title: Enzymatic hydrolysis of chestnut purée: process optimization using mixtures of alpha-amylase and glucoamylase.
abstract: The enzymatic hydrolysis of starch present in chestnut purée was performed through a one-step treatment with a mixture of a commercial thermostable alpha-amylase (Termamyl 120 L, type S) and glucoamylase (AMG 300 L) at 70 degrees C. The effect of the enzyme concentration and the ratio of both amylases in the reaction mixture was studied by means of a factorial second-order rotatable design, which allowed conditions to be set leading to the total conversion of starch to glucose after 15 min of incubation (60 total enzymatic units g(-1) of chestnut; ratio of alpha-amylase/glucoamylase enzymatic units, 0.35:0.65). At lower enzyme concentration, the delay in the addition of the glucoamylase with regard to the addition of the alpha-amylase allowed a slightly higher hydrolysis percentage to be reached when compared to the simultaneous addition of both amylases at the same low enzyme concentration. The kinetics of liberation of glucose supports the existence of a synergistic effect between these two enzymes only in the first moments of the reaction. Finally, a sequential one-step hydrolysis was assayed, and more concentrated glucose syrups were thus obtained.
authors.affiliation: Department of Biochemistry, Genetics and Immunology, University of Vigo, Ourense, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: López
authors.forename: Ana
authors.initials: A
authors.lastname: Torrado
authors.forename: Pablo
authors.initials: P
authors.lastname: Fuciños
authors.forename: Nelson P
authors.initials: NP
authors.lastname: Guerra
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pastrana
mesh_terms: D031319:Aesculus / Q000737:chemistry / Q000378:metabolism*; D005511:Food Handling; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D012639:Seeds / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D013213:Starch; D000516:alpha-Amylases; D005087:Glucan 1,4-alpha-Glucosidase; D005947:Glucose