Английский язык (Пищевой профиль). Учебное пособие

Food manufacturers may list dextrose produced from cornstarch as «corn sugar» in an ingredient statement. If the dextrose comes from another source like rice or wheat, the ingredient list would read «rice sugar» or «wheat sugar», respectively.

Dextrose is used in many baking products like cake mixes and frostings, snack foods like cookies, crackers and pretzels, and desserts like custards and sherbets. Dextrose is also used as a filler in the singleserve, table-top packets of the common artificial sweeteners.

The term «corn syrup”» is used to identify a group of sweeteners that differ from one another simply by the amount of dextrose (glucose) present in the commercial syrup. Consumers have no idea how much glucose is contained in the particular «corn syrup» listed in an ingredient statement. A commercial «corn syrup» may contain between 20 % and 98 % dextrose. «Corn syrup» may also be called «glucose syrup» in an ingredient list.

Corn syrups are used in many of today’s salad dressings, tomato sauces, powdered drink mixes, fruit drinks and juices, and frozen desserts like pudding and ice milk.

When a corn syrup has been concentrated to contain less than 10 % water, it can be listed as «corn syrup solids» in an ingredient statement. To qualify as «corn syrup solids», the glucose (dextrose) content must be at least 88 % of the weight of the concentrated syrup. This product can be called «dried glucose syrup» or «glucose syrup solids» in an ingredient list.

Corn syrup solids are used in the same types of foods as dextrose and corn syrups.

A maltodextrin is a short chain of molecularly linked dextrose molecules, and is manufactured by regulating the hydrolysis of starch.

The term «maltodextrin» can be applied to any starch hydrolysis product that contains fewer than 20 dextrose units linked together. Today’s commercially important maltodextrin products are produced from corn, potato or rice. Unlike the other starch sweeteners, the undefined term «maltodextrin» can be used in an ingredient list no matter the original source of starch.

Maltodextrins are used in a wide array of foods, from canned fruits to snacks. Maltodextrins may also be an ingredient in the single-serve, table-top packet of some artificial sweeteners.

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Corn syrups enriched with fructose are manufactured from syrups that have been treated to contain as much dextrose (glucose) as possible. Nearly all the glucose in these dextrose-rich corn syrups is transformed into fructose with enzymes. The fructose-enriched syrups are then blended with dextrose syrups. After blending, commercial fructose corn syrups contain either 42 % or 55 % fructose by weight.

The generic term «high fructose corn syrup» or its acronym «HFCS» is used in food and beverage ingredient statements.

The vast majority of the high fructose corn syrup containing 55 % fructose is used to sweeten carbonated soft drinks and other flavored beverages. Minor amounts are used in frozen dairy products. Essentially all foods listing “high fructose corn syrup” as an ingredient contain the syrup with 42 % fructose. The 95 % fructose corn syrup is becoming more common in beverages, canned fruits, confectionery products and dessert syrups.

Crystalline fructose is produced by allowing the fructose to crystallize from a fructose-enriched corn syrup. The term «crystalline fructose» is listed in the ingredient statements of foods and beverages using this corn sweetener. It is important to understand that the «crystalline fructose» listed as an ingredient comes from cornstarch, not fruit.

Crystalline fructose can be used in the same foods as the high fructose corn syrups, or in any food that contains sugar.

Juice concentrates may be used to directly replace sugar. These syrups are made by first heating fruit juices to remove water, and then treating with enzymes and filtering to strip all characteristic color and natural flavor from the original juice. Because of their bland initial color and flavor, grapes and pears are the primary sources of the juice concentrates used as sugar replacers. Juice concentrates that replace sugar contain traces of sucrose, and variable amounts of fructose and glucose.

Juice concentrates are used in any foods where corn syrups have replaced sugar. They are particularly prominent in baked goods, jams and jellies, and frozen confections.

SUGAR ALCOHOLS

The common sugar alcohols – sorbitol, mannitol, maltitol, erythritol, and hydrogenated starch hydrolysates – are manufactured

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from cornstarch. Xylitol, another common sugar alcohol, is manufactured from such sources as corn cobs, sugar cane bagasse (stalk residue remaining after sugar extraction), or birch wood waste. Isomalt and lactitol are becoming more common and are manufactured from sucrose and whey, respectively. Isomalt and lactitol are commonly called bulk sweeteners because their sizes are nearly the same as sugar. Sugar alcohols are sometimes referred to as polyols, a generic term that represents a family of different products, not a unique single ingredient.

Although small amounts of sorbitol are present is some fruits, the commercial source of sorbitol is the dextrose (glucose) produced from cornstarch. Sorbitol is manufactured by hydrogenating (adding hydrogen) the recovered dextrose. While another name for sorbitol is glucitol (resembling glucose), sorbitol is the term used by the food industry. Sorbitol is about 60 % as sweet as sucrose, and is considered to have 2.6 calories per gram.

Sorbitol is used in hard and soft candies, flavored jam and jelly spreads, baked goods and baking mixes, chewing gum and cough drops.

Mannitol is widespread in nature, being present in the fruit, leaves and other parts of various plants. Strawberries, celery, onions, pumpkins and mushrooms are particularly good sources.

Commercially, mannitol is manufactured from fructose. Today, the source of fructose is cornstarch. Prior to the commercialization of starch hydrolysis, mannitol was produced from the fructose component of invert sugar. During hydrogenation (hydrogen addition), the fructose molecule rearranges to the sugar mannose. That is why this sugar alcohol is called mannitol. Mannitol is about 60 % as sweet as sucrose, and is considered to have 1.6 calories per gram.

Mannitol is used in hard and soft candies, flavored jam and jelly spreads, confections and frostings, chewing gum and cough drops.

Maltitol is manufactured by hydrogenating maltose, the glucoseglucose disaccharide (two sugars) derived from cornstarch. The use of maltitol in food is approved in most countries including Canada, Europe, Australia, New Zealand and Japan.

Maltitol is about 90 % as sweet as sugar. This feature makes it attractive to the food manufacturer as a one-for-one replacement of sugar.

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Maltitol is used in the same food categories approved for sorbitol and mannitol.

The singular term «hydrogenated starch hydrolysate» is applied to a family of polyol products. Hydrogenated starch hydrolysates (HSH) are produced by the partial hydrolysis of starch – corn being the most prominent – and the subsequent hydrogenation the various starch fragments (dextrins). In practice, «hydrogenated starch hydrolysate» is used to describe products that contain more hydrogenated dextrins than sorbitol or maltitol.

This expansive term «hydrogenated starch hydrolysate» does not identify the primary polyol used in the food. However, if a HSH contains 50 % or more sorbitol, for example, it can be labeled as «sorbitol syrup». The same would also be true for the labeling of «maltitol syrup».

Hydrogenated starch hydrolysates are 20 % to 50 % as sweet as sugar. HSH sweetness depends on its particular composition. For example, a HSH containing more maltitol would be sweeter than one containing more sorbitol.

Hydrogenated starch hydrolysates can be used in the same types of products that use the other common sugar alcohols. HSH products are generally blended with other sweeteners, both caloric and artificial.

Erythritol is the newest sugar alcohol to be manufactured from cornstarch. Unlike sorbitol, maltitol or hydrogenated starch hydrolysates, erythritol is produced by a fermentation process.

Erythritol is approximately 70 % as sweet as sucrose, supplies about two-tenths of a calorie per gram, and has a mild cooling effect in the mouth. Erythritol is used mainly in confectionery and baked products, chewing gum and some beverages.

Xylitol has approximately the same sweetness as sugar. Xylitol provides the greatest cooling effect of any of the sugar alcohols. Xylitol has a pronounced mint flavor. These characteristics make xylitol the polyol of choice for sugar-free chewing gums, candies and chewable vitamins.

The main application is foods formulated to meet the dietary needs of diabetics.

Isomalt is manufactured from sugar. The fructose portion of sugar is converted to equal amounts of sorbitol and mannitol. The glucose

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portion is unchanged. Thus, isomalt is a mixture of two disaccharides, glucose-sorbitol and glucose-mannitol.

Isomalt is about half as sweet as sugar and, unlike most polyols, produces no cooling effect in the mouth. Isomalt is considered to have 2 calories per gram.

Because the original glucose-fructose bond remains, isomalt can be heated with no loss of sweetness or change in texture. While isomalt can provide nearly the bulk that sugar gives, baked products containing isomalt tend to be crispier and do not brown the same when heated.

Isomalt is used in hard and soft candies, chocolates, ice cream, jams and preserves, baked goods, fillings and fondants, chewing gum and cough drops. Isomalt may be mixed with an artificial sweetener to bring the level of sweetness up to what it would be if sugar were used.

Lactitol is manufactured from whey, the lactose (milk sugar) rich by-product of cheese making and processed dairy foods. Lactitol is slightly less than half as sweet as sugar and is considered to have 2 calories per gram.

Lactitol is used in a wide range of reduced-sugar or sugar-free foods, from baked goods and frozen dairy desserts to candies, chocolate confections and preserves. Lactitol is often mixed with artificial sweeteners.

In laboratory studies, lactitol has been shown to promote the growth of the two bacteria recognized to improve the health of the large intestine. As a result, the prebiotic potential of lactitol is sometimes highlighted for the foods using this sugar replacer.

SUGAR PRODUCTION AND THE MULTIPLE EFFECT

EVAPORATOR

Sugar cane had been planted as early as 1750 near New Orleans, but with only limited success. By the 1790s, interest in sugar revived. Production rose steadily thereafter, and by 1830 Louisiana was producing over 33,000 tons of sugar annually.

Sugar cane is normally harvested in the fall. After cutting, the cane is milled to produce sugar cane juice. Originally animal power was used to grind the cane; by the 1830s, steam power began to replace animal power. In either case, the cane juice was boiled in four large open kettles

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arranged in a kettle train. Each kettle was of different size, and the kettles were arranged from the largest, which held up to five hundred gallons, to the smallest. The first kettle, the largest one, was called the grande, the next the flambeau, then the sirop, and finally, the smallest, the batterie.

Norbert Rillieux’s great innovation was his understanding of how latent heat could be used repeatedly in processing sugar. The result was his Multiple Effect Evaporator under Vacuum, which one expert, John Heitman in The Modernization of the Louisiana Sugar Industry, 18301910, called «the premier engineering achievement in nineteenth-century sugar technology».

Rillieux utilized the latent heat produced from evaporating sugar cane juice by employing a series of three or four closed evaporating pans in which vapor was piped out of each pan to heat the juice in the next, with the vapors in the end going to a condenser. At the same time, pressure in the system was reduced by pumps, which created partial vacuums and lowered the boiling point of the liquid. A description of the invention’s design is given in Rillieux’s 1846 patent:

«A series of vacuum pans, or partial vacuum pans, have been so combined together as to make use of the vapor of the evaporation of the juice in the first, to heat the juice in the second and the vapor from this to heat the juice in the third, which latter is in connection with a condenser, the degree of pressure in each successive one being less. The number of sirup-pans may be increased or decreased at pleasure so long as the last of the series is in conjunction with the condenser».

Rillieux’s invention allowed for the production of better quality sugar with less manpower and at reduced cost. One of the major economies was the conservation of fuel, because wood was needed to heat only the first chamber. Each successive chamber used the latent heat released by steam from the preceding chamber.

Sugar manufacturers around the world in Cuba, Mexico, France, and Egypt, as well as the United States, adopted Rillieux’s evaporator. Moreover, the device was not limited to sugar production but came to be recognized as the best method for lowering the temperature of all industrial evaporation and for saving large quantities of fuel. Multiple effect evaporation under vacuum is still used in sugar production as well as in the manufacture of condensed milk, soap, glue, and many other products.

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The Rillieux evaporator was one of the earliest innovations in chemical engineering and remains the basis of all modern forms of industrial evaporation. He was successful because he understood the principles of thermodynamics and latent heat and applied that knowledge to the technical needs of the sugar industry.

SUGAR IN JELLIES AND PRESERVES

Gelling

Sugar is essential in the gelling process of jams, preserves and jellies to obtain the desired consistency and firmness. This gel-forming process is called gelation—the fruit juices are enmeshed in a network of fibers. Pectin, a natural component of fruits, has the ability to form this gel only in the presence of sugar and acid. Sugar is essential because it attracts and holds water during the gelling process. In addition, acid must be present in the proper proportions. This optimum acidity is a pH between 3.0 and 3.5. Some recipes include lemon juice or citric acid to achieve this proper acidity. The amount of gel-forming pectin in a fruit varies with the ripeness (less ripe fruit has more pectin) and the variety (apples, cranberries and grapes are considerably richer in pectin than cherries and strawberries). In the case of a fruit too low in pectin, some commercial pectin may be added to produce the gelling, especially in jellies. In recipes that use commercial pectin, the proportions of sugar may be slightly higher or lower than the one part fruit to one part sugar ratio.

Preserving

Sugar prevents spoilage of jams, jellies, and preserves after the jar is opened. Properly prepared and packaged preserves and jellies are free from bacteria and yeast cells until the lid is opened and exposed to air. Once the jar is opened, sugar incapacitates any microorganisms by its ability to attract water. This is accomplished through osmosis (the process whereby water will flow from a weaker solution to a more concentrated solution when they are separated by a semi-permeable membrane). In the case of jellies and preserves, the water is withdrawn from these microorganisms toward the concentrated sugar syrup. The microorganisms become dehydrated and incapacitated, and are unable to multiply and bring about food spoilage. In jellies, jams and preserves, a concentrated sugar solution of at least 65 % is necessary to perform this function. Since the sugar content naturally present in fruits and their juices

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is less than 65 %, it is essential to add sugar to raise it to this concentration in jellies and preserves.

Color Retention

Sugar helps retain the color of the fruit through its capacity to attract and hold water. Sugar absorbs water more readily than other components, such as fruit, in preserves and jellies. Thus, sugar prevents the fruit from absorbing water which would cause its color to fade through dilution.

EXTRACTION OF JUICE

The oldest method of extracting juice consists in subjecting the crushed fruit to pressure in such a manner that the fruit flesh remains behind in the press and the juice flows free. The fruit may be crushed by either grater or hammer mills which reduce the fruit to a coarse pulp from which the juice may be pressed readily. Certain fruits such as grapes yield juices of improved quality if they are heated before pressing.

The crushed fruit is wrapped in a heavy, coarsely woven press cloth to form a cheese. Pressure is commonly applied by a hydraulic press.

Crushing or heating followed by pressing are commonly used in the preparation of apple and grape juice and yield products relatively free from insoluble suspended matter. A somewhat different product results from utilization of a more recently developed type of press which is continuous in operation. In this type, a combined crushing and pressing action forces the fruit into contact with screens under comparatively gentle pressure. The most desirable machines, on the basis of flavor, color and vitamin retention in the juice, are those which reduce to a minimum the contact of juice with air. Another method for extraction of juice from fruit having a firm texture consists in passing the fruit through disintegrating machines which reduce it to a very fine pulp before pressing. Juice high in suspended solids results from this process. This method is used very successfully in preparing pineapple juice.

A specialized type of equipment is required for extracting citrus juices to avoid the inclusion in the juice of peel oils which give an undesired flavor.

After extraction, fruit juice is strained or screened when necessary to remove seeds and other objectionable solids which may present.

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Screens are preferably of the self-cleaning type such as rotating, inclined cylindrical screens, or vibrating screens.

WINE-MAKING

Winemaking was practiced in ancient Greece. It was dark and usually drunk with water. It was kept in casks, goatskins and stoppered with oil or a greasy rag; air was working on it all the time. The full maturing of wine had been impossible until the bottle and the cork were generally used. Wine reaches its maturity in about three years; retained longer it may not improve and may deteriorate. Hocks were indeed kept in cask for 20 years until the end of the 18th century and considered to improve.

The proper use of wine bottles and corks seems to have become common toward the end of the 17th century; another important change was the discovery by accident in 1775, that grapes left to rot on the vines produced a sweetness and bouquet unobtainable in any other way. In the middle of 1750s the Madeira shippers first began to fortify their wines by adding a proportion of brandy to them. By that time vineyards were planted in Latin America, in South Africa, in North Africa, in France, in England and other places.

Wine is the fermented juice of the grapes. It is one of the most ancient fermentative industries. It is based on the alcoholic fermentation. Wine is made from grapes of the various form. The two main types of wine are red (made from black grapes only) and white is in fact yellow in colour and may be made from either black or green grapes. Less important are the rose (pink) wines, usually made by leaving the grape juice, called must, in contact with the black skins for a very short space of time, enough to extract only a little of the colour.

The main stages of wine-making are the following ones: preparation of grape juice, fermenting it with yeast, racking and aging. The grapes are crushed, the juice is separated from the crushed grapes by pressing them. Thus, the grape must is produced. After clarification it is ready for fermenting. The main change in the grape juice fermentation is the conversion of glucose and fructose into alcohol and carbon dioxide. It is done with the aid of pure culture yeast. They are called wine yeasts. The grape juice fermentation is conducted at the temperature of

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+15-25 °C for 14-24 days. After the fermentation is completed a young wine is produced. It is separated from the yeast sediment and is stored in wooden vats for maturing. During aging the wine is cleared, racked for several times. Different types of wines are aged for different periods: from some months till some years.

RAW MATERIALS IN FERMENTATION

Raw materials for fermentative industries include those rich in sugar and those rich in cellulose. Among raw materials of the first group mention should be made on barley, oats, maize, rye, wheat and rice. As to the chemical constitution of the raw materials mentioned above they contain carbohydrates, proteins, fats and ashy elements. Carbohydrates, i.e. starch, sugars, dextrin-like substances and cellulose are of particular importance for fermentative industries. Nitrogenous substances are important constituents of the cereals. Among them proteins are of particular importance. They have a significant influence upon malting and brewing processes.

Potatoes are used as raw materials for ethyl alcohol production. Grapes and molasses are raw materials rich in sugars. Grapes are

used in wine-making. Grape juice contains glucose, fructose and sucrose (over 32 % of sugar). Molasses is a by-product of beet sugar production and is used as the main raw material for ethyl alcohol and baker’s yeast production. Molasses is a dark brown thick liquid. Its main constituent is sucrose. It also contains invert sugar and nitrogen. Wood pulp is the raw material for hydrolytic production. There some auxiliary materials which sugar and starch don’t contribute. These are spices, coloring matters, blending agents imparting a pleasant aroma, colour and taste to the liquor. Hop is one of them. It is used in brewing.

YEASTS

Yeasts were used in ancient times in wine-making, in brewing and in the alcohol production. Yeast is a round or oval plant. It consists of one cell. Yeasts form a number of enzymes affecting the process of fermentation. There are two main kinds of yeasts: true and false or pseudo-yeasts. True yeasts are subdivided into three types of yeasts:

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