Cheese Ripening

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Cheese Ripening
2
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, ?, ?
• Chymosin hydrolyzes the peptide bond between 105
  (Met) and 106 (Phe) in ? casein, releases
  glycomacropeptide fraction of ? 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
  (gt85C)
• Contain also whey proteins
• Ricotta cheese, and Hispanic-style cheeses and a
  Gjetost (Norway)

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Key Points in Cheese Making

• Cultures
• Mesophilic versus thermophilic
• Gas production
• Homolactic versus heterolactic fermentation
• Starters versus adjuncts
• Bacteriophage attack
• Stability
• Inhibitory compounds

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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

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Key Points in Cheese Making

• Ripening
• Enzymes from milk, or added, such as rennet,
  lipase extracts
• Microbial enzymes
• Endogenous
• Starters
• Ripening conditions affect activities

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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

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Key Points in Cheese Making

• Accelerated cheese ripening
• Proteolysis
• Cell lysis
• Accelerate cell lysis
• Starters, non-starters, endogenous

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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 70C
• 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