Ingredients

Cheese

  • any type of natural cheese
  • in U.S. and Canada, the cheese base is usually Cheddar or Cheddar types where a 3 month blend (some old cheese with young cheese for an average age of 3 months) is preferred
  • frequently plants use processing as an outlet for trimmings and 2nd grade cheese but this represents a small portion of total process cheese volumes
  • most Cheese used in processing is prepared especially for processing; usually stirred curd Cheddar or cheese base prepared by ultra filtration
  • younger cheese is now more frequently used: flavour compensated for with spices, and Cheddar flavour preparations (e.g. enzyme modified Cheddar)
  • too much young cheese gives a corky firm texture to the process cheese because with aging the proteins are broken down to shorter chains which have less interaction with each other and less elasticity, water holding capacity and emulsification capacity

Non-cheese Non Fat Milk Solids (NFMS)

  • skim milk powder, whey protein concentrate (usually 35% protein), whey powder, sodium caseinate
  • caseins bind water, especially sodium caseinate which is formed by reaction with emulsifying salts
  • denatured whey proteins also impart water holding capacity if denaturation occurs during process cheese manufacture
  • amounts of NFMS limited by texture (body) and lactose content (i.e., 15% of lactose in moisture phase will cause crystallization during cold storage.
  • too much whey protein will impair meltability -- an educated guess of an upper limit is about 1.5%

Fat

  • from cheese or added as cream, butter or butter oil
  • cheese fat is generally present in fat globules with intact fat globule membranes
  • if butter or butter oil is used artificial membranes composed mainly of casein are formed during processing
  • the fat source is apparently of little consequence except for moisture considerations

Melting Salts

  • also 'emulsifying salts' but not emulsifiers in the true sense
  • commonly: sodium citrate, sodium aluminium phosphate (SALP), Monosodium phosphate (MSP), Disodium phosphate (DSP, Trisodium phosphate (TSP), various polyphosphates; most common are NaCit and MSP
  • functional roles: chelate Ca, solubilize and disperse proteins, hydrate and swell proteins, emulsify fat, stabilize the emulsion
  • emulsifier blends are designed for specific products--for example process cheese slices require a different texture than process cheese

Acid

  • citric acid commonly used to adjust pH
  • melting salts raise the pH or at least increase the buffer capacity of the cheese
  • pH should be < 5.6 to prevent germination and growth of anaerobic spores
  • the risk is probably greater with high moisture cheese spreads
  • too low pH: crumbly firm texture, deemulsification
  • high pH: protein bonding and solubility improve, elastic, smooth, better emulsification, more risk of germination of bacterial spores

Emulsifiers

  • mono- and diglycerides may be added in small quantities but may actually interfere with emulsification by preventing protein-fat interactions

Preservatives

  • Sorbic acid commonly used as mould inhibitor
  • inverting jars for a minute or two after filling also helps to control mould
  • by destroying mould spores in the head space

Colour

  • annatto present in natural cheese such as Cheddar is not stable in process cheese
  • water dispersable preparations of -Carotene are more successful

Moisture

  • when heated by direct steam injection, about 10% of batch weight is incorporated as condensate for most systems
  • additional moisture added as required