Cheese Ripening

Key Points in Cheese Making Converting a liquid into a solid pH 4.6 comprised mostly of casein and water Addition of chymosin (or rennet) Casein micelles, contain casein, with subunits  s1 ,  s2 ,  , κ Chymosin hydrolyzes the peptide bond between 105 (Met) and 106 (Phe) in κ casein, releases glycomacropeptide fraction of κ casein, remaining part sensitive to calcium-precipitation Coagulated casein network trap also milk fat Recombinant chymosin now also produced by E. coli Moderate acid addition (pH 6.0) plus high heat (>85 ° C) Contain also whey proteins Ricotta cheese, and Hispanic-style cheeses and a Gjetost (Norway)

Converting a liquid into a solid

pH 4.6

comprised mostly of casein and water

Addition of chymosin (or rennet)

Casein micelles, contain casein, with subunits  s1 ,  s2 ,  , κ

Chymosin hydrolyzes the peptide bond between 105 (Met) and 106 (Phe) in κ casein, releases glycomacropeptide fraction of κ casein, remaining part sensitive to calcium-precipitation

Coagulated casein network trap also milk fat

Recombinant chymosin now also produced by E. coli

Moderate acid addition (pH 6.0) plus high heat (>85 ° C)

Contain also whey proteins

Ricotta cheese, and Hispanic-style cheeses and a Gjetost (Norway)

Key Points in Cheese Making Cultures Mesophilic versus thermophilic Gas production Homolactic versus heterolactic fermentation Starters versus adjuncts Bacteriophage attack Stability Inhibitory compounds

Cultures

Mesophilic versus thermophilic

Gas production

Homolactic versus heterolactic fermentation

Starters versus adjuncts

Bacteriophage attack

Stability

Inhibitory compounds

Key Points in Cheese Making Heat treatment With and without pasteurization Microbial quality issues In US, cheese aged for more than 60 days at temp no less than 1.7  C is OK Chemical issues Whey proteins Enzyme inactivation (flavor and texture) Temperature in cheese making Hard versus soft

Heat treatment

With and without pasteurization

Microbial quality issues

In US, cheese aged for more than 60 days at temp no less than 1.7  C is OK

Chemical issues

Whey proteins

Enzyme inactivation (flavor and texture)

Temperature in cheese making

Hard versus soft

Key Points in Cheese Making Ripening Enzymes from milk, or added, such as rennet, lipase extracts Microbial enzymes Endogenous Starters Ripening conditions affect activities

Ripening

Enzymes from milk, or added, such as rennet, lipase extracts

Microbial enzymes

Endogenous

Starters

Ripening conditions affect activities

Ripening Surface ripened by bacteria Most aromatic and flavorful Limburger, Muenster, Brick, etc. Sulfury volatile compounds by Brevibacterium linens Applied to cheese after its manufacture, produce orange-red pigment Mold-ripened cheese Blue-mold cheeses have Penicillium roqueforti grown at the surface and within the curd Spores of which added to curds or milk along with LAB, prior to setting Grow and produce proteases, peptidases and lipases White-mold ripened cheese Camembert and Brie Spores of P. camembertis or P. caseicolum added to milk or later on the surface Proteolysis and lipolysis

Surface ripened by bacteria

Most aromatic and flavorful

Limburger, Muenster, Brick, etc.

Sulfury volatile compounds by Brevibacterium linens

Applied to cheese after its manufacture, produce orange-red pigment

Mold-ripened cheese

Blue-mold cheeses have Penicillium roqueforti grown at the surface and within the curd

Spores of which added to curds or milk along with LAB, prior to setting

Grow and produce proteases, peptidases and lipases

White-mold ripened cheese

Camembert and Brie

Spores of P. camembertis or P. caseicolum added to milk or later on the surface

Proteolysis and lipolysis

Key Points in Cheese Making Accelerated cheese ripening Proteolysis Cell lysis Accelerate cell lysis Starters, non-starters, endogenous

Accelerated cheese ripening

Proteolysis

Cell lysis

Accelerate cell lysis

Starters, non-starters, endogenous

Key Points in Cheese Making Pickled cheese High-salt, high-acid Feta Processed cheese Made by adding emulfifying salts to natural cheese, along with water and other dairy and non-dairy ingredients Mixed and heated to ~70 ° C Sodium or potassium polyphosphate and citrate emulsifying salts raise pH, displace calcium ions forming more soluble sodium casein, which has both lipophilic and hydrophilic regions Blend aged and young cheese

Pickled cheese

High-salt, high-acid

Feta

Processed cheese

Made by adding emulfifying salts to natural cheese, along with water and other dairy and non-dairy ingredients

Mixed and heated to ~70 ° C

Sodium or potassium polyphosphate and citrate emulsifying salts raise pH, displace calcium ions forming more soluble sodium casein, which has both lipophilic and hydrophilic regions

Blend aged and young cheese