Allulose to Tagatose in Sugar Replacement

Originally Published: October 30, 2020
Last Updated: October 30, 2020
Image of a plate of delicious cookies and a cup of hot tea with a cinnamon stick and a spoonful of brown sugar on wooden background, conveying a holiday concept and warm mood

MANY OF OUR FAVORITE BAKERY TREATS contain about one third sugar, noted Melanie Goulson, MSc, General Manager & Principal Scientist, Merlin Development in her presentation, “New Kids on the Block: From Allulose to Tagatose, Properties & Performance in Sugar Replacement,” prepared for the 2020 Sweetener Systems Conference. “There is no magical drop-in solution that can replace the taste and function of sugar, so food scientists must use all of the tools in their toolbox to optimize sugar reduction,” she said.

Bulking sweeteners include sucrose, glucose, fructose, sugar alcohols, and the newer, rare sugars—allulose and tagatose. When bulking sweeteners are used to replace sucrose, the usage level is often close to one-to-one.

Non-bulking sweeteners include sucralose, acesulfame potassium, stevia and monk fruit. These high-potency sweeteners are used at very low parts per million (ppm) levels and need to be combined with a bulking agent in bakery applications.

Sucrose provides sweetness, bulking, tenderizing, browning, caramelization, freezing-point depression and preservation. Replacing the functionality of sucrose is difficult enough, but food formulators must also consider regulatory issues, taste profile, nutritional targets, digestive tolerance, shelflife issues and product claims. Rare sugars exist in nature in extremely low quantities. They are not fully digested and, therefore, provide a lower energy content.

Allulose is produced by enzymatic conversion of fructose. It is GRAS in the U.S., but it is not currently approved in Europe.

While sucrose yields 4 calories/gram, allulose only provides 0.4 calories/gram. Allulose has recently been exempted from being labeled as a sugar; has a very low glycemic index; and is non-cariogenic, Goulson said. Erythritol is a sugar alcohol which is also not labeled as a sugar; has a low glycemic index; and is non-cariogenic.

Erythritol is fully absorbed and excreted in the urine, so little reaches the large intestine, where it might be fermented, explaining why it is the best tolerated of all the polyols.

Tagatose, another rare sugar, is a monosaccharide isomer of fructose. It is naturally occurring in dairy and some fruits. Commercially, it is produced by isomerization of galactose from lactose or by enzymatic conversion of galactose. Tagatose delivers 1.5 calories/gram. It is currently labeled as sugar but may eventually follow the precedent set by allulose regulations and become exempt from sugar/added sugar regulation in the U.S. Tagatose is about 20% absorbed and fully metabolized. Its digestive tolerance is comparable to allulose. It has a low glycemic index and is “tooth friendly.”

A trained panel in Merlin Development’s laboratory evaluated the sweetness intensity of these bulk sweeteners in water and found that tagatose is 90% as sweet as sucrose, while allulose and erythritol are both 70% as sweet as sucrose. Tagatose has a clean, sweet taste profile, similar to sucrose. However, allulose is significantly more bitter, at both 5% and 10% sucrose equivalent sweetness (SEV). At 10% SEV, allulose has significantly greater chemical and astringent taste.

Temporal dynamics of sweeteners include time for sweetness onset; time to meet maximum sweetness; and time for sweetness decay. The temporal properties of allulose and tagatose are similar to sucrose. Neither exhibited the delayed sweetness onset and linger that is often seen with high-potency sweeteners. Blending a rare sugar with a high-intensity sweetener can round out taste dynamics.

In baking applications, sugar contributes to spread, bulking, tenderness, aeration, shelflife and more. The food technologists at Merlin Development used drop sugar cookies to screen allulose, tagatose and erythritol for functionality, both at 100 and 50% sucrose replacement levels.

Tagatose and allulose are both monosaccharides and reducing sugars, and both contributed to browning more than the sucrose control. Although all three alternative sweeteners have a lower melt point than sucrose, none spread like the sucrose control. Goulson noted the 50% replacement formula was subsequently adjusted to increase the fat-to-flour ratio, and baking time was reduced. This modified recipe produced spread comparable to the sucrose control. In the modified formula, allulose produced more surface browning, but none of the alternate sweeteners provided the same level of surface cracking as the sucrose control.

Tagatose and allulose produced cookies that were softer, less crispy and “cakier” than the control. There was no significant difference in sweetness. Tagatose and allulose produced more caramel notes. Cookies baked with allulose were more bitter than those with erythritol or the control.

With formula adjustments, these new sugars show great potential for reducing total and added sugar in bakery applications, Goulson concluded.

“New Kids on the Block: From Allulose to Tagatose, Properties & Performance in Sugar Replacement,” Melanie Goulson, MSc, General Manager & Principal Scientist, Merlin Development

This presentation was given at the 2020 Sweetener Systems Conference. To download presentations from this event, go to: https://sweeteners.globalfoodforums.com/category/sweetener-systems-rd-academy/

See past and future Sweetener Systems Conference Events at: https://sweeteners.globalfoodforums.com/sweetener-systems-events/