PRINCIPLES OF CHEESE MAKING LEARNED FROM NEPAL DAIRY TRAINING.

INTRODUCTION

Cheese is the generic term for diverse group of milk –based formed product.

It is Coagulated form of milk/curdled milk. To curdle milk means to separate the whey from the

curds by coagulation of the milk protein casein by acidification by the enzyme rennet.

Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, then the addition of rennet completes the curdling.

The solids are separated and pressed into final form.

BENEFITS OF CHEESE

Relief from Hypertension & Osteoporosis:

- Reduces homocystine, an agent related to heart disease. Maintains bone health Gain weight Dental care Other benefits: Conjugated Linoleic Acid, Sphingolipids that prevent cancer. Rich in Vit.B Enhances blood formation Facilitates absorption of nutrition in body etc.

CASEIN

There are two types of protein in milk

1.Whey protein(20%)

2.Casein(80%)

3.Individual casein know as alpha casein,

beta casein and kappa casein.

Kappa casein are ca insensitive whereas

other casein are Ca sensitive.

Coagulation occurs in two phase.

Coagulation process 1st Stage:

-ve charge part of kappa

(k) casein is released.

Loss of –ve charge which otherwise prevents from caogulating which is paracasein (insoluble in presence of calcium)

•2nd Stage:

•Precipitation formed

•It is because casein particles having lost part of their –ve charge can amalgamate through so called hydrophobic bonds between amino acid side chains of the protein.

•Calcium is necessary for linkage of +ve charge to –ve charge.

INGREDIENTS OR CHEESE MAKING

Cheese starterRennetMould culture ( in case of mould cheese)Lipase enzyme (Feta cheese)Cheese coatingAdditives ( Salt, color)

TYPES OF CHEESECoagulation Agent Hardness(%MFFS) Acidity pH (min) Common Varieties

Rennet Extra Hard(<50-55%)

5.10 Parmesan

Emmental

Rennet Hard ( <50-55%) 5.30 Yak Cheese,Cheddar,Close textured with round eyeholes

Rennet Semi-Hard ( 55-60%)

5.20 Danbo, Gouda, Edam.

Rennet Hard ( 60-65%) 5.15

4.7

Ripened in Brine

Feta, Blue veined/ mould,Danablue, Roquefort

Rennet Soft (65-70%) 4.5 White Surface mould: Camembert

Acid Very soft (75-85%) 4.5 Whole curd grains

Cottage cheese.

Retention figure It is the percentage of given constituent eg protein, fat etc

retained in the cheese.

-1st it is 3D Coagulum(casein network)- It contracts-Water and dissolved particles squeezed out-Fat globules & bacteria retained.

-ProteinCasein is the principal constituent in the coagulum,the retention figure for protein is about 75%.

-FatThe fine meshed casein network retains the fat globules.The retention figure for fat is around 92.

-BacteriaAppox. 90% of the bacteria of the milk are concentrated in the curd grain.

-Lactose Lactose is found as true solution in milk so follows the whey. Retention Figures is low around 3-5% eqvt of amount of whey in

cheese.

- Ash Ash constituents of milk are found as:1. true solution (as ions) and2. colloidal particles linked to the casein particles (Calcium and

phosphorus) When rennet cheese is manufactured approx.30-40% of ash goes

in the cheese. With acid it is low because ash is released.

- Citric AcidCitric acid-approx. 10% of citric acid is linked to the casein together

with calcium in the same way as phosphate.

Basic principles of cheese making

1.Concentration Milk can be made to coagulate by means of

AcidificationLess cohesive

Both method entails that the casein of milk becomes insoluble and forms unbroken network through out the

milk.Cutting can accerate the contraction and therefore causes whey exudation.

Renneting

Firm and elastic

Preservation Cheese curd contains valuable nutrients and it is exposed

to destruction by bacteria, yeast and mould. It is therefore necessary to keep the number of harmful

microorganism as low as possible and inhibit growth of harmful microorganism that do exit.

The no of microorganism can be limited by-good milking hygiene-pasteurization of milk -Good Production hygiene

Ripening Cheese curd may be eaten as fresh but it may be

subjected to ripening process-a process in which milk solids are changed so as to bring characteristic flavour,consistency and apperance of each variety of cheese.

RENNET It causes the milk to coagulate. It contains natural complex of enzymes like proteolytic

enzymes and active enzyme is the Chymosin or rennin.

There are different types of Rennet:

1. Calf rennet: Chymosin

2. Other types: Pepsin or lipase, bovine, porcine.

3. Genetically engineered Rennet: Modified with bacteria, fungi, & yeast to produce chymosin mostly in Aspergillus niger.

-Ideal for vegeterian.

RENNET

Factors:1. pH2. Temperature3. Calcium concentration4. Amount of Rennet5. CaCl26. Nitrate

DANISH BLUE CHEESE( DANABLUE) It is light blue veined cheese, creamy cheese which is rindless with distinctly sharp &

salty taste. It is representative of semi-hard and semi-soft types of cheese with inside mould

formation by Penicillim roqueforti. It was invented in 1927 by Danes in alternative to Roquefort.

CAMEMBERT CHEESE Invented by Marie Harel, 1791. It is representive of semi-soft/soft types of cheese with outside surface mould

formation by Penicillum camemberti and Penicillium candidum It has characteristic flavour of chemical substances including Ammonia, Succinic

Acid & bitter taste is due to ornithine, Caloverine, citriline. It has texture that does not survive on heating.

PROCEDURE OF CHEESE MAKING

1. Pasteurization of the Cheese Milk2. Homogenization3. Inoculation with the Starter culture4. Pre-Ripening5. Cutting of Coagulum6. Separation of whey and forming curd grain7. Agitation of whey and cheese grain8. (Moulding) and turning of the cheese9. Removing cheese from Moulds10. Salting11. Maturing of cheese12. Packaging and storage.

PROCESS OF CHEESE MAKING

CHEESE MILK

• Before the making of the cheese, the milk should be properly evaluated.

• The milk that we received at Nd’s had 4% Fat, Acidity of 0.15, specific gravity 0.235, pH 6.7 and SNF 7.37.

1. Quality & evaluation of the Cheese milk: Bacterial Content Acid development Renneting ability Aroma, taste & appearance 2. Pasteurization &Treatment

1. Pasteurization:

-Must be sufficient to kill bacteria like coliforms which cause early blowing and disagreeable taste.

- Done at 63oC for 30 mins.

- We pasteurized the cheese milk by heating and made cheese in home cheese kit.

2. Homogenization: Done at 200 Bar

3. Inoculation with the Starter Culture: 1.6 gm per 8 lts of milk of Mesophilic cultures like Streptococcus

lactis, St. cremonis, St. diacetolactis were used and inoculated at 30oC.

Starter Culture

2 Types: Mesophilic Thermophilic

- These produce lactic acid and also aroma components and Co2.

Characteristics of Starter Culture Ability to produce lactic acid in the curd Ability to break down the protein Ability to produce Co2

LACTIC ACID BACTERIA USED IN CHEESE MAKINGFUNCTIONS:1. Acid Formation

Lactic acid bacteria Lactic Acid1. Formation of Co2 & Aroma

Lactose+Citric Acid Lactic Acid+Acetic diacetyl+Co2

1. Formation of protein splitting enzymes2. Inoculation amount & pre-ripening time3. Acid development in Cheese

a.Lactose / protein ratioPre-ripening & Acidification

4.PRE-RIPENING:- Done for the culture to mix well at 30oC for 1 hour.

5. Renneting and addition of mould:-Done at 30oC for 90 mins.

5.Renneting and Moulding

6.Cutting of Coagulum( 20mm) 9.Whey Drainage

7.Separation of whey8. Agitation

11.Moulding and Turning of the cheese

12.Removing cheese from Mould

10.Wheying off of cheese grains

13.SALTING

14.Maturing

& Storage.

(IV) SALTING:1. Dry Salting2. Brine Salting

(V) CHEESE RIPENING:Fermentation of lactose and Citric Acid

(VI) PROTEIN BREAKDOWN (PROTEOLYSIS):

1. Factors:a. Types & amount of enzymesb. Moisture concentration of cheesec. pH & NaCld. Storage Temperature