Artificial neuronal networks (ANN) to model the hydrolysis of goat milk protein by subtilisin and trypsin

2018 ◽  
Vol 85 (3) ◽  
pp. 339-346 ◽  
Author(s):  
Francisco Javier Espejo-Carpio ◽  
Raúl Pérez-Gálvez ◽  
Antonio Guadix ◽  
Emilia María Guadix

The enzymatic hydrolysis of milk proteins yield final products with improved properties and reduced allergenicity. The degree of hydrolysis (DH) influences both technological (e.g., solubility, water binding capacity) and biological (e.g., angiotensin-converting enzyme (ACE) inhibition, antioxidation) properties of the resulting hydrolysate. Phenomenological models are unable to reproduce the complexity of enzymatic reactions in dairy systems. However, empirical approaches offer high predictability and can be easily transposed to different substrates and enzymes. In this work, the DH of goat milk protein by subtilisin and trypsin was modelled by feedforward artificial neural networks (ANN). To this end, we produced a set of protein hydrolysates, employing various reaction temperatures and enzyme/substrate ratios, based on an experimental design. The time evolution of the DH was monitored and processed to generate the ANN models. Extensive hydrolysis is desirable because a high DH enhances some bioactivities in the final hydrolysate, such as antioxidant or antihypertensive. The optimization of both ANN models led to a maximal DH of 23·47% at 56·4 °C and enzyme–substrate ratio of 5% for subtilisin, while hydrolysis with trypsin reached a maximum of 21·3% at 35 °C and an enzyme–substrate ratio of 4%.

2013 ◽  
Vol 80 (2) ◽  
pp. 214-222 ◽  
Author(s):  
Francisco Javier Espejo-Carpio ◽  
Raúl Pérez-Gálvez ◽  
Emilia M Guadix ◽  
Antonio Guadix

Goat milk protein was hydrolysed with subtilisin and trypsin. As input variables, temperature was assayed in the interval 45–70 °C for subtilisin and 30–55 °C for trypsin, while the enzyme-substrate ratio varied from 1 to 5%. The effect of the input variables on the degree of hydrolysis and ACE-inhibitory activity (output variables) was modelled by second order polynomials, which were able to fit the experimental data with deviations below 10%. The individual maximum values of the degree of hydrolysis and the ACE-inhibitory activity were found at conflicting conditions of temperature and enzyme-substrate ratio. Since such maximum values could not be reached simultaneously, a bi-objective optimisation procedure was undertaken, producing a set of non-inferior solutions that weighted both objectives.


1998 ◽  
Vol 4 (2) ◽  
pp. 91-98 ◽  
Author(s):  
F. Mendonça Diniz ◽  
A.M. Martin

Muscle tissue from the spiny dogfish ( Squalus acanthias) was enzymatically hydrolysed using a bacterial endopeptidase. The influence of the process variables (temperature, pH, enzyme/ substrate ratio and reaction time) was investigated with regards to the extent of proteolytic degra dation and the recovery of soluble nitrogen from the substrate. Maximum significant nitrogen recovery (NR) was found to be 76.2%, in a 2 h proteolytic reaction. Optimum conditions were 55 °C, pH 8.0 and an enzyme/substrate ratio of 40 mg enzyme/g minced shark muscle (wet weight basis). Under these conditions, a degree of hydrolysis (DH) of 18.6% was obtained. A linear corre lation ( R2 = 0.99) was found to exist between the two measured parameters, NR and DH.


2012 ◽  
Vol 554-556 ◽  
pp. 1387-1394
Author(s):  
He Jian Xiong ◽  
Longfei Cao ◽  
Huajun You ◽  
Qingpi Yan ◽  
Ying Ma

Tilapia frames were subjected to enzymatic hydrolysis using Flavouzryme and Papain with a ratio of 2:1. The relationship of temperature (40 to 60°C), enzyme: substrate ratio (0.5% to 4.5%), initial pH (6.0 to 8.0) and hydrolysis time (1h to 9h) to the degree of hydrolysis were determined. The enzymatic hydrolysis was optimized for maximum degree of hydrolysis using surface response methodology. The optimum conditions for enzymatic hydrolysis of tilapia frames were temperature 53°C, enzyme : substrate ratio of 3.5%, initial pH 7.2, and reaction time 7h. Under these conditions a degree of hydrolysis of 40.01% were obtained. The yield of free amino acids in the hydrolysate was 46.61mg/g tilapia frames. The flavor amino acids and essential amino acids occupied up to 31.8% and 49.0% of the total free amino acids respectively. The hydrolysate of waste tilapia frames showed good potential for applications such as protein supplementation in food system.


2019 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Arijit Nath ◽  
Geremew Geidare Kailo ◽  
Zsuzsanna Mednyánszky ◽  
Gabriella Kiskó ◽  
Barbara Csehi ◽  
...  

Enzymatic hydrolysis of soybean milk proteins with cysteine protease papain was performed in an advanced bioreactor, operated with batch mode. In soybean milk protein hydrolysis reaction, enzyme and substrate ratio and reaction temperature were varied, ranging from 0.029:100–0.457:100 and 30–60 °C, respectively. The degree of hydrolysis of soybean milk proteins was increased with increase of enzyme and substrate (soybean milk protein) ratio. However, the degree of hydrolysis was increased due to change of reaction temperature from 30 °C to 60 °C with enzyme and substrate ratio 0.229:100 and was reduced when hydrolysis reaction was performed with enzyme and substrate ratio 0.11:100 at hydrolysis temperature 60 °C. Antioxidant capacity of enzyme-treated milk had a similar trend with degree of hydrolysis. In a later exercise, a membrane bioreactor was adopted for continuous production of antioxidant and antibacterial peptides from soybean milk. The membrane bioreactor was operated for 12 h with constant feeding. Ceramic-made tubular membrane with a pore size 20 nm was used. Application of static turbulence promoter in a membrane separation process was investigated and its positive effects, with respect to higher permeate flux and lower energy consumption in filtration process, were proven. Antioxidant capacity and antibacterial activity against Bacillus cereus of enzyme-hydrolyzed milk and permeate from membrane were confirmed.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5366
Author(s):  
Alexandra Dion-Poulin ◽  
Myriam Laroche ◽  
Alain Doyen ◽  
Sylvie L. Turgeon

The low consumer acceptance to entomophagy in Western society remains the strongest barrier of this practice, despite these numerous advantages. More positively, it was demonstrated that the attractiveness of edible insects can be enhanced by the use of insect ingredients. Currently, insect ingredients are mainly used as filler agents due to their poor functional properties. Nevertheless, new research on insect ingredient functionalities is emerging to overcome these issues. Recently, high hydrostatic pressure processing has been used to improve the functional properties of proteins. The study described here evaluates the functional properties of two commercial insect meals (Gryllodes sigillatus and Tenebrio molitor) and their respective hydrolysates generated by Alcalase®, conventionally and after pressurization pretreatment of the insect meals. Regardless of the insect species and treatments, water binding capacity, foaming and gelation properties did not improve after enzymatic hydrolysis. The low emulsion properties after enzymatic hydrolysis were due to rapid instability of emulsion. The pretreatment of mealworm meal with pressurization probably induced protein denaturation and aggregation phenomena which lowered the degree of hydrolysis. As expected, enzymatic digestion (with and without pressurization) increased the solubility, reaching values close to 100%. The pretreatment of mealworm meal with pressure further improved its solubility compared to control hydrolysate, while pressurization pretreatment decreased the solubility of cricket meal. These results may be related to the impact of pressurization on protein structure and therefore to the generation of different peptide compositions and profiles. The oil binding capacity also improved after enzymatic hydrolysis, but further for pressure-treated mealworm hydrolysate. Despite the moderate effect of pretreatment by high hydrostatic pressures, insect protein hydrolysates demonstrated interesting functional properties which could potentially facilitate their use in the food industry.


Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1465 ◽  
Author(s):  
Mirian Angelene González-Ayón ◽  
Ángel Licea-Claveríe ◽  
José Benigno Valdez-Torres ◽  
Lorenzo A. Picos-Corrales ◽  
Rosabel Vélez-de la Rocha ◽  
...  

This work shows an optimized enzymatic hydrolysis of high molecular weight potato galactan yielding pectic galactan-oligosaccharides (PGOs), where endo-β-1,4-galactanase (galactanase) from Cellvibrio japonicus and Clostridium thermocellum was used. For this, response surface methodology (RSM) by central composite design (CCD) was applied. The parameters varied were temperature (°C), pH, incubation time (min), and enzyme/substrate ratio (U/mg). The optimized conditions for the production of low degree of polymerization (DP) PGOs were obtained for each enzyme by spectrophotometric assay and confirmed by chromatography. The optimal conditions predicted for the use of C. japonicus galactanase to obtain PGOs of DP = 2 were T = 51.8 °C, pH 5, E/S = 0.508 U/mg, and t = 77.5 min. For DP = 3, they were T = 21 °C, pH 9, E/S = 0.484 U/mg, and t = 12.5 min; and for DP = 4, they were T = 21 °C, pH 5, E/S = 0.462 U/mg, and t = 12.5 min. The efficiency results were 51.3% for substrate hydrolysis. C. thermocellum galactanase had a lower yield (35.7%) and optimized conditions predicted for PGOs of DP = 2 were T = 60 °C, pH 5, E/S = 0.525 U/mg, and time = 148 min; DP = 3 were T = 59.7 °C, pH 5, E/S = 0.506 U/mg, and time = 12.5 min; and DP = 4, were T = 34.5 °C, pH 11, E/S = 0.525 U/mg, and time = 222.5 min. Fourier transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) characterizations of PGOs are presented.


Revista EIA ◽  
2013 ◽  
Vol 9 (17) ◽  
pp. 71
Author(s):  
Omar Alfredo Figueroa ◽  
José Édgar Zapata ◽  
Gail Albeiro Gutiérrez

Se utilizó un modelo cinético para estudiar la velocidad de reacción en la hidrólisis de proteínas de plasma de bovino con alcalasa 2,4 L en un reactor batch. Se estudió la influencia de variables como la concentración inicial de sustrato y enzima sobre el grado de hidrólisis y se determinaron los parámetros cinéticos de la ecuación de velocidad, analizando su relación con las variables de trabajo. Se ajustó un modelo cinético de orden cero y desactivación enzimática por sustrato, de segundo orden, así como la relación directa entre la fracción enzima-sustrato y la tasa de formación de productos de hidrólisis.Abstract: A kinetic model was used to study the reaction rate of hydrolysis of bovine plasma proteins and alcalase 2.4 L, in a batch reactor. The influence of variables, such as the concentration of initial enzyme substrate and the degree of hydrolysis was studied, and kinetic parameters of the rate equation were determined by analyzing its relationship with the work variables. A zero-order kinetic model and enzyme deactivation by substrate was found, as well as the direct relationship between the fraction of enzyme-substrate and the rate of formation of hydrolysis products.


2019 ◽  
Author(s):  
Jennifer Nill ◽  
Tina Jeoh

AbstractInterfacial enzyme reactions require formation of an enzyme-substrate complex at the surface of a heterogeneous substrate, but often multiple modes of enzyme binding and types of binding sites complicate analysis of their kinetics. Excess of heterogeneous substrate is often used as a justification to model the substrate as unchanging; but using the study of the enzymatic hydrolysis of insoluble cellulose as an example, we argue that reaction rates are dependent on evolving substrate interfacial properties. We hypothesize that the relative abundance of binding sites on cellulose where hydrolysis can occur (productive binding sites) and binding sites where hydrolysis cannot be initiated or is inhibited (non-productive binding sites) contribute to rate limitations. We show that the initial total number of productive binding sites (the productive binding capacity) determines the magnitude of the initial burst phase of cellulose hydrolysis, while productive binding site depletion explains overall hydrolysis kinetics. Furthermore, we show that irreversibly bound surface enzymes contribute to the depletion of productive binding sites. Our model shows that increasing the ratio of productive- to non-productive binding sites promotes hydrolysis, while maintaining an elevated productive binding capacity throughout conversion is key to preventing hydrolysis slowdown.


DYNA ◽  
2020 ◽  
Vol 87 (214) ◽  
pp. 173-182
Author(s):  
Juan Camilo Acosta Pavas ◽  
Laura Alzate Blandón ◽  
Ángela Adriana Ruiz Colorado

An analysis of the enzymatic hydrolysis of wheat starch was performed. The gelatinization stage was carried out between 90-95°C for 15min. In the liquefaction stage, a commercial α-amylase was used with an enzyme-substrate ratio (E/S ratio) 0.036%w/w at 60°C and pH 5.8 for 4h. In the saccharification stage, a commercial amyloglucosidase was used with an E/S ratio of 0.11% w/w at 60°C and pH 4.3 for 6h. A second hydrolysis was evaluated using a E/S ratio of  0.18%w/w in the saccharification stage. Two methods of enzymatic deactivation, boiling temperatures and pH were evaluated. Inhibitory effects were studied by adding 180g/L of glucose to the process. It is concluded that increases in the E/S ratio decrease reaction times but reaches similar concentrations than lower ratios, the most efficient enzymatic deactivation method is pH. In the inhibition tests, it was determined that there are no glucose inhibitory effects.


2011 ◽  
Vol 20 (No. 1) ◽  
pp. 1-6 ◽  
Author(s):  
m. Karamać ◽  
r. Amarowicz ◽  
h. Kostyra

Two pea protein isolates, Pisane and Propulse, were hydrolysed by trypsin. The degree of hydrolysis (DH) was computed using a pH-stat method. Enzymatic treatment of the pea protein isolates was conducted at four different temperatures, namely 35, 40, 45 and 50°C. The relationship between DH and E/S ratio was studied at 50°C and at four different E/S ratios; these were 5, 15, 25, 35 mAU/g (AU – Anson unit). For Pisane the highest value of the final DH (10.4%) was obtained at 45°C, whereas for Propulse the optimal temperature was 50°C and a DH value of 13.2% was attained. In the case of Pisane, the highest DH (11.5%) was recorded if the enzyme/substrate ratio was 35 mAU/g whereas for Propulse, the highest DH (13.2%) was observed at an E/S ratio of 15 mAU / g.  


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