Polyols as formulation problem solvers

Prepared Foods, Feb, 1996 by Claudia D. O'Donnell

Too many calories" has been the downfall of unsuccessful dieters and foods trying to ride the "light" bandwagon. Recently, one category of ingredients managed to shed excess calories by governmental "decree." This resulted in easing the formulation of reduced-calorie foods.

Although the European Community had assigned a caloric value of 2.4 kcal/gm to a group of ingredients called sugar alcohols (a.k.a. polyols), U.S. processors had to use a value of 4.0 (equivalent to sucrose).

"The Calorie Control Council (CCC) sponsored a FASEB [Federation of American Societies for Experimental Biology] study to review the data on the caloric value of commercially used polyols in the U.S.," says Lyn Nabors, of Atlanta-based CCC.

Requests were then submitted to the FDA for lower values, and in 1994 and 1995, the FDA issued letters which now allow the following values to be used: Maltitol and hydrogenated starch hydrolysates (made by hydrogenating maltose syrup) weigh in with 3.0 kcal/gm, sorbitol at 2.6, xylitol at 2.4, lactitol and isomalt (palatinit) at 2.0. and mannitol at 1.6 kcal/gm.

Polyols, which are hydrogenated mono-, di- or oligosaccharides, can replace some of sugar's properties when sugar is removed. However, polyols possess a number of properties -- from antioxidant abilities to inhibition of sugar crystalization -- that makes them useful in many situations.

COMMERCIAL USE

Usage of sorbitol, the most popular polyol at more than 100 million pounds a year used in the U.S., has increased 3% annually from 1991 to '94 in the U.S. and Japan, says Amy Stockwell of Analytech Associates, an ingredient consultant in Decatur, Ill. The use of isomalt, mannitol and other polyols is harder to track. However, these names increasingly turn up in ingredient legends on "low-calories" or "no added sugar" products -- particularly confectionery, frozen dairy desserts and bakery items.

Isomalt finds its way into Simply Lite Foods Corp.'s Sweet N' Low hard candies, mannitol into Eskimo Pie's aspartame-sweetened ice cream novelty, and maltitol into the fudge sauce of a Breyer's no sugar added, reduced-fat ice cream.

Polyols provide benefits beyond enabling "no-sugar" claims, however. Even though Nabisco uses corn syrup, sugar and pear concentrate sweeteners in its Life Savers Gummi Savers, the candy formulation still contains a touch of sorbitol.

PROBLEM-SOLVING PROPERTIES

With physical properties similar to sugar, the ability of polyols to replace sugar's volume (i.e., "bulk") when sugar is removed is one of their key assets. Here is a selection of other polyol attributes to consider during the development of a new food product:

Health benefits -- Polyols are non-cariogenic. Plaque-forming microorganisms ferment food to produce cavity-causing acids. One lactitol supplier ranked sugars and polyols -- from most easily fermented to least -- as glucose, sucrose, mannitol, sorbitol, xylitol, and lactitol. (Lactitol can be used as a fermentable substrate for yogurt if given a long enough incubation time, however.)

Polyols do not significantly raise blood sugar levels. "The insulin response and rise in blood glucose levels are reduced, although there is a response and it depends to some extent on how sensitive the person is," says Jim Luchsinger, technical correspondent with a polyol supplier.

However, neither an overt health claim nor a direct endorsement from American Diabetic Assoc. can be made. Instead, packaging labels of polyol-based retail products refer to the ADA with phrases such as "A proud sponsor of [ADA]" or "A contribution from the sale of this product has been made to [ADA]." One product notes that sorbitol "is a slowly metabolized carbohydrate which generally causes only a small rise in blood glucose levels" Freezing point depress -- Maltitol, lactitol and sorbitol lower a food matrix's freezing point similar to sucrose and are thus used in products such as frozen dairy desserts. Sorbitol also inhibits ice and sugar crystal formation.

Sorbitol is an effective cryoprotectant in protein products. Long used in frozen surimi, researchers at the Centre for Poultry Research and Information Service, Ministry of Agriculture in the Netherlands, found levels of 2.8% sorbitol with 4% potato starch to be the most effective combination to prevent the denaturation of chicken myofibrillar protein isolates as well. Osmotic pressure increase -- Polyols increase solids content (and reduce [A.sub.w]) for microbial control in products such as jams. However, their individual solubility, and thus tendency toward crystallization, should be taken into account. At 20[degrees]C, only 18g of mannitol dissolves in 100g of water; 235g of sorbitol will dissolve in 100g of water. Antioxidant -- Although they don't possess antioxidant properties in and of themselves, polyols are synergistic to antioxidants. They "deactivate" or chelate oxidation-promoting metals to various extents. Light, bright color -- unlike most sugars, polyols do not participate with proteins or amino acids in the Maillard reaction to produce brown colors, an advantage where a light or bright-colored cooked or baked food is preferred. Sensory contribution -- If a 10% sucrose solution is assigned a sweetness of 100, a 10% solution of xylitol checks in at about 80 to 100; maltitol at 75; sorbitol, mannitol and isomalt (an equimolar mixture of glucopyranosyl-sorbitol and -mannitol) at 50 to 60, and lactitol with a relative sweetness of 30 to 40. Isomalt has a synergistic effect with other polyols and high-intensity sweeteners.