Official Solid Fat Content (SFC) Methods

The first version of an AOCS official method for SFC determination by low resolution NMR was published in 1993 (AOCS Official Method Cd 16b-93). Bruker has fully supported the NMR Committee and its work.

Presently, the AOCS official methods are:

  • AOCS Cd 16b-93 revised in 2000; Direct Method
  • AOCS Cd 16-81 revised in 2000, Indirect Method

Official methods for SFC in Europe:

  • ISO 8292
  • IUPAC 2.150

Solid Fat Content (SFC) and Solid Fat Index (SFI) Measurements

In the United States, the traditional method used for measuring the solids content of edible oils is to measure the solid fat index (SFI) by dilatometry.

Solid Fat Content

An SFC value is determined by detecting the NMR signal from both liquid and solid components in the fat sample, or by detecting the change in the liquid signal as it is displaced by solid.

Our methodology employs the "pulse" method to perform the NMR experiment, recording the time evolution of the NMR response and the resulting signal contains the analytical information from which fractions of Hydrogen in solid and liquid state may be deduced. The result is a direct measurement of the solids content that can be repeated accurately and reliably, even in the presence of emulsifiers.

Contact our Customer Service to receive more information on how we can help with your product analysis and development. If you have already found the services that fit your needs, please request a quote from one of our representatives.

Solid Fat Index (SFI)

SFI is an empirical value that is derived from expansion of a fat as a chilled sample is warmed. In the process of melting, previously crystallized parts of the sample become liquefied. Since the fat molecules in a liquid state are less efficiently arranged in space compared to closely packed crystalline regions, liquid fat takes up more volume. Therefore, the degree of expansion is related to the change in the solid content.

  • Dilatometry does not directly measure the solids content of fat at any given time, rather it measures the change in volume compared to the starting point.
  • SFI measurements depend on consistent operator skill and judgment for accuracy and reproducibility.
  • Leaky dilatometer burettes, bubble formation and other artifacts can ruin an entire series of SFI determinations.
  • SFI values for fats that contain emulsifiers are not very accurate due to some dissolution of emulsifiers into the indicator at the fat/indicator boundary.
  • A strong impetus therefore exists to adapt an alternative method.