Cocoa processing

Winnowing. Winnowing, often called cracking and fanning, is one of the most important operations in cocoa processing. It is a simple process that involves separating the nib, or kernel, from the inedible shell. Failure to remove shell results in lower quahty cocoa and chocolate products, more wear on nib grinding machines, and lower efficiency in all subsequent operations. 

The polyphenols in cocoa (Theobroma cacao L.) and cocoa products can be attributed mainly to procyanidins (flavan-3-ols) (37%) [15]. The procyanidins identified range in size from monomers (catechin and epicatechin) to long polymers (with a degree of polymerization higher than 10 or decamers). The concentrations of polyphenols in cocoa products depend on their origin [16] and the cocoa processing... 

Lipase from pancreas or Rhizopus nigricans Triacylglycerol Glycerol + Fatty acids Isolation of labile fatty acids, improvement of cheese aroma, cocoa processing, digestion aid. 

Considerable research has looked into the chemistry of cocoa flavor, i.e the precursors responsible and the reactions involved at the various stages of production. Due to the wealth of information available on this product, the reader is encouraged to go to the following references for detail on cocoa processing [50-52] and flavor development [53-55], The major reactions leading to flavor include ... 

A more complex flavor development occurs in the production of chocolate. The chocolate beans are first fermented to develop fewer complex flavor precursors upon roasting, these give the chocolate aroma. The beans from unfermented cocoa do not develop the chocolate notes (84—88) (see Chocolate and cocoa). The flavor development process with vanilla beans also allows for the formation of flavor precursors. The green vanilla beans, which have Htfle aroma or flavor, are scalded, removed, and allowed to perspire, which lowers the moisture content and retards the enzymatic activity. This process results in the formation of the vanilla aroma and flavor, and the dark-colored beans that after drying are the product of commerce. 

The boric and sulfuric acids are recycled to a HBF solution by reaction with CaF2. As a strong acid, fluoroboric acid is frequently used as an acid catalyst, eg, in synthesizing mixed polyol esters (29). This process provides an inexpensive route to confectioner s hard-butter compositions which are substitutes for cocoa butter in chocolate candies (see Chocolate and cocoa). Epichlorohydrin is polymerized in the presence of HBF for eventual conversion to polyglycidyl ethers (30) (see Chlorohydrins). A more concentrated solution, 61—71% HBF, catalyzes the addition of CO and water to olefins under pressure to form neo acids (31) (see Carboxylic acids). 

The terms cocoa and cacao often are used interchangeably in the Hterature. Both terms describe various products from harvest through processing. In this article, the term cocoa will be used to describe products in general and the term cacao will be reserved for botanical contexts. Cocoa traders and brokers frequendy use the term raw cocoa to distinguish unroasted cocoa beans from finished products this term is used to report statistics for cocoa bean production and consumption. 

Fermentation (Curing). Prior to shipment from producing countries, most cocoa beans undergo a process known as curing, fermenting, or sweating. These terms are used rather loosely to describe a procedure in which seeds are removed from the pods, fermented, and dried. Unfermented beans, particularly from Haiti and the Dominican RepubHc, are used in the United States. 

The age-old process of preparing cocoa beans for market involves specific steps that allegedly promote the activities of certain enzymes. Various methods of fermentation are used to the same end. 

Gleaning. Cocoa beans are imported in the United States in 70-kg bags. The beans can be processed almost immediately or stored for later use. They are usually fumigated prior to storage. 

Commercial cocoa powders are produced for various specific uses and many cocoas are alkaH treated, or Dutched, to produce distinctive colors and flavors. The alkaH process can involve the treatment of nibs, chocolate Hquor, or cocoa with a wide variety of alkalizing agents (9). 

The Codex Committee on Cocoa and Chocolate Products defines cocoa butter as the fat produced from one or more of the following cocoa beans, cocoa nibs, cocoa mass (chocolate Hquor), cocoa cake, expeUer cake, or cocoa dust (fines) by a mechanical process and/or with the aid of permissible solvents (10). It further states that cocoa butter shall not contain sheU fat or germ fat ia excess of the proportion ia which they occur ia the whole bean. 

Codex has also defined the various types of cocoa butter ia commercial trade (10). Press cocoa butter is defined as fat obtained by pressure from cocoa nib or chocolate Hquor. In the United States, this is often referred to as prime pure cocoa butter. ExpeUer cocoa butter is defined as the fat prepared by the expeUer process. In this process, cocoa butter is obtained direcdy from whole beans by pressing ia a cage press. ExpeUer butter usuaUy has a stronger flavor and darker color than prime cocoa butter and is filtered with carbon or otherwise treated prior to use. Solvent extracted cocoa butter is cocoa butter obtained from beans, nibs, Hquor, cake, or fines by solvent extraction (qv), usuaUy with hexane. Refined cocoa butter is any of the above cocoa butters that has been treated to remove impurities or undesirable odors and flavors. 

Cocoa butter substitutes and equivalents differ greatly with respect to their method of manufacture, source of fats, and functionaHty they are produced by several physical and chemical processes (17,18). Cocoa butter substitutes are produced from lauric acid fats such as coconut, palm, and palm kernel oils by fractionation and hydrogenation from domestic fats such as soy, com, and cotton seed oils by selective hydrogenation or from palm kernel stearines by fractionation. Cocoa butter equivalents can be produced from palm kernel oil and other specialty fats such as shea and ilHpe by fractional crystallization from glycerol and selected fatty acids by direct chemical synthesis or from edible beef tallow by acetone crystallization. 

Fig. 2. Process flow diagram for milk chocolate, chocolate symp, and cocoa powder.

Refining. The next stage in chocolate processing is a fine grinding in which a coarse paste from the mixer is passed between steel rollers and converted to a drier powdery mass. Refining breaks up crystalline sugar, fibrous cocoa matter, and milk soflds. 

Flavors, emulsifiers, or cocoa butter are often added during conching. The flavoring materials most commonly added in the United States are vanillin, a vanillalike artificial flavor, and natural vanilla (25) (see Flavors AND SPiCEs). Cocoa butter is added to adjust viscosity for subsequent processing. 

Tempering. The state, or physical stmcture, of the fat base in which sugar, cocoa, and milk soHds are suspended is critical to the overall quaHty and stabiHty of chocolate. Production of a stable fat base is compHcated because the cocoa butter in soHdified chocolate exists in several polymorphic forms. Tempering is the process of inducing satisfactory crystal nucleation of the Hquid fat in chocolate. 

A stable crystalline form for chocolate depends primarily on the method used to cool the fat present in the Hquid chocolate. To avoid the grainy texture and poor color and appearance of improperly cooled chocolate, the chocolate must be tempered or cooled down so as to form cocoa butter seed crystals (31). This is usually accompHshed by cooling the warm (44—50°C) Hquid chocolate in a water jacketed tank, which has a slowly rotating scraper or mixer. As the chocolate cools, the fat begins to soHdify and form seed crystals. Cooling is continued to around 26—29°C, during which time the chocolate becomes more viscous. If not further processed quickly, the chocolate will become too thick to process. 

The quantity, quality and purity of the template DNA are important factors in successful PGR amplification. The PGR is an extremely sensitive method capable of detecting trace amounts of DNA in a crop or food sample, so PGR amplification is possible even if a very small quantity of DNA is isolated from the sample. DNA quality can be compromised in highly processed foods such as pastries, breakfast cereals, ready-to-eat meals or food additives owing to the DNA-degrading action of some manufacturing processes. DNA purity is a concern when substances that inhibit the PGR are present in the sample. For example, cocoa-containing foodstuffs contain high levels of plant secondary metabolites, which can lead to irreversible inhibition of the PGR. It is important that these substances are removed prior to PGR amplification. Extraction and purification protocols must be optimized for each type of sample. 

Subsequent to removal of fats by extraction with petroleum ether, and processing with ammonia, alkaloids of mate, cola, and cocoa were isolated by extraction with CHC13, and separated by thin layer chromatography. On UV irradiation, the alkaloids showed dark spots on a light fluorescent... 

This chapter defines the methylxanthine composition of raw and processed cocoa, as well as various chocolate foods and beverages. Patterns of consumption for cocoa and chocolate products are discussed and dietary intakes of caffeine from chocolate products are reported. 

The first important technical development in the chocolate manufacturing process occurred when water-powered mills superseded the use of manual labor to grind cocoa beans. This led to the establishment of many chocolate factories from 1804 to 1840. Early production consisted entirely of a type of chocolate beverage that was somewhat indigestible since none of the cocoa butter was removed during processing. In 1828, the Dutch firm of Van Houten invented the cocoa press, which facilitated the production of cocoa powder by partial removal of the cocoa butter from beans. 

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