Low fat cheese

Importance of Fat In Cheese

  • contributes lubrication and creamy mouth feel
  • contributes flavour and acts as a reservoir for other flavours
  • globules disperse light and suppress translucence making the cheese appear darker
  • alteration of polar/non-polar constituents affects biochemistry
  • occupies space in the protein matrix and prevents the formation of a dense matrix which produces a hard, corky cheese

Current Status of Low-fat Cheese

  • low-fat process cheese slices have been available for some time
  • rubbery texture but semi-acceptable
  • low-fat Cheddar at 1/3 reduction (20% fat vs 31% full fat) is semi-successful
  • available in most supermarkets
  • low-fat Cheddar at less than 1/3 reduction requires fat substitutes
  • most successful to date are protein based beads designed to imitate fat globules
  • starch is also being used to replace fat

Effects of Reduced-Fat On Cheese Composition

  • in order to maintain yield and avoid excessive hardness, low-fat cheese requires higher moisture
  • this results in reduced salt in moisture (S/M) and increased moisture in the non-fat substance (MNFS)
  • high acidity due to high moisture = high lactose retention
  • may be desirable to include a washing step to leach out lactose-optimum S/M is difficult to achieve because salt greater than 2% gives a salty flavour
  • typical target moistures for low fat Cheddar range from 42 - 48%
  • lower moisture (near 42%) can achieve 6 - 9 month aging and may have some typical medium Cheddar flavour, but texture is hard
  • higher moisture (towards 48%) gives softer texture but shorter shelf life and is often gummy

Defects

  • rubbery, flaky due to lack of lubricity and tight protein matrix
  • gummy, chewy
  • bitterness in cheese is caused by hydrophobic (fat soluble) peptides (protein fragments) which result from curing--the amount, or at least the perceived amounts of these peptides, is increased in low-fat cheese, perhaps because these hydrophobic peptides are normally absorbed by the fat and are more available for tasting in low fat cheese
  • certain cultures have the ability to further break down these peptides and reduce bitterness so that bitterness in low-fat cheese often peaks after a few weeks and then decreases with further ripening
  • astringency is common in low fat cheese--it is distinct from bitterness but often confused with bitterness--it is not detected by the taste buds but rather a textural/physical perception at the back of the mouth ---related to interaction of saliva with cheese components, probably certain peptides
  • meaty/brothy flavour is typical of low fat cheese--this is also related to interaction of amino acids (from protein breakdown) with alpha-dicarbonyls
  • unclean flavours related to non-starter bacteria are more pronounced in low fat cheese--this can be reduced by micro-filtration to remove most bacteria before cheese manufacture
  • increased gas formation probably due to non-starter bacteria encouraged by low S/M causes slits---again could be controlled by micro-filtration

Low-fat Cheddar Make Schedule

General Principles

  • adjust each stage to include more moisture
  • keep pH higher at each stage relative to normal cheddar

Standardization

  • standardize to obtain about 35% FDM or about 20% fat in the cheese assuming 45% moisture

Pasteurization

  • normal is recommended
  • may be some advantage in higher temperature to denature whey proteins and increase moisture retention

Culture

  • normal level recommended

Calcium Chloride

  • recommended especially if higher pasteurization temperatures used

Cutting

  • larger than normal cheddar to promote more moisture retention

Cooking Temperature

  • lower than normal, 37C

Draining

  • high pH, near 6.4
  • shorter cooking time

Stirring Out

  • none

Washing

  • may be necessary for high moisture cheese to reduce lactose content

Salting

  • normal, about 2.5% of expected yield

Curing

  • normal temperatures
  • shorter time, especially for high moisture

Reduced Cholesterol

  • three methods:
  1. Chemical extraction with Beta-cyclodextrin
  2. Extraction with Supercritical carbon dioxide--90% removal
  3. Steam extraction--75% removal
  • problem is that all procedures require separation of butter oil, with subsequent milk recombination
  • necessity of homogenization makes cheese making difficult