Terra at Work: Polymorphic phases of triglycerides
Summary: X-Ray Diffraction has been widely used to study the polymorphic phases of edible fats since the mid 1960s. The
crystallization behavior of triglycerides (TGA) is a very important factor that determines such physical properties as
consistency and plasticity of margarine and shortenings. The metastable Beta prime form is most functional in margarine and
shortening, because of its crystal morphology and fat crystal lattice which gives rise to the optimal rheological and textural
properties. With the introduction of the inXitu Terra/BTX series of portable and benchtop XRD/XRF instruments, a new class of
easy to use instruments can be employed very close to the production process, which speeds the resolution of issues arising
when changing process parameters or raw materials.
With the advent of a an instrument based on a simultaneous collection of the X-ray pattern, a typical analysis time for
identification of the key phases can be made in 30 seconds. This rapid collection time allows for a snapshot of the present
polymorphic state of the triglyceride which is frequently in transition; thus rapid collection and analysis is a key factor in
successful implementation of this technology.
Figure one below, shows the key polymorphic phases of a typical TGA raw material. Figure two demonstrates the transition of
a sample which when initially collected and analyzed demonstrated considerable alpha phased balance and transitioned to the
metastable Beta prime phase after several hours at room temperature.
Beta prime phase
Figure one: Stacked overlay of three typical triglyceride samples with polymorphic phases identified
Figure two: Typical transition of an Alpha phase triglyceride to a Beta prime phase: (Red line: sample analyzed within 3 minutes from process
line. Blue line: sample analyzed after seven hours at room temperature)
inXitu inc. 2551 Casey Ave, Mountain View, CA 94043 email:Sales@inxitu.com www.inxitu.com