Lactose intolerance in infants can be overcome by adding lactase enzyme formulations to milk, hydrolysing the lactose present. Commonly, such formulations require a significant incubation period after addition to milk to allow time for hydrolysis to take place at desired temperature. Such incubation is often problematic for household conditions, and therefore, formulations with short or, ideally, no incubation period are needed. Development of such formulations requires understanding of the complex process of lactose hydrolysis within the variable temperature and pH conditions in the milk bottle and in the gastrointestinal tract. The current paper describes the application of high-resolution ultrasonic spectroscopy for detailed characterisation of the effect of pH, temperature, and proteases present in the digestive tract on hydrolysis of lactose. The results were employed in the development of a predictive model of lactose hydrolysis within conditions of the infant digestive system. The model was applied for analysis of the whole infant feeding process: from hydrolysis in the bottle, to the stomach and small intestine, and for assessment of the impact of enzyme dosage, the incubation period, and bottle temperature profile on the levels of lactose and galacto-oligosaccharides (produced during hydrolysis), released from the stomach and reaching the large intestine where symptoms of intolerance arise. The results showed that the activity of Ha-Lactase in the stomach and small intestine assists significantly in the reduction of lactose load to 10 % or less of the amount of lactose in the feed, depending on conditions.
Keywords: High-Resolution Ultrasonic Spectroscopy; In-vitro modelling; Infant milk; β-galactosidase.
Copyright © 2022. Published by Elsevier Ltd.