Simultaneous enzymatic hydrolysis and lactic fermentation to obtain a yogurt with low lactose content

• Autor(a) principal: Martins,André Rosa
• Data de Publicação: 2012
• Outros Autores: Monteiro,Ricardo Lemos, Burkert,Janaína Fernandes de Medeiros, Burkert,Carlos André Veiga
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Ciência e Agrotecnologia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542012000500008
• topic: Enzymatic catalysis; lactose hydrolysis; yogurt physical properties; β-galactosidase

In a single-stage process with the simultaneous addition of β-galactosidase and lactic culture, the lactose conversion, the processing time, viscosity and syneresis were evaluated. Fermentation was promoted by lactic culture containing two probiotic microorganisms, Bifidobacterium animalis and Lactobacillus acidophilus, associated with the typical microorganisms of yogurt. An enzymatic preparation containing β-galactosidases from Kluyveromyces lactis and Aspergillus niger was used. A central composite design (2³ trials plus three central points) was proposed in order to evaluate the effects of initial lactose concentration, enzyme concentration and the time of addition of the enzyme. The following conditions were established: initial lactose concentration of 91 g L-1, enzyme concentration of 0.5 g L-1 and enzyme addition at the beginning of fermentation. In these conditions, a decrease in processing time (from 4.55 to 3.68 h) and an increase in lactose conversion (from 15.2 to 97.9%) were observed in relation to the fermentation without enzyme addition, and no detrimental changes in some physical properties of yogurt (viscosity, and syneresis).