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Cited by 173Food Nutrient Composition and Product DevelopmentProteins in Food SystemsAdvanced Scientific Research Methods

The DOI matches its Crossref record; 72 of the 80 references it cites were found in a registry or an index; none of the 195 sources its claims cite is checked for support yet.

Chemical methods for the characterization of proteolysis in cheese during ripening

Open access
McSweeney, P. L.H., Fox, P. F.·1997·Le Lait
DOI 10.1051/lait:199713
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Abstract

Proteolysis is the principal and most complex biochemical event which occurs during the maturation of most cheese varieties.

Overview

AI snapshot

Written from the paper’s full text.

## TL;DR

This paper is a methodological review of chemical approaches for tracking proteolysis during cheese ripening. It argues that simple nitrogen-based and reactive-group assays are useful for routine monitoring, while peptide-resolving methods such as chromatography and electrophoresis are needed for deeper characterization.

## Key findings

  • Proteolysis is presented as the main and most complex biochemical change in most ripened cheeses, and the paper notes that a mature Cheddar typically has about 25% WSN (water-soluble nitrogen) relative to total nitrogen.
  • pH 4.6-soluble nitrogen and 12% TCA-soluble nitrogen are widely used indices of ripening; in one cited comparison, about 15% of total N in mature Cheddar was soluble in 2.5% TCA, and about 90% of WSN was soluble in 2.5% TCA.
  • The paper states that Cd-ninhydrin is about five times more sensitive than TNBS for amino acid nitrogen, but it cannot be used with TCA-soluble fractions because of interference.
  • For free amino acids, it reports that pre-column derivatization RP-HPLC gives rapid, simple, and sensitive analysis, with better peak shape and baseline stability than classical ion-exchange amino acid analysis.

## Methods

  • The article is a narrative review of chemical methods used to assess proteolysis in cheese during ripening, organized into non-specific assays, reactive-group methods, peptide-separating techniques, and amino acid analysis.
  • It draws on published studies across many cheese varieties, with examples and quantitative comparisons from Cheddar, blue cheeses, Gouda, Emmental, Camembert, Mozzarella, and others.
  • The main analysis is comparative evaluation of methods rather than new experimental data; it discusses extraction/fractionation procedures, detection chemistries, and separation platforms such as PAGE, HPLC, size-exclusion chromatography, ultrafiltration, and capillary electrophoresis.

## Limitations

  • The paper itself says it is meant to assess methodology rather than simply catalogue methods, so it is not an exhaustive methods compendium.
  • It notes that comparisons across studies are difficult because different columns, buffers, solvents, and detection wavelengths are used, which makes chromatograms hard to compare directly.
  • Evident from the text: most results are drawn from prior literature and laboratory experience, and several methods are described as unpublished or only illustrated schematically, so the review does not provide a single standardized validation dataset.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1051/lait:199713

Cites

72 of 72 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 of 195 cited sources checked · 0 supported · 0 flagged

Show all 73 claims

  • Probably not a substantial claim. 118
  • It may state two separate claims as one. 105
  • The quote only partly states this claim. 2
181 of 181

  • The paper relies on this without support.

    Only proteins and large peptides can be visualized by staining.

    “Since only proteins and large peptides can be visualized by staining”

  • The paper relies on this without support.

    Electrophoretic mobility in the presence of SDS is inversely proportional to the logarithm of the molecular weight of the peptide.

    “electrophoretic mobility in the presence of SOS is inversely proportional to the logarithm of the molecular weight of the peptide.”

  • The paper relies on this without support.

    The caseins have similar molecular weights (20,000 to 25,000).

    “the caseins have similar molecu-Jar weights (20 000 to 25 000)”

  • The paper relies on this without support.

    UV absorbance allows detection of small peptides which cannot be visualized by staining.

    “UV absorbance allows the detection of small peptides which cannot be visualized by staining”

  • The paper relies on this without support.

    Small peptides may not contain aromatic residues.

    “since small peptides may not contain aromatic residues.”

  • The paper relies on this without support.

    Cleavage of a peptide bond liberates a new amino group that can react with chromogenic or fluorogenic reagents.

    “The c1eavage of a pepitde bond results in the liberation of a new amino group which can react with several chromogenic or fluorogenic reagents.”

  • The paper relies on this without support.

    TNBS reacts stoichiometrically with primary amines to produce a chromophore.

    “2,4,6-Trinitrobenzenesulphonic acid (TNBS) is one such reagent which reacts stoichiometrically with primary amines, producing a chro-”

  • The paper relies on this without support.

    Ninhydrin reacts with free amino groups to form a chromophore that can be estimated spectrophotometrically.

    “The principle of the ninhydrin reaction is the spectrophotometric estimation of a chromophore formed when ninhydrin reacts with free ami no groups (fig 2b).”

  • The paper relies on this without support.

    OPA reacts with 2-mercaptoethanol and primary amines to form a fluorescent complex that also absorbs strongly at 340 nm.

    “o-Phthaldialdehyde (OPA) reacts with 2-mercaptoethanol and primary amines to fonn a fluorescent complex (I-alkylthio-2-alkylisoindole; fig 2d), which also absorbs strongly at 340 nm.”

  • The paper relies on this without support.

    Proteolysis is one of the principal biochemical events during cheese ripening.

    “Since proteolysis is one of the principal biochemical events during cheese ripening, it is desirable to include an assay for proteolysis in most chee se ripening studies.”

  • The paper relies on this without support.

    Ammonia is a major product of proteolysis in mould and bacterial surface-ripened cheese varieties.

    “Likewise, since ammonia is a major product of proteolysis in mould and bacterial surface-ripened varieties, it may be desirable to quantify ammonia.”

  • The paper relies on this without support.

    The coagulant does not produce free amino acids.

    “Since the coagulant does not produce free amino acids, their determination does not directly measure the contribution of the coagulant.”

  • The paper relies on this without support.

    The contribution of cheese microflora to cheese ripening is mainly in the production of short peptides and free amino acids.

    “since the contribution of cheese microflora (natural or modified) to cheese ripening is mainly in the production of short peptides and free amino acids”

  • The paper relies on this without support.

    The extractability of N varies with pH.

    “since the extractability of N varies with pH, an alternative method should be adopted.”

  • The paper relies on this without support.

    The pH of mould and bacterial surface-ripened cheese varieties increases during ripening.

    “mould and bacterial surface-ripened varieties are characterized by an increase in pH during ripening”

  • The paper relies on this without support.

    The rate and/or pattern of proteolysis may be influenced by location within a cheese.

    “The rate and/or pattern of proteolysis may be influenced by location within a cheese, eg, surface-ripened or young, brine-salted cheeses.”

  • The paper relies on this without support.

    Most MS techniques used to identify peptides involve the production of ions of the intact peptide.

    “Most MS techniques used to identify peptides involve the production of ions of the intact peptide.”

  • The paper relies on this without support.

    If high energies are used in MS, the peptide is fragmented and the masses obtained are those of the resulting fragments.

    “However, if high energies are used, the peptide is fragmented and the masses obtained are those of the resulting fragments.”

  • The paper relies on this without support.

    The microflora of essentially all cheeses is characterized by the growth of adventitious nonstarter lactic acid bacteria.

    “The microtlora of essentially ail chee ses is characterized by the growth of adventitious nonstarter lactic acid bacteria, NSLAB (typically Lactobacillus spp but also Pediococcus spp and perhaps other genera).”

  • The paper relies on this without support.

    The buffering capacity of cheese increases during ripening owing to the formation of ammonia, amino, imino and carboxyl groups.

    “The buffering capacity of cheese increases during ripening owing to the formation of ammonia, amino, imino and carboxyl groups.”

  • The paper relies on this without support.

    The caseins are insoluble in many solvents, but peptides produced from them may be soluble and thus the proportion of soluble nitrogen will increase with proteolysis.

    “The caseins are insoluble in many solvents, but peptides produced from them may be soluble and thus the proportion of soluble nitrogen will increase with proteolysis.”

  • The paper relies on this without support.

    Chitosan is polycationic at acid pH and can complex with negatively-charged molecules, leading to their flocculation.

    “Chitosan is polycationic at acid pH and thus can complex with negatively-charged molecules, leading to their flocculation.”

  • The paper relies on this without support.

    Ammonia is formed in cheese on the deamination of free amino acids.

    “Ammonia, formed in cheese on the deamination of free amino acids, is an important product of proteolysis in certain cheese varieties”
23 of 23

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Metadata

Authors
McSweeney, P. L. H., & Fox, P. F.
Affiliations
University College Cork (IE)
ORCID
McSweeney, P. L.H.
Venue
Le Lait
Publisher
EDP Sciences
Published
1997
Volume
77
Issue
1
Pages
41-76
ISSN
0023-7302 (ISSN-L)
DOI
10.1051/lait:199713
OpenAlex
W2167370004
Cited by
173
References
80
Citations by year
2026: 5 · 2025: 5 · 2024: 5 · 2023: 10 · 2022: 5 · 2021: 4 · 2020: 9 · 2019: 9 · 2018: 12 · 2017: 9 · 2016: 10 · 2015: 4 · 2014: 5 · 2013: 3 · 2012: 7
FWCI
14.26
Type
journal article
Language
en
Open access
Locations
  • Le Lait (publishedVersion)
  • HAL (submittedVersion, other-oa)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Food Nutrient Composition and Product Development
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Proteins in Food Systems
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Advanced Scientific Research Methods
Keywords
proteolysis, cheese ripening, soluble nitrogen, free amino acids, peptide identification, reactive functional groups

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