14
5.
Enzymatic Hydrolysis – The fat in processed cheese and dairy products
is often tightly bound to the protein. In order to achieve accurate test
results, the fat must be released from the protein prior to the fat extraction
process. This can be accomplished by a protease enzymatic hydrolysis of
the sample. Note: The sample must be in a liquid or “pourable” state for
the enzymatic hydrolysis to be effective.
(A) Thoroughly mix approximately 100g of sample. Heat sample in a
water bath at 60
°
C (
±
5
°
C) for five minutes.
(B) Add eight (8) drops of CEM Enzyme (p.n. 302630) and mix well.
(C) Return sample to water bath for five minutes.
Weight
Sample weight can be very critical to the final test result. As with most analytical
procedures, a consistent sample size helps ensure precision and accuracy. Sample
sizes can vary, based on type of sample, from 1 gram on the low end (high percent
solids level) to 10-15 grams on the high end (very low percent solids level). Test
procedures documented by CEM and included in this manual, are for specific
sample types and suggested sample size. Sample size should remain within the
weight guidelines. CEM has determined that the suggested sample size results in
the most consistent drying and test results. Heavier sample weights may cause
sample degradation or burning, resulting in high moisture results. Lower sample
weights may result in under-drying of the sample.
Holders
Sample holders should be transparent to microwave energy.
CEM Square Sample Pad – The square pad is the most commonly used sample
holder. Typically, two (2) pads are used with the sample “sandwiched” between
the pads. For heat sensitive samples, only one pad is recommended to minimize
heat buildup. For low solids samples, three or four pads are used for absorption.
CEM Round Sample Pad – The round pad is used as a collection pad for fat
extraction and is recommended, but not required, for thermapad applications.
Sample Pads – CEM glass fiber pads are designed to provide optimum
conditions for rapid, thorough and repeatable drying. CEM Corporation
follows strict specifications in the manufacture of sample pads. Specifications
include low moisture content and optimum absorbency, density, porosity, and
strength for microwave drying.
•
Moisture Content – Excessive moisture in sample pads will cause
moisture or solids values to be incorrect. Controlling the moisture
ensures that residual moisture is maintained to very close
tolerances.