title: Continuous method to determine the trypsin inhibitor activity in soybean flour.
abstract: The determination of trypsin inhibitor (TI) activity is of importance to evaluate the nutritional value of soybean flours. An analytical method, which involves a continuous spectrophotometric rate determination for trypsin activity against the substrate N-benzoyl-DL-arginine p-nitroanilide, is proposed as an alternative to the standard discontinuous assay. Stopping the reaction with acetic acid and a centrifugation/filtration step to decrease turbidity are not required, thus reducing costs and sample preparation time. The TI activity of different flour samples, determined by both assays, demonstrated to be statistically comparable, irrespective of the TI concentration level. The coefficients of variation of the novel method did not exceed 8% at any concentration level. The curves of progress reaction showed a non-linear behavior in samples without TI. A reduction of incubation time from 10min to 2min increased the method sensitivity and extended its linear range. A more economical, faster and simpler assay was developed.
authors: IPROBYQ (Instituto de Procesos Biotecnológicos y Químicos), UNR, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Suipacha 570, S2002LRK Rosario, Argentina; CBQF (Centro de Biotecnologia e Química Fina), Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4200 Porto, Portugal.
authors: Ezequiel R
authors: ER
authors: Coscueta
authors: CBQF (Centro de Biotecnologia e Química Fina), Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4200 Porto, Portugal.
authors: Manuela E
authors: ME
authors: Pintado
authors: IPROBYQ (Instituto de Procesos Biotecnológicos y Químicos), UNR, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Suipacha 570, S2002LRK Rosario, Argentina.
authors: Guillermo A
authors: GA
authors: Picó
authors: IPROBYQ (Instituto de Procesos Biotecnológicos y Químicos), UNR, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Suipacha 570, S2002LRK Rosario, Argentina.
authors: Gastón
authors: G
authors: Knobel
authors: IPROBYQ (Instituto de Procesos Biotecnológicos y Químicos), UNR, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Suipacha 570, S2002LRK Rosario, Argentina.
authors: Carlos E
authors: CE
authors: Boschetti
authors: IPROBYQ (Instituto de Procesos Biotecnológicos y Químicos), UNR, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Suipacha 570, S2002LRK Rosario, Argentina.
authors: Luciana Pellegrini
authors: LP
authors: Malpiedi
authors: IPROBYQ (Instituto de Procesos Biotecnológicos y Químicos), UNR, CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Suipacha 570, S2002LRK Rosario, Argentina. Electronic address: bnerli@fbioyf.unr.edu.ar.
authors: Bibiana B
authors: BB
authors: Nerli
mesh_terms: D005433:Flour / Q000032:analysis*; D009753:Nutritive Value; D013025:Glycine max / Q000737:chemistry*; D013053:Spectrophotometry; D014361:Trypsin Inhibitors / Q000032:analysis*
chemical_list: D014361:Trypsin Inhibitors
keywords: Analytical method; Antinutritional factors; Soybean flour; Trypsin inhibitor activity