title: Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases.
abstract: This work aimed at evaluating the influence of enzyme concentration, temperature, and reaction time in the lactose hydrolysis process in milk, cheese whey, and whey permeate, using two commercial β-galactosidases of microbial origins. We used Aspergillus oryzae (at temperatures of 10 and 55°C) and Kluyveromyces lactis (at temperatures of 10 and 37°C) β-galactosidases, both in 3, 6, and 9 U/mL concentrations. In the temperature of 10°C, the K. lactis β-galactosidase enzyme is more efficient in the milk, cheese whey, and whey permeate lactose hydrolysis when compared to A. oryzae. However, in the enzyme reaction time and concentration conditions evaluated, 100% lactose hydrolysis was not reached using the K. lactis β-galactosidase. The total lactose hydrolysis in whey and permeate was obtained with the A. oryzae enzyme, when using its optimum temperature (55°C), at the end of a 12 h reaction, regardless of the enzyme concentration used. For the lactose present in milk, this result occurred in the concentrations of 6 and 9 U/mL, with the same time and temperature conditions. The studied parameters in the lactose enzymatic hydrolysis are critical for enabling the application of β-galactosidases in the food industry.
authors.affiliation: Laboratório de Biotecnologia de Alimentos, Programa de Pós-Graduação em Biotecnologia, Centro Universitário UNIVATES, Avenue Avelino Tallini 171, P.O. Box 155, 95900-000 Lajeado, RS, Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Dutra Rosolen
authors.affiliation: Laboratório de Biotecnologia de Alimentos, Programa de Pós-Graduação em Biotecnologia, Centro Universitário UNIVATES, Avenue Avelino Tallini 171, P.O. Box 155, 95900-000 Lajeado, RS, Brazil.
authors.forename: Adriano
authors.initials: A
authors.lastname: Gennari
authors.affiliation: Curso de Biotecnologia, Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul (IFRS), Câmpus Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Giandra
authors.initials: G
authors.lastname: Volpato
authors.affiliation: Laboratório de Biotecnologia de Alimentos, Programa de Pós-Graduação em Biotecnologia, Centro Universitário UNIVATES, Avenue Avelino Tallini 171, P.O. Box 155, 95900-000 Lajeado, RS, Brazil.
authors.forename: Claucia Fernanda
authors.initials: CF
authors.lastname: Volken de Souza