Transcript cheesemaking basics - Lectures For UG-5

Group A
Ayesha Ishfaq
Lubna Tauhidi
Komal Binte Ajmal
Husam Bin Tawseen
Muhammad Ahmed
Sehrish Javed
Zara Taimoor
CHEESEMAKING
BASICS
MILK
STARTER CULTURE
ACIDIFICATION
RENNET
COAGULATION
CURDS
CUTTING
SALTING
SHAPING
RIPENING
WHEY
COTTAGE CHEESE
CHEDDAR CHEESE
•14-30% DM and 0-75% fat
•44-55% DM and 30-55% fat
•Acid dominated coagulation
•coagulation rennet dominant
•Spontaneous draining by
•Draining by mechnical
optional slicing or moulding
treatments : Slicing, mixing,
pressing
•Salting: mixing with salt
•Salting to 1.5%-2% NaCl by
•No ripening, cheeses
bringing
consumed after packaging
•Ripening : 12-60 d (or longer)
SIGNIFICANCE IN PAKISTAN
• 5th position among the top milk producing countries of
the world.
• Major industries: Dairy House Pakistan®,
Adam's Milk Foods (Pvt.) Ltd., Azhar & Co
and Tetra Pak®.
Necessity of cheese fermentation
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For preservation purposes.
For flavor
For texture
As a carrier for probiotics
Rich in nutrients: high content in protein,
calcium, riboflavin, and vitamins A and D
Preservation of milk
• For people of that time, the most important
incentive for cheese production was that
cheese constituted a highly nutritious, high
energy food with a much longer shelf life than
liquid milk.
• Caesin and whey proteins are concentrated
• Reduced water content from 80% to 20%-56%
Flavor and texture
• Primary fermentation
The texture of the coagulum is dependent on the starter culture
used, protein content of the milk, the pH, and the level of calcium
ions in the milk.
• Cheese ripening
– Individuality and unique characteristics.
– Flavor and texture development is due to glycolytic, proteolytic,
and lipolytic activities being the primary events during cheese
ripening.
– The extent of protein and fat degradation is determined by the
moisture, pH, and salinity in the cheese. excessive proteolysis
and lipolysis can lead to rancid flavors and undesired texture.
Cheese as a carrier for Probiotics
• Sufficient number of bacteria should be
present at the time of consumption,
expressing health benefits
• Should not exert adverse effects on the aroma
and flavour of the final product
Fresh cheese as a carrier
• Ideally suited to serve as a carrier for probiotic
bacteria
– Unripened cheese, storage occurs at refrigeration
temperatures, shelf life is rather limited
• Probiotic addition:
– Together with the starter culture
– Together with cream and salt
Starter Cultures
Primary Cultures
• mesosphelic culture
• use when a clean cheese flavor and a very
close curd texture.
• Ideal for semi-soft and fresh cheeses such as:
Cheddar and cottage etc.
• Contains
– Lactococcus lactis subsp. lactis
– Lactococcus lactis subsp. cremoris
• Temp growth range is 10° - 42°C (50°- 102° F.)
Secondary cultures
Secondary Cultures
These are mold, yeast, enzyme, and bacterial powders.
These cultures are either added to the milk between
layers of curds, or applied to the surface of the finished
cheese.
• Brevibacterium linens, requiring a high pH reading for
successful growth.
• Geotrichum candidum is a rapid-developing mold that
overpowers unwanted mold on moist cheese.
Secondary cultures cont
• Penicillium candidum produces a white, fuzzy
mold on the surface of the cheese.
• Penicillium roqueforti creates colored veins
and streaks in cheeses such as blue,
gorgonzola, Roquefort and Stilton.
Biochemical Pathways
Involved in Cheese making, ripening
and its effect on cheese quality.
Main Steps in Cheese Making
• Milk, the substrate used for cheese Making contain,
– Water, fats, Carbohydrates, Proteins, phosphate & Ca++
• Milk Sugar (Lactose) is converted into Lactic acid by
Lactic acid Bacteria.
• Milk protein Caseinogens is converted into Casein by
an enzyme renin.
• Casein Molecules form micelles which aggregate curd.
• Tri-glycerides (Fats) and minerals trap in Casein
network.
Factors that Alter the End Product
PH:
• Melting requires fusion of casein
micelles. Lower PH favors casein fusion.
• But PH lower then optimum results in
aggregation of Casein.
• Cheese become brittle, have Reduced
Melt, Non-stretchy .
Fat content:
• If more Fat globules, Casein aggregates
are less dense & further apart.
• This weakens the casein network, results
in a cheese that melts and stretches more
readily and at a cooler temperature than
a lower fat cheese
Factors affecting cheese
properties
• The question here is :
“ What makes
one kind of cheese different from
another?”
• Milk
– Different animals
• Cow
• Goat
• Sheep
– Different fractions
• Whole, partially skim, skim.
Factors affecting cheese
properties
• Temperature of processing
– Higher temperature of processing = tougher
cheese curd
• Method of curd precipitation
– Rennin = more elastic curd
– Acid = less elastic curd
• Pressure used in whey removal
– No pressure = soft cheese
– Pressure = harder cheese
• Microorganisms used
Factors affecting cheese
properties
• Length of ripening
– Short ripening - mild cheese
– Long ripening - sharp cheese
• Amount of salt added
–Results in slow ripening
Optimum Conditions for the Process
• Pasteurization:
 72-73 Degree Celcius.
 15-20 seconds.
• Coagulation:
 Acidification of casein is required.
 PH = 4.6-4.7
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• Salting:
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Salt is added, usually 0.5-2%.
Curd is exposed to salt at PH of 5.3-5.6
5-6 Hours.
Salt content of Cheddar = 1.75-1.95%
• Ripening and Storage:
 Different environmental conditions for different
varieties of cheese.
 For Cheddar Cheese, ripening temperature is is 48 Degree Celcius.
 Ripening Time may vary from a few months upto
8-10 months.
Preservation of Fermented
Product
Bacteriocins action
Unwanted Microbes During
Fermentation
• Competitive bacteria: share common
ecological niche
– For example: closely related species of producer
organism
• Spoilage and Pathogenic bacteria: harmful for
final product and human health
How to Avoid Unwanted Microbes
• Using lactobacillus bacteria as starter culture
leads to production of “Bacteriocins”
• Adding carbohydrates to alter pH
• Addition of salt to inhibit microbial growth
Bacteriocins
• Antimicrobial proteins produced by lactic acid
bacteria
1. Against the competitive bacteria.
• Lactacin
2.Against the spoilage and pathogenic bacteria.
• Nicin and Pediocin
Interesting facts about cheese
• Ancient legend: Arab merchant accidently stored
his milk in a pouch made out of sheep stomach.
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• Cheddar cheese : named after a village, Cheddar
in Somerset, England, and was popular during the
reign Queen Elizabeth.
• There are about 2000 names assigned to cheeses
out of which 800 varieties has been well
established and 400 varieties described by USDA