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Determination of % FAT

Reagent

  1. HEXANE

Apparatus

  1. SOXHLET EXTRACTION APPARATUS
  2. THIMBLES (should be kept in oven at 100oC)
  3. KIMWIPES

Procedure

  1. Weigh approximately 2 g of sample. Wrap sample up in kimwipe and place kimwipe inside thimble.
  2. Record weight to 4 decimal places.
  3. Place thimble in labeled beaker. Dry overnight at 100oC, reweigh immediately from oven and record weight to 4 decimals.
  4. Place thimble inside extraction unit.
  5. Fill boiling flask « to 2/3 full with hexane. (After cleaning flasks add a small amount of zinc metal to serve as boiling chips.)
  6. Turn on cooling water.
  7. Turn on heating units.
  8. Allow to extract for 6 h.
  9. Remove thimbles and place in beakers. Pour excess hexane into reserve jug.
  10. Place thimbles in oven at 100oC to dry overnight.
  11. Weigh immediately from oven. Record weight to 4 decimal places.
  12. Calculate fat % and record with one decimal.

Calculations

  1. %FAT = ((wt. after drying) - (wt. after extraction)) x 100/(thimble and sample wt.) - (thimble wt.))

Quality Control

  1. Analyze AAFCO check sample along with each set.

References

  1. Horwitz, W. (ed). 1970. Official Methods of Analysis of the Association of Official Analytical Chemists, 11th Edition, Washington, D. C., p.128.