title: Impact of the environmental conditions and substrate pre-treatment on whey protein hydrolysis: A review.
abstract: Proteins in solution are subject to myriad forces stemming from interactions with each other as well as with the solvent media. The role of the environmental conditions, namely pH, temperature, ionic strength remains under-estimated yet it impacts protein conformations and consequently its interaction with, and susceptibility to, the enzyme. Enzymes, being proteins are also amenable to the environmental conditions because they are either activated or denatured depending on the choice of the conditions. Furthermore, enzyme specificity is restricted to a narrow regime of optimal conditions while opportunities outside the optimum conditions remain untapped. In addition, the composition of protein substrate (whether mixed or single purified) have been underestimated in previous studies. In addition, protein pre-treatment methods like heat denaturation prior to hydrolysis is a complex phenomenon whose progression is influenced by the environmental conditions including the presence or absence of sugars like lactose, ionic strength, purity of the protein, and the molecular structure of the mixed proteins particularly presence of free thiol groups. In this review, we revisit protein hydrolysis with a focus on the impact of the hydrolysis environment and show that preference of peptide bonds and/or one protein over another during hydrolysis is driven by the environmental conditions. Likewise, heat-denaturing is a process which is dependent on not only the environment but the presence or absence of other proteins.
authors.affiliation: a Global Applied Science & Technology (GAST) , Verden (Aller) , Germany.
authors.forename: Seronei Chelulei
authors.initials: SC
authors.lastname: Cheison
authors.affiliation: b Chair for Food Process Engineering and Dairy Technology Department , ZIEL Technology Section, Technische Universität München , Weihenstephaner Berg 1, Freising , Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kulozik
mesh_terms: D000818:Animals; D055162:Biocatalysis; D002021:Buffers; D002918:Chymotrypsin / Q000737:chemistry / Q000378:metabolism; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005503:Food Additives / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005511:Food Handling; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010434:Pepsin A / Q000737:chemistry / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011487:Protein Conformation; D011489:Protein Denaturation; D011492:Protein Hydrolysates / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D059748:Proteolysis; D012995:Solubility; D013696:Temperature; D013820:Thermolysin / Q000737:chemistry / Q000378:metabolism; D014357:Trypsin / Q000737:chemistry / Q000378:metabolism; D000067816:Whey Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D002021:Buffers; D004800:Enzymes, Immobilized; D005503:Food Additives; D010446:Peptide Fragments; D011492:Protein Hydrolysates; D000067816:Whey Proteins; D002918:Chymotrypsin; D014357:Trypsin; D010434:Pepsin A; D013820:Thermolysin
keywords: Acid Protease A; Whey proteins; pH-stat; selective hydrolysis; α-lactalbumin; β-lactoglobulin