Butter physical properties

There are physical—chemical differences between fats of the same fatty acid composition, depending on the placement of the fatty acids. For example, cocoa butter and mutton tallow share the same fatty acid composition, but fatty acid placement on the glycerin backbone yields products of very different physical properties. 

Butter. In the United States about 10 wt % of edible fats used are butter. Butter is defined as a product that contains 80% milk fat with not more than 16% moisture. It is made of cream with 25—40% milk fat. The process is primarily a mechanical one in which the cream, an emulsion of fat-in-semm, is changed to butter, an emulsion of semm-in-fat. The process is accompHshed by churning or by a continuous operation with automatic controls. Some physical properties are given in Table 16 (see Emulsions). 

Cocoa butters have a natural variation in physical properties related to the triacylglycerol structure Malaysian, Indian and Indonesian butters are harder than those from Africa, and Brazilian butters are the softest. The hardness of typical butters from some continents has changed over the years (Timms and Stewart, 1999). Because the hardness affects the processing required for chocolate manufacture, suppliers of cocoa butter to that trade blend butters to attempt to produce a uniform product. 

Non-cocoa fats are added to certain chocolates for a number of reasons. Their introduction was prompted by a sharp rise in the cost of cocoa butter in the 1960s which coincided with the emergence of technologies suitable to analyse butter composition and produce substitute fats. Principally, chocolate manufacture can be made more economical by using more stable processing conditions when other fats are added. The variations in processing required by changes in the chemical composition and physical properties of different batches of cocoa butters, and the effects of erratic harvests, can be ameliorated by the incorporation of the tailored non-cocoa fats. 

II. The modified Bingham body - a useful rheological model. J. Text. Stud. 3, 194-205. Enjalbert, F., M. C., Nicot, C., Bayourthe, M., Vernay, Moncoulon, R. 1997. Effects of dietary calcium soaps of unsaturated fatty acids on digestion, milk composition, and physical properties of butter. J. Dairy Res. 64, 181-195. 

Sone, T., Okada, M., Fukushima, M. 1966. Physical properties of butter made by different methods. Proc.l7th Int. Dairy Congr. (Munich) C 2, 225-235. 

Rousseau, D., Marangoni, A.G. 1998b. Tailoring attributes of butter fat/canola oil blends via Rhizopus arrhizus lipase-catalyzed interesterification. 2. Modification of physical properties. J. Agric. Food Chem. 46, 2375—2381. 

The sensory properties, especially texture and appearance, of milk fat-based products such as butter, cream, cheese, ice cream and milk chocolate are largely dependent on the physical properties of the product, especially properties governed by the phase change behavior of the fat, used here to mean melting and crystallisation behavior, crystal polymorphism and microstructure (Birker and Padley, 1987 O Brien, 2003). The same may be said of the functional properties of milk fat, milk fat fractions and milk fat-based products when these are used as food ingredients. 

Morton WE, and Hearle JWS, "Physical Properties of Textile Fibres", The Textile Institute and Butter-worth, London, 1962. 

Several aliphatic carboxylic acids have been known for centuries, and their common names reflect their historical sources. Formic acid was extracted from ants formica in Latin. Acetic acid was isolated from vinegar, called acetum ( sour ) in Latin. Propionic acid was considered to be the first fatty acid, and the name is derived from the Greek protos pion ( first fat ). Butyric acid results from the oxidation of butyraldehyde, the principal flavor of butter butyrum in Latin. Caproic, caprylic, and capric acids are found in the skin secrehons of goats caper in Lahn. The names and physical properties of some carboxylic acids are listed in Table 20-1. 

Fats provide fundamental structural and textural attributes to a wide range of consumer products, including lipstick, chocolate, and everyday products such as butter and margarine (1, 2). Within these fat-based products, certain textural properties are required to meet desirable sensory attributes to gain consumer acceptance (3). This has led to an increase in research efforts on the physical properties of fats, particularly their rheology. 

Solid Fat Content and the Fat Crystal Network The solids content of a fat crystal network is of critical importance to the final physical properties of the system. Generally, an increase in SFC leads to an increase in fat firmness. The SFC measurement has been widely used as a determinant quantity for the structural properties of fat systems. Estimations for commercial plastic fats, including butter, predict firmness increases of 10% for every percent increase in SFC (45). As a result, models used to describe the rheological properties of fats incorporate references to SFC values. 

Body and Texture. By means of appropriate qualifications of the terms body and texture, butter graders describe the physical properties of butter that are noted by the senses. The exact meanings of these terms have not been clearly outlined. Frequently, they are used as if they had the same meaning. Certain properties such as hardness and softness refer to the body of butter, whereas properties such as openness refer to texture. However, some of the properties, such as leakiness or crumbliness, are confusing. Usually, most body and texture terms are used to describe a defect, e.g., gritty, gummy, and sticky (86). Good butter should be of fine and close texture have a firm, waxy body and be sufficiently plastic to be spreadable at cold temperatures. 

Confectionery-Liquors and Liqueur. In chocolate confectionery and for pastry creams, it is the physical properties linked to the fusion and the crystallization of the fat that are essential. For milk chocolate, for coating or in bars, AMF can be used in proportions that depend on its compatibility with cocoa butter, whose properties of hardness and rapid fusion at 35°C cannot be altered. Thus it is currently accepted that AMF with high fusion levels obtained by the fractionation technique can be used. In general, milkfat has an interesting characteristic it inhibits the appearance of fat bloom (133). 

Laurie cocoa butter substitutes (lauric CBS). These are fats that are incompatible with cocoa butter but that have physical properties resembling those of cocoa butter. 

This category offers a range of confectionery fats with different levels of physical properties, but all having triacylglycerol compositions that make them incompatible with cocoa butter i.e. they are aU used in formulations with cocoa powder, mainly for compound coating. 

Timms (21) has heat of fusion to 17.7-22.3 kcal/kg for milkfat, 24-31 kcal/kg for fully hardened milkfat, 26-29 kcal/kg for cocoa butter in the p polymorph, 22.6 kcal/kg for refined, bleached, and deodorized (RBD) palm oil, 29.7 kcal/kg for RBD palm kernel oil, 26.0 kcal/kg for RBD coconut oil, 31.6 kcal/kg for fully hardened palm kernel oil, and 31.2 kcal/kg for fully hardened coconut oil. The heat of fusion is an empirical physical property dependent on the thermal history or tempering of the oil. 

The new European Chocolate Directive [14] allows the addition of up to 5% of vegetable fats other than cocoa butter (CB), the so-called cocoa butter equivalents (CBEs), in chocolate. CBEs resemble the chemical composition and physical properties of CB very closely, making them therefore extremely difficult to quantify and even in some cases to detect (especially at very low levels). There is a perceived need within official control laboratories for reliable analytical methods for the quantification (around the 5% level) of CBEs in chocolate, as Member States laws and administrative provisions need to comply with the new Chocolate Directive before August 2003. All proposed analytical methods have been evaluated by the JRC in collaboration with EU expert laboratories [15]. The performance of several methods has been compared and a final method based on the analysis of the main components, triglycerides, has been proposed for further validation. 

Cocoa butter may be substituted only by special fats (such as CBE, CBS and CBR fats) which have similar physical properties. 

The chocolate paste needs tempering before further operations take place. Tempering is required because of the polymorph property of the cocoa butter. Polymorphy is a phenomenon when a given material is able to produce crystal-modifications of different physical properties. Out of four possible modifications only one, the P-crystal modification is stable. Through tempering it is possible to obtain P -crystal modification which is transformed into stable P-modification in the finished product. 

The type of fatty acids present in milk fat can influence the flavor and physical properties of dairy products. There are reports that butter produced from cows fed high-oleic sunflower seeds and regular simflower seeds were equal or superior in flavors to the control butter (Middaugh et al., 1988). The experimental butter was softer, more unsaturated and exhibited acceptable flavor, manufacturing, and storage characteristics. Other workers (CSIRO, 1999 Mason, 2001) have also reported the increase in the unsaturated fatty acids content in milk fat, leading to an improvement in the spreadability of butter even at refrigerated temperatures (Section III.A). 

Sabariah, S., Md Ali, A.R. and Chong, C.L. (1998) Physical properties of Malaysian cocoa butter as affected by addition of milk fat and cocoa butter equivalent. Int. J. Food Sci. Nutr., 49, 211-218. 

The physical properties of PKOs resemble particularly closely those of cocoa butter, and it is generally acknowledged that the best types of CBS are made from this fat. Substantial quantities of PKO are therefore fractionated in Western Europe, the US and Malaysia for this purpose. Coconut stearin, on the other hand, while having exceptionally sharp melting properties and mouth feel, has a melting point which is too low for substitute chocolate and most coatings. It is also obtained in lower yield and so is more costly to produce. Its uses, therefore, are restricted to the finest biscuit creams and a small number of luxury products. 

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