COMPOSITION AND STRUCTURE OF MALTODEXTRIN
The chemical structure of maltodextrins falls somewhere between the complex polysaccharide chains of starch and the simpler molecules of syrup solids or sugars.
They do consist of a mixture of different saccharide polymers by the hydrolysis process. Even those products with the same Dextrose Equivalent may contain a different distribution of molecules – more medium-range molecules, and fewer larger molecules, for example. The process, its conditions, and the type of starch used as the starting material affect the exact composition and structure of the resulting chains. This, in turn, affects the functionality. Following are the functions of maltodextrin:
FUNCTIONS OF MALTODEXTRIN
1. THICKER/FILLER
Maltodextrin has many functions that include its use as a filler ingredient, to extend shelf life, improve powdery appearance, mitigate sweetness, prevent melting, avert or retard granulation and reduce nutrient losses.
2. ROLE IN FOOD TEXTURE AND DESIGN
Both the very low sweetness and the water solubility make maltodextrins interesting in partial sugar replacement in filling creams, at the expense of some sticky character of the cream texture.
These deceptively simple compounds are evolving beyond the basics by playing an increasingly important role in the design of food products. By controlling the various factors, manufacturers control the degree of hydrolysis and obtain a consistent product.
Still, most commercial maltodextrins are a mixture of different carbohydrate polymers. The disaccharide profile that is created influences the properties of the maltodextrin. However, maltodextrins are usually classified by Dextrose Equivalent. The Dextrose Equivalent offers the food designer a guide to the properties these ingredients exhibit
3. PREVENTION OF CRYSTALLIZATION
Adding maltodextrins to candy can help modify sugar crystallization and prevent sugar bloom. In soft confections, such as fruit rolls, they can act as a humectant and increase flexibility. The requirements concerning the syrup/sugar type are oriented towards the product’s needs. In confectionery, it prevents the crystallization in high-boiling sweets, creaminess in caramels, and chewiness in chewing gums.
4. BULKING CARRIER
Maltodextrins are frequently used as bulking agents; however, when used at sufficiently high concentrations, maltodextrins have the ability to bind water, thereby contributing significantly to mouthfeel and meat product viscosity. Maltodextrins can also act as a carrier agent, which protects encapsulated ingredients from oxidation.
The bland flavor and inert character of maltodextrins have historically given them a significant presence as an economical carrier or bulking agent. They act as an extender for more expensive ingredients, and as a diluent for micro-ingredients, so they may be more accurately handled and packaged. Mixing maltodextrins with gums and other hydrocolloids aids in dispersion, wetting without clumping, and proper hydration.
5. FAT REPLACER
Many food companies are seeking maltodextrins or maltodextrin-based ingredients that perform a specific function – fat replacement in a specific application, solubility under certain conditions, for example.
The study, which was published in the Journal of Texture Studies, looked at how well-hydrated maltodextrin gel particles could replace fat in a vegetable oil ingredient. The researchers from the University of Novi Sad in Serbia discovered that substituting maize maltodextrin for 50% of the vegetable oil had no effect on the rheological characteristics of the fat in its solid-state.
The reduced-fat oil/maltodextrin blend, according to the authors, may provide a way to make lower-fat products without sacrificing quality.
6. STABILIZER
“You can use maltodextrins, in combination with other stabilizers, and it will improve the stability of the system,” says Tonya Armstrong, applications scientist, Grain Processing Corporation (GPC), Muscatine, IA. “Maltodextrins complement other stabilizers and can often be synergistic with starches and gums.
7. MOUTHFEEL
As with carbohydrates, the characteristics and properties of maltodextrins suggest their utility in packed foods. High solution viscosity indicates their use to provide body and mouth feel to fruit and vegetable drinks without adding to the sweetness.
For example, maltodextrin can be used in tomato cocktails to help suspend tomato solids and to improve the mouthfeel. Likewise, maltodextrins have been used in fruit juice-based beverages to improve flavor and provide a superior mouthfeel.
8. MOISTURE BARRIER
“Maltodextrins act as secondary film-formers when used in combination with starches and gums,” says Tonya Armstrong, applications scientist, Grain Processing Corporation (GPC), Muscatine, IA. “They’ve been used as coatings for candies or on pizza crusts, where they act as a moisture barrier between the crust and the sauce to resist moisture migration. The lower DE products will be better film-formers, but if you are looking for clarity and sheen, like for a cereal coating, a 15 or 18 DE will provide that.”
9. FILM FORMING PROPERTY
Spray-drying flavors not only turn liquids into solids but also provides some protection to the flavors themselves. Some of this occurs in normal spray-drying operations when the flavor is partially surrounded by the maltodextrin matrix.
However, maltodextrins often are used in true encapsulation systems by taking advantage of their film-forming characteristics to form a protective coating for flavors and other sensitive ingredients.
10. VISCOSITY MANAGEMENT
The high viscosity of maltodextrins, an important property in many applications, is due to high levels of high-molecular-weight saccharides. In higher moisture, fat-reduced food systems – such as meats, dressings, sauces, and bakery and dairy products – maltodextrins provide some of the characteristics of fat. They retain moisture, and add viscosity and texture, without contributing sweetness. By increasing viscosity, they improve mouth feel, and aid in aeration for baked goods and frozen desserts.
CONCLUSION
Maltodextrins are involved in many technical and/or food applications (carrier and bulking agent, oil well drilling fluids, spray-drying aids, medical/nutritional products, food coatings, icings/fondants, frozen desserts, dairy/nondairy products, salad dressings, and fat replacers). Their main function there is to regulate hygroscopicity and give viscosity/body to food products.
