Physical-mathematical model to predict the kinetic coagulation process by clotting activity of bacterial endopeptidases

A physical-mathematical model was used to evaluate the capability of an enzymatic pool of Bacillus sp. P7 (isolated from Piaractus mesopotamicus) to promote the bovine casein micelles coagulation. Experiments were designed to assess the effects of temperature, pH, and enzyme activity/mass of substrate ratio on the kinetic parameters of the coagulation process and the microstructure of the obtained clots. Descriptive and predictive equations indicate that the temperature and the pH modified these parameters significantly. In optimal conditions, the clot’s mean pore size was 3.6 times smaller using chymosin. On the other hand, rheological measurements evidence a moderate elasticity of clot, which indicates the usefulness of P7 protease preparation as a clotting agent in spreadable or soft cheese manufacture. Also, the hydrolysis products, which are in the whey after casein micelles coagulation, demonstrated antioxidant activities. Equations to model and predict the process kinetics were combined with rheological and microstructure analyses of the obtained clots, and whey bioactivities were evaluated. Nevertheless, the use of P7PP requires further investigation concerning the stability of the enzyme preparation during storage, its performance, and how these variables could be related to the proposed models.Fil: Mancilla Canales, Manuel Arturo. Grupo de Física Biomédica. Instituto de Física Rosario (CONICET-UNR); Argentina.Fil: Riquelme, Bibiana Doris. Grupo de Física Biomédica. Instituto de Física Rosario (CONICET-UNR); Argentina.Fil: Mancilla Canales, Manuel Arturo. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Riquelme, Bibiana Doris. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Risso, Patricia Hilda. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Folmer Côrrea, Ana Paula. Universidade Federal de Rio Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos; Brasil.Fil: Brandelli, Adriano. Universidade Federal de Rio Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos; Brasil.Fil: Risso, Patricia Hilda. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; Argentina

Biological and physicochemical properties of bovine sodium caseinate hydrolysates obtained by a bacterial protease preparation

In this work, we aimed at the production of bovine sodium caseinate (NaCAS) hydrolysates by means of an extracellular protease from Bacillus sp. P7. Mass spectrometry was carried out to evaluate peptide mass distribution and identified sequences of peptides with a signal/noise ratio higher than 10. Antioxidant and antimicrobial properties of hydrolysates were evaluated. An acid-induced aggregation process of the hydrolysates and their corresponding mixtures with NaCAS were also analyzed. The results showed that the enzymatic hydrolysis produced peptides, mostly lower than 3 kDa, with different bioactivities depending on the time of hydrolysis (ti). These hydrolysates lost their ability to aggregate by addition of glucono-delta-lactone, and their incorporation into NaCAS solutions alter the kinetics of the process. Also, the degree of compactness of the NaCAS aggregates, estimated by the fractal dimension of aggregates, was not significantly altered by the incorporation of hydrolysates. However, at higher protein concentrations, when the decrease in pH leads to the formation of NaCAS acid gels, the presence of hydrolysates alters the microstructure and rheological behavior of these gels.Fil: Hidalgo, María Eugenia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Física Rosario (IFIR-CONICET); Argentina.Fil: Folmer Côrrea, Ana Paula. Universidade Federal de Rio Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos; Brasil.Fil: Mancilla Canales, Manuel Arturo. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Física Rosario (IFIR-CONICET); Argentina.Fil: Daroit, Daniel. Universidade Federal da Fronteira Sul. Campus Cerro Largo; Brasil.Fil: Brandelli, Adriano. Universidade Federal de Rio Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos; Brasil.Fil: Risso, Patricia Hilda. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Facultad de Ciencias Veterinarias. Instituto de Física Rosario (IFIR-CONICET); Argentina

Milk protein suspensions enriched with three essential minerals: Physicochemical characterization and aggregation induced by a novel enzymatic pool

Structural changes of casein micelles and their aggregation induced by a novel enzymatic pool isolatedfrom Bacillus spp. in the presence of calcium, magnesium or zinc were investigated. The effect of cationson milk protein structure was studied using fluorescence and dynamic light scattering. In the presenceof cations, milk protein structure rearrangements and larger casein micelle size were observed. Theinteraction of milk proteins with zinc appears to be of a different nature than that with calcium ormagnesium. Under the experimental conditions assayed, the affinity of each cation for some groupspresent in milk proteins seems to play an important role, besides electrostatic interaction. On the otherhand, the lowest aggregation times were achieved at the highest calcium and zinc concentrations (15 mMand 0.25 mM, respectively). The study found that the faster the aggregation of casein micelles, the lesscompact the gel matrix obtained. Cation concentrations affected milk protein aggregation kinetics andthe structure of the aggregates formed.Fil: Lombardi, Julia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Lombardi, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Spelzini, Darío. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Spelzini, Darío. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Folmer Côrrea, Ana Paula. Universidade Federal de Rio Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos. Laboratório de Bioquimica e Microbiologia Aplicada; Brasil.Fil: Brandelli, Adriano. Universidade Federal de Rio Grande do Sul. Instituto de Ciência e Tecnologia de Alimentos. Laboratório de Bioquimica e Microbiologia Aplicada; Brasil.Fil: Risso, Patricia Hilda. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Física Rosario (IFIR-CONICET); Argentina.Fil: Risso, Patricia Hilda. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; Argentina.Fil: Boeris, Valeria. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina.Fil: Boeris, Valeria. Universidad Católica Argentina. Facultad de Química e Ingeniería del Rosario; Argentina