Ahmed Hammam Lloyd Metzger 01 100 m 001 01 m 0001 001 m lt0001 m Bacteria UF NF RO Lactose Minerals Water MF Whey Protein Fat 10000 Daltons 1000 Daltons 50 Daltons ID: 915745
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Slide1
Utilization of micellar casein in manufacture of clean label process cheese
Ahmed HammamLloyd Metzger
Slide20.1 - 10.0
m
0.01 - 0.1
m
0.001 - 0.01
m
<0.001 m
Bacteria
UF
NF
RO
Lactose
Minerals
Water
MF
Whey Protein
Fat
10,000 Daltons
1,000 Daltons
50 Daltons
Pore Size (Microns):
Molecular Weight Cut-Off (Daltons):
1,000,000 Daltons
15-150 PSI
100-500 PSI
250-1500 PSI
Operating Pressure (PSI):
5-30 PSI
Types of filtration
Casein micelle
Slide310,000 polypeptide chains of the four caseins
micro-granules of calcium phosphate
glyco-macro peptide portion on k-casein is concentrated on the surface
rennet coagulation - remove hairs
Casein – designed by nature as a packaging system for calcium and phosphate
Adapted from Adv. Prot. Chem – 1992, Holt 43:63-151
Slide4Categories
of cheese
Rennet curd cheese
Acid curd cheese
Process cheese
Slide5Calcium and phosphate
microgranules
play a critical role in the aggregation of the
casein micelle
Calcium ions
Phosphate ions
Calcium phosphate complexes
Organic phosphate
Ca
2+
Slide6Primary phase –
k
-casein in hydrolyzed between 105
th
and 106th amino acid – net negative charges is removed from the surface of the micelleSecondary phase – casein micelles aggregate and form a gel
Stages
Rennet coagulation
Slide7Adapted from Kiely et al 1992
Natural Cheese Structure
The protein matrix contains embedded fat and moisture
Protein matrix is cross-linked by calcium and phosphate
Slide8What is process cheese?
Process cheese (PC) and process cheese products (PCP) are dairy foods prepared by blending dairy ingredients (such as natural cheese, protein concentrates, butter, non-fat dry milk, whey powder, and permeate) with nondairy ingredients (such as sodium chloride, water, emulsifying salts, color, and flavors)
Then heating the mixture with continuous agitation to produce a homogeneous product with an extended shelf-life
Slide9Natural cheese casein – calcium/phosphate cross-linked network
Emulsifying salts hydrate, donate sodium ions and bind calcium ions
The principles of making PC & PCP
Intact casein after interaction with emulsifying salts
P
O
O
O
O
H
Na
Na
P
O
O
O
O
H
Na+
Na+
Heat and mixing induce interactions between the dispersed casein and fat
Intact casein after heating and mixing
Slide10Consumers perceive the emulsifying salts as chemicals, which reduce their acceptability for the PC and PCP
Emulsifying salts utilized in the typical PC and PCP increase the levels of sodium, which lead to high blood pressure
As a result, manufacture of PC and PCP without emulsifying salts would meet this consumer desire
Problem statement
Slide11Acid curd cheese (cottage cheese)
Milk can be clotted by lowering the pH to 4.6 (the isoelectric point of casein is 4.6 and casein becomes insoluble at pH 4.6) – this is how we make yogurt and cottage cheese
Warm milk at rest will form a gel similar to a rennet coagulated gel (slightly firmer, virtually all of the calcium and phosphate is solubilized, very small amount of
syneresis
)
Can also acidify at low temp with stirring to form a precipitate that can be separated by centrifugation (continuous process)Can add acid directly or the acid can be produced by micro organisms (starter culture – can take 4 to 12 hours)
Slide12Intact casein - calcium cross-linked network
colloidal calcium phosphate complexes
Acid curd
cross-linked network
pH = 4.6
Starter cultures or acids
Micellar casein concentrate (MCC)
High level of casein bound calcium
pH of 6.5-6.7
How is acid curd produced?
Slide13MCC
Acid curd
Heat and mixing induce interactions between the dispersed casein and fat
Intact casein after heating and mixing
Gel formation during cooling
Process cheese without emulsifying salt?
Slide14Acid curd can be produced from skim milk in a process similar to cottage cheese manufacture. It is also possible to produce acid curd from MCC
Making acid curd from MCC has advantages as compared to skim milk, since manufacturing MCC using microfiltration results in milk derived whey protein as a by-product which can be utilized in many applications, particularly making whey protein isolate (WPI)
In contrast, acid curd produced from skim milk results in acid whey as a by-product which is more difficult to utilize
Can micellar casein be used to make acid curd?
Slide15The typical composition of MCC (3-stages using 3x concentration factor with a diafiltration) is > 9% true protein (TP) and > 13% solids
This MCC could be used immediately in making acid curd or diluted to lower protein levels prior for making acid curd if required
Typical composition of MCC
Slide16We hypothesized that a ratio of 2 parts of protein from acid curd: 1 part of protein from MCC will create a partially
deaggregated casein network similar to a typical process cheese that utilizes emulsifying salt
We also hypothesized that MCC can be used as an ingredient to produce acid curd
The hypothesis
Slide17Objectives
The objectives of the study was:
To determine if PCP could be produced without emulsifying salt if a combination of acid curd and MCC are utilized in the formulation
To determine the optimum protein content of MCC for use in acid curd manufacture
Slide18Manufacture of MCC using microfiltration (MF)
Protein ~9%, TS~13%
TEMP:
50 ͦC (120 ͦF)
- Pressures:
Rpi
: 4 bar;
Rpo
: 2 bar;
Ppo
: 2 bar
Flux:
71.4 L/m2 H
- CF: 3X Feed-bleed mode4 ͦC
Slide19Manufacturing of MCC powder
Part of this MCC was spray dried using a Niro-dryer to manufacture dried MCC
The rest of the MCC was utilized to produce acid curd
Adopted from Virtual Element Studios
Slide20Water
Liquid MCC
3% MCC
6% MCC9% MCC
Addition of lactic acidAddition of lactic acidAddition of lactic acidpH=4.6 at 4°C
Manufacturing of acid curdSchematic manufacture of acid curd
MCC
3% protein
MCC6% proteinMCC9% proteinMCC
Slide21The acidified MCC was then placed at 30°C water bath. The curd set at approximately 25°C, then it was cut and mixed gently during heating
to 45°C
Subsequently, the whey was drained from the curd and the curd was pressed. After pressing, the curd was frozen until further analyses
The moisture adjusted yield of the acid curd was calculated. This experiment was repeated three times
Slide22Formulation programs -
TechWizardTM
Desired Final Properties
PCP formulationsComposition(%)
Moisture49.0Fat20.0Protein18.0
Salt2.0Table 1. The targeted composition of process cheese products (PCP)
Slide23PCP formulations
Ingredients (%)
Treatment
1
3%6%9%Acid curd32.8
26.6 30.8 Unsalted butter20.6 20.6 20.6 Aged Cheddar cheese10.0
10.0 10.0 Deproteinized whey6.4 6.6 5.8 Dry MCC7.8
7.8 7.8 Salt (sodium chloride)2.0 2.0 2.0 Water20.4 26.4
23.0 Total 100 100 100 Table 2. Formulations utilized to manufacture process cheese product (PCP)1
Treatments: 3%= PCP made from acid curd that has been produced from 3% protein MCC; 6%= PCP made from acid curd that has been produced from 6% protein MCC; 9%= PCP made from acid curd that has been produced from 9% protein MCC
Slide24PCP formulations were prepared by mixing all ingredients in a kitechen
aid at room temperature for 30 min to produce a homogenous paste
Process cheese manufacture
Slide25A 25 g sample of the paste was weighed in a canister and then cooked in a rapid visco
analyzer (RVA)The canisters were cooked in the RVA for 3 min at 95°C
The stirring speed was 1000 rpm during the first 2 min of the test and then it was decreased to 160 rpm during the last minute
Slide26Total solids (TS), protein, ash, and pH of MCC and acid curd were determined before being utilized in PCP formulations
TS and pH of the final PCP were also determined
Chemical and functional analyses
Slide27The cooked apparent viscosity of PCP was measured at 95 °C at the end of the cooking time in the RVA by calculating the mean of the last 5 values of viscosity
Apparent cooked viscosity
Slide28Viscosity
Temperature
Speed
Cooked viscosity
Measuring the apparent cooked viscosity of process cheese using the RVA
Slide29The hardness
20 mm
20 mm
Slide3050-mm diameter cylindrical flat probe (TA-25)
10% compression
1 mm/s crosshead speed
The hardness of the PCP was measured by texture profile analysis (TPA) using Uniaxial double bite compression:
Slide31Hardness
Force (g)
Time (sec)
Measuring the hardness of process cheese using the TPA
Slide32The melting temperature
The melting temperature was measured by using dynamic stress rheometer
The PCP was prepared by cutting the cheese into slices (2 mm thick) using a wire cutter
A stress sweep test of the PCP was performed at a frequency of 1.5 Hz and a stress ranged from 1 to 1000 Pa at 20°C using a rheometer with parallel plate geometryThe stress sweep experiment determined that the maximum stress limit for the linear viscoelastic region was 50 Pa
Slide33The dynamic rheological properties of the PCP were then analyzed with a dynamic temperature ramp test that ranged from 20 to 90°C with a ramp rate of 1°C/min using a frequency of 1.5 Hz and a constant stress of 50 Pa
The temperature at which tan δ=1 (G′′/G′) was referred to as the cheese melting point
The melting temperature
Slide34Melt temperature
Storage modulus G' (Pa)
Loss modulus G" (Pa)
Temperature (°C)
Measuring the melting point of process cheese using the DSR
Slide35The PCP samples were cut into cylinders with a 28.5 mm diameter and 7 mm height (4 cylinders each ~5 g) and placed in Petri dishes
The dishes were transferred to a forced draft oven at 90°C for 7 min
The
meltability of PCP samples was reported as the diameter of the melted cheese in millimeters (mm)Schreiber melt test
28.5 mm
Slide36Statistical analysis was performed to study the effect of treatment (3, 6, and 9%) on the functional properties of PCP
The ANOVA test was done by using R softwareMean separation was done using the least significant difference (LSD) test
Significant difference at P < 0.05
Statistical analysis
Slide37Results and discussion
Table 3. The composition of liquid and dry micellar casein concentrate (MCC)
Treatment
Composition (%)
TSTPAshpH
Liquid MCC 13.89.51.06.8Dry MCC97.2
65.47.16.8
Slide38Table 4. The composition of acid curd used in PCP formulations
Treatment
1
Composition (%)
TSTPAshpH
Moisture adjusted yieldAcid curd 3%37.532.10.74.6
6.6cAcid curd 6%43.837.91.14.616.9b
Acid curd 9%41.634.51.34.032.0a
SEM1.81.70.10.14.4
1Treatments: 3%= PCP made from acid curd that has been produced from 3% protein MCC; 6%= PCP made from acid curd that has been produced from 6% protein MCC; 9%= PCP made from acid curd that has been produced from 9% protein MCCa-cMeans in the same columnnot sharing a common superscript are different (P < 0.05)
Adjusted yield=actual yield x 100-actual%moisture100-desired%moisture
Slide39Table 5. The composition of the PCP made from acid curd
Treatment
1
Moisture (%)pH
3%48.55.46%48.15.49%
48.55.4SEM0.10.01
1Treatments: 3%= PCP made from acid curd that has been produced from 3% protein MCC; 6%= PCP made from acid curd that has been produced from 6% protein MCC; 9%= PCP made from acid curd that has been produced from 9% protein MCC
Slide40Table 6. The
functional properties of the PCP made from acid curd
Treatment
1Cooked viscosity (cP
)Hardness (g)Melt temperature (°C)Melt diameter (mm)3%
483.2383.751.329.96%402.1363.3
48.430.29%474.9354.650.531.4
SEM81.650.00.80.4
1Treatments: 3%= PCP made from acid curd that has been produced from 3% protein MCC; 6%= PCP made from acid curd that has been produced from 6% protein MCC; 9%= PCP made from acid curd that has been produced from 9% protein MCC
Slide41Acid curd could be made from MCC and used for manufacture a process cheese without emulsifying salt
No differences were detected in the functionality of PCP made from acid curd produced from 3-9%
Conclusions
We determined that a ratio of acid curd protein to MCC protein of 2:1 created a partially deaggregated casein network that resulted in a process cheese with functionality similar to process cheese produced with emulsifying salts1
34The adjusted yield of acid curd significantly (P < 0.05) increased with protein content
2
Slide42Acid curd will be manufactured from MCC
using starter culture Evaluation of a continuous process
that utilizes a
decanter centrifuge instead of cheese vat to maximize the yield and increase the efficiency of acid curd manufacturingExplore opportunities for exporting “cheese base in a bag”Future work