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50 The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008
Introduction
Increasingly, the characteristics of cheddar and other cheeses
that are used for secondary processing or as an ingredient in other
foods are being defined in business-to-business relationships.
Such specifications include inter alia ranges for pH and contents
of moisture, calcium and intact casein. This trend is expected, as
these compositional-related parameters affect the processability
of the curd/cheese and the resultant products containing the
cheese, e.g. hydration characteristics, chewiness, deformation-
related characteristics (e.g. stress and strain at facture) and
cooking properties (e.g. softening temperature and degree of
spread/melt). In contrast, apart from compliance with standard of
identity compositional requirements (usually minimum levels of
fat or FDM, and maximum moisture content), such specifications
are not imposed on table cheeses despite the fact that levels of
S/M, pH and MNFS have major affects on quality (O’Connor
1974; Fox 1975; Pearce and Gilles 1979; Lelievre and Gilles
1982). Surveys of retail cheddar cheeses have identified large
variations in composition and biochemistry when all categories
(e.g. mild, mature, extra mature, vintage) for both full-fat and
reduced-fat variants were considered together (Fenelon et al.
2000a; Guinee et al. 2000). Consequently, it would appear that
cheeses are frequently graded and selected to suit a particular
variety category, e.g. mild, mature or vintage in the case of
cheddar. Yet, a frequent question is whether manufacturing and
storage conditions can be selected to achieve certain biochemical
changes, sensory characteristics and category (e.g. vintage) of
cheddar cheese.
The objective of the current study was to assess the consistency
of leading retail brands of vintage cheddar cheese on the Irish
and UK market by evaluating the compositional, biochemical
and sensory parameters over a six-month period; it was hoped
that these analyses would suggest strategies for consistent
production of ‘generic’ vintage cheddar cheese.
Materials and methods
Cheese samples
Six different brands of full-fat cheddar cheese were procured
from retail stores in Ireland on six separate occasions, over a
six-month period; three were manufactured in Ireland and three
in the UK. These were arbitrarily assigned codes of A, B, C, D,
E and F. The brands would be generally considered as market
leaders in the vintage/mature cheddar cheese category. On
each purchasing occasion, a sufficient number of retail packs
(typically ~150 to 200 g) with the same sell-by dates were
purchased for each brand to enable the complete analysis.
Following purchase, samples were placed at refrigerated
temperatures (4 to 8°C) within ~3 h and grated for analysis
within 12 to 48 h.
How variable are retail vintage
brands of cheddar cheeses in
composition and biochemistry?
The authors
T.P. Guinee, K.N. Kilcawley and T.P. Beresford
Moorepark Food Research Centre, Teagasc Moorepark, Ireland.
Corresponding author: Tim Guinee, Moorepark Food Research
Centre, Teagasc Moorepark, Fermoy, County Cork, Ireland.
Fax: + 353 25 42340; E-mail: tim.guinee@teagasc.ie
Abstract
Six leading brands of mature/vintage full-fat cheddar cheese were
procured from retail stores in Ireland and the UK on six separate
occasions over a six-month period, and analysed for composition,
proteolysis, lipolysis and sensory characteristics. The aim of the
study was to assess the consistency of leading retail brands
of vintage cheddar cheese. Significant inter-brand differences
were evident for gross composition, with the magnitude of the
differences between means depending on the parameters: mean
salt-in-moisture, S/M 4.18% to 5.74% (w/w); moisture-in-non-fat
substances, MNFS 52.0% to 54.78% (w/w); fat-in-dry matter,
FDM 50.0% to 52.63% (w/w); total lactate 1.06% to 1.46%
(w/w); pH 5.09-5.38. The coefficient of variation (cv) of the mean
of the six brand means indicated that this variation was highest for
concentrations of L(+) and D(-) lactate (cv 25% and 50%) and
S/M (cv ~12%), and comparatively low (<5%) for MNFS, pH and
calcium-to-protein ratio. Similarly, significant inter-brand variation
was noted for degrees of proteolysis with the mean pH 4.6 soluble
N varying from 28% to 34% of total N, total free amino (FAA)
acids from 27,000 to 57,000 mg/kg, ratio of FAA nitrogen to pH
4.6 soluble N from 30% to 70%, and free fatty acids (FFA) from
~900 to 1600 mg/kg. Intra-brand inconsistency in composition,
and degrees of proteolysis and lipolysis were also notable,
especially for concentrations of S/M (cv 4% to 20%), D(-) lactate
(cv 30% to 110%), total FFA (cv 7% to 35%) and total FAA acids
(cv 11% to 63%). Inter- and intra-brand variations in composition
and biochemistry coincided with differences in aroma, flavour and
texture attributes, and the scores for maturity and acceptability.
Variations in milk composition, manufacturing conditions/
technology, and added starter cultures/enzyme preparations are
discussed as probable causes of the inconsistencies between
and within brands.
Aust. J. Dairy Technol. 63, 50-60
RESEARCH PAPER
The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008 51
Cheese analyses
Cheese composition
Grated cheeses were analysed in triplicate for protein, fat, salt,
moisture, Ca and P, using standard IDF methods, as described by
Guinee et al. (2007); the pH was measured on a cheese slurry
prepared from 20 g of cheese and 12 g de-ionised water (British
Standards Institution 1976). The concentrations of D(-)- and L(+)-
lactate were measured using a Boehringer Mannheim UV test kit
(Cat. No. 11 112 821 035, Boehringer Mannheim/R-Biopharm
AG, Darmstadt, Germany), as described by Rynne et al. (2007).
Proteolysis
Urea-polyacrylamide gel electrophoresis (urea-PAGE) of cheese
samples was performed on a PROTEAN® II xi cell vertical slab
gel unit (Bio-Rad Laboratories Ltd, Hemel Hempstead, Herts,
UK), using a separating and stacking gel system, as described by
Fenelon et al. (2000a). The sample buffer (pH 8.7) was prepared
by dissolving 0.75 g Tris (hydroxymethyl)-methylamine, 49 g
urea, 0.7 mL mercaptoethanol and 0.15 g bromophenol blue
in de-ionised water to a final volume of 100 mL. Cheeses
(i.e. ~15.6-16 mg) were dissolved on a protein basis (4.9 mg
protein) in 1 mL of sample buffer and were incubated at 55°C
for 15 min; a sample of sodium caseinate, dissolved in 1 mL of
sample buffer at a level (5.8 mg) to give an equivalent protein
load, was used as a control marker. The gels (1 mm thick) were
pre-run at 280 V for 35 min before sample loading.
The level of pH 4.6-soluble cheese nitrogen (pH 4.6-SN),
expressed as percentages of total nitrogen (TN), was measured
as described by Fenelon et al. (2000b). Free amino acids
(FAA) were determined on filtrates prepared by mixing equal
quantities of 24% trichloroacetic and pH 4.6 soluble-SN extract,
as described by Kilcawley et al. (2006). Supernatants were
removed and diluted with 0.2 M sodium citrate buffer, pH 2.2
to give approximately 250 nmol of each amino acid residue.
Samples were then diluted one in two with the internal standard,
norleucine, to give a final concentration of 125 nm/mL. Amino
acids were quantified using a Jeol JLC-500/V amino acid
analyser (Jeol, UK Ltd, Garden city, Herts, UK) fitted with a Jeol
Na+ high-performance cation exchange column.
Free fatty acids
Free fatty acids (FFA) (C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0,
C18:0, C18:1, C18:2 and C18:3) were determined in cheeses by gas
chromatograph flame ionised detection, using the method of de
Jong and Badings (1990), as modified by Hickey et al. (2006).
Cheese grading
Five personnel at Moorepark Food Research Centre experienced
in the sensory assessment of cheddar cheese graded each batch
of cheese the day after purchase. The cheeses were allowed
to stand at room temperature for 1 hr before evaluation. Each
assessor commented on their overall acceptability in terms of
flavour and texture and made comparisons to other batches of the
same cheese and to the other cheeses sampled at that time. These
comments were compiled and an agreed general description of
each cheese was taken. To summarise intra-brand variability and
inter-brand acceptability each cheese was assigned a score 1, 2,
3, 4 or 5 based on the agreed general descriptions, where 1 =
excellent, 3= average and 5 = poor.
Descriptive sensory analysis
The six samples of cheese in the last batch were vacuum
packed in dry ice and shipped to Charis Food From Thought Ltd
(Hannah Research Park, Ayr, Scotland, UK). On arrival they were
transferred to the cold store at 4°C until evaluated within one
week. The samples were equilibrated to room temperature before
presentation to a trained panel for assessment. The assessors
rated the cheese according to the following attributes:
1. Aroma – intensity, creamy/milky, sulphur/egg, fruity/sweet,
rancid, acid/sharp, musty, pungent and unclean/manorial.
2. Flavour – intensity, creamy/milky, sour/acid, sulphur/egg,
fruity/sweet, rancid, bitter, unclean/manorial and salty.
3. Texture – firmness, rubbery, crumbly, grainy and mouth-
coating.
4. Maturity Index – where a score of 1 corresponds to the most
mature and 6 to the least.
The samples were coded and presented in a defined order to
allow assessment of sample, assessor order, of tasting, carry over
and session effects. Kitchen sheets were prepared using Sensory
software (KwikSense) and data was collected using a computer-
assisted interface. The panel of 14 assessors was highly trained
and experienced in the evaluation of cheese. Assessment of each
of the six cheeses was carried out in triplicate, with three samples
being assessed in each of six sessions. Sample assessment was
carried out in isolated, purpose-built booths with controlled air
flow and lighting. Assessors were invited to rinse their palates
between samples using a plain savoury biscuit and cold mains
water. The experimental results were collated and analysed using
KiwkSense package. The panel mean values for each attribute
(three replicates) were computed. Sensory space maps were
constructed after principal component analysis of the correlation
matrix of the attributes.
Statistical analysis
The data were analysed using a randomised complete block
design which incorporated six treatment levels (cheese brands)
and six blocks (replicate samples of each brand). Analysis of
variance (ANOVA) was carried out using a SAS procedure (SAS
2003) where the effect of treatment and replicates were estimated
for all response variables. Duncan’s multiple-comparison test
was used as a guide for pair comparisons of the treatment means.
The level of significance was determined at p<0.05. Descriptive
analysis was performed on one batch of samples and the data are
included as observations only.
The data for some response variables were also analysed by
linear regression to establish possible correlations between
the response variables (e.g. salt-in-moisture and pH). The
significance of correlations were determined by applying
Students t test to r2 with n-2 df where n is the actual number of
data points, and df is the degrees of freedom.
Results and discussion
Composition
The compositions of the cheeses are shown in Table 1. Based
on the compositional specification of cheddar (≤39% w/w
moisture, ≥50% w/w FDM) as defined in the Code of Federal
Regulations (FDA 2005), the mean composition of each cheese
type was within specification. However, examination of the total
how variable are reTail vinTage brands of cheddar cheeses in comPosiTion and biochemisTry?
52 The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008
data set (Figure 1) indicated that a total of six of the 36 cheeses
(two from each of groups A, C and F) had FDM <50% (w/w).
Linear regression analysis indicated that S/M content was
negatively correlated with concentration of lactate (p<0.001;
r = - 0.78, df = 34) and positively with pH (p<0.01; r = - 0.78,
df = 34) (Figure 2). The role of the S/M level in regulating the pH
and lactate content of cheddar cheese was clearly demonstrated
in earlier studies (O’Connor 1974; Thomas and Pearce 1981)
and has been attributed to the strain-specific inhibitory effects
of NaCl on the growth of starter culture bacteria and lactic acid
production (Martley and Lawrence 1972; Turner and Thomas
1980). The importance of lactic acid content in regulating
cheese pH is evident from the relationships between pH with
S/M level (Figure 2). Hence, in washed curd cheeses that are not
brine-salted until after pressing (e.g. gouda), the pH is carefully
regulated by controlling the level of lactose (and ultimately lactic
Table 1. Composition of different retail brands of cheddar cheese.1,2
Cheese brand
Cheese composition A B C D E F SED3
Moisture (%, w/w) 35.81b 34.24c 36.02b 34.92c 35.72b 37.70a 0.35
Fat (%, w/w) 32.43c 34.21a 32.00d 34.34a 33.25b 31.18 0.30
Protein (%, w/w) 25.61b 25.77ab 26.12a 24.75c 24.57d 25.25bc 0.30
S/M (%, w/w) 5.55ab 5.20ab 4.86bc 55.74a 5.57ab 4.18c 0.34
FDM (%, w/w) 50.38b 52.02a 50.01b 52.63a 51.85a 50.05b 0.40
MNFS (%, w/w) 52.92bc 52.05c 53.00bc 53.11b 53.57b 54.78a 0.44
pH (%, w/w) 5.21bc 5.12bc 5.19bc 5.38a 5.28ab 5.09c 0.08
Ca (mg g-1 protein) 28.99ab 27.98b 28.46ab 29.36a 29.09a 28.24ab 0.54
D(-)-lactate (%, w/w) 0.35ab 0.06c 0.34ab 0.31ab 0.41a 0.19bc 0.09
L(+)-lactate (%, w/w) 0.94b 1.17a 0.93b 0.75b 0.85b 1.27a 0.09
pH 4.6 soluble N (% of total N) 28.91b 32.13ab 29.0b 29.43ab 33.98a 29.19ab 2.15
Notes:
1. Cheeses were purchased from retail outlets in Ireland and UK, and were chosen to represent the major brands of mature to very mature flavoured
cheese.
2. Values presented are the means of six replicate samples for each cheese; the six samples of each brand were purchased from the same store on
six different occasions at monthly intervals.
3. SED, standard error of difference.
51
52
52
53
53
54
54
55
55
56
56
MNFS(% w/w
)
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
S/M (% w/w
)
4.9
5.0
5.1
5.2
5.3
5.4
5.5
5.6
pH
0.6
0.8
1
1.2
1.4
1.6
1.8
A
A
A
A
A
A
B
B
B
B
B
B
C
C
C
C
C
C
D
D
D
D
D
D
E
E
E
E
E
E
F
F
F
F
F
F
Cheese Brand
Total lactate (% w/w)
48
49
50
51
52
53
54
FDM (% w/w
)
24
28
32
36
40
A
A
A
A
A
A
B
B
B
B
B
B
C
C
C
C
C
C
D
D
D
D
D
D
E
E
E
E
E
E
F
F
F
F
F
F
Cheese Brand
pH 4.6-SN (% total N
)
Figure 1: Moisture in
non-fat substances
(MNFS), fat-in-dry
matter (FDM), salt-in-
moisture (S/M), pH,
total lactate and pH 4.6
soluble N (pH4.6-SN) in
retail brands of vintage
cheddar cheese: A (),
B (), C (), D (),
E () and F (). For
each brand, there are
six replicate samples
corresponding to repeat
purchases at monthly
intervals over a six-
month period.
guinee, kilcawley and beresford
The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008 53
acid) in the moisture phase of the cheese by adding water to
the curd-whey mixture in the vat, at a level proportional to the
lactose concentration of the milk (van den Berg et al. 2004).
There were significant inter-brand differences in the mean
values for all compositional parameters (Table 1), with the
magnitude of the difference dependent on the compositional
parameter. The CV of the mean of the means of the six brands
indicates that this variation was highest for concentrations of
L(+) and D(-) lactate (cv, 25 and 50%) and S/M (cv ~12%),
intermediate (7-10%) for pH 4.6 S-N and total lactacte, and
comparatively low (cv ~3%) for other parameters (MNFS, pH
and calcium-to-protein ratio) known to effect quality (Lelievre
and Gilles 1982). The inter-brand differences suggest that
leading brands of retail cheddar can be obtained by different
combinations of compositional parameters. For example
the D-cheese had high mean levels of S/M, FDM and pH, a
medium level of MNFS (Figure 1), and relatively low levels
of total lactate (Figure 1), compared to F-cheese which had
low levels of FDM, S/M and pH and high levels of MNFS and
total lactate. However, the inter-brand compositional variation
in these cheeses was associated with differences in flavour, as
discussed later.
Intra-brand variation was also clearly evident, as reflected by
the compositional differences between the six samples of each
cheese brand purchased on different occasions over the six-
month monitoring period (Figures 1-3). Again, this was most
pronounced for concentrations of S/M and lactic acid (especially
for D(-)-lactate), and was higher than the corresponding inter-
brand variation.
The inter- and intra-brand compositional differences can be
ascribed to: differences in milk composition (e.g. casein level,
protein-to-fat ratio; Guinee et al. 2006, 2007), as evidenced by
the inter-brand variation in protein-to-fat ratio of the cheeses (cv,
5.6%); activity of starter cultures used (Fenelon et al. 20002), and/
or manufacturing conditions such as pasteurisation temperature,
gelation conditions, cut firmness, pH at different stages, level of
salt addition and others. In commercial practice, rennet and starter
culture are generally added to milk at a level based on milk volume
(rather than on weight of casein) and the resultant gel is cut after a
defined (recipe) time rather than at a given firmness. This practice
is conducive to differences in gel firmness at cut, moisture content
of the curd, salt uptake at milling, level of curd lactose and pH of
the cheese (Guinee and Fox 2004), when using a milk supply that
varies in the contents of casein, fat and lactose throughout the year.
Consequently, intra-brand compositional differences in cheddar
cheese associated with seasonal variation in milk composition could
be significantly reduced by standardisation of the casein or protein
content (e.g. by ultrafiltration, microfiltration and/or addition of
micellar casein powders or milk protein concentrates) and casein-
to-fat ratio of the cheese milk (Guinee et al. 2006, 2007).
The relatively high degree of variation of NaCl and S/M
within brands is somewhat surprising considering that salting
technologies in large modern factories are highly automated
(Bennett and Johnston 2004) and would appear to be particularly
amenable to ensuring accurate control of salt concentration
with respect to level and uniformity. It may reflect differences
in the level of salt application, salt uptake by the curd and
salt distribution (Guinee and Fox 2004). For a given salting
rate, the level of added salt absorbed by curd may be affected
by many factors including inter alia moisture level of curd;
curd pH as influenced by starter-to-casein ratio and rate of
acid development; rate of curd throughput which depends on
0.6
0.8
1.0
1.2
1.4
1.6
1.8
3 4 5 6 7 8
Total la ctate (% w/w
)
4.8
5.0
5.2
5.4
5.6
5.8
345678
Salt-in-moisture (% w/w)
pH
Figure 2: Relationships between compositional parameters
in retail brands of vintage cheddar cheeses; the pooled
data set comprised 36 values from six brands with six
replicate samples of each. Linear regression lines (─) were
fitted to the experimental data () in each case.
0
5
10
15
20
25
A B C D E F
Coefficient of variation (%)
FDM
MNFS
S/M
pH
0
20
40
60
80
100
120
A B C D E F
Cheese Brand
Coefficient of variation (%)
D (-) Lac
L(+) Lac
Total Lac
pH 4.6 S-N
Figure 3: Coefficient of intra-brand variation in retail brands
of vintage cheddar cheese for (3a): fat-in-dry matter (FDM),
moisture-in-non-fat substances (MNFS), salt-in-moisture
(S/M) and pH, and (3b): D(-) lactate, L(+) lactate, total
lactate, and pH 4.6 soluble N (pH4.6-SN). Six replicate
samples of six brands of cheese were procured at monthly
intervals; the presented data show the coefficient of
variation of the data for each brand (A-F) for the different
compositional parameters.
how variable are reTail vinTage brands of cheddar cheeses in comPosiTion and biochemisTry?
54 The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008
concentrations of protein and fat in milk and which can affect
the size of curd chip, depth of curd on salting belts and curd
temperature (Guinee and Fox 2004). The large intra-variation
in lactate undoubtedly resides in the seasonal variation in the
concentration of milk lactose which is highest in early/mid
lactation and thereafter decreases progressively with stage
of lactation; however, differences in moisture also contribute
(Rynne et al. 2007). Washing of cheddar curd, as practiced in the
manufacture of gouda cheese, by adding water to the curd/whey
mixture in the vat, should help to standardise the concentration of
lactose, and hence lactic acid, in the moisture phase of the curd
and thereby assist the manufacture of cheese more consistent in
lactate content and pH throughout the year. However, cheese pH
is also affected by other factors, such as the buffering capacity
of cheese which is affected by pH at whey drainage and degree
of casein mineralisation.
Proteolysis
pH 4.6 Soluble N (pH 4.6S-N)
The level of pH 4.6 soluble N in cheese is an index of the
overall degree of proteolysis, with the pH 4.6 soluble extract
comprising a very heterogeneous mixture (Singh et al. 1994)
mainly of peptides with molecular mass <10 kDa and free amino
acids (Fenelon et al. 2000a). The overall levels of pH 4.6 soluble
N ranged from ~26% to 40% total N (Figure 1). The scale of
values, though similar in magnitude to that (19% to 38% total
N) reported by Reville and Fox (1978) for commercial cheeses
ranging in age from 2.5 to 18 months, was quite high relative
to values reported more recently for retail cheddar cheeses,
e.g. 22% to 27% (Fenelon et al. 2000a; Kilcawley et al. 2007)
and 13.2% to 24.7% (Guinee et al 2000). This undoubtedly
reflects the mature/vintage designation of the current cheeses.
Significant inter-brand differences were evident between
the current cheeses, with the E-cheese having a significantly
higher level than that of A-cheese and the remaining cheeses
having intermediate values (Table 1). The higher level of pH
4.6S-N in the E-cheese is consistent with the very high level of
breakdown of αs1-and β-CN (Figure 4). Based on composition,
one might expect higher levels in the F- or C-cheeses because
of their significantly lower values of S/M and pH, and higher
mean MNFS content (Guinee and Fox 2004). However, the
degree of proteolysis is also strongly influenced by factors other
than composition, e.g. including ripening time and temperature,
type and level of coagulant, and the addition of exogenous
proteinases to the cheese milk or curd. Thus, linear regression
analysis indicated the lack of significant relationships between
the level of pH 4.6 S-N and S/M, MNFS, FDM or pH. The
current results highlight the complexity of proteolysis in cheese
and the difficulty in assigning inter-brand differences to specific
compositional factors, especially when comparing retail cheeses
that may vary with respect to milk composition, make procedure
and storage conditions.
Intra-brand variations in pH 4.6 S-N were also evident, with
the CV ranging from ~8% for the D-cheeses to 14.5% for the
E- and F-cheeses. Since the manufacture of a given brand
(recipe) of cheese within a plant presumably has a ‘standard’
operating procedure, then intra-brand variation is most likely
associated with variations in ratio of residual coagulant (as
affected by addition of rennet on a volume basis to cheese milk
varying seasonally in protein content), and the associated intra-
variety variations in cheese composition, as discussed above.
However, changes in manufacturing procedure throughout
the cheesemaking may also contribute. Feedback from the
production sector, suggests that, because of seasonal variations
in volume and composition of the milk supply, cheeses of a
given type (e.g. vintage) are frequently made with different
recipes and to different compositions so as to alter maturation
rates and achieve an end product that is as consistent as possible
for delivery to the consumer after different ripening times; this
approach assists in provision of continuous supply of particular
brands on a year-round basis.
αS1-CN(f24-199)
αS1-CN(f102-199)
αS1-CN(f24-199)
αS1-CN(f102-199)
αS1-CN(f24-199)
αS1-CN(f102-199)
γ2-CN
γ1-CN
γ3-CN
β-CN
αS1-CN
CN A A A A A B B B B B
CN E E E E F F F F F
γ2-CN
γ1-CN
γ3-CN
β-CN
αS1-CN
CN C C C C C D D D D D γ2-CN
γ1-CN
γ3-CN
β-CN
αS1-CN
(i)
(ii)
(iii)
Figure 4: Urea polyacrylamide gel electrophoretograms
of sodium caseinate (CN) and retail brands of vintage
Cheddar cheese: A and B (i), C and D (ii) and E and F (iii).
For each brand, five replicates amples (e.g. A1, A2, A3, A4,
A5 for the A-cheese) purchased at monthly intervals, were
analysed, except in the case of brand F where only four
replicate samples were tested.
guinee, kilcawley and beresford
The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008 55
Urea Polyacrylamide Gel Electrophoresis (PAGE)
The gel electrophoretograms of five of the six samples of each
brand are shown in Figure 4. The brands differed with respect to the
degree of degradation of αs1- and β-caseins and to a lesser extent
with pattern of breakdown fractions. Overall, casein hydrolysis was
most extensive in the E-cheese and least in the C-cheeses.
For all the A-, B-, C-, D- and F-cheeses (apart from A1 and
B1), the degree of intact β-casein was notably higher than that
of αs1-casein. This concurs with the general pattern observed for
experimental and retail cheddar cheeses of varying fat content
(Fenelon et al. 2000b). The opposite trend was noted for the
E-cheeses, where β-casein, which would have been present in the
freshly made cheese, was completely degraded in all samples.
For all brands, including the E-cheeses, the major breakdown
products of the β-casein were γ-CNs.
Despite differences between the cheeses within any one brand,
some inter-brand differences were notable. The level of intact
β-casein decreased in the following order: B-cheeses ≈ C-cheeses
≈ F-cheeses > D-cheeses > A-cheeses > >E- cheeses. The lower
level in the E- and A-cheese brands may reflect increasing
proteolytic activity of residual coagulant, as affected by higher
addition levels to the milk during cheese manufacture (de Jong
1977), higher ripening temperatures (Feeney et al. 2001) and/or
longer maturation times. It may also indicate a higher activity of
plasmin (the alkaline milk proteinase) (Upadhyay et al. 2004),
even though the relatively low pH of the current cheeses (all
brands), compared to varieties such as gouda or swiss, would
be unfavourable to plasmin activity. Differences in composition
(Figure 1, Table 1) and make procedure (e.g. pH at whey drainage
and coagulant retention) may also have contributed to differences
between the gel electrophoretic profiles of the brands.
αs1-Casein was extensively hydrolysed in all cheeses, with
levels of residual αs1-CN being generally lowest for B- and
E-cheeses. The main breakdown products for the A-, B-, C-,
D- and F-cheeses were αs1-CN(f24-199) (αs1-I), the primary
degradation product αs1-CN by chymosin or pepsin (O’Keeffee
et al. 1978; Visser and de Groot-Mostert 1977), and peptides
with higher electrophoretic mobility that probably correspond
to αs1-CN(33-+) and αs1-CN(60-+), as identified by McSweeney
et al. (1994) and Mooney et al. (1998). The E-cheeses differed
quite markedly, their patterns showing little or no αs1 -CN
(f24-199) and relatively high concentrations of peptides with
higher electrophoretic mobility.
The more extensive degradation of β-casein and advanced
hydrolysis of αs1-CN(f24-199) in the E-cheeses suggest the use of
a more proteolytic coagulant/coagulant blend (e.g. Cryphonectria
parasitica proteinase, CPP) (Dave et al. 2003) and/or the addition
of exogenous proteinases such as Neutrase or Papain to the cheese
milk or curd (Wilkinson et al. 1992; Madsen and Qvist 1998;
Guinee 2005). It is noteworthy that a decrease in the ratio of
chymosin-to-CPP in the coagulant for cheddar cheese resulted in
more extensive hydrolysis of β-casein, slightly less breakdown
of αs1-casein, less accumulation of αs1-CN(f24-199), and higher
levels of αs1-casein fractions with higher elctrophoretic mobility
(Dave et al. 2003). Indeed, the electrophoretic pattern of a
120-old cheese made using a 33:66 chymosin-to-CPP blend was
quite similar to the degradation pattern of the E-cheeses (Kim
et al. 2004). It is unlikely that differences in the electrophoretic
pattern between the E- and other cheeses could be ascribed
to differences in types of starter culture and/or starter culture
adjuncts, as these are generally regarded as having little
impact on casein degradation patterns (O’Keeffe et al. 1978;
Table 2. Levels of free amino acids in different retail brands of cheddar cheese.1,2
Cheese brand
Free amino acid (mg kg-1) A B C D E F SED3
Cysteic acid 718b 1,062a 830b 661b 880ab 717b 311
Aspartic 856b 1,606a 616b 484b 1,606a 746b 179
Threonine 1,106b 1,003b 780b 746b 1,863a 846b 279
Serine 1,193ab 1,194ab 881b 548b 1,930a 998ab 454
Glutamic 7,371b 6,822b 5,249b 4,889b 11,486a 6,025b 1,274
Glycine 778b 661b 538b 521b 1,162a 579b 134
Alanine 908b 727b 663b 573b 1,614a 692b 160
Cysteine 73ab 130a 91ab 74ab 48b 120a 26
Valine 2,435b 2,246b 1,768b 1,632b 4,297a 1,941b 471
Methionine 887cb 973b 714cb 602c 1,592a 785cb 150
Isoleucine 1,829b 1,433b 1,110b 953b 3,627a 1,316b 463
Leucine 4,010b 4,299b 3,293b 3,200b 5,568a 3,548b 548
Tyrosine 948ab 1,075a 832ab 745b 1,008a 976ab 112
Phenylalanine 2,272b 2,131b 2,040b 1,751b 3,227a 2,029b 245
Histidine 1,533b 1,191b 1,142b 1,162b 2,210a 1,198b 211
Lysine 4,244b 4,244b 2,634b 2,757b 6,839a 2,970b 890
Arginine 546b 2,226a 51c 560b 59c 99c 137
Proline 2,817b 905c 1,563bc 1,706bc 4,562a 1,672bc 719
Total (%, w/w) 3.56b 3.34b 2.62b 2.43b 5.73a 2.83b 0.62
Notes:
1. Cheeses were bought from retail outlets in Ireland and UK, and were chosen to represent the major brands of mature to very mature flavoured cheese.
2. Values presented are the means of six replicate samples for each cheese; the six samples of each brand were purchased from the same store on
six different occasions at monthly intervals.
3. SED, standard error of difference.
how variable are reTail vinTage brands of cheddar cheeses in comPosiTion and biochemisTry?
56 The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008
Hannon et al. 2003), except at very high levels of coagulant usage
(e.g. six x normal levels) (Dave et al. 2003).
Free Amino Acids (FAA)
The concentrations of total and individual free amino acids
(FAA) are shown in Table 2. Reflecting the mature flavour
descriptions of the current cheese, the mean concentrations
(mg/kg) of total FAA in all brands were comparatively high
(24,000 to 57,000) relative to those reported in previous studies
for full-fat cheddar, e.g. 28,000 (Fox and Wallace 1997), 10,000
(Fenelon et al. 2000a) or 21,000 (Fenelon et al. 2000b).
The E-cheese had a significantly higher level of total FAA than
that of all the other cheeses, for which the concentrations did not
statistically differ (Table 2). Moreover, the degree of intra-brand
variation was markedly lower for the E-cheese, as evidenced by
the relatively low CV (11.7%), which in the remaining cheeses
ranged from 21% (B-cheese) to 63% (C-cheese). Relative to
the level of pH 4.6-SN, the mean concentration of FAA was
also highest in the E-cheese (Figure 5). The very high level in
the E-cheese suggests a high level of peptidase activity, which
degrades large peptides in the pH 4.6 soluble N fraction that are
produced by residual coagulant and/or plasmin. Such peptidase
activity may reflect: the use starter cultures or culture adjuncts
containing strains that are strongly autolytic and rich in peptidase
activity (Fenelon et al. 2002; Hannon et al. 2003); addition of
exogenous peptidase; and/or environmental conditions within
the cheese matrix more suitable to bacterial proteinase/petidase
activity (Gobbetti et al. 1999a,b). Because of the contribution
of FFA to flavour, it is expected that the differences in FAA type
and concentrations in the current study would lead to differences
in flavour and aroma.
Taking the complete set of 36 cheeses, the major free amino
acids in descending order were glutamic acid, leucine, lysine,
alanine, phenylalanine, proline and isoleucine. However, the
relative concentrations of the individual FAA as a percentage
of total FAA varied with cheese brand, reflecting the trend
reported in different studies (Fox and Wallace 1997, Fenelon
et al. 2000a,b; Hannon et al. 2007). The principal free amino
acids in descending order for the cheese brands with the
highest (E), lowest (D), and intermediate (closest to mean of
all brands) (B) levels were: Glu, Lys, Leu, Pro, Val, Ile; Glu,
Leu, Lys, Phe, Pro, Val, His; and Glu, Leu, Lys, Val, Arg, Phe,
and Ile, respectively. The different ratios undoubtedly represent
differences in peptidase activities as affected by the use of
different preparations of starter culture (Fenelon et al. 2002;
Hannon et al. 2007) and/or commercial enzymes.
Lipolysis
Short chain free fatty acids (C4-C10), in particular, have
low flavour perception thresholds, and contribute to rancid,
cheesy, piccante flavours (Molimard and Spindler 1996). The
concentrations of individual and total FFA for all cheeses are
given in Table 3. The mean levels for all cheeses were within the
range typically reported in commercial cheddar cheeses (Woo
and Lindsay 1982; Kilcawley et al. 2007) and for experimental
10
20
30
40
50
60
70
80
A B B D E F
Cheese Brand
Amino Acid N ( % of pH 4.6 Sol-N
)
Figure 5: Mean levels of amino acid N (as % pH 4.6 soluble
N) in retail brands (A-E) of vintage cheddar cheese;
presented data show the mean of the six replicate samples
for each brand and error bars show the standard deviation
of each brand mean.
Table 3: Levels of free fatty acids in different retail brands of cheddar cheese.1,2
Cheese brand
Free fatty acid (mg/kg) A B C D E F SED3
C4:0 63b 67b 54b 53b 97a 46b 9.3
C6:0 20b 28a 18b 15b 30a 15b 3.5
C8:0 13bc 16ab 13bc 10c 19a 10bc 2.6
C10:0 40ab 43ab 36b 31b 51a 35b 6.9
C12:0 53b 57ab 56ab 46b 68a 48b 18.6
C14:0 134b 148ab 130b 121b 173a 112b 16.8
C16:0 287cb 342b 294cb 314cb 440a 245c 34.9
C18:0 93b 86b 97b 81b 139a 77b 13.5
C18:1:0 340b 317b 315b 349b 510a 281b 52.0
C18:2:0 9b 8b 5b 15b 30a 7b 4.9
C18:3:0 4ab 6ab 3b 6ab 8a 5ab 2.3
Total 1,055b 1,118b 1,021b 1,040b 1,565a 882b 137.5
Total FFA (% total fat) 0.326b 0.327b 0.319b 0.303b 0.470a 0.282b 0.042
Notes:
1. Cheeses were bought from retail outlets in Ireland and UK, and were chosen to represent the major brands of mature to very mature flavoured cheese.
2. Values presented are the means of six replicate samples for each cheese; the six samples of each brand were purchased from the same store on
six different occasions at monthly intervals.
3. SED, standard error of difference.
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The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008 57
cheeses ripened at 8°C for six to nine months (Hickey et al. 2006,
2007). The total FFA content in the E-cheeses was significantly
higher than that in the other cheeses. The F-cheeses had the
lowest variation (cv 6.7%), with A-cheeses having the highest
(cv 34.7%). The variation of the remaining cheese groups was
between 15.1% and 21.0%. Some differences were observed for
individual FFA between the samples, but the proportions of short
chain (SCFA), medium chain (MCFA) and long chain (LCFA)
fatty acids, as percentage of total FFA, were similar, except that
the D-cheeses had a non-statistically lower ratio of SCFFA and
the B-cheeses had a lower ratio of LCFFA. When expressed as a
percentage of milkfat, the total FFA concentration in all cheeses
(0.2 to 0.5) was lower than that (2%) considered necessary to
induce rancid off flavours in cheeses such as cheddar and gouda
(Gripon, 1993). However, perception of lipolytic rancidity is
influenced by the extent of proteolysis and pH, with lower FFA
inducing rancid flavour at low levels of proteolysis and pH
(Hickey et al. 2006).
Cheese grading and descriptive sensory analysis
The mean assessment scores and sensory attributes for each
cheese brand are given in Tables 4 and 5, respectively. While the
mean score was not significantly affected by brand, the D-cheeses
received the highest (numerical) score for overall acceptability
and were also deemed to be the least variable. These cheeses were
characterised by their creamy smooth texture, balanced medium
flavour with a hint of sweetness. The F-cheeses also scored well
and were less variable than the A-, B-, C- and E-cheeses, being
Table 4: Acceptability grading assessment on each batch of cheese.1,2
Cheese Brand Description Score3 Mean (cv %)4
A A1 Very sweet, fruity, not like cheddar, lactate crystals, crumbly 5
A2 Sweet, unlike cheddar, brittle and crumbly 5
A3 Sour, salty, unbalanced, body acceptable, poor cheese 5
A4 Hint of sweetness, cheddar like, creamy texture, nice cheese 2
A5 Balanced, medium cheddar, slightly sweet, clean a good firm body 2
A6 Mature balanced cheddar, slightly fruity with a good firm body 2 3.50a (46.8%)
B B1 Mild, balanced, slightly salty with a creamy texture 4
B2 Balanced, good mature cheddar, firm, slightly crumbly, very good 1
B3 Ok, balanced, but slight off-flavour (astringent/metallic), gritty body 3
B4 Not balanced, bitter, salty, brothy, but intense – mature 4
B5 Very mature, sharp but clean, nice cheese 2
B6 Mild, dry texture, burnt after taste, poor cheese 5 3.17a (46.4)
C C1 Good strong flavour, sharp, slightly mealy, gritty 2
C2 Intense, but rancid/gastric notes, brittle and crumbly – poor 5
C3 Sour, savoury, slight putrid notes, not balanced, slightly crumbly 4
C4 Clean balanced medium mature, smooth texture 2
C5 Not balanced, a little sour, slightly crumbly 4
C6 Acidic, sharp, sour aftertaste, slightly pasty/sticky texture 4 3.50a (34.8)
D D1 Mature, slightly salty, well balanced with a creamy texture 1
D2 Good medium balanced, slightly acidic, hint of bitterness/astringency 2
D3 Strong mature, balanced, little salty, a little sweet 2
D4 Quite sweet a nice little cheese, creamy texture 2
D5 Medium cheese, slightly bitter, smooth texture 3
D6 Hint of acid, fruity, brittle texture 3 2.17a (34.6)
E E1 Ok cheese, slightly sweet with a crumbly body 3
E2 Strong mature, acidic going sweet, firm body, nice cheese 2
E3 Very acidic, hint of sweetness, crystals but firm body 3
E4 Brown, toffee, caramelised unlike cheddar 5
E5 Very sweet, sharp with a firm body 3
E6 Slightly sweet, hint of acid, nearly balanced, slightly brittle 2 3.00a (36.6)
F F1 Astringent, wet, slightly crumbly and crunchy 4
F2 Very strong mature, little acidic/sweet, not balanced, firm body 3
F3 Very intense mature, balanced with hint of lactate, slightly crumbly 2
F4 Intense mature, slightly sweet/savoury, mealy texture but good 2
F5 Sweet mature with slight rancidity, firm body 4
F6 Good mature, hint of acidity and nutty notes, crumbly with crystals 2 2.83a (34.6)
Notes:
1. Cheeses were purchased from retail outlets in Ireland and UK, and were chosen to represent the major brands of mature to very mature flavoured
cheese.
2. Values presented are the means of six replicate samples for each cheese; the six samples of each brand were purchased from the same store on
six different occasions at monthly intervals.
3. The standard error of difference (SED) was 0.77.
4. cv, coefficient of variation.
how variable are reTail vinTage brands of cheddar cheeses in comPosiTion and biochemisTry?
58 The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008
characterised by a crumbly texture and mature acid flavour.
Cheeses A, B and E received identical scores; A cheeses were
found to have variable texture, with sweet notes, B-cheeses had
variable texture and flavour, while E-cheeses had firm texture but
variable flavour. The C-cheeses received negative scores and were
deemed to be crumbly with variable flavour.
The last batch of cheese sampled was assessed by a descriptive
panel for aroma, flavour and texture attributes, and indexed based
on perceived maturity and acceptability. Significant differences
(p<0.05) between cheese brands were evident for ‘intensity’,
‘acid/sharp’ and ‘unclean/manurial’ aroma attributes and
‘intensity’, ‘sour/acid’, ‘sulphur/eggy’, ‘fruity/sweet’, ‘rancid’,
‘bitter’ and ‘unclean/manurial’ flavour attributes. Brands also
differed for all five textural attributes (‘firmness’, ‘rubbery’,
‘crumbly’, ‘grainy’ and ‘mouthcoating’). As these cheeses
are marketed as vintage cheddar, they were also assessed for
their perceived maturity and found to be significantly different.
Cheese E was perceived as the most mature (index score = 1) and
Cheese D (index score = 6) was deemed the least mature (Table
5). Figure 6 is a PCA plot of the most significantly different
attributes that best described the cheeses. Both cheese A and D
were deemed quite similar. The remaining cheeses were shown
to be quite different and characterised by ‘rubber’, ‘bitter’,
‘crumbly’ or ‘grainy’ nature.
Table 5: Descriptive sensory analysis of retail brands of vintage cheddar cheese.1,2
Cheese brand A B C D E F SED3 p<0.05
Flavour attributes
Intensity 59.2 29.6 66.1 56.1 64.5 61.3 1.80 Yes
Creamy/milky 38.0 36.6 40.6 40.5 33.6 34.7 3.65 No
Sour/acid 30.9 36.0 34.3 25.0 33.8 34.2 1.66 Yes
Sulphur/eggy 5.3 8.4 4.9 2.4 11.9 6.0 1.60 Yes
Fruity/sweet 29.9 15.8 30.9 23.9 20.5 13.2 3.86 Yes
Rancid 0.7 2.4 1.6 0.5 7.8 3.4 1.47 Yes
Bitter 14.9 19.6 14.7 10.8 28.1 34.5 4.48 Yes
Unclean/manurial 3.1 4.7 6.8 3.6 14.7 6.8 1.45 Yes
Salty 30.5 31.4 33.2 32.3 31.3 27.7 2.23 Yes
Aroma attributes
Intensity 33.4 38.6 44.0 30.9 41.8 44.3 2.28 Yes
Creamy/milky 17.5 23.2 19.1 21.0 15.3 15.1 2.98 No
Sulphur/eggy 2.3 3.0 5.3 3.3 5.7 5.1 1.76 No
Fruity/sweet 7.2 14.0 11.2 7.8 7.1 7.3 3.61 No
Rancid 0.6 2.2 1.3 1.1 2.0 3.0 1.18 No
Acid/sharp 12.7 15.8 21.6 9.7 18.7 16.7 3.12 Yes
Musty 1.3 1.2 0.8 1.3 3.5 2.5 0.82 No
Pungent 8.6 10.7 16.7 7.8 15.2 16.0 3.21 No
Unclean/manurial 2.4 0.6 3.1 1.6 10.2 4.9 1.47 Yes
Texture attributes
Firmness 58.6 53.7 55.2 55.7 67.2 57.1 2.28 Yes
Rubbery 6.7 11.8 3.9 6.6 2.3 11.9 1.31 Yes
Crumbly 30.1 26.9 41.8 30.6 39.5 27.3 3.07 Yes
Grainy 2.7 2.0 14.0 1.6 4.8 0.2 1.72 Yes
Mouth-coating 36.1 37.8 33.3 33.9 40.5 38.4 1.76 Yes
Maturity index
Rating 4 5 2 6 1 3 2.31 Yes
Notes:
1. Cheeses were purchased from retail outlets in Ireland and UK, and were chosen to represent the major brands of mature to very mature flavoured
cheese.
2. Values presented are the means of 3 replicate analyses for 1 batch of the six different cheese brands.
3. SED, standard error of difference.
Figure 6. Principal Component Analysis
B
A
D
E
C
PC2 Score [grainy]
20
30
40
50
60
PC1 Score
[
bitter
]
-90 -80 -70 -60
Rubber
y
Bitter
Grain
y
Crumbl
y
Fruit
y
/Sweet
F
Figure 6: Principal component analysis showing the first
two Principal Components (PC) of the descriptive sensory
analysis for six retail brands (A-E) of vintage cheddar
cheeses. The results shown are the means of triplicate
analysis on one batch of the six cheeses.
guinee, kilcawley and beresford
The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008 59
Conclusions
Significant inter-and intra-brand differences were evident
in the composition, biochemistry (proteolysis and lipolysis)
and acceptability scores of leading brands of retail vintage
cheddar cheeses. Inter-brand differences can be expected,
reflecting the efforts of different manufacturers to develop
their distinct brand by optimising cheese composition and the
use of proprietary manufacturing conditions including inter
alia milk standardisation practice, make procedure and starter
culture/enzyme preparations. However, intra-brand variations in
composition and biochemistry of individual brands is most likely
associated with the use of defined (constant) manufacturing
conditions (e.g. level of coagulant per unit volume of milk,
cutting of gel after defined times, salting the curd) in combination
with seasonal changes in milk composition. Such an approach
is conducive to variations in some key process parameters, such
as gel firmness at cut, pH at whey drainage and salting, degree
of coagulant retention, pH and the moisture content of curd at
milling, the fracture characteristics of the curd at milling, the
size of curd chips and ease of compaction, and the degree of salt
uptake by curd. These variations, in turn, contribute to seasonal
variations in cheese composition that are expected to contribute
to the differences in biochemistry and acceptability, at least in
the case of intra-brand variations, e.g. variations in S/M affect
pH which, in turn, effects the degree to which individual SCFFA
are partitioned between acid and base forms, the degree to which
they contribute to flavour and the acceptability characteristics of
the resultant cheeses.
Undoubtedly, an integrated approach to cheese manufacture,
involving a more uniform milk supply and composition,
standardisation of milk casein content, casein-to-fat ratio, make
procedure standardisation (e.g. ratios of rennet activity and
starter quantity to casein) and effective process intervention
where necessary, would help manufacturers to optimise standard
operating procedures to consistently produce cheese to standard
compositional specifications. Milk casein standardisation
has become much more feasible in recent years through the
developments in membrane filtration (e.g. ultrafiltration and
microfiltration) and the manufacture of native casein-based
ingredients low in lactose content (Guinee et al. 2006).
Acknowledgements
The authors gratefully acknowledge the technical
assistance of Mr E.O. Mulholland and Ms C. Mullins and
the financial assistance of the Dairy Levy Trust.
References
Bennett, R.J. and Johnston, K.A. (2004), General aspects of cheese technology. In
Cheese Chemistry, Physics and Microbiology, Vol. 2 Major Cheese Groups, 3rd edn
(Eds P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P. Guinee). Elsevier Academic
Press, Amsterdam, pp 23-50.
BSI (1976), Chemical analysis of cheese. Part 5: Determination of pH value. British
Standard 770. British Standards Institution, London.
Dave, R.I., Sharma, P. and McMahon, D.J. (2003), Melt and rheological properties
of Mozzarella cheese as affected by starter culture and coagulating enzymes. Lait
83, 61-77.
de Jong, C., and Badings, H.T. (1990), Determination of free fatty acids in milk and
cheese. Procedures for extraction, clean up, and capillary gas chromatographic
analysis. J. High Resolution Chromatography Commun. 13, 94-98.
de Jong, L.(1977), Protein breakdown in soft cheese and its relation to consistency. 2.
The influence of rennet concentration. Neth. Milk Dairy J. 31, 314-327.
Feeney, E.P., Fox, P.F. and Guinee, T.P. (2001), Effect of ripening temperature on the
quality of low moisture Mozzarella cheese: 1. Composition and proteolysis. Lait
81, 463-474.
Fenelon, M.A. Guinee, T.P., Delahunty. C., Murray. J. and Crowe, F. (2000b),
Composition and sensory attributes of retail Cheddar cheeses with different fat
contents. J. Food Comp. and Analysis 13, 13-26.
Fenelon, M.A., Beresford, T.P. and Guinee, T.P. (2002), Comparison of different
culture systems for the production of reduced-fat Cheddar cheese. Int J. Dairy
Technol. 55 194-203.
Fenelon, M.A., O’Connor, P. and Guinee, T.P. (2000a), The effect of fat content on
the microbiology and proteolysis in Cheddar cheese during ripening. J. Dairy Sci.
83, 2173-2183.
Food and Drug Administration (2005), Cheeses and related cheese products. In Code
of Federal Regulations 21: Food and Drugs, Part 133. Office of Federal Register,
National Archives and Records Administration, US Government Printing Office.
Washington, DC.
Fox, P.F. (1975), Influence of cheese composition on quality. Irish J. Agric. Res. 14,
33-42.
Fox, P.F. and Wallace, J.M. (1997), Formation of flavour compounds in cheese. Adv.
Appl. Microbiol. 45, 17-85.
Gobbetti, M., Lanciotti, R., de Angelis, M., Corbo, M.R., Massini, R. and Fox,
P.F. (1999a), Study of the effects of temperature, pH and NaCl on the peptidase
activities on non-starter lactic acid bacteria (NSLAB) by quadratic response surface
methodology. Int. Dairy J. 9, 865-875.
Gobbetti, M., Lanciotti, R., de Angelis, M., Corbo, M.R., Massini, R. and Fox, P.F.
(1999b), Study of the effects of temperature, pH, NaCl and aw on the proteolytic and
lipolytic activities of cheese-related lactic bacteria by quadratic response surface
methodology. Enz. Microb. Technol. 25, 795-809.
Gripon, J.C. (1993), Mould-ripened cheeses. In Cheese Chemistry, Physics and
Microbiology, General Aspect, 2nd edn, Vol. 2 Major Cheese Groups (Ed P.F.Fox),
Chapman & Hall, London, pp 207-259.
Guinee, T.P. and Fox, P.F. (2004). Salt in cheese: Physical, chemical and biological
aspects. In Cheese Chemistry, Physics and Microbiology, Vol. 1 General Aspects,
3rd edn (Eds P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P. Guinee). Elsevier
Academic Press, Amsterdam, 207-259.
Guinee, T.P. (2005), Reduced-fat cheese for pizza. End of Project Report 2003, MFRC
No. 47. Teagasc, Oakpark Carlow, Ireland.
Guinee, T.P., Harrington, D., Corcoran, M.O., Mulholland, E.O. and Mullins, C.
(2000), The composition and functional properties of commercial Mozzarella,
Cheddar and analogue Pizza cheese. Int. J. Dairy Technol. 53, 51-56.
Guinee, T.P., Mulholland, E.O., Kelly, K. and O’Callaghan, D.J. (2007), Effect of
protein-to-fat ratio of milk on the composition, manufacturing efficiency and yield
of Cheddar cheese. J. Dairy Sci. 90, 110-123.
Guinee, T.P., O’Kennedy, B.T. and Kelly, P.M. (2006), Effect of milk protein
standardization using different methods on the composition and yields of Cheddar
cheese. J. Dairy Sci. 89, 468-482.
Hannon, J.A., Kilcawley, K.N., Wilkinson, M.G., Delahunty, C.M. and Beresford,
T.P. (2007), Flavour precursor development in Cheddar cheese due to lactococcal
starters and the presence and lysis of Lactobacillus helveticus. Int. Dairy J. 17,
316-327.
Hannon, J.A., Wilkinson, M.G., Delahunty, C.M., Wallace, J.M., Morrissey, P.A. and
Beresford, T.P. (2003), Use of autolytic starter systems to accelerate the ripening
of Cheddar cheese. Int. Dairy J. 13, 313-323.
Hickey, D.K., Kilcawley, K.N., Beresford, T.P. and Wilkinson, M.G. (2006), Starter
bacteria are the prime agents of lipolysis in Cheddar cheese. J. Agric. Food Chem.
54, 8229-8235.
Hickey, D.K., Kilcawley, K.N., Beresford, T.P., Sheehan, E.M. and Wilkinson, M.G.
(2007), Starter strain related effects on the biochemical and sensory properties of
Cheddar cheese. J. Dairy Res. 74, 9-17.
Kilcawley, K.N., Wilkinson, M.G. and Fox, P.F. (2006), A novel two-stage process for the
production of enzyme-modified cheese. Food Research International, 39, 619-627.
Kilcawley, K.N., O’Connell, P.B., Hickey, D.K., Sheehan, E.M., Beresford, T.P. and
McSweeney, P.L.H. (2007), Influence of composition on the biochemical and
sensory characteristics of commercial Cheddar cheese of variable quality and fat
content. Int. J. Dairy Technol. 60, 81-88.
Kim, S-Y., Gunasekaran, S. and Olson, N.F. (2004), Combined use of chymosin and
protease from Cryphonectria parasitica for control of meltability and firmness of
Cheddar cheese. J. Dairy Sci. 87, 274-283.
Lelievre, J. and Gilles, J. (1982), The relationship between the grade (product value)
and composition of young commercial Cheddar cheese. N.Z. J. Dairy Sci. Technol.
17, 69-75.
Madsen, J.S. and Qvist, K.B. (1998), The effect of added proteolytic enzymes on
meltability of Mozzarella cheese manufactured by ultrafiltration, Lait 78, 258-272.
Martley, F.G. and Lawrence, R.C. (1972), The effect of cell numbers in streptococcal
chains on plate-counting. N.Z. J. Dairy Sci. Technol. 7, 38-44.
McSweeney, P.L.H., Pochet, S., Fox, P.F. and Healy, A. (1994), Partial identification
of peptides from the water-insoluble fraction of Cheddar cheese. J. Dairy Res.
61, 587-590.
how variable are reTail vinTage brands of cheddar cheeses in comPosiTion and biochemisTry?
60 The AusTrAliAn JournAl of DAiry Technology. Vol. 63, no. 2 – ocTober 2008
Molimard, P. and Spinnler, H.E. (1996), Compounds involved in the flavour of surface
mould-ripened cheeses: origins and properties. J. Dairy Sci. 79, 169-184.
Mooney, J.S., Fox, P.F., Healy, A. and Leaver, J. (1998), Identification of the principal
water-insoluble peptides in Cheddar cheese. Int. Dairy J. 8, 813-818.
O’Connor, C.B. (1974), The quality and composition of Cheddar cheese. Effect of
various rates of salt addition. Part III. Irish Agric. Creamery Rev. 27, 11-13.
O’Keeffe, R.B., Fox , P.F. and Daly, C. (1978), Proteolysis in Cheddar cheese: role of
coagulant and starter bacteria. J. Dairy Res. 45, 465-477.
Pearce, K.N. and Gilles, J. (1979), Composition and grade of Cheddar cheese
manufactured over three seasons. N.Z. J. Dairy Sci. Technol. 14, 63-71.
Reville, W.J. and Fox, P.F. (1978), Soluble protein in Cheddar cheese: a comparison
of analytical methods. Irish J. Food Sci. Technol. 2, 67-76.
Rynne N.M., Beresford T.P., Kelly A.L. and Guinee T.P. (2007), Effect of milk
pasteurisation temperature on age-related changes in lactose metabolism, pH and
the growth of non-starter lactic acid bacteria in half-fat Cheddar cheese. Food
Chem. 100, 375-382.
SAS (2003), SAS® User’s Guide: Statistics, Version 9.1.3 Service Pack 2. Cary, NC,
USA: SAS Institute Inc.
Singh, T.K., Fox, P.F. and Healy, A. (1994), A scheme for the fractionation of cheese
nitrogen and identification of principal peptides. Int. Dairy J. 4, 111-122.
Thomas, T.D. and Pearce, K.N. (1981), Influence of salt on lactose fermentation and
proteolysis in Cheddar cheese. N.Z. J. Dairy Sci. Technol.16, 253-259.
Turner, K.W. and Thomas, D.T. (1980), Lactose fermentation in Cheddar cheese and
the effect of salt. N.Z. J. Dairy Sci. Technol. 15, 265-176.
Upadhyay, V.K., McSweeney, P.L.H., Magboul, A.A.A. and Fox, P.F. (2004), Proteolysis
in cheese during ripening. In Cheese Chemistry, Physics and Microbiology, Vol. 1
General Aspects, 3rd edn (Eds P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P.
Guinee). Elsevier Academic Press, Amsterdam, pp 391-433.
van den Berg, G., Meijer, W.C., Düsterhöft, E.-M. and Smit, G. (2004), Gouda and
related cheeses. In Cheese: Chemistry, Physics and Microbiology Vol. 2. Major
Cheese Groups, 3rd edn (Eds P.F. Fox, PL.H. McSweeney, T.M. Cogan and T.P.
Guinee). Elsevier Academic Press, London, pp 103-140.
Visser F.M.W. and de Groot-Mostert, A.E.A. (1977), Contribution of enzymes from
rennet, starter bacteria and milk to proteolysis and flavour development in Gouda
cheese. 4. Protein breakdown: a gel electrophoretical study. Neth. Milk Dairy J.
31, 247-264.
Wilkinson, M.G., Guinee, T.P., O’Callaghan, D.M. and Fox, P.F. (1992), Effects of
commercial enzymes on proteolysis and ripening in Cheddar cheese. Lait 72,
449-459.
Woo, A.H. and Lindsay, R.C (1982), Rapid method for the quantitative analysis of
individual free fatty acids in Cheddar Cheese. J. Dairy Sci. 65, 1102-1109.
guinee, kilcawley and beresford
