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

Abstract

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%.

Bioactive peptides from milk: animal determinants and their implications in human health

“…In milk, bioactive peptides are inactive within the native protein and are activated by (1) proteases present in milk, (2) digestive enzymes and enzymes produced by the gut microbiota and (3) enzymes secreted by microorganisms (i.e. starter cultures) and/or purified enzymes added to the milk during milk processing (Espejo-Carpio et al ., 2018). Because of their multiple putative benefits on human health, bioactive peptides from milk are commonly used in the formulation of functional foods, nutraceuticals and natural drugs (Muro et al ., 2011).…”

Whey Protein Hydrolysates of Sheep/Goat Origin Produced by the Action of Trypsin without pH Control: Degree of Hydrolysis, Antihypertensive Potential and Antioxidant Activities

“…Total protein (TP) was estimated as total nitrogen (TN) × 6.38. Nitrogen fractions were prepared as follows: the pH of substate solutions was adjusted at pH 4.6 using 1 M HCl; after centrifugation at 3000× g for 30 min, the supernatants were filtrated using a Whatman No 41 filter paper and the filtrate was the SN fraction; equal quantities of SN and 24% ( w / w ) trichloroacetic acid (TCA) were mixed and remained at room temperature for two hours; the precipitate was removed using Whatman No 40 filter paper and the filtrate was the TCASN fraction; the concentration of the major native whey proteins of the substrates was estimated by reversed-phase HPLC (RP-HPLC) using a Vydac C4 214 TP 515 column [ 14 ]; the major whey proteins of the profiles were the caseinomacropeptide (CMP), α-lactalbumin (α-LA), and β-lactoglobulin (β-LG).…”

“…The antioxidant and ACE-IA of sheep cheese whey hydrolyzed by bacterial protease has been presented [ 12 ]. Commercial goat milk was hydrolyzed by subtilisin and trypsin to optimize the conditions resulting in the maximum degree of hydrolysis and ACE-IA [ 13 ]; later, the same hydrolysis scheme was used to develop artificial neuronal networks for modelling hydrolysis [ 14 ]. Recently, the suitability of various proteases for the production of goat milk WPHs regarding their emulsifying ability and hypoglycemic potential has been investigated [ 15 ].…”

Antidiabetic Food-Derived Peptides for Functional Feeding: Production, Functionality and In Vivo Evidences

“…The reaction conditions (pH and temperature) are determined by the protease, and many factors, such as enzyme/substrate ratio or substrate concentration, must be taken into consideration too. The optimal conditions for obtaining highly bioactive hydrolysates are usually achieved via different kinds of experimental designs [55][56][57]. The enzymatic hydrolysis is generally carried out in a jacketed reactor, under stirring, in order to ensure the homogeneity and constant temperature of the reaction.…”