Utilization of micellar casein in manufacture of clean label process cheese - PowerPoint Presentation

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Utilization of micellar casein in manufacture of clean label process cheese

Ahmed HammamLloyd Metzger

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0.1 - 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

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10,000 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

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Categories

of cheese

Rennet curd cheese

Acid curd cheese

Process cheese

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Calcium 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+

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Primary 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

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Adapted 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

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What 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

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Natural 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

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Consumers 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

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Acid 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)

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Intact 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?

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MCC

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?

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Acid 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?

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The 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

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We 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

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Objectives

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

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Manufacture 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

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Manufacturing 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

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Water

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

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The 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

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Formulation programs -

TechWizardTM

Desired Final Properties

PCP formulationsComposition(%)

Moisture49.0Fat20.0Protein18.0

Salt2.0Table 1. The targeted composition of process cheese products (PCP)

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PCP 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

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PCP 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

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A 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

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Total 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

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The 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

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Viscosity

Temperature

Speed

Cooked viscosity

Measuring the apparent cooked viscosity of process cheese using the RVA

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The hardness

20 mm

20 mm

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50-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:

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Hardness

Force (g)

Time (sec)

Measuring the hardness of process cheese using the TPA

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The 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

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The 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

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Melt temperature

Storage modulus G' (Pa)

Loss modulus G" (Pa)

Temperature (°C)

Measuring the melting point of process cheese using the DSR

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The 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

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Statistical 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

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Results 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

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Table 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

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Table 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

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Table 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

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Acid 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

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Acid 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