Begin with the end product in mind and you're well on your way to formulation success. A simple statement such as this is applicable across all food formulations. However, it is particularly prudent when creating healthier, better-for-you food products that are increasing in demand.

Sugar alcohols, more commonly referred to as polyols, are among the top choices in formulating reduced-sugar, low-calorie or sugar-free foods in the confectionery, bakery, dairy, dessert and oral-care market segments.

Often misunderstood are the reasons for choosing a specific polyol over other polyols or other forms of sugar substitutes such as high-intensity sweeteners, fibers or low-digestible carbohydrates.

Mannitol, sorbitol, xylitol, maltitol, lactitol, isomalt, erythritol, maltitol syrups and polyglycitols are the polyols most commonly used in the food industry. Not to be confused with high-intensity or 'non-nutritive' sweeteners, polyols are typically used as a one-for-one substitute for sugar.

Polyols have varying properties, including relative sweetness to sucrose, caloric value, laxative effect, solubility, heat of solution, melt point and molecular weight.

All of these properties contribute to the finished product's processing and packaging considerations, as well as the visual and sensory properties seen by consumers. Choosing the best polyol for your application, however, can be somewhat overwhelming. Again, to help make this process easier, begin with the end product in mind.

Begin at the beginning

First, determine what properties the finished product should have. For example, are you making a soft, chewy candy piece, or a hard-boiled candy?

A high-quality soft, chewy candy is best made using a maltitol syrup because of the distributed molecular weight that comprises the syrup and extends shelf life through moisture control.

A stable and visually appealing hard candy piece may best be achieved using a blend of isomalt and polyglycitol or maltitol syrup — isomalt as the bulking agent to form product shape and give mouthfeel, while polyglycitol syrup is best to control recrystallisation of isomalt to avoid a white-crystal coated appearance, and to increase the laxation tolerance to multiple servings of hard candy.

Maltitol syrup may be used in place of polyglycitol syrup, depending on labelling preferences. An additional benefit of blending polyglycitol or maltitol syrup with isomalt is that they increase the viscosity of the molten-candy mass, which in turn makes the mass easier to work with during processing.

Often a high-intensity sweetener such as sucralose or acesulfame potassium (ace-K) will be used to increase the sweetness of isomalt to match that of sugar. Sometimes, with the addition of maltitol syrup, the high-intensity sweetener is not needed.

Another option for formulators is to look at the ingredient they are trying to remove from the product, such as sugar, corn syrup, fat or gelling agents. Often these ingredients are substituted out to make claims such as 'no sugar added,' 'reduced sugar,' 'low calorie' or even kosher. Looking at sugar and its molecular weight, the two most similar ingredients are maltitol and isomalt.

Maltitol's sweetness, solubility and heat of solution are nearly identical to sucrose, not to mention similarities of mouthfeel, taste and texture in the finished product.

Maltitol syrups and poly-glycitol syrups (also known as hydrogenated starch hydrolosates) are nearly identical to corn syrups.

High-maltitol content maltitol syrups can replace high-fructose corn syrup on a one-for-one basis, while polyglycitol syrups typically replace 26DE and 43DE corn syrups.

Just as corn syrups are less sweet and more viscous than sugar slurries, polyglycitol syrups are typically less sweet and more viscous than maltitol in solutions. These attributes are key when looking to control moisture migration and increase shelf life, particularly in baked and confectionery applications.

When baking, crystalline maltitol is the ideal candidate to replace sucrose. By looking at finished cookies all made with various sugar substitutes, one can clearly see that maltitol makes a cookie that looks most like its sugar counterpart. The physical properties of a cookie are very important, including spread, cell structure, crystallisation, starch gelatinisation temperature and maillard reaction.

Stay focused on the goal

Again, while trying to replicate a sugar-based cookie, the end product should be kept in mind through the entire formulation process.

Generally speaking, as molecular weight of the bulk sweetener decreases (erythritol and sorbitol), the spread of the baked cookie also decreases. Similarly, as molecular weight increases (polydextrose and fructo-oligosaccharide), spread of the baked cookie also increases.

Cell-structure formation, which leads to volume and mouthfeel of the cookie, is dependent upon starch-gelatinisation temperatures of bulk-sweetener systems. Some cookies have inclusions such as nuts or chips that give crunch in the mouth; however, sugar is not an ingredient that should yield crunch to a cookie.

Therefore, bulk-sugar replacers should also not contribute to crunch. Polyols such as isomalt and erythritol have low-solubility rates and also tend to favour their crystalline form, and should not be used in baking applications due to their grainy mouthfeel. Crystalline maltitol or maltitol syrups should be utilised instead because they typically do not recrystallise after baking. Maltitol syrups are often used in lieu of crystalline maltitol to control costs.

Certainly there are many considerations when changing formulations to meet consumer demands. Fortunately, food scientists and product developers have a vast array of new and renewed ingredients and ingredient suppliers with the knowledge to ease their quest.

To begin with the finished product in mind sounds all too elementary to marketers and consumers. It is up to product developers to continue to understand the complexity of such an elementary exercise.

Rick Francolino is a food scientist with Corn Products Specialty Ingredients working in the applications, research and technical services lab, focusing on product formulation and ingredient applications. Respond:[email protected]

Chart: Polyols comparison - Laxication threshold (g/day)