Enzymatic Hydrolysis of Heat-Induced Aggregates of Whey Protein Isolate

O’Loughlin, Ian B.; Murray, Brian A.; Kelly, Philip M.; Fitzgerald, Richard J.; Brodkorb, André

doi:10.1021/jf205213n

Cited by 83 publications

(58 citation statements)

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“…As a result of changes in protein structure, the profile of peptides released may differ as digestive enzymes may be capable of digesting these regions of the protein that were previously inaccessible to the enzyme. This has been previously shown to be the case for whey protein [121][122]. Furthermore, ACE inhibitory peptides from whey protein isolates (WPI) pretreated at 65 °C were shown to have greater inhibitory activity than peptides from WPI pretreated at 95 °C.…”

Section: Hypotensive Peptides As Functional Food Ingredientsmentioning

confidence: 66%

Antihypertensive Peptides from Food Proteins

Norris¹,

Fitzgerald²

2013

Bioactive Food Peptides in Health and Disease

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Section: Hypotensive Peptides As Functional Food Ingredientsmentioning

confidence: 66%

Antihypertensive Peptides from Food Proteins

Norris¹,

Fitzgerald²

2013

Bioactive Food Peptides in Health and Disease

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“…Therefore, endo-protease activity can be affected by the degree of protein denaturation where a positive influence on hydrolysis reaction rates has been demonstrated in individual protein fractions (Guo, Fox, Flynn & Kindstedt, 1995;Schmidt & van Markwijk, 1993) and heterogeneous concentrates (Kim et al, 2007a). Kim et al (2007a) reported that a prehydrolysis heat-treatment (100 ºC for 10 min) increased peptic and tryptic hydrolysis of WPC, while heat-treatments > 70 ºC for 15 min also have a positive effect on the rate of hydrolysis of WPI that may be associated with differing aggregation phenomena (O'Loughlin, Murray, Kelly, FitzGerald & Brodkorb, 2012).…”

Section: Introductionmentioning

confidence: 99%

Whey protein isolate polydispersity affects enzymatic hydrolysis outcomes

et al. 2013

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The effects of heat-induced denaturation of whey protein isolate (WPI) on the enzymatic breakdown of α-La, caseinomacropeptide (CMP), β-Lg A and β-Lg B were observed as hydrolysis proceeded to a 5 % degree of hydrolysis (DH) in both unheated and heat-treated (80 ºC, 10 min) WPI dispersions (100 g L -1 ). Hydrolysis of denatured WPI favoured the generation of higher levels of free essential amino acids; lysine, phenylalanine and arginine compared to the unheated substrate. LC-MS/MS identified 23 distinct peptides which were identified in the denatured WPI hydrolysate -the majority of which were derived from β-Lg. The mapping of the detected regions in α-La, β-Lg, and CMP enabled specific cleavage points to be associated with certain serine endo-protease activities. The outcomes of the study emphasise how a combined approach of substrate heat pre-treatment and enzymology may be used to influence proteolysis with attendant opportunities for targeting unique peptide production and amino acid release.

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“…For β-cas, the relatively low molar sequence coverages in two parts of the sequence, i.e. and [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48], might be due to the fact that these peptides contain phosphoserines. Yet it has been reported that phosphorylated peptides are typically not well ionised 32, 33 .…”

Section: Towards Predicting Bovine Tryptic Hydrolysis 51mentioning

confidence: 99%

“…In addition, chemical modifications on the enzyme might affect the enzyme secondary specificity. For instance, modifying lysine residues in bovine trypsin by succinylation led to a 8-10 times higher acceptance of positively charged AAs (KR) on the P1' position of the binding site sequence, while the modification by guanylation showed no effects 36 .…”

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Towards predicting enzymatic protein hydrolysis

Deng¹

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The experimental maximum degree of hydrolysis (DHmax,exp) was typically lower than the theoretical maximum degree of hydrolysis (DHmax,theo), calculated using the number of cleavage sites (as based on protease specificity) on the protein. The aim of this thesis is, therefore, to develop a method to better define expectations of the DHmax,exp. The developed method is based on the molecular properties of the protein and the protease, and the effects of modifications on protein primary structure and changes in system conditions. Protein primary structure was modified by glycation, the initial stage of the Maillard reaction upon heating proteins in the presence of carbohydrates. The effect of glycation on DHmax,exp for five different enzymes could be predicted based on the protease primary and secondary specificity, and the sensitivity of the enzyme to modifications of the binding site. Secondary specificity was determined by linking the molecular properties of the amino acids on the binding site positions of cleavage sites with the enzyme selectivity. The enzyme selectivity, i.e. the relative hydrolysis rate constants towards cleavage sites in a protein, of bovine, porcine and human trypsins was determined after full quantitative analysis of peptides formed during hydrolysis. The prediction of DHmax,exp for bovine trypsin based on the secondary specificity was 5 times better than the prediction based on the primary specificity (DHmax,theo). The large differences found in DHmax,exp by the three trypsins could be predicted based on enzyme secondary specificity. The substrate concentration, one of the system conditions varying in the in vitro digestion models, also showed large effect on DHmax,exp. This was found to be related to changes in the mechanism of hydrolysis, illustrated by the differences in the percentage of intact protein in the hydrolysates as a function of DH. Due to the changes in mechanism, different amounts of inhibitory peptides for the protease were proposed to be present in the hydrolysates, leading to various DHmax,exp. Based on these findings, a model to predict the DHmax,exp of hydrolysis of any given protein by any specific protease was developed. The concept was shown to adequately explain the hydrolysis of proteins with various structural states and in hydrolysis by a sequential addition of enzyme. The study of in vivo protein digestibility has received a lot of attention from food and feed producers. In vitro enzymatic protein hydrolysis is often used as a screening tool to investigate the protein digestibility since the in vivo protein digestion experiments are not always feasible options. Enzymatic protein hydrolysis is also used to produce protein hydrolysates, which are used as ingredients in food products. The outcome of an enzymatic protein hydrolysis is affected by many factors, including the structure of the substrate protein, the protease used and their sensitivities towards system conditions. For example, the modifications on the protein structure during industrial process...

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Enzymatic Hydrolysis of Heat-Induced Aggregates of Whey Protein Isolate

Cited by 83 publications

References 39 publications

Antihypertensive Peptides from Food Proteins

Antihypertensive Peptides from Food Proteins

Whey protein isolate polydispersity affects enzymatic hydrolysis outcomes

Towards predicting enzymatic protein hydrolysis

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