Particle Size Distribution (Microtrac) Test

Method description

The instrument provides a particle size distribution without the physical separation required by sieves. Particle size distributions are characterized by percentages of a sample in up to 140 channels covering a total range of 0.12 to 1500 micrometers diameter. This range enables the analysis of smaller particles than can be sized with sieve analysis. An added advantage is that emulsions, suspensions, and pastes can also be tested, as long as a compatible carrier fluid is available. Care must be exercised with non-spherical particles, as the size will be expressed as an equivalent spherical diameter. Particles are typically dispersed in a compatible liquid carrier fluid (a liquid that does not dissolve or agglomerate particles). Atypical samples may require special handling or technique.

Acceptable matrices

Powders, particulates, emulsions, and suspensions

Unacceptable matrices

Particle greater than 2000 micrometers

Limit of quantitation

Particles with a diameter in the range of 0.0117 to 2000 micrometers

Equipment

Microtrac Particle Size Analyzer

Method reference

Internally Developed Method

Reportable unit

% sample in size range channels within 0.0117 to 2000 micrometers

Sample size requirements

40 g

Information required by submitter

Please supply estimates

Additional information

Peroxidase is an enzyme that can catalyze the cross-linking of phenolic residues by H2O2 resulting in undesirable color changes (graying) and the potential generation of off-flavors in a food product. Determining the average level of peroxidase in different cultivars can help guide breeding decisions. Additionally, because peroxidases are relatively stable enzymes, they can serve as an indicator for the efficacy of enzyme inactivating treatments in grains and flours (heat treatment, chemical treatment, etc.) Please keep and ship samples frozen, if possible.