FOOD BIOTECHNOLOGY

CHEESE MAKING

Presented byG.Suganeshwari

II- M.Sc., Food Science and Nutrition

CHEESE MAKING

• Cheese is perhaps the most important and popular products of

the dairy world.

• Cheese making has been an age old practice as it served as a

very effective means of preserving milk solids through moisture

removal by coagulation and had a longer shelf-life besides high

nutritive value.

• Cheese making process as an art several hundred years before

christ exactly the same way as the Indian products like dahi.

• The method of cheese-making differed from country- to – country and

region-to-region meet the divers local tastes and requirements which led to

the development of numerous varieties of cheeses.

DEFINITION:

Cheese is “the curd of milk separated from the whey and pressed into solid

mass”. It is defined as “a product made from the curd obtained from milk by

coagulating the casein with the help of rennet or similar enzymes in the

presence of lactic acid produced by added or adventitious micro-organisms,

from which part of the moisture has been removed by cutting, cooking

and/or pressing, which has been shaped in and then ripened by holding it for

sometimes at temperatures and humidities.”

TYPES OF CHEESES The classification of cheeses is based on a number of factors like raw material, type of

consistency, appearance (interior and exterior), fat content, moisture content and ripening methods.

However, the most commonly used criteria are the moisture content of the finished product and the mode ripening.

Types based on moisture content:a. Very hard (maximum 34% moisture)b. Hard (maximum 39% moisture)c. Semi-hard/Semi-soft (39-50% moisture)d. Soft (50-80% moisture)

Types based on mode of ripening:

a. Bacteria ripened: Ripening is brought about by different bacteria like lactoccoci, lactobacilli, leuconostocs, propionibacteria and brevibacteria etc.

b. Mold ripened: Ripening is brought about by mold species like Penicillium.c. Unripened: Ripening is not done.

COMPOSITIONCheese constituents, viz., fat, protein, moisture, minerals and vitamins differ greatly with the variety of the product.

Types of cheese

Moisture (%)

Fat (%) Protein Calcium (%)

Vitamins Energy content

(Kcal/100g)Vit-A(µg/100g)

Thaimin (mg/100g)

Riboflavin(µg/100g)

Hard (Cheddar)

35.0 33.0 26.0 0.83 380 50 0.50 400

Semi-Hard(Edam)

43.0 24.0 26.0 0.76 250 60 0.35 320

Blue-Veined (Roquefort)

40.0 31.0 21.0 0.32 300 30 0.70 360

Soft (camembert

51.0 23.0 19.0 0.38 240 50 0.45 280

Unripened (Cottage)

79.0 0.4 16.9 0.09 3 30 0.28 82

Method of ManufactureThe following steps are involved in the manufacture of different varieties of cheese.

Preparation of milk (standardization, maturation, heat treatment etc.)Ripening of milk (with starter culture)Coagulation / Setting (with rennet)CuttingHealing/contractingForeworkingPre-drawingCooking/ScaldingAgitation or stirring outDraining and washingCheddaringMillingSaltingHooping/mouldingPressingCuring/ripening

CHEESE

MICROBIOLOGICAL ASPECTS OF CHEESE-MAKING

Biological agentsFollowing three biological agents are required for cheese making, Milk Starter Cultures Rennet

MILK FOR CHEESE MAKING:

Milk

Pasteurization

Starter Addition (0.5-1.25%) and Souring

Renneting

Cont..... Curd

Cutting and Healing

Cooking/Scaling

Setting of Curd Without Stirring (Matting)

Cutting into Block “Cheddaring” or Turning and Stacking

Milling

Salting

Whey

Cont.......

Moulding (Hopping)

Pressing

Cheese Curd Blocks

Packaging/Boxing

Ripening

Cheese

Manufacture of Emmental (swiss) Cheese.Milk (Raw)

Starter Addition and Souring

Renneting

Curd

Cutting

Scalding /Cooking

Setting of Curd

Whey

Cont.... Mould filling

Pressing and Turning

Salting

Drying

Warm /storage (Eye formation 22⁰ – 24 ⁰ C/6-8 weeks)

Ripening

Cheese

Production of Edam and Gouda Cheese.Milk

Pasteurization

Renneting

Curd

Cutting

Stirring

Washing

Whey (Half)

Cont....Scalding/Cooking

Moulding(Hopping)

Pressing

Salting

Ripening (3-4 weeks at 12⁰ – 14 ⁰ c)

Turning

Washing

(Complete) whey

Cont....Turning

Waxing, Wrapping

Cheese

BASIC STEPS IN CHEESE MAKING

The process of cheese making involves two basic phenomenon:

Preparation of cheese curd

Ripening of cheese which are accomplished through a series of steps,

namely, preparation of milk, addition of starter, rennet coagulation of

milk, processing of the curd (cutting, healing, fore working, predrawing,

cooking, agitation, washing, draining, matting, cheddaring, milling, mixing,

hooping, pressing) salting of cheese curd and ripening / curing of cheese

curd into final product.

SALTING OF CHEESE CURD

The different varieties of cheese are salted at the rate of 1 to 10% of sodium

chloride.

Salt is added to cheese either as dry salt or as brine by one of the following

methods or their combination.

Dry salt may be added to cheese milk, dusted on the milled curd in the vat

just before hooping (e.g. In cheddar cheese), rubbed on cheese surface or

added to creaming mixture.

The distribution is affected by different factors, namely, moisture content of

the cheese, concentrations of salt/brine applied, time and temperature of

exposure and surface area to volume ratio of the cheese.

RIPENING OF CHEESE Ripening (also referred to as curing, maturing of ageing) of cheese is a process

of fresh cheese curd at suitable temperature(s) till it transforms into a finished product of desirable body, texture and flavour.

The transforms involves the activity of ripening agents, viz., micro-organisms) on various cheese constituents (mainly lactose, protein and fat) to cause physical, chemical (biochemical) and microbiological changes in the product.

i) Ripening agents: Cohn was the first to correlate the cheese maturation with bacterial activity in 1875.

ii) Most of the micro-organisms isolated by him from, cheese were rods which when inoculated in milk produced cheesy aroma.

iii) Subsequently, a number of theories were proposed on cheese ripening.iv) It believed that cheese maturation is an enzymatic process wherein enzymes

are liberated on autolysis of micro-organisms.v) Micro-organisms and enzymes are, therefore, believed to constitute the two

basically required biological agents for cheese ripening.

PHYSICAL CHANGES

Body:The body of cheese, which refers to its consistency, covers the following characteristics:Firmness, elasticity, plasticity, and cohesiveness.

Texture:In cheese, texture refers to the extend of openness due to presence or absence of ‘holes’ or spaces in the cheese mass.

Flavour:Production of desirable flavour in cheese is the primary change during ripening process.

MICROBIOLOGICAL SPOILAGES OF CHEESE AND THEIR CONTROL

Cheese is extremely susceptible to microbiological spoilage.

However, there are a number of limiting factors inherent in

cheese which can influence the microbiological quality of

cheese.

These factors include moisture content, residual lactose

content, oxygen level, salt concentration and pH of the

product.

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