Solid fat index

The fat present pays an important role in puff pastry since it has to separate the layers of pastry. To produce the most effective barrier a fat with the highest possible solid fat index is required, i.e. a very hard fat. Fat suppliers have developed special very hard margarines expressly for... 

Apart from butter or butter oil most fats that are used in biscuits are defined in terms of their physical and chemical properties. Fat suppliers are skilled at producing products with controlled physical and chemical properties from a range of raw materials. The baker can either buy fat on a physical and chemical specification, e.g. solid fat index, slip melting point, and not to contain lauric fat, or on an origin basis, e.g. to be coconut oil. The advantage of the botanical specification is that the item is a commodity and can be obtained from numerous sources. The disadvantage of this approach is that the product is tailored for a particular use. 

Traditionally, another use of IV has been to monitor the hydrogenation process and establish the hydrogenation end point relative to the finished product s functionality (solid fat index or SFI). A typical result from a hydrogenation of canola oil is shown in Table D 1.4.5. As the level of hydrogenation increases, as evidenced... 

Table D1.4.5 Iodine Value (IV), Fatty Acid Composition, and Solid Fat Index (SFI) of Canola Oil" ...

Solid fat content (SFC), 567-573 Solid fat index (SFI) canola oil, 474 (table) defined, 572... 

SD standard deviation SDE simultaneous distillation extraction SDS sodium dodecyl sulfate SFC solid fat content SFI solid fat index SHAM salicylhydroxamic acid SIM selected ion monitoring SNIF-NMR site-specific natural isotope fractionation measured by nuclear magnetic resonance spectroscopy SP-HPLC straight-phase high-performance liquid chromatography... 

It should be mentioned that DSC and NMR do not measure the same parameters, and in this way, these techniques are complementary. DSC is a dynamic method, which gives information about the transitions between different phases of lipids, whereas NMR allows quantitation of liquid and solid phases at equilibrium. Indeed, NMR and DSC methods give different values for the solid fat index (SFI) (Walker and Bosin, 1971 Norris and Taylor, 1977) NMR values are much lower than those given by DSC below 20°C. For example, for milk fat at 5°C, DSC and NMR indicate 78.1% and 43.7% solid fat, respectively. The observed difference can be explained by the presence of an amorphous phase which, due to its melting enthalpy, is seen as a solid by the DSC method. Using time-domain NMR, Le Botlan et al. (1999) showed that in milk fat samples, an intermediate component exists between the solid and liquid phases, constituting about 6% of an aged milk fat. 

Dilatometry is a technique for measuring the solid fat index (SFI), which is an estimate of the mass fraction of a fat that is solid at the temperature of measurement. 

Fig. 34.25. Solid Fat Index (SFI) profiles for six hydrogenated soybean oil (H-SBO) base stocks. (From O Brien, R. D., Shortening technology, in Introduction to Fats and OilsTechnology, 2nd edn., R. D. O Brien,W. E. Farr, and R J.Wan (Eds.), pp. 421-451, AOCS Press, Champaign, IL, 2000. With permission.)...

Fig. 34.33. Solid Fat Index (SFI) profiles for hard stick, soft stick and tub margarines, and for all-purpose shortening and heavy duty frying oil. (Data plotted from Erickson, D. R., and M. D. Erickson, "Hydrogenation and Base Stock Formulation," in Practical Handbook of Soybean Processing and Utilization, D. R. Erickson (Ed.), pp. 218-238, AOCS Press, Champaign, IL, 1985.)...

Solid Fat Index—Dilatometric Method (SFI) (Cd 10-57) estimates the percentage of solids in a semi-solid fat on the basis of changes in volume with temperature. This method utilizes glass dilatometers, and is the primary method in the United States. Totox Value an estimate of the degree of oxidation of a fat or oil, calculated as ... 

List, G. R., Steidley, K. R., Palmquist, D., and Adlof, R. O., Solid fat index vs. solid fat content A comparison of dilatometry and pulsed nuclear magnetic resonance for solids in hydrogenated soybean oil, in Crystallization and Solidification Properties of Lipids, N. Widlak, R. Hartel, and S. Narine (Eds.), pp. 146-152, AOCS, Champaign, IL, 2001. 

The density of fats and oils is an index of the weight of a measured volume of the material. This property is important not only for designing of equipment but also for the estimation of the solid fat index (SFI). The SFI is related, approximately, to the percentage of solids in a fat at a given temperature. When determined at a number of specified temperatures, it can be especially useful to margarine manufacturers or other processors who need to control the characteristics of their manufactured products by blending. 

The relationship among composition, melting point, titer, and solid fat index of beef tallow and its liquid and solid fractions obtained by dry fractional crystallization has been described (93). This study was conducted with Urguayan tallow, which has been reported to have a higher titer (43.2-47.8°C) and melting point (45.0-48.8°C) than is average for beef tallow (94). 

Nuclear magnetic resonance (NMR) is widely used for the determination of solid fat content in fats and oils. The old dilatometry method, which gives solid fat index values, is time consuming and inadequate as a quick means for control purposes in the processing of fats. The NMR method is quicker, more precise, and closer to the absolute solid fat content than dilatometry (see Table 7). 

Solid Fat Index. This analysis has become the most important criterion for the melting behavior and crystalline structure of fats and oils products. It determines the proportion of solid and liquid materials at a given temperature. The solid fat index (SFI) analysis is an empirical measure of the solid fat content. It is calculated from the specific volume at various temperatures using a dilatometric scale graduated in units of milliliters times 1000. Values for the solid contents are usually determined at 50°F, 70°F, 80°F, 92°F, and 104°F or 10°C, 21.1°C, 26.7°C, 33.3°C, and 40°C. Unlike the tropical oils, cottonseed and the other oleic- and lino-leic-classification oils do not contain any significant quantity of triglycerides made up of two or three saturated fatty acids therefore, the solid fat index at the lowest temperature usually measured would have minimal values. Natural cottonseed oil can have a solid fat index content at 50°F or 10°C but not at the higher temperature measurements. 

Cloud Point. An empirical cloud point analysis is performed by stirring a sample of fat while it is being cooled until the oil has clouded enough to block a light beam of known intensity. Both cloud point and congeal point values are more closely related to consistency than melting points. A definite relationship exists between the cloud point results and the solid fat index values at 92°F or 33.3°C. Cottonseed oil that has not been winterized or hydrogenated will have a cloud point of 30°F to 38°F or —1.1°C to 3.3°C. Winterized cottonseed salad oil, with the hard fraction removed, will have a cloud point of approximately 22°F to 26°F or —5.6°C to -3.3°C. 

Physical Characteristics. The proper blend of basestocks and hardstocks must be identified that provide the physical, functional, and organolepic properties required by the finished product. These characteristics are usually identified analytically with solids fat index, melting point, and iodine value determinations. 

Nondairy shortenings are used to replace butter fat in applications such as imitation cheese, mellorine, an ice cream substitute, coffee whiteners, vegetable-oil-based whipped toppings, dip bases, milk analogs, etc. The solid fat index values... 

Temperature % Solids Affected Solid Fat Index (SFI) Influence... 

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