CHOICE OF SWEETENER

IV. CHOICE OF SWEETENER

Sweetness is important for food acceptability, but in a food sweetness is seldom tasted alone. Sweet tastes are almost always mixed with a variety of complex flavors, and sweet- ness is also affected by the texture and aroma of the food. Therefore, the overall properties of a food determine the amount and choice of sweeteners. When considering the choice of sweeteners, one of the most important aspects is naturally the degree or intensity of sweetness. However, nutritive sweeteners especially have many other functions in food systems. Sucrose or sugars have a great influence on the texture and bulking of many foods. These include baked foods, sugar confectionery, soft drinks, and dairy foods. In soft drinks, sugars produce viscosity and a pleasant mouth-feel, which are difficult to mimic in products sweetened with nonnutritive sweeteners. In preserves and jams as well as marmalades, sugars affect texture, sweetness, and bulk properties. Additionally they have osmotic effects and thereby help preserve the product and extend its shelf-life. An additional property is the ability to absorb water in baked products to help retain the moist texture. In many applications nutritive sweeteners also offer an energy source for food fermentations. The most important properties of sweeteners in foods are summarized in Table 4.

The general properties of nutritive polyol sweeteners are summarized in Table 3 . The substitution of sugars with polyols is often easily accomplished. In many cases sorbitol and xylitol can be used in place of sucrose in foods. Polyols in general (except for lactitol) also have humectant properties. All polyols act as bulking agents, and their use for bulking and texturizing may reduce the energy content of foods. This is especially true for lactitol and mannitol, which have relatively low sweetness. In terms of reduced cariogenicity, xylitol offers an excellent substitute for most common sugars. Fructose, on the other hand, also appears to be a less cariogenic alternative to sucrose and sorbitol. An added advantage of polyols is their suitability for special dietary foods and diabetic foods. Fructose, xylitol, and lactitol appear to be especially suitable sugar substitutes for diabetics provided their calories are taken into account.

The properties of nonnutritive sweeteners are summarized in Table 2 . Most nonnutri- tive sweeteners are suitable sugar substitutes for special dietary foods and foods manufac- tured for diabetics. The sweeteners in this group have a relatively intense sweetness, and therefore only small amounts of these compounds are needed in food products. This results in the need of bulking agents in many food products sweetened with the compounds in this group. Until recently the choice of bulking agents has been limited. However, now polydextrose is a good low-calorie bulking agent suitable to many baked foods and dairy

Table 4 Properties of Sweeteners in Foods Sweetener, functional ingredient, prebı´otic

Bulking agent, texturing agent, viscosity modifier Preservative, antimicrobial Substrate for fermentations and fermentation processes Humectant (water adsorption modifier) Freezing point modifier Crystallization modifier Noncariogenic or anticariogenic agent Mouth-feel modifier Bulking agent, texturing agent, viscosity modifier Preservative, antimicrobial Substrate for fermentations and fermentation processes Humectant (water adsorption modifier) Freezing point modifier Crystallization modifier Noncariogenic or anticariogenic agent Mouth-feel modifier

The manufacture of jams and marmalades sweetened with nonnutritive sweeteners requires the use of pectins or other thickening agents to obtain normal viscosity. Often antimicrobials are also needed to obtain a shelf-life similar to that of sucrose jams.

Other uses for nonnutritive sweeteners include pharmaceutical preparations (sweet- ness to cover the flavor of the product), tabletop sweeteners, and nonnutritive sweetener preparations for home use. For these purposes the stability and taste properties are most

important, as indicated in Tables 2 and 3 . In some cases, noncariogenic properties are important, as in pharmaceutical preparations for children. Another important factor is the price of the sweetener. Nonnutritive sweeteners usu- ally appear to be relatively cheap compared to the intensity of sweetness they produce. However, if bulking agents or other special measures are required, the cost may increase significantly. Table 5 summarizes the relative costs of some sweeteners as reported in Scandinavia by the Swedish National Food Administration (Hallstro¨m and Janelm, 1985). Also included in Table 5 are some suggestions of products for which particular sweeteners are suitable.

In conclusion, for the practical choice of sweetener, at least the following aspects should be considered: regulatory acceptability, availability, price for sweetening equiva- lent (including other ingredient and additive costs), nutritional value, sensory characteris- tics, and functional properties in the food system. After deciding the general direction for the development of a product and choice of sweetener, product optimization may be of further help. Wu¨rsch and Daget (1987) have reviewed both the overall problems of sweet- ness in product development and product optimization, which was introduced by Sidel and Stone (1983).

The ideal sweetener has been described by the Calorie Control Council (1985). Ac- cording to their definition it should have the same sweetness as sucrose or greater sweet- ness than sucrose. In addition it should be odorless, colorless, stable,and readily soluble in food systems. It should be functional and economically feasible. It should also be nonca- loric or its use should produce reduced caloric content in foods. The ideal sweetener should additionally be noncariogenic and nontoxic. At present we do not have an ideal sweetener,

Table 5 Price of Various Sweeteners on a Sweetness Equivalent Basis in Scandinavia in 1985 and Suitable Food Uses