Optical determination of solid fat content in fats and oils: effects of wavelength on estimated accuracy

The melting profile of solid fat content (SFC) is a parameter of primary importance for the food industry since it affects many important product characteristics such as stability, physical appearance, spreadability, and sensation in the mouth. Reference techniques to measure SFC in fats and oils include pulsed nuclear magnetic resonance (pNMR) and differential scanning calorimetry (DSC), which are reliable and accurate, but require expensive instrumentation and trained personnel. Herein, the accuracy of a recently proposed optical technique to measure SFC is investigated in terms of peak wavelength of incident radiation. A sensor system featuring an array of seven LEDs with peak wavelength in the visible and NIR range is built, and the results compared with data from DSC. All the wavelengths investigated have high accuracy in SFC estimation, especially at 590 (yellow) and 880 nm (NIR). Practical applications: Quick and easy determination of solid fat content in fats and oils by a simple experimental setup. The technique is based on optical attenuation measurements during a thermal cycle. The technique can be implemented in a measurement instrument for in-situ analysis of solid fat content.