Margarine crystal structure

In many instances, TGs exist in polymorphic forms. Crystal structure is very important to the properties of margarines, shortenings, and specialty fats. The very unstable a form is readily transformed to the more stable ft form, which in some TGs has a higher melting point (more stable) than the /3 form. In single-acid TGs, the order is a — f3 — a, but some mixed TGs show a lower-melting (less stable) (3 form. This is further complicated by the existence of multiple / and /3 forms, depending upon the detailed TG structures at hand. 

The physical state of fats and oils and their crystal structures are important for application of such products. In addition, formulation of products for special applications such as bakery, confectionary, frying, salad dressing, margarines, and spreads requires special characteristics that make the products suitable for such purposes. Thus, each source material will be important for its physical and chemical characteristics and hence suitability as a food component. 

The crystal structures of margarines based on sunflower or canola oil (rape-seed) along with hydrogenated oil are stabilized in the p form by interesterification leading to randomization of the glycerol esters. 

In order to achieve and maintain the desirable body, texture, and performance characteristics, it is essential that the crystals in the solid fat portion of margarines and shortenings be very small (approximately 10 x or less). The proper crystal structure is achieved by solidifying the product rapidly (see Section II,G). 

Weiss etai, 1961 Sreenivasan, 1978). Similarly the crystal structures of margarines based on sunflower oil (Faur, 1977) and Canola oil (Teasdale, 1980) are stabilized in the P form by random interesterification. 

Here you find the pastes. Hazelnut paste is a dispersion of particles in a thick emulsion of two liquids, as is peanut butter. Jam is thickened by natural polymers. Soft cheese, butter and margarine are in the refrigerator these are complicated structures of fat crystals, oil, water and many other components. All these pastes have a yield stress that is low enough to let them be spread by a knife, but not so low that they run off bread. Users do find the cold butter a bit stiff and the jam a bit thin. As a developer you might want to improve these things. Bread - a solid foam - is a surprising structure when looked at it closely. Fresh bread is often too soft to cut easily. 

Polymorphism. The structural stabihty of margarine is influenced by the properties of the crystal lattice and by the actual amount of solid fat present. Many organic compounds or mixtures such as fats can sohdify in more than one crystalline pattern. The primary crystal forms of triglycerides are designated a, p, and p, which correspond to three principal cross-sectional arrangements of the fatty acid chains (71). These may be differentiated by characteristic x-ray diffraction patterns (72) and heats of transition observed in calorimetric studies (73). Phase behavior of... 

The crystal network can immobilize other structural elements in the system. A good example is given by margarine, where the network prevents coalescence of the aqueous droplets. 

The three commonly observed fat crystal forms are the a, ( >, and ( > forms. The ( ) form, with small and needle-like crystals which form smooth and fine-grained structures, is the most desired form in shortening and margarine applications. Oil composition plays an important role in crystal formation. Unmodified soybean oil has a tendency to form -crystals but the hydrogenated soybean oil can be crystallized in the ( /-form. Controlled crystallization (under defined conditions of temperature, time and mixing) and tempering is used to manipulate or stabilize the crystal forms to achieve products with the desired functional properties. 

Products such as margarine and butter contain, apart from oil and fat, about 20% water. This water is present as finely dispersed droplets (a few micrometers in diameter) covered by a shell of fat crystals. Typical margarine is formed by a continuous fat matrix (Figure 2.15) that appears to be an interconnected network structure composed of single crystals and sheet-like crystal aggregates. The shells of the water droplets, showing the crystalline nature of the interface, are inserted in this fat network. 

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