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FAQ

Why do I get low values when I hydrolyze my high-fat samples?

Research with high fat samples has given us the following understandings:

  • Some samples with fats that have low melting point triacylglycerides or emulsifiers may encounter fat migration during hydrolysis.
  • To improve fat retention, increase the level of diatomaceous earth (DE) to sample ratio. A ratio of up to 7:1 can be used by reducing the amount of sample and increasing the amount of DE. No more than 1.5g of DE and sample should be placed in each bag.
  • The increased volume of DE inside the bags will limit the number of samples processed in the hydrolysis chamber to ten.
  • Reducing the hydrolysis temperature and time may also improve fat retention.
  • If, after increasing the DE-to-sample ratio, fat continues to migrate from the bag then a crude fat extraction before hydrolysis may be necessary. By running a crude fat extraction first, the readily available fats are removed before the hydrolysis but are accounted for. This additional extraction step does add time to the analysis but is useful for some high fat samples and produces accurate results.
  • Fat migration can be detected by placing an empty bag next to suspect samples. Place a blank XT4 bag filled with 0.5g of DE next to high-fat samples in the holder and perform the hydrolysis. If an empty bag gains more than 0.0025g of weight during the extraction, this is an indication of fat migrating from the neighboring high-fat sample during the hydrolysis.