title: Influence of lactose hydrolysis on galacto-oligosaccharides, lactose, volatile profile and physicochemical parameters of different yogurt varieties.
abstract: BACKGROUND
  Different types of reduced-lactose yogurt, obtained by lactose hydrolysis using β-galactosidase enzyme, are commercially available. The breakdown of lactose modifies the carbohydrate profile, including the production of prebiotic galacto-oligosaccharides (GOS), which could affect the survival and activity of starter and probiotic cultures and the parameters of yogurt quality. The extension of these changes is dependent on the yogurt matrix composition. This study aimed to evaluate the influence of lactose hydrolysis on GOS, lactose, volatile profile and physicochemical parameters of different yogurt varieties during storage.
  
  
  RESULTS
  The presence of β-galactosidase enzyme did not affect either the global composition or the survival of cultures. Overall, the hydrolyzed products had lower acidity than traditional ones. GOS were found at similar levels in fresh hydrolyzed yogurts, whereas in traditional yogurts they were not detected. The proportion of ketones, acids and aldehydes seems to be more dependent on yogurt variety than on addition of the enzyme. Likewise, the storage period affected the volatile fraction to different degree; the increase in acid compounds was more pronounced in hydrolyzed than in traditional yogurts.
  
  
  CONCLUSIONS
  This work shows that it is possible to obtain different varieties of reduced-lactose yogurt, some of them with additional benefits to health such as reduced fat, reduced calories, added with probiotic/inulin and enriched in GOS, with similar characteristics to traditional products. © 2016 Society of Chemical Industry.
authors.affiliation: Instituto de Lactología Industrial (INLAIN), Universidad Nacional del Litoral/Consejo Nacional de Investigaciones Científicas y Técnicas (UNL/CONICET), Facultad de Ingeniería Química (FIQ), Santiago del Estero 2829, S3000AOM, Santa Fe, Argentina. clauvenica@fiq.unl.edu.ar.
authors.forename: Claudia I
authors.initials: CI
authors.lastname: Vénica
authors.affiliation: Instituto de Lactología Industrial (INLAIN), Universidad Nacional del Litoral/Consejo Nacional de Investigaciones Científicas y Técnicas (UNL/CONICET), Facultad de Ingeniería Química (FIQ), Santiago del Estero 2829, S3000AOM, Santa Fe, Argentina.
authors.forename: Irma V
authors.initials: IV
authors.lastname: Wolf
authors.affiliation: Instituto de Lactología Industrial (INLAIN), Universidad Nacional del Litoral/Consejo Nacional de Investigaciones Científicas y Técnicas (UNL/CONICET), Facultad de Ingeniería Química (FIQ), Santiago del Estero 2829, S3000AOM, Santa Fe, Argentina.
authors.forename: Carina V
authors.initials: CV
authors.lastname: Bergamini
authors.affiliation: Instituto de Lactología Industrial (INLAIN), Universidad Nacional del Litoral/Consejo Nacional de Investigaciones Científicas y Técnicas (UNL/CONICET), Facultad de Ingeniería Química (FIQ), Santiago del Estero 2829, S3000AOM, Santa Fe, Argentina.
authors.forename: María C
authors.initials: MC
authors.lastname: Perotti
mesh_terms: D055598:Chemical Phenomena; D005285:Fermentation; D061353:Food Storage; D005690:Galactose / Q000032:analysis*; D006868:Hydrolysis; D007785:Lactose / Q000032:analysis* / Q000378:metabolism*; D009844:Oligosaccharides / Q000032:analysis*; D056692:Prebiotics; D019936:Probiotics; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis*; D015014:Yogurt / Q000032:analysis*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D009844:Oligosaccharides; D056692:Prebiotics; D055549:Volatile Organic Compounds; D001616:beta-Galactosidase; D007785:Lactose; D005690:Galactose
keywords: compositional parameters; galacto-oligosaccharides; hydrolyzed-lactose yogurts; volatile compound profile