Presence of galactooligosaccharides and furosine in special dairy products designed for elderly people.

An evaluation of the formation of prebiotic carbohydrates during lactose hydrolysis has been carried out in industrially elaborated dairy preparations designed for elderly people. Due to the hydrolysis of lactose, high levels of galactose and glucose were found together with galactooligosaccharides (GOS), mainly allolactose, 6-galactobiose and 6'-galactosyl lactose. Total GOS content was between 7.1% and 13.4% of total carbohydrates, depending on lactose hydrolysis extent. In addition, the determination of furosine as indicator of lysine loss during the Maillard reaction (MR) has been also studied. The high content of monosaccharides promoted the progress of the MR during UHT processing, as reflected by the levels of furosine found in samples. After storage at 20 °C for 4 months the content of furosine increased by 74-90%. These results underline the importance of controlling lactose hydrolysis, and processing and storage conditions to preserve the quality and increase the bioactivity of dairy preparations designed for elderly people.