MONITORING CRYSTAL DEVELOPMENT IN PALM OIL-BASED FLUID SHORTENING PRODUCTION BY FT-IR SPECTROSCOPY

ABSTRACT The extent of crystal development of palm oil-based fluid shortening was determined using attenuated total reflectance (ATR) of Fourier transform infrared (FT-IR) spectroscopy. The molten fat was cooled, heated and cooled again while agitating at constant speed. Samples for solid fat content (SFC) measurements by nuclear magnetic resonance (NMR) and FT-IR spectroscopy were taken during the crystallization process at 20C and heating process at 30C. Standards producing the best coefficient of determination (R2) and standard error of estimation for each temperature, calibrated with the spectrum obtained by FT-IR spectroscopy using partial least square (PLS) chemometric analysis, were selected as the PLS model. The model was independently validated by the “leave one out” method. The model accuracy and repeatability was good with a R2 > 0.9 at 20 and 30C, thus providing good SFC estimates during the production of palm oil-based fluid shortening. The advantage of this method is that it mainly reduces the tedious sample preparation needed for the NMR measurement. PRACTICAL APPLICATIONS Formulation, processing, transportation and storage are factors influencing the quality of fat-based products. In the processing of a fluid shortening, good control of temperature, stirring and time are critical for achieving the right amount of solid at the right time. Thus, over-crystallization will form into solid, while insufficient crystallization will be watery, both of which are not desirable. Thus, a rapid method is required to determine the end point. FT-IR is a versatile and user-friendly instrument, just like others, but more practical in this production situation because sample preparation is minimal. Our study showed that FT-IR spectroscopy and using PLS chemometric regression method had good accuracy and repeatability in predicting the SFC of palm oil-based fluid shortening at 20 and 30C. The method could be used to monitor the crystal development in a palm-based fluid shortening production and determines the right consistency for filling the product into containers.