Confectionery (i.e., candy) can be divided into two broad categories: those in which sugar is the principal ingredient and those which are based on chocolate. Differences in sugar-based candies depend largely on manipulating the sugar to achieve special textural effects. This is accomplished primarily by controlling the state of crystallization of the sugar and the sugar-moisture ration. Examples of sugar-type confections include nougats, fondants, caramels, toffees, and jellies. Examples of chocolate-based confectioneries include chocolate-panned confectioneries, chocolate bars, and chocolate-covered fruits, nuts, and creams. Many ingredients, including milk products, egg white, food acids, gums, starches, fats, emulsifiers, flavors, nuts, fruits, and other are used in candy-making.
SUGAR BASED CONFECTIONS
When the sugar in confections is crystalline, the crystal may be large or small, or the sugar may be no crystalline, that is, amorphous and or glasslike. Whether crystalline or not, the sugar structure may be hard or soft, softness being favored by a higher level of moisture, by air whipped into the sugary mass, and by the modifying influences of other ingredients.
Table 20.1 is a simplified classification of some major candy types based on the physical state of the sugar. Candies that have sugar in the crystalline form include rock candy, which contain smaller sugar crystals. A fondant is a saturated sugar solution in which small sugar crystals are dispersed. Examples of fondants would be cream centers, crystallized creams, and thin mints. Candies that contain the sugar in various degrees of crystallization are also referred to as grained candies.
Candies that have sugar in non-crystalline form include sour balls, butterscotch, and nut brittles, all of which contain sugar in an amorphous glasslike state, and all of which are hard, containing 2% moisture or less. Non-crystalline candies also include chewy types, such as caramel and taffy, with about 8-15% moisture, and gummy candies, such as marshmallows, gumdrops, and jellies, with about 15-22% moisture. Marshmallows are further softened by having air whipped into them. Candies in which the sugar is non-crystalline are referred to as non-grained.
Although the candy types listed in Table 20.1 include the major varieties, there also are intermediate types; the preparation of these, though intermediate, follows the same principles that govern sugar crystallization and water removal in the major types. The wide use of garnishes (e.g., fruits, nuts, flavors, colors, and chocolate) add interest and variety to the different candy types, but the condition of the sugar and the degree of moisture are still recognizable.
The state of crystallinity and the percentage of moisture in finished confections is determined largely by their functional ingredients, the heat used in cooking and concentrating the sugar syrups, and the way in which these syrups are cooled, including whether or not they are agitated. All of these factors may be controlled by the candy-maker.
INGREDIENTS
Many ingredients are available to the confectionery manufacturer; some of these are listed in Table 20.2 along with their gross compositions. From these, the high-energy value of the concentrated foods represented by various confections also can be judged.
Sucrose
The principal ingredient in sugar based candies and a major component of chocolate is the sweetener. The most common sweetener in candy-making is sucrose, the sugar from sugar cane or sugar beets. At room temperature, about two parts of sucrose can be dissolved in one part of water, giving a concentrated solution of approximately 67%. If the solution is cooled without agitation, it becomes supersaturated. Upon further cooking, especially with agitation, the sucrose crystallizes. Crystallization can be speeded enormously if even a single minute sucrose crystal is added to the supersaturated solution.
Greater concentration of sucrose can be dissolved by raising the temperature of the water. The higher the sucrose concentration, the higher the boiling point of such solutions. Candy-makers take advantage of the precise relationship between boiling point and sucrose concentration to control the final degree of water in confections. This is done by heating a sugar syrup to a selected temperature corresponding to the sugar and water concentrations desired.
When the boiling syrup reaches temperature, it will have the desired sugar concentration.
More concentrated solutions glass, a totally crystalline mass, or a partially crystalline mass with the crystals suspended in a glass; or they may partially solidify as a viscous or semi plastic crystalline suspension in the remaining saturated solution. An emulsifier glass might be made into to sour ball; a totally crystalline mass could be used for candy; a partially crystalline mass with small crystals suspended in a glass cold be suitable for the manufacture of partially grained confections; and a crystalline suspension in a saturated sugar solution could become a fondant cream center or a thin mint of the kind that is usually chocolate coated.
Invert Sugar
Invert sugar is related to sucrose and common in confections. Sucrose can be hydrolyzed acids or enzymes into two monosaccharides, glucose and fructose.
The confectionery trade refers to glucose as dextrose, and fructose as laevulose. The hydrolyzed mixture of dextrose and laevulose is called invert sugar. Invert sugar can prevent or help control the degree of sucrose crystallization. It can do this for at least two reasons. First, both dextrose and laevulose crystallize more slowly than sucrose, and so substitution of part of the sucrose with invert sugar leaves less sucrose for rapid crystallization during cooling of syrups, when most of the crystals are formed, and during subsequent storage, when additional crystals precipitate and grow in size.
Second, a mixture of sucrose and invert sugar has greater solubility in water than sucrose alone; increased solubility is equivalent to less crystallization.
Invert sugar may be obtained commercially and substituted for part of the sucrose in the candy formula, or it may be formed directly from sucrose during candy-making by including a food acid such as cream of tartar in the formula. During boiling of the sugar syrup, the acid hydrolyzes part of the sucrose; the resulting effects on crystallization and other candy properties are related to the concentration of invert sugar produced.
Invert sugar not only limits the amount of sucrose crystallization but it encourages the formation of small crystals essential to smoothness in fondant creams, soft mints, and fudges. Because it is hygroscopic, invert sugar helps prevent chewier candies from buying out and becoming overly brittle. In terms of sweetness, the components of invert sugar differ from sucrose. Dextrose is less sweet and laevulose is sweeter than sucrose. A mixture of invert sugar and sucrose alone.
Other sweeteners such as maple sugar generally are used for their particular flavor properties rather than for special functional attributes. Brown sugar is obtained from the cane sugar refining process and is made up of sucrose with greater amounts of ash, invert sugar, and compounds derived from the process that give the sugar its characteristic color and flavor. Brown sugar is used in several confections such as caramels, toffees, and butterscotch. Molasses is similar to brown sugar in that it is also a product of the refining process but contains less sucrose, more invert sugar, and more of the color and flavors. Honey is also used in confections as a sweetener. It contained about 31% glucose and 38% fructose.
Corn Syrups and Other Sweeteners
Corn syrups are viscous liquids containing dextrose, maltose, higher sugars, and dextrin. They are produced by the hydrolysis of corn starch using acid or acid-enzyme treatments. The extent of hydrolysis or conversion to lower-molecular-weight substances influenced and controlled by the time, temperature, pH, and enzymes used. A wide variety of syrup compositions is commercially available.
Corn syrups retard crystallization of sucrose, and do so with less tendency toward hygrocrpicity than invert sugar. Corn syrups further add viscosity to confections (largely because of their dextrin content), reduce friability of the sugar structures from temperature or mechanical shock, slow the dissolving rate of candies in the mouth, and contribute chewiness to confections.
As mentioned in Chapter 3, glucose can be enzymatically converted to its isomer fructose. This glucose or dextrose commonly has its origin in starch, which may be hydrolysis to corn syrup or very largely to dextrose. The dextrose then may be enzymatically converted to fructose or laevulose. The degree of such conversion determines the properties of those sugar syrup, which together with sucrose, invert sugar, and corn syrup give confectionery manufacturers considerable choice with respect to sweeteners and their functional properties. Corn syrup solids are simply corn syrup that has been added and granulated.
Sugar Substitutes
The ability of sucrose to cause dental cavities and its calorie content have led to the use of sugar substitutes in some confections. These substitutes can be divided into two types; bulk sweeteners and high-intensity sweeteners. The latter can be divided into caloric and non-caloric high intensity sweeteners.
The major bulk sweeteners are alcohol derivatives of sugars made by chemically reducing the sugar to the alcohol. Sugar alcohols are not fermentable by the bacterial in the mouth, so do not contribute to cavities. They are 50-75% less sweet than sucrose, depending on the specific sugar alcohol. Commonly used examples of sugar alcohols are sorbitol, xylitol, and mannitol. Confections using these sweeteners are often labeled “sugar-free” but this does not mean that they do not contain calories. The caloric content of sugar alcohols is the same as sucrose.
High-intensity sweeteners are used in confections to reduce the caloric content. They do this in one of two ways. They may contain calories, but because they are used in such small amounts due to their intense sweetness, they reduce the caloric content of the confections. They may also be chemicals which have sweetness but are not metabolized so they do not add caloric content. Examples of both include saccharin, sucralose, thaumatin, aspartame, glycyrrhizin, and Acesulfame K. Not all of these sweeteners are approved for use at this time. High-intensity sweeteners often do not have other functional properties such as bulking or mouthfeel of sugar, and so additional additives are often used to impart desirable characteristics.
Some Additional Ingredient
Other ingredients often used in candy-making may influence sucrose crystallization, although this effect may b secondary to the main reason for their use. Thus, besides the thickening and chewiness properties of starch, the whipping and toughening properties of egg white and gelatin; the favor and coloring properties of milk; and the flavor, tenderizing, and lubricating qualities of fats, all of these ingredients interfere with sucrose crystal formation. This is due to adsorption of these materials onto crystal surfaces during formation. A barrier between attractive forces of the crystal lattice and sucrose molecules in solution is produced, limiting the crystals from growing in size.
Some softer candies (e.g., marshmallows, gumdrops, and jellies) owe their chewiness in part to pectin, gums, and gelatin. The chewiness of caramel is due largely to prevention of the grained condition by corn syrup and invert sugar plus the chewiness of dextrin. These and other soft candies also are characterized by a moderate level of moisture as indicated earlier. When the moisture content of a candy is 20% or less, slightly drying during storage will have marked effects on optimum textures. In addition to protective packaging, humectants are used to hold moisture within-such confections. Common humectants, in addition to invert sugar, include glycerin (glycerol) and sorbitol. Colloidal materials such as pectin and gums, which are hydrophilic, also have humectant properties in confections.
Thus, the candy-maker can combine a wide range of functional ingredients into an almost unlimited number of formulations to affect confectionery properties. The possibilities are further enlarged by the order of ingredient addition. If crystal inhibitors are added together with sucrose to the cooking kettle, a different result will be obtained than when some of these ingredients are subsequently mixed into a smooth fondant produced by seeding, cooking, and agitation to promote rapid formation of minute crystals. The hardness –softness aspect of texture, largely controlled by the amount of water lost from the cooking kettle prior to cooling and solidifying the batch, is obviously affected also by the choice of ingredients. The incorporation of flavors, nuts, and fruits into the sugary mass further modifies the confection in a more easily predictable manner.
CHOCOLATE AND COCA PRODUCTS
Chocolate is not only one of the principal ingredients used by the confectioner, but its widely enjoyed flavor properties make it a favorite material of bakers, ice cream producers, and other food manufacturers. In its many forms, chocolate may be consumed as a beverage, a syrup, a flavoring, a coating, or a confection in itself. It, therefore, warrants brief consideration before proceeding with some of the processing practices of the confectionery manufacturer.
Cacao Beans
Chocolate and related products begin with cacao beans, which grow in elongated melon-shaped seed pods attached to the cacao tree. The pods each contain about 25-40 cacao beans arranged in rows along the length of the pod around a central placenta. The rows of beans are surrounded by mucus and a pulpy layer beneath the pod husk.
The beans, which may be white or pale purple and are slightly larger than coffee beans, are removed from the pod and fermented microbiologically and enzymatically. This may be done by heaping the beans and covering them with leaves. Fermentation removes adhering pulp and mucus, kills the germ of the bean, and modifies the flavor and color of the bean. After fermentation, the beans, which are now cinnamon to brown in color, are sun-dried or machine-dried to about 7% moisture to give them good keeping quality. Fermentation and drying also alter the seed coat, changing it to a friable skin, which can be easily removed in a subsequent operation. The beans are now ready to be exported for further processing.
Cacao Bean Processing
At a chocolate and cocoa manufacturing plant, the beans are roasted to further develop flavor and color. They are then passed through winnowing machines to remove seed coats and separate the germ. The hulled and de-germ beans are called nibs. The nibs are passed through various types of mills where they are torn apart and ground, releasing fat from the cells. The heat of grinding melts the fat, and the ground nibs acquire a liquid consistency. The liquid discharged from the mill is known as chocolate liquor. These and subsequent manufacturing operations are outlined in Fig. 20.1
Chocolate Liquor
Chocolate liquor contains approximately 55% fat, 17% carbohydrate (most of which is digestible), 11% protein, 6% tannin compound, 3% ash, 2.5% organic acids, 2% moisture, traces of caffeine, and about 1.5% theobromine, an alkaloid related to caffeine that is responsible for the mildly stimulating properties of cocoa and chocolate.
This chocolate liquor solidifies on cooling and is the familiar bitter chocolate used in baking and other applications. It can be further processed with sugar to yield sweet chocolate, or with sugar and milk to produce milk chocolate. The chocolate liquor also may be partially defatted in a hydraulic press.
Cocoa Butter
The fat removed from chocolate liquor is known as cocoa butter. The brittle snap of chocolate at room temperature and its quick melting properties in the mouth (releasing maximum flavor) are due to the rather narrow melting range of cocoa butter (30-36C). This temperature range is the basic for selecting tempering conditions for molten chocolate and subsequent storage temperature for solidified chocolate. This is to prevent uncontrolled fat crystallization which gives chocolate an impaired texture and a gray surface appearance referred to as “fat bloom.” Fat bloom is not to be confused with “sugar bloom” which also occurs on chocolate surfaces from crystallization of sugar under poor temperature and humidity conditions.
Cocoa
After much of the cocoa butter is pressed from the chocolate liquor, the remaining press cake is the raw material for the manufacture of cocoa or cocoa powder. The amount of the fat left in the press cake can be varied by the conditions of pressing; grinding of the press cake produces cocoa, which is classified according to its fat content. The fat content of different types of cocoa is fixed by law. In the United States, for example, “breakfast cocoa” must contain a minimum of 22% cocoa fat, medium fat “cocoa” must contain 10-22% fat, and products containing less than 10% fat must be labeled “low-fat cocoas.” It is possible to remove nearly all the cocoa fat by solvent extraction to give special-use cocoas. One such use in the manufacture of chocolate-flavored angel cakes, in which traces of fat would adversely affect the whipping properties of egg whites.
Some cocoa is treated with alkali to darken its color and modify its flavor. This is called “Dutch Process” cocoa since the process originated in Holland. The flavor of Dutch Process cocoa, which may have a dark mahogany color, generally is somewhat more bitter and astringent than the same material not treated. The “Dutch Process” treatment with alkali is usually applied to the nibs before they are made into chocolate liquor. One use for alkali-treated cocoa is in the manufacture of dark-colored devil’s food cake.
Cocoa is ground to a very fine powder so that it has a smooth mouthfeel when suspended in cocoa butter and used to make chocolate. These very small particles are perceived in the mouth as a smooth continuous material rather than a solid suspended in a liquid.
Chocolate
There are many types of chocolate that differ in the amounts of chocolate liquor, cocoa butter, sugar, milk, and other ingredients they contain. In the United States, “sweet chocolate” or “sweet chocolate coating” must contain at least 15% of chocolate liquor, “milk chocolate” at least 10%, and “bittersweet chocolate” at least 35%. The standards also specify the amounts of other components.
A high-quality sweet chocolate formulation might consist of 32% chocolate liquor, 16% additional cocoa butter, 50% sugar, and minor quantities of vanilla bean plus other materials. After the ingredients are combined, the mixture is subjected to fine grinding (referred to as “refining”) by being passed through close-clearance revolving roller (Fig. 20.2). These reduce sugar crystals and other particulates to about 25µm or less in size to ensure smoothness, and the mixture scraped from the rolls takes on the character of a flaky powder.
Chocolate is next “conches” or kneaded in special heated mixing tanks. These tanks have pressure rollers that grind and aerate the melted mass to develop increased smoothness, viscosity, and flavor (Fig 20.3). Conching may be done at about 60C for 96-120h. Conching is not essential to chocolate manufacture but is rarely omitted in producing a high quality product.
Following conching, the liquid chocolate is tempered by being stirred in a heated and then cooled kettle promote control crystallization of the cocoa fat. The object here is to melt all the glycerides of the fat and then initiate uniform crystallization of the different glyceride fractions. This is in contrast to uncontrolled crystallization in which the higher-melting-point glycerides solidify within an oily mass. When the latter occurs, as mentioned earlier, uneven crystallization results in impaired chocolate texture and development of fat bloom on subsequent cool storage. Tempering conditions vary but may involve stirring at 54C, cooling to about 32C, and continued stirring for about 1h more. The thickened chocolate mass is then poured into molds for subsequent hardening or into tanks maintained at about 32C for coating of confections.
Figure 20.2
Imitation Chocolate
Imitation chocolate is made by replacing some or all of the cocoa fat with other vegetable fats. Imitation chocolates are formulated for special applications such as the coating of ice cream bars, crackers, or candies, where selected vegetable fats can give the chocolate product improved coating properties or resistance to melting. In the latter case, a hydrogenated vegetable fat with a higher melting point than cocoa fat also will impart to the product a greater melt resistance during summer storage conditions. Imitation chocolates generally are less costly than full cocoa fat chocolate and must be appropriately labeled.
CONFECTIONARY MANUFACTURING PRACTICES
In modern confectionery manufacturing, batch or continuous process may be used to prepare and cook the basic fondants, toffees, brittles, and hard candies. A number of specialized machines further extrude, divide, enrobe, and otherwise process these confections. For example, in the preparation of thin mints, the supersaturated, partially crystallized sugar mixture from the boiling kettle is flavored with mint and cooled to dabs onto a moving belt. The mints quickly solidify on further cooling.
Generally firmer chewy centers are extruded by being pressed through dies. The candy pieces are then cut off by the movement of a thin wire (Fig 20.4). Like thin mints, these may travel on a moving belt to be covered or enrobed with molten chocolate.
Figure 20.4 and 20.5
Candies formed from a highly liquid mixture are shaped by molding before they harden. This may be done in a starch-molding machine known as a Mogul (Fig 20.5). In this case, trays of powdered corn starch are continuously imprinted with concave impressions. The hot liquid candy is filled into the impressions as the trays are conveyed under a hopper. Quick cooling solidifies the candies, which are then automatically dumped over a screen that separates the candies from the starch. A brush further removes the starch from the candies, and the starch is returned to the machine to be imprinted again. This is the way certain jellies, gum drops, marshmallows, and Easter egg centers are formed. Another type of forming utilizes metal, plastic, or rubber molds.
Other candies are aerated to give them softer texture. In the case of marshmallows and nougats, the formulations contain gelatin, egg white, or vegetable proteins, which impart whipping (i.e., foaming) properties; aeration is achieved in batch or continuous mixers before the confections are molded. On the other hand, taffy is aerated by pulling and folding. With each fold of the taffy, air is entrapped, and with subsequent folds, it is subdivided.
Various kinds of small and round candies glazed by coating nuts and other centers with sugar. This is done by a process known as panning. The centers are placed in revolving heated pans and a sugar syrup is sprayed into the pan. As the center gently tumble, they become uniformly coated with the syrup, which dries as water is evaporated from the heated pan. The thickness of the glasslike sugar coating can be easily varied by continued syrup addition. This is the way candy-coated chocolate centers that do not melt in the hand are made. Candies also are coated with chocolate by this method except that the pans are chilled with cool air to solidify the chocolate coating. Chocolate-panned items frequently are further polished or glazed by spraying a solution of gum Arabic or zein into the pan after the chocolate coating is applied. Another polish, known as confectioner glaze, is an edible shellac preparation. These glazes not only improve the glossy appearance of chocolate items but protect the chocolate from the effects of humidity and air during storage.
Larger candy pieces and those that are not round are coated with molten chocolate by the method known as enrobing. In this case, the candy centers first are “bottomed” by passing on a screen over a layer of molten chocolate. They then pass through a tunnel in which they are showered by molten chocolate. Excess liquid chocolate is drained and returned to the tunnel, and the merging pieces quickly cool, solidifying the coating. It is in enrobing that special chocolate compositions with closely specified melting, covering, and solidifying properties are important. Uniform coating at high speeds requires close control of the temperature of the incoming candy centers as well as the molten chocolate.
A special type of confection of particular interest has a liquid center and is typified by chocolate-covered cherries and fruits in a syrup. Since the center must be firm to be enrobed, the method of getting the liquid inside the chocolate shell is a good example of food processing ingenuity. First, the fruit is covered with a sugar fondant in a form such as a starch mold and the fondant cools and solidifies. The firm fondant is then enrobed with chocolate in the usual way. However, the fondant is prepared with an invert as enzyme, which slowly hydrolyzes sucrose to invert sugar. This inversion takes place during the normal storage of the candy. Because invert sugar is more soluble than sucrose in the moisture of the fondant, it melts under the chocolate layer and converts the firm center to a creamy liquid.
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