Galactooligosaccharides (GOS) are prebiotic compounds that can be produced in milk through transgalactosylation reactions catalyzed by β-galactosidase. This study quantified GOS formation in UHT milk after lactose hydrolysis using three commercial β-galactosidases from Kluyveromyces lactis at enzyme dosages of 0.3, 0.75, and 1.5 g L−1, and compared the results with 11 commercial lactose-hydrolysed milks. In experimental samples, total GOS ranged from 470 to 2055 mg (100 mL)−1, whereas commercial products contained 120–660 mg (100 mL)−1. The optimal formulation for lactose-free, GOS-enriched milk was obtained using Bonlacta™ at 0.75 g L−1, yielding 1527 mg (100 mL)−1 GOS and residual lactose of 0.038 g (100 mL)−1. Maximum GOS production (2055 mg (100 mL)−1) and about 95% lactose hydrolysis were achieved with Bonlacta at 0.3 g L−1. Approximately 7% of sugars had a degree of polymerization ≥3, indicating enhanced prebiotic potential. These results highlight differences among β-galactosidases and the need for targeted technological strategies to produce functional milk products.
Effect of different β-galactosidases on galactooligosaccharides formation in lactose-hydrolysed milk
De Arcangelis, Elisa;Marconi, Emanuele;
2026-01-01
Abstract
Galactooligosaccharides (GOS) are prebiotic compounds that can be produced in milk through transgalactosylation reactions catalyzed by β-galactosidase. This study quantified GOS formation in UHT milk after lactose hydrolysis using three commercial β-galactosidases from Kluyveromyces lactis at enzyme dosages of 0.3, 0.75, and 1.5 g L−1, and compared the results with 11 commercial lactose-hydrolysed milks. In experimental samples, total GOS ranged from 470 to 2055 mg (100 mL)−1, whereas commercial products contained 120–660 mg (100 mL)−1. The optimal formulation for lactose-free, GOS-enriched milk was obtained using Bonlacta™ at 0.75 g L−1, yielding 1527 mg (100 mL)−1 GOS and residual lactose of 0.038 g (100 mL)−1. Maximum GOS production (2055 mg (100 mL)−1) and about 95% lactose hydrolysis were achieved with Bonlacta at 0.3 g L−1. Approximately 7% of sugars had a degree of polymerization ≥3, indicating enhanced prebiotic potential. These results highlight differences among β-galactosidases and the need for targeted technological strategies to produce functional milk products.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
