Quantitative Phase Analysis of Complex Fats during Crystallization
Naomi Arita‐Merino, H.J.F. van Valenberg, Elliot P. Gilbert, Elke Scholten
Abstract
The quantitative study of polymorphism in fats is<br/>complicated due to their complex composition and consequent<br/>intricate crystallization behavior. We aimed to illustrate how<br/>quantitative phase analysis can be performed in crystallizing<br/>complex fats. The advantages of our proposed method are that<br/>detailed structural information or internal standards are not needed<br/>and that it can be applied even to wide-angle X-ray diffraction<br/>patterns with a high noncrystalline (liquid fat) contribution and<br/>overlapping peaks. Diffraction patterns of palm oil and anhydrous<br/>milk fat during crystallization were decomposed by fitting a model<br/>based on Pearson type VII functions. From the decomposed<br/>patterns, the contribution of each phase was quantified as a function of time. Each contribution to the pattern was then converted to<br/>its mass fraction using response factors derived from the corresponding solid fat content, which was measured using low-resolution<br/>nuclear magnetic resonance (NMR). This approach allowed us to quantify the evolution of liquid and polymorphic phases during<br/>the early crystallization of complex fats and, for the first time, to quantify coexisting α, β′, and β phases. This method is flexible<br/>enough for fats with diverse triacylglycerol profiles yet detailed enough to quantify phase transitions in a system as complex as milk<br/>fat.