatization.

In any food fortification program, the stability of added micronutrients is an important factor. Cholecalciferol or vitamin D3 is known to isomerise under various conditions, thereby making its analysis challenging. In the current study, the effects of different parameters, such as temperature, iodine, acidic conditions, and oxidation, on the isomerisation of vitamin D3 were studied using HPLC-DAD and UHPLC-MS/MS.

Investigation of concentration of thiocyanate ion in raw cow's milk from China, New Zealand and the Netherlands.

Thiocyanate ion is a natural component of cow's milk (hereinafter as milk) which may be artificially augmented to activate the lactoperoxidase milk preservation system. This study presents a survey of thiocyanate levels in raw milk and proposes a naturally occurring baseline concentration of thiocyanate in milk, which is the basis for market supervision. 1669 raw milk samples from China, 270 samples from New Zealand and 120 from the Netherlands were collected in the survey.

Analysis of Vitamin D2 and Vitamin D3 in Fortified Milk Powders and Infant and Nutritional Formulas by Liquid Chromatography-Tandem Mass Spectrometry: Single-Laboratory Validation, First Action 2016.05.

A method for the determination of vitamin D2 and vitamin D3 in fortified milk powders and infant and adult nutritional formulas is described. Samples are saponified at high temperature and lipid-soluble components are extracted into isooctane. A portion of the isooctane layer is transferred and washed, and an aliquot of 4-phenyl-1,2,4-triazoline-3,5-dione is added to derivatize the vitamin D to form a high-molecular-mass, easily ionizable adduct.

Generation of semicarbazide from natural azine development in foods, followed by reaction with urea compounds.

This paper proposes a mechanism to explain the trace levels of natural semicarbazide occasionally observed in foods. The analytical derivative of semicarbazide, 2-nitrobenzaldehyde semicarbazone, is often measured as a metabolite marker to detect the widely banned antibiotic nitrofurazone. However, this marker is not specific as semicarbazide may be present in foods for several reasons other than exposure to nitrofurazone.

Lactose semicarbazone as a marker for semicarbazide adulteration in milk.

A liquid chromatography-mass spectrometry method to detect semicarbazide and lactose semicarbazone in milk was developed as part of a programme to set up methods for detecting the economically motivated adulteration of raw milk with nitrogen-containing compounds. The detection of semicarbazide was hampered by that fact that this compound tended to give broad, poor intensity peaks in the hydrophobic interaction chromatographic method employed. When spiked into milk at levels of 20-200 ppm, semicarbazide either partially or completely reacted with the matrix, which both increased the limit of detection of the method and made the setting of a threshold by using low level spikes almost impossible.

Rapid detection of economic adulterants in fresh milk by liquid chromatography-tandem mass spectrometry.

A method to aid in the detection of the economically driven adulteration of fresh milk with a range of small, nitrogen containing compounds, including melamine, ammeline, ammelide, cyanuric acid, allantoin, thiourea, urea, biuret, triuret, semicarbazide, aminotriazine, 3- and 4-aminotriazole, cyanamide, dicyandiamide, guanidine, choline, hydroxyproline, nitrate, and a range of amino acids, has been developed. (15)N2-Urea is used as an internal standard. The adulteration of milk with exogenous urea has previously been difficult to detect because of the variation in the naturally occurring levels of urea in milk.

Detection of 3-amino-1,2,4-triazine adulteration in milk using an oxidation product 3-amino-1,2,4-triazin-5(2H)-one.

A rapid liquid chromatography-mass spectrometry method to detect 3-amino-1,2,4-triazine (ATZ) in milk was developed as part of a programme to set up methods for detecting the economically motivated adulteration of raw milk with nitrogen-containing compounds. When ATZ was added to unpasteurised or pasteurised milk at levels of 10-1000 ppm, the levels declined over a period of a few days and in some cases declined below the limit of detection of the analytical method (1 ppm). ATZ did not degrade in deproteinised milk extracts, in aqueous standards or in aqueous (non-milk) controls, suggesting that degradation was mediated by a pasteurisation-resistant enzymatic or microbial process.

A rapid analytical method for cholecalciferol (vitamin D3) in fortified infant formula, milk and milk powder using Diels-Alder derivatisation and liquid chromatography-tandem mass spectrometric detection.

A method for analysing vitamin D(3) (VD3, cholecalciferol) has been established and validated. This method is rapid and cost effective and is intended for use in quality control in the manufacture of fortified infant formulae and milk powders. Milk or reconstituted milk powder was solubilised in methanol and extracted in one step into isooctane, which was separated by centrifugation.

Determination of immunoglobulin G in bovine colostrum and milk powders, and in dietary supplements of bovine origin by protein G affinity liquid chromatography: collaborative study.

An AOAC collaborative study was conducted to evaluate an affinity LC procedure for measuring immunoglobulin G (IgG) in selected dairy powders. The powders were extracted with 0.15 M sodium chloride solution and the pH was adjusted to 4.