Investigation of the presence of ß-hydroxy-ß-methylbutyric acid and α-hydroxyisocaproic acid in bovine whole milk and fermented dairy products by a validated liquid chromatography-mass spectrometry method.

ABSTRACT

A simple, rugged, quantitative, and confirmatory method based on liquid chromatography-mass spectrometry was developed and comprehensively validated for the analysis of the leucine metabolites ß-hydroxy-ß-methylbutyric acid (HMB) and α-hydroxyisocaproic acid (HICA) in bovine whole milk and yogurt. Mean accuracy (90-110% for HMB and 85-115% for HICA) and total precision (<10% RSD in most cases, except for <20% RSD for HMB at the limit of quantitation) at four concentration levels across three validation runs have been determined. Limits of quantitation for HMB and HICA in whole milk were 20 and 5 µg/L, respectively. Measured concentrations of HMB and HICA were <20-29 and 32-37 µg/L, respectively, in bovine whole milk and <5 and 3.0-15.2 mg/L, respectively, in yogurt. These concentrations are insufficient by large margins to deliver any musculoskeletal benefits, and fortification of milk and dairy products with HMB and/or HICA appears to be justified.