Replacing sugar: A game of three stages
Traditional ice creams commonly contain sugar in two forms – sucrose and glucose syrup. Together, they typically account for up to half of the total solids in the ice cream, and replacing them can be difficult because of the important functional roles they perform.
“When you take out sugar, you’re taking out a major part of the recipe,” Claus explains. “As well as providing sweetness, it affects freezing point and solid content, so really what you have to do is to replace one Ingredient with three or more ingredients. You then have to balance the recipe according to the ingredients you’re choosing, and there are a lot of different combinations you can use. It can feel like a complicated game sometimes.”
Freezing point depression
The first factor that has to be addressed in the process isn’t sweetness but the freezing point. “When you add water-soluble ingredients like sugar to water as in an ice cream mix, you lower the freezing point,” Claus explains. “This is important because it gives you softness and prevents the product from being rock-hard when the consumer is eating it. So if you take out sugar you have to add something that allows you to keep that freezing point depression.”
This is commonly achieved by using sugar alcohols such as erythritol, maltitol and xylitol. They can be added in different concentrations to give the right freezing point and freezing curve or profile, with many manufacturers using a combination of two or three. These sugar alcohols are often stronger in the freezing point depression than sugar, and will therefore be used in a lower dosage than the removed sugars, leading to a lack of solids in the recipe.
Boosting solid content
The next consideration is solid content. “You have to add solids to maintain creaminess and mouthfeel and prevent the product from feeling watery when eaten,” Claus explains. “Bulking agents such as inulin, fibre or polydextrose allow you to increase the solid content without affecting the sweetness or the freezing point depression. Depending on which you choose, you can affect the texture and mouthfeel.”
Sweetening the deal
Adding high-intensity sweeteners is the final step of the process. “Of course, it’s a dessert product so it’s expected to be sweet,” Claus says. Again, a range of options are available: “Aspartame used to be the most commonly used high-intensity sweetener but now there’s sucralose and plant-based options like stevia glycosides. They’re used at a very low dosage, so they don’t affect the freezing point, the solid content or the texture, allowing you to add them as the last ingredient in the substitution of sugar.”