The Importance Of Crystals

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The crystal size is also affected by the rate of cooling and larger crystals were shown to be formed when fat was cooled at a slower cooling rate83. However the samples were not subjected to changes in the rate of cooling in this study. At higher temperatures (or lower supercooling conditions) due to decrease in the driving force, less crystals are formed although the crystals are larger in size as compared to those formed at lower temperatures83. At lower temperatures, due to the higher driving force, nucleation is favored and a lot of small crystals are generated in the system83. Also, the microstructure of sample with higher agitation speed had smaller crystals83. The crystals can vary in shape from spherulites to needle like or clusters84. …show more content…
Rheology of food is an important factor that affects the organoleptic properties of foods as it determines the texture and the mouthfeel 94. Foods in which texture plays a major role are potato chips, cookies, emulsion based beverages, pickled cucumbers, etc. Bourne lists descriptors of texture in US, Austria and Japan and some of the common ones include Crisp, Crunchy, Hard, Soft and Creamy among others 95. Hydrocolloids such as gums and stabilizers are widely used to manipulate the texture of foods by changing the viscosity 96 although fats also affect the rheological properties of foods as well 97 depending on the type and the amount of fat. Increase in viscosity can be used as tool to inhibit sedimentation in beverages. An increase in the G’ and G’’ of the ice cream mix was shown with an increase in the fat content 98. Marangoni and Rousseau found that the hardness index and the G’ of the fat increased with the increase in the SFC. Also, upon interesterification, the HI and G’ was higher for the interesterified lard canola oil samples, while it was not affected for the Palm oil-soybean oil blend 31. Veereckren et. al. showed that the hardness of the fat was also dependent on the composition of the fat and the crystallization conditions 99 including the rate of crystallization 87. Ahmadi et. al correlated the G’ of the fat samples to the composition, SFC and the fat crystal network and was further correlated with the fractal dimensions 33. Application of HIU was also shown to affect the rheological properties of the fat samples 70,

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