A novel method for quantification of lactose in mammalian milk through HPTLC and determination by a mass spectrometric technique

Abstract

Lactose molecules are disaccharides and the basic core unit of sugars (oligosaccharides), and are enriched in mammalian milk. Lactose plays multiple roles in the health of neonates, by stimulating the growth of selected beneficial bacteria in the gut, and participating in the development and growth of newborns. All mammalians produce lactose with oligosaccharides (LOS) in different concentrations during their lactation period. In this study, we present a novel high-performance thin-layer chromatography (HPTLC) method for the estimation of lactose concentration present in milk of different mammalians, viz. mare (Equus caballus), cow (Bos primigenius indicus), buffalo (Bubalus bubalis), camel (Camelus dromedarius) and donkey (Equus asinus). Separation and quantification were achieved using the ternary mobile phase of n-butanol–glacial acetic acid–water (75 : 10 : 15 v/v/v) on precoated silica gel 60F₂₅₄ aluminium plates; lactose standard in milk samples was also confirmed by mass spectrometric determination, and densitometric determination of HPTLC plates was carried out after derivatization with methanol–sulphuric acid reagent. After HPTLC densitometric scanning, the concentrations of free lactose in milk of the mare, cow, camel, buffalo and donkey were 2.16%, 5.70%, 6.70%, 7.17% and 6.38%, respectively.