Butter chemical composition

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. 

In general, free radical chain reactions proceed with a very low overall activation energy (Waters, 1971). However, in foods, such as butter, the rate of oxidation may be as much a feature of their microscopic structure which affects diffusion of oxygen, as of their chemical composition. 

Foubert, 1. (2003). Modelling isothermal cocoa butter crystallization Influence of temperature and chemical composition. University of Ghent, PhD, p. 263. 

Nucleation of fats may either be enhanced or inhibited by the presence of these minor components. Dimick (57) has argued that the phospholipids in cocoa butter, with higher melting point than the cocoa butter TAG, crystallize first and subsequently catalyze formation of cocoa butter TAG. The appearance and chemical composition of cocoa butter crystals formed from refined cocoa butter (phospholipids removed) was different from that of the initial crystals formed in nonrefined cocoa butter. Recent studies where these minor components have been separated and then added back to the purified TAG have shown that they invariably inhibit nucleation (21). 

Textural characteristics of butter significantly depend on milkfat composition and the method of manufacture. If the chemical composition of the milkfat is known, it is possible to select the appropriate technological parameters of the buttermaking to improve its texture. To obtain butter with constant rheological characteristics and to control the parameters of the buttermaking process, it is necessary to take into account the difference in the chemical composition and the properties of the milkfat in various seasons. Table 13 shows various compositional changes of milkfat derived from summer and winter mUk (36). 

Because of the similarity in the chemical compositions of the symmetrical-type fats and cocoa butter, they are compatible with each other in almost any proportions, and for this reason these specialty fats are usually called cocoa butter equivalents (105). In certain countries, legislation allows up to about 15% of the cocoa butter in chocolate to be replaced by symmetrical-type specialty fat and the product may still be described as chocolate. In terms of texture and flavor these products are very close to real (cocoa butter) chocolate. 

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. 

In order to choose between butter and maigarine, some information about the differing chemical composition is probably helpful. About 99% of natural fats and oils are usually triglycerides, which are esters of glycerol with long chain fatly acids (—>2.4,2.13), Saturated and unsaturated fats are both present. In the latter, there are double carbon-carbon bonds in the chain of fatty acids (Fig. 2.8). Another aspect focuses on omega fatty acids (—>2.13). 

Food industries are looking for alternative fats to cocoa butter (CB) from natural matrices that are denoted as cocoa butter replacers (CBRs), cocoa butter equivalents (CBEs) and cocoa butter substitutes (CBSs) fat [41 83], CBRs are defined as non-lauric fats that could replace cocoa butter either partially or completely in the chocolate or other food products. On the other hand, a cocoa butter equivalent (CBE) is a type of fat that has a very similar chemical composition, but its triglycerides derive from other source than cocoa beans, such as palm kernel oil, palm oil, mango seed fat, kokum butter, sal fat, shea butter, illipe butter, soya oil, rape seed oil, cotton oil, ground nut oil and coconut oil [43]. 

The production of lecithin from soybeans is described in Section 5.4. Lecithin is the commercial name given to a mixture of phospholipids, naturally occurring in animal or vegetable products such as egg yolk (8-10% phospholipids), butter (0.5-1.2%), wheat lipids (approx. 0.5%) soybean (1.5-3%) and other oil seeds. More details on the chemical composition and physical properties of lecithin appear in Sections 2.3,3.11,6.3,8.10 and 11.2. 

Kalo, P, Huotari, H and Antila, M (1989) Chemical composition of butter fat interesterified with Pseudomonas fluorescens lipase at various temperatures. Finn. J. Dairy ScL, 47, 29-38. 

Many researchers have studied the effect of lipid composition and polymorphism on macroscopic rheological properties but have not sufficiently considered the importance of the microstmcture of the network. Depending on the source and the refining process, the chemical composition of cocoa butter may vary (Dimick, 1999). This has been shown to influence crystallization rates and hardness characteristics. Within the microstmctural level, the polymorphic form of cocoa butter has been shown to affect the shape and size of the crystals (Vaeck, 1960). In terms of final product quality the polymorphic form of the crystals will determine melting characteristics. However, lipid composition and polymorphism alone cannot be used to predict the macroscopic properties of a fat crystal network. 

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. 

The two main assumptions underlying the derivation of Eq. (5) are (1) thermodynamic equilibrium and (2) conditions of constant temperature and pressure. These assumptions, especially assumption number 1, however, are often violated in food systems. Most foods are nonequilibrium systems. The complex nature of food systems (i.e., multicomponent and multiphase) lends itself readily to conditions of nonequilibrium. Many food systems, such as baked products, are not in equilibrium because they experience various physical, chemical, and microbiological changes over time. Other food products, such as butter (a water-in-oil emulsion) and mayonnaise (an oil-in-water emulsion), are produced as nonequilibrium systems, stabilized by the use of emulsifying agents. Some food products violate the assumption of equilibrium because they exhibit hysteresis (the final c/w value is dependent on the path taken, e.g., desorption or adsorption) or delayed crystallization (i.e., lactose crystallization in ice cream and powdered milk). In the case of hysteresis, the final c/w value should be independent of the path taken and should only be dependent on temperature, pressure, and composition (i.e.,... 

Raw milk is a unique agricultural commodity. It contains emulsified globular lipids and colloidally dispersed proteins that may be easily modified, concentrated, or separated in relatively pure form from lactose and various salts that are in true solution. With these physical-chemical properties, an array of milk products and dairy-derived functional food ingredients has been developed and manufactured. Some, like cheese, butter, and certain fermented dairy foods, were developed in antiquity. Other dairy foods, like nonfat dry milk, ice cream, casein, and whey derivatives, are relatively recent products of science and technology. This chapter describes and explains the composition of traditional milk products, as well as that of some of the more recently developed or modified milk products designed to be competitive in the modern food industry. 

The complexity of chocolate manufacture arises from the polymorphic nature of its constituent fats, which can come in at least five crystal forms, each with an individual melting point. Cocoa butter is chemically a multicomponent mixture of triglycerides and trace compounds (Davis and Dimick 1986). Approximately 85% of the composition consists of just three triglycerides POP ( 20%), POS ( 40%) and SOS ( 25%), where palmitic (P), oleic (O) and stearic (S) are the fatty acids attached to the glycerol base. The precise composition depends on factors such as growing conditions and therefore can vary between batches, especially from different geographic regions (Chaiseri and Dimick 1989). 

As a result of the close packing of the aqueous-phase droplets, the composition of the water phase is critical. Protein concentrates, caseinate, gelling agents, and special emulsihers have been recommended to simplify the emulsification and to stabilize the end product (93-98). For manufacture, the basic material for production is a mix that is chemically identical to the end product. This mix consists of mUkfat in the form of butter, butter oil, and fractionated butter oil or cream, in many cases, it also has milk solids, milk concentrates (including dissolved milk powder and caseinates), and emulsifiers (see Figure 10) (81). The fat mix (i.e., butter, butter oil, etc.) is melted and pasteurized. 

Since fats and oils form essential nutrient of human diet, it is necessary to identify a pure fat or to determine the proportion of different types of fat or oil mixed as adulterant in edible oils and fats like butter and ghee. With an adequate knowledge of the characteristic composition of fats or oils, it is possible to identify the fat or oil under investigation. The chemical constants also give an idea about the nature of fatty acids present in fats or oils. Eventhough gas chromatographic method is available to identify and quantify the fatty acids present in fat or oil, the physical and chemical constants are still used in routine public health laboratories where such sophisticated facilities are lacking. 

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