Paul Wassell

Synchrotron Radiation Macrobeam and Microbeam X-ray Diffraction Studies of Interfacial Crystallization of Fats in Water-in-Oil Emulsions

Using macrobeam and microbeam techniques, we performed synchrotron radiation X-ray diffraction (SR-XRD) analyses of fat crystallization in water-in-oil (W/O) emulsion, in combination with DSC and polarized optical microscopic observation. Particular focus was on the crystallization of the fats around water droplets in the W/O emulsion systems using food emulsifiers of polyglycerol polyricinoleate (PGPR) alone (PGPR emulsion), and PGPR and monobehenoylglycerol (MB) (PGPR+MB emulsion). We obtained the following results: (1) macrobeam SR-XRD confirmed that adding MB promoted fat crystallization during cooling, (2) microbeam SR-XRD indicated that the lamellar planes of fat crystals near the water and oil interfaces are arranged almost parallel to the interface planes in both PGPR emulsion and PGPR+MB emulsion, and (3) adding MB resulted in the formation of tiny fat crystals because it promoted crystallization, which occurred both in the bulk oil phase and at the W/O interfaces. The present study is the first to apply microbeam SR-XRD to observe the microscopic features of fat crystallization in W/O emulsion, following fat crystallization in the oil droplets in the oil-in-water (O/W) emulsion (Arima, S.; Ueno, S.; Ogawa, A.; Sato, K. Langmuir 2009, 25, 9777-9784).

Margarines and Spreads

Margarines and spreads looks at the historical perspective of how margarine rose to compete with butter, and explores the technical terminology of the field as well as examining and explaining the structural building blocks and crystallisation of fat based systems. Broadening this out to include emulsifiers; their role and their structure, the chapter outlines the basics of what is required to produce robust, viable and commercially acceptable spread type products. Exploring the use of such margarine types in real case areas: Cakes and Creams, Puff Pastry, and Industrial Fillings, the chapter offers balanced academic and practical understanding in support of wide ranging studies. Insight is also given into the realm of low fat spreads, where additional stabilisation can be required and presents a view of how to deal with, and avoid microbiological spoilage in such cases.