Liquid fats

The structure of whipped cream is quite complex. A coating of milk protein surrounds small globules of milk fat containing both solid and liquid fats. These globules stack into chains and nets around air bubbles. The air bubbles are also formed from the milk proteins, which create a thin membrane around the air pockets. The three-dimensional network of joined fat globules and protein films stabilizes the foam, keeping the whipped cream stiff. 

As warm liquid fats react with lye and begin to saponify, they thicken like pudding. At this point dyes and perfumes are often added. The hardening liquid is then poured into molds, where it continues to react by generating heat. After a day, the bars can be cut and wrapped, but the saponification process continues for a few weeks, until all of the lye has reacted with the oils. 

The usefulness of NMR in such analysis is because the proton spin-relaxation time constants are different for different components, such as water, liquid fat and solid fat. For example, the signal from solid fat is found to decay rapidly while the liquid signals decay much slower. This phenomenon is the basis for an NMR technique to determine the solid fat content [20], However, as the relaxation time constant of water, for example, could depend on its local environment, such as protein concentration, it may overlap with that of oil and other components. As a result, it could be difficult to formulate a robust and universal relaxation analysis. It... 

To illustrate the results obtained by this method, a few data are selected from investigations on the contamination of chicken flesh with 7-hexachlorocyclohexane and of cabbage with parathion. These cases are especially interesting because with the chicken flesh the liquid fats alter contact with the hexachlorocyclohexane and also cause considerable mortality of flies and because with cabbage chemical analysis of parathion is difficult on account of very high blanks with untreated samples when the usual colorimetric method is used. 

The high temperatures used in cooking convert solid fat in the food into liquid fat, which more readily forms an emulsion, especially in combination with bile acids in the small intestine. In this form, the fat is more accessible to digestive enzymes (see below). 

All fats are esters, that is, combinations of fatty acids with the alcohol, glycerol (glycerin). Some fats (butter, lard) are solid at usual room temperature, others are liquid (olive oil, corn oil). But- when heated, the solid fats melt, and, when cooled, the liquid fats turn solid. 

Mulder and Walstra (1974) presented data for liquid fat, which is synonymous with butter or the core fat of globules. Variations exist, but the causes are usually unknown (Mulder and Walstra 1974). The authors state that the thermal conductivity is about 4 X 10 4 call cm"1/51/°9C 1 at room temperature and the specific heat of the liquid fat is about 0.5 cal/g V C"1. The latter is temperature dependent. The electrical conductivity is less than 10 12 S/cm (mho/CM) and the diele-tric constant is about 3.1. 

The solubility of air in fat is 8.7 ml/100 g, of oxygen 2.8 ml/100 g and of nitrogen 5.9 ml/100 g at room temperature and atmospheric pressure. Liquid fat in contact with air contains 0.004% oxygen. These values are related to the oxidative stability and effectiveness of the packaging of stored milk fat. 

Other forms of agitation, including shaking raw milk containing liquid fat (Crowe 1955 Demott 1960 Sjostrom and Willart 1956), chum-... 

Sharp, P. F. and Krukovsky, V. N. 1939. Differences in adsorption of solid and liquid fat globules as influencing the surface tension and creaming of milk, J. Dairy Sci. 22, 743-751. 

It is essential to ensure that the test portion of the fat being analyzed completely covers the horizontal surface of the ATR crystal for the quantitative determination to succeed. In some cases, after placing a fat test portion on the ATR crystal, the melted or liquid fat beads up and partially rolls off the surface of the ATR crystal. The only recourse the analyst would have is to try again. 

The principal cause of poor image quality using CLSM is poor dissolution of the dyes, especially Nile Blue. In the method as described, Nile Red co-crystallizes with the fat crystals and, thus, a higher resolution of crystal surface is obtained. However, it is difficult to distinguish solid from liquid fat with only Nile Red. Nile Blue is necessary because it is dissolved in the liquid phase and provides fluorescence for contrast. As a result, the quality of images is very much improved. The disadvantage of Nile Blue is its low solubility. Special attention should be paid to sufficiently dissolving the dye at 60°C. 

As already mentioned above, the functional properties of whippable emulsions depend largely on the properties of the fat globules they contain. The fat globules form the skeleton of the foam. The crystallization behaviour inside the fat globules of whippable emulsions is decisive for the stabilization of the foam structure after aeration. It is a well-known fact in the food industry that whippable emulsions made with liquid fats are totally devoid of functionality. 

Liquid hydrocarbon. This can include, for example, liquid petroleum (crude oil), synthetic hydrocarbon liquid, bitumen from oil (tar) sands, fractions obtained from crude oil, and liquid fats (e.g., triglycerides). 

Fats are esters of glycerol and fatty acids. Liquid fats are often called oils. Whether a fat is solid or liquid depends on the nature of the fatty acids. Solid animal fats contain mostly saturated fatty acids, while vegetable oils contain high amounts of unsaturated fatty acids. To avoid arteriosclerosis, hardening of the arteries, diets which are low in saturated fatty acids as well as in cholesterol are recommended. 

Fat is a general term applied to light-colored animal solids that melt at low temperatures. Oil or grease is liquid fat, and the definitions of these materials vary widely. 

The proportion of solid fat is crucial. Partial coalescence can not occur if there are no fat crystals, but if there is too much solid fat, there may not be enough liquid fat to hold globules together (Boode et al., 1993). 

The principal determinant of butter consistency is the ratio of solid to liquid fat (Rohm and Weidinger, 1993). Therefore, the extent of crystallization is critical to the texture of butter. Milk fat is composed of literally hundreds of unique and varied triacylglycerol (TAG) species (Jensen et al, 1991). This results in milk fat having complicated crystallization, melting, and rheological behaviour (Mulder, 1953 Hannewijk and Haighton, 1957). 

Effect of Solid-to-Liquid Fat Ratio on Fracture Properties... 

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