Table of content A-Z

 

natural sweeteners

 

natural sweeteners

 

Introduction and overview

All substances are termed sweeteners that are used to sweeten foods, drinks and medicinal products. This therefore includes all sugars, sugar substitutes, artificial sweeteners and sugar alcohols.

Most sweeteners are found in nature. Only a few are always synthetically produced: the artificial sweeteners (with the exception of thaumatin) and four of the sugar substitutes. This article does not deal with these.

Sweeteners can be divided into two groups: those with a caloric value, i.e. that deliver energy in the form of kcal, and those that have no caloric value. Sugars, i.e. grape sugar (glucose), malt sugar (maltose), milk sugar (lactose) and granulated sugar (sucrose), have a caloric value. Fruit sugar (fructose) counts nutritionally as one of the so-called sugar substitutes owing to its metabolization in the body, but it has a similar amount of calories as sucrose. In addition there are the substances mannitol, sorbitol, xylitol and erythritol. Like lactitol, isomalt, maltitol and maltitol syrup, these are always synthetic in origin. A newer sweetener, not yet approved in Germany, is stevia. The only artificial sweetener that has no caloric value and is found in nature is thaumatin, which is derived from the West African cactus fruit.

Sugar

Sugar is the common term for sucrose. Chemically speaking, however, sugars are various types of carbohydrates and supply the body with energy. We differentiate between simple sugars (monosaccharides), twofold sugars (disaccharides) and complex sugars (polysaccharides). Only the first two are suitable for sweetening, however. Monosaccharides are galactose, glucose and fructose. They are found in fruits and honey, for example, or can be bought as dextrose. As they are the most quickly digested, they supply the energy that is most quickly available to the body.


Di- and polysaccharides are chains of two or more monosaccharides. The longer the chains, the longer it takes for the organism to digest them, because they must first be broken down again into monosaccharides. Lactose, maltose and sucrose are disaccharides.

In its pure form, sugar is colourless and odourless. Too much sugar in the diet leads to overweight and promotes the development of caries. It dissolves easily in water and in higher concentrations it has a preserving effect.

Forty-five percent of all sugar worldwide is produced from sugar beets, the rest from sugar cane. In principle, however, sugar or sugar syrup can also be made from other plants, e.g. maple syrup, agave syrup and date syrup. A number of different sugars are found in nature, and many different products are made from them. Following are listed in alphabetical order first the types of sugar and then the commercial or processed varieties.

Some types of sugar

* Fructose (fruit sugar) is found in various forms in plant foods. Many fruits contain pure fructose, while in other fruits and parts of plants it is bound to sucrose or occurs in other compounds. Honey contains both free and bound fructose. Diabetics tolerate fructose better than sucrose or glucose, and it is therefore often used as a sugar substitute. This always gives the impression of a diet product, but it is not: fructose contains the same amount of energy as sucrose or glucose. The only dietary advantage of fructose is that it has a higher sweetening power than glucose and sucrose, which makes it possible to use smaller amounts and thus to reduce the number of calories consumed.
* Galactose is a component of lactose and is otherwise usually bound to other substances. It does not taste very sweet.
* Glucose (grape sugar, dextrose) is the sugar most frequently found in plants. They produce it during photosynthesis from the carbon dioxide that they take from the air and from water. For this they require sunlight and chlorophyll. During glucose production, oxygen is released into the air. The glucose is then further processed by the plant, for example to sucrose, proteins and fats.
* Lactose (milk sugar) is obtained from whey, and is not as sweet as glucose, sucrose or maltose. Some people develop an intolerance to lactose, but it can improve the absorption of calcium from the diet. Lactose is found in milk and dairy products and is frequently used in the production of medicines.
* Maltose (malt sugar) is the not very sweet sugar obtained from malted barley that has a slight taste of malt. It is found in beer but is not added to it. Maltose is not sold in crystalline form.
* Sucrose (table sugar, white sugar) is the ‘normal’ sugar used in the household. It is white; brown colourings are caused by impurities. Sucrose is obtained from sugar beets or sugar cane and consists of glucose and fructose. Sugar from sugar cane is chemically and physically identical to sugar from sugar beets, except for negligible inclusions or agglomerations of non-sugar substances.

Special sugars

* Brown sugar is treated as if it were in its original state or ‘natural’, but it is an intermediate stage between raw sugar and completely purified white sugar. In some cases molasses or caramel is added again later to white sugar to make it brown. Owing to the purification, there are practically no nutrients left in brown sugar; it is also really only finely granulated sucrose with decorative characteristics and a light malt-caramel flavour.
* Preserving sugar is refined sugar from which the saponin, an ingredient of the sugar beet that produces a soap-like foam, has been completely removed. It is not the same thing as gelling sugar.
* Gelling sugar, or canning sugar, is refined or white sugar whose granules have been coated with the gel-forming plant substance pectin; it is used to make jams, marmalades and jellies. It usually contains citric acid as well, which aids in the gelling process.
* Glucose syrup is a viscous, concentrated solution made of starch. Depending on the extent to which the starch is saccharified, glucose syrup consists to differing degrees of glucose, maltose and polysaccharides. It has very little sweetening power and its flavour is described as pleasant. Glucose syrup is used frequently for marmalades, jams, preserved fruit and confectionery.
* Glucose-fructose syrup is actually the same as invert sugar syrup.
* Industrial sugar is a disparaging term for white or refined sugar.
* Invert sugar consists of equal parts of glucose and fructose, as it results from the effect of acid or enzymes on sucrose. In contrast to other kinds of sugar, invert sugar does not have the tendency to crystallize. It is the main component of honey and is also found in many sweet fruits.
* Invert sugar syrup is produced by dissolving sugar in water to make a syrup which is then filtered, completely demineralized, decolourized and finally treated with the enzyme invertase. This splits the sugar molecules so that they can react with water. The pleasant flavour of invert sugar syrup does not change, even during storage.
* Isoglucose is formed during further processing of glucose syrup. The main components are glucose and fructose. It resembles invert sugar syrup and is used to preserve fruit and to make soft drinks.
* Candied sugar or rock candy is sugar with relatively large crystals obtained from a pure sugar solution. It is sold white or in various shades of brown, the latter produced by the addition of caramel or caramel colouring.
* Caramel forms when sugar is heated. It is a decomposition product of sucrose, glucose and other sugars. Depending on the heating temperature and the length of the process, caramel is light- to dark-brown. It is characterised by its typically intensive flavour and scent.
* Granulated sugar
* Powdered or confectioners’ sugar must have granules with a much smaller diameter than those of refined sugar, namely maximally 0.05 mm (refined: 2 mm).
* Refined sugar is purified and crystallized sucrose that must meet specific requirements, for example, a maximum of colouring ingredients and minerals and a maximal granule diameter of 0.2–0.8 for the designation ‘fine’, 0.8–1.25 mm for the designation ‘medium’ and 1.25–2 mm for the designation ‘coarse’. Refined sugar results when raw sugar (see below), which still contains impurities and brown colouring is first centrifuged (thus separating the molasses) and then further purified. This purification can be done either by washing with water or with steam. This produces brown sugar (see above) that still differs in taste from white sugar. The other method of purification is refining, by which the raw sugar is dissolved three times in water and then newly crystallized, resulting in white sugar. Following subsequent purification and recrystallization of the white sugar, refined sugar is finally obtained. Refining twice produces double-refined sugar, which is especially fine.
* Cane sugar is produced from sugar cane (sucrose). This does not differ chemically or physically from beet sugar, apart from negligibly small inclusions or agglomerations of non-sugar substances.
* Raw sugar is produced when crude sugar cane juice is purified, vaporised and thus thickened until raw sugar crystallizes. It has a limited shelf life, a dark colour and a slightly alkaline taste.
* Beet sugar is produced from sugar beets (sucrose) and does not differ chemically or physically from cane sugar, apart from negligibly small inclusions or agglomerations of non-sugar substances.
* Vanilla sugar is sugar to which 5% real, finely ground vanilla has been added.
* Vanillin sugar is sugar mixed with 1% vanillin, a nature-identical flavouring substance with the main aroma of real vanilla.
* White sugar is purified and crystallized sucrose, one processing step prior to refining (see ‘refined sugar’).
* Caramel colouring is an additive used to make foods brown and has the food additive number E150. Caramel colouring is obtained by heating sugar with ammonium salts, which gives it a smoky or bitter taste. E150 is no longer sweet.
* Sugar-beet molasses / black treacle is concentrated sugar beet juice. It is clear and dark brown and contains at least 60% sugar. Its good spreadability at 18°C makes it a popular bread spread.

Sugar substitutes

When for dietary reasons (e.g. because of diabetes) or for economic or technological reasons sugar is to be avoided in food products, sugar substitutes are often used.
They produce a sugar-like taste, are similar to sugar in mass and energy and are as a rule metabolized independent of insulin, making them suitable for diabetic products. Fructose, i.e. fruit sugar, is the best-known sugar substitute. There are numerous others in addition, the sugar alcohols being the most important. Some sugar substitutes are found in nature and obtained by extraction, while others must be synthesised. We deal here only with those that occur naturally in plants. Because sugar alcohols have a mildly laxative effect, the recommended amount to be added to foods is limited.

* Erythritol (E968) can be used not only as a sweetener but also as a flavour enhancer, a humectant, and a thickening agent. With the help of yeasts, simple sugars such as glucose or sucrose are fermented to create this sweetener, which is considered to be harmless to health. Its sweetening power is 60–80% that of granulated sugar.
* Fructose is actually a sugar, but owing to its metabolic behaviour it is treated as a sugar substitute. Nevertheless, fructose is described in more detail on this site under sugar.
* Lactitol (E966) is made from lactose. Its sweetening power is somewhat less than half that of sucrose. To enhance its sweetness, lactitol is frequently used together with saccharin or acesulfame-K (K for potassium).
* Mannitol (E421) is found in the secretion of the sieve tubes of the flowering, or manna ash, in plane trees, olive trees, marine algae (seaweed) and in small amounts also in fruits such as pumpkin, onions, and strawberries. Nevertheless, mannitol is not obtained by extraction from these plants; it is synthesized. Its sweetening power is less than that of sucrose. Toxicological studies have supplied no proof of carcinogenicity or mutagenicity.
* Sorbitol (E420) is a sugar alcohol found in many plants and fruits. It represents an intermediate stage in the synthesis of ascorbic acid, cellulose, sorbic acid and starch. It also occurs as an intermediate stage in the animal organism. It is usually obtained from glucose or sucrose, which in turn are derived primarily from maize (corn) starch or wheat starch. Its sweetening power is 50–60% that of sucrose, but it increases with increasing concentration. Heating does not damage the sugar substitute. Sorbitol produces a slightly cooling effect in the mouth, does not promote caries, and poses no health hazard. However, the ingestion of more than 25 g can cause diarrhoea.
* Xylitol (E967) is a sugar alcohol found in many fruits and vegetables. It is extracted from other raw materials, however, by chemical processes. Birchwood, nut shells, straw and corn cobs are all rich in xylitol. It is a white, crystalline, sweet, odourless powder. Its sweetening power is similar to that of sucrose and its taste closely resembles that of real sugar. In addition it is heat-resistant. This makes xylitol a good substitute for sugar in candy and chewing gum, particularly as it does not cause caries. No toxic properties have been determined.

Other natural sweeteners

* Honey is produced by bees. “They collect flower nectar, other secretions of living plant parts, or secretions from insects found on living plants, enrich and modify these with their own natural secretions, store them in combs and allow them to mature there” (German Honey Ordinance). A fundamental distinction is made between blossom honey and honeydew honey, and these are in turn divided into different varieties, depending on the place of collection. More on the subject of honey can be found in the corresponding chapter.
One hundred grams of honey contain about 80 g of easily resorbed carbohydrates. These are mainly glucose and fructose, or invert sugar syrup.
* Maple syrup is obtained from the sap of the sugar maple (Acer saccharum), by boiling it down and thus thickening it (45 l sap yield about 1 l syrup). Its main component is sucrose (58–65%). Maple syrup is divided into quality classes according to its translucency: grade AA is very light to amber, grade A light, grade B medium, grade C dark brown and grade D dark. The aromatic intensity increases as the translucency decreases. Grades AA and A are mildly aromatic and are considered to be the highest-quality maple syrups; grades C and D with their typical caramel flavour are used only for industrial processing.
* Agave syrup is a juice extracted from the blossoms of the agave plant which is thickened by cooking. The heat converts the carbohydrates to sugar, producing primarily inulin, a special form of fructose that cannot be digested in the human intestine. It is somewhat sweeter than sugar. Thanks to its relatively neutral flavour, agave syrup can be used in many ways. Compared with sucrose it supplies less energy. Special syrup from the blue agave has a larger portion of fructose and can therefore be used in moderation for diabetics.
* Date syrup is produced especially in Iraq from sugar-rich varieties. Sugar and arak can be made from it.
* Stevia, actually stevioside, is a substance found in the leaves of the stevia plant, which grows in South America and in South and East Asia. This new sweetener is obtained in varying degrees of purity from the dried leaves of the plant. Depending on its purity, it may also contain other sweet-tasting substances. The sweetness of stevia is approximately the same as that of the sweeteners acesulfame and aspartame and thus more than 300 times that of sucrose. Because in addition to sweetness other taste impressions such as liquorice and bitterness are also conveyed, stevia is not suitable for all sweetening purposes.

Ingredients

Pure sugars contain no other substances. Minerals are present in traces at most. Fructose, lactose, glucose and sucrose supply 406 kcal and 100 g carbohydrates per 100 g. With syrups and honey the compositions fluctuate, depending on production. The blossom or the plant from which the bees gathered the pollen also influences the ingredients of honey. Sugar beet syrup contains a considerable amount of potassium.

100 g contain on average:

 

Honey

Maple syrup

Sugar beet syrup

Energy (kcal)

307

261

273

Water (g)

 

 

 

Protein (g)

<1

0

1

Fat (g)

0

<1

0

Carbohydrates (g)

75

67

67

Fibre (g)

0

0

3

Vitamin A (RE) (µg)

0

0

0

Vitamin E (TE) (mg)

0

0

Traces

Vitamin C (mg)

2

0

0

Sodium (mg)

7

9

90

Potassium (mg)

47

204

1450

Calcium (mg)

 

 

 

Magnesium (mg)

6

14

140

Iron (mg)

1.3

1.2

9

 

Most Germans and Americans consume more sugar (pure sugar, not carbohydrates from bread, etc.!) than is healthy and recommended by the German Society for Nutrition (DGE) and the World Health Organization (WHO). According to these two institutions, no more than 10% of one’s daily energy requirement should be covered by pure sugar (ca. 50 g sugar for women and 65 g for men). These amounts correspond to about 30 gummy bears or one large bar of chocolate. People often take in more of this energy-rich substance than they are aware of, not only in the form or sweets or with pure sugar, e.g. for coffee, but also with sweetened beverages, spreads and other processed foods. To prevent certain diet-related diseases you should try to keep your sugar consumption within the recommendations of the DGE and the WHO.

Artificial sweeteners

Artificial sweeteners produce a sweet taste in the mouth. Their sweetening power is considerably greater than that of sugar. Mixing various artificial sweeteners can enhance the taste and even increase the sweetening effect.


As they generally cannot be metabolized, they are a low-calorie substitute for sugar.


Their use is allowed only in certain foods and concentrations, however, because health concerns continue to be raised and the stated intake per day should not be exceeded.

Artifical sweetener and E-number

Sweetening power and taste

Particular characteristics

Metabolization and health

ADI value* [mg/kg body weight9

Acesulfame K (potassium)

E 950

120 times the sweetening power of retail sugar

Suitable for cooking and baking

According to current knowledge, does not degrade to toxic substances. There are still no definitive assessments regarding its toxicity; therefore, it should be used with care.

9 mg/kg body weight

Aspartame

E 951

160 to 180 times the sweetening power of retail sugar

Sensation of sweetness only after a time lag

High temperature and acidity eliminate sweetening power; thus not suitable for cooking and baking

Energy content 4 kcal, insignificant when used in small amounts

Enhances the flavours of citrus and fruit aromas

Is processed by the metabolism; no substances are formed that can cause damage to humans

Exception: decomposition releases the amino acid phenylalanine, which is problematic for persons who suffer from phenylketonuria.

Classified as harmless by the EFSA (European Food Safety Authority)

40 mg/kg body weight

Cyclamate

E 952

35 times the sweetening power of retail sugar

No aftertaste

Frequently used in combination with sucrose to increase its sweetening power or with other artificial sweeteners to improve the taste

 

Is excreted unchanged; but if it remains in the intestines its transformation product can impair fertility (shown in animal experiments) and affects the human autonomic nervous system

Non-carcinogenic, but if consumed in high concentrations facilitates the formation of bladder tumours in rats; epidemiological studies with humans did not confirm the increased incidence of bladder tumours in connection with the artificial sweetener.

Transformation products toxic for the central nervous system of rats and growth-inhibiting; therefore, not allowed in USA and not approved at this time, or approved only for dietetic purposes in several other countries

 

7 mg/kg body weight

This value is easily reached if one drinks many sweetened beverages.

Saccharin

E954

450 to 500 times the sweetening power of retail sugar

Somewhat bitter aftertaste, which can be minimized by blending with other artificial sweeteners

As such hardly soluble in water, thus mostly used as a salt (e.g. saccharin-sodium)

Sweetening effect lost when heated, thus not suitable for cooking and baking

Is excreted almost 99% unchanged in the urine

Ongoing discussion whether it is a health hazard: said to increase cancer risk, possible weak chromosome-damaging effect

However, epidemiological studies with humans did not confirm the higher incidence of bladder tumours in connection with the artificial sweetener that was determined in rats.

2.5 g/mg body weight

Sucralose

E 955

600 times the sweetening power of retail sugar

 

Only recently approved

Not metabolized by the human body and excreted largely unchanged

Regarded as safe

15 mg/kg body weight

Thaumatin

E 957

2500 times the sweetening power of retail sugar, which sets in with a delay but is long-lasting

Liquorice-like aftertaste

Also used as flavour enhancer for aromas

Only natural sweetener approved in the EU

Extracted from the seeds of the liquorice tree or produced with the aid of GMOs (genetically modified organisms)

Regarded as safe

No ADI value

 

*The ADI value is set for all additives by a committee of experts of the FAO (Food and Agriculture Organization of the UN) and the WHO (World Health Organization), based on scientific studies such as animal experiments and epidemiological investigations. ADI stands for Acceptable Daily Intake. According to current knowledge, the specified amounts of each substance can be consumed daily, lifelong, without causing damage to one’s health.

 

 

 

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