Fibers
Fibers play a crucial role in the world of confections, contributing not only to the structural integrity of products but also to their impact on human health. In the context of confectionery science, fibers are defined as complex carbohydrates that resist digestion in the human small intestine. These compounds, predominantly polysaccharides, are derived from various plant and animal sources.
Chemically, fibers can be categorized into two main types: soluble and insoluble. Soluble fibers, such as pectins and gums, dissolve in water and form a gel-like substance. On the other hand, insoluble fibers, like cellulose and hemicellulose, do not dissolve and contribute to the bulk of the material.
Lately, confectionery industry has turned its head to fibers like corn fiber, tapioca fiber, inulin.
Corn fiber, derived from the corn kernel through the wet milling process, It contributes to product texture and structural integrity. With moderate hygroscopicity, corn fiber aids in moisture retention.
Tapioca fiber, extracted from cassava roots. Widely used in gummies and candies, tapioca fiber enhances chewiness and moisture retention.
Inulin, derived from chicory roots or agave, inulin is a soluble fiber, highly hygroscopic. Contributes to moisture retention, improving overall texture and freshness. Inulin's solubility in water allows it to form clear, viscous solutions, influencing the smoothness of confectionery products. Beyond its role as a fiber, inulin serves as a bulking agent and sweetener, providing a versatile and health-conscious option for confectionery formulations.
Other used fibers include Psyllium, Cellulose, Guar gum, Resistant starch.
Source and Processing
Fibers are predominantly sourced from plants, including fruits, vegetables, grains, and legumes. The extraction process involves mechanical separation, often followed by purification methods. In some cases, fibers are also obtained from seaweed and microbial sources. The production process aims to retain the structural and functional properties of the fibers, ensuring their effectiveness in confections.
Main function in Confections
In confections, fibers serve as multifunctional ingredients. They enhance texture, providing a desirable mouthfeel, and contribute to the overall product structure. Fibers also act as water-binding agents, influencing the product's moisture content and preventing staleness. Moreover, they play a role in controlling sugar crystallization, affecting the sensory attributes of confections.
In recent times the have been used in sugar free confections to replace the bulk that sugar used to give to regular confections.
Molecular Structure
The most common insoluble fibers used are:
- Cellulose is made up of D-glucopyranose units linked together by β-(1-4)-glucosidic bonds. Due to the large proportion of hydroxyl groups within the cellulose structure, there is a high affinity for moisture.
- Lignin is a class of hydrocarbon polymers consisting of aliphatic and aromatic structures. Lignin has a three-dimensional amorphous polymer with a high molecular weight, and this polymer contains phenyl propane units, which are formed from hydroxyl- and methoxy-substituted phenylpropane units
Dietary fibers are carbohydrate polymers with 3 or more monomeric units which. Among them we can find:
- Pectins, made up of a linear homopolymer of α-1,4-linked D-galacturonic acid residues in the principal chain, which is partly esterified with methyl and acetyl groups.
- Soluble corn fiber, or resistant maltodextrin molecular structure comprises a small ratio of saccharides with a degree of polymerisation (DP) 1–9 and many polysaccharides with a DP 10 or more connected by glycosidic linkages.
- Soluble Tapioca fiber is made up of amylopectin with a relatively high proportion of short branch chains of DP 6–12, a highly branched glucose polymer that gives it its high viscosity.
- Inulin is built of up of 2–60 fructose units linked via β-(2, 1) glycosidic bonds with a terminal glucose. Naturally occurring inulin is polydisperse varying in its degree of polymerization (i.e., molecular weight). The term fructo-oligosaccharides is frequently used for inulin with < 10 fructose units.
Properties
Hygroscopicity: Fibers exhibit hygroscopic properties, meaning they have the ability to absorb and retain moisture from the surrounding environment. This property influences the texture and shelf life of confections, helping to maintain optimal moisture levels and preventing undesirable changes in product quality.
Crystallization: Fibers, especially soluble ones, can influence sugar crystallization in confections. They act as crystallization inhibitors, preventing the formation of large sugar crystals and promoting a smoother texture in products like candies and chocolates.
Solubility: The solubility of fibers varies depending on their type. Soluble fibers dissolve in water, forming viscous solutions, while insoluble fibers remain largely unaffected. This solubility behavior contributes to the functional characteristics of confections, affecting attributes like viscosity and mouthfeel.
Shelf Stability: Fibers contribute to the shelf stability of confections by influencing water activity and moisture retention. This, in turn, helps prevent microbial growth and maintains the product's quality throughout its shelf life.
Regulatory
In the United States, the use of fibers in confections is subject to regulatory standards outlined by the Food and Drug Administration (FDA). Manufacturers must adhere to guidelines related to ingredient declaration, labeling, and health claims associated with fiber content. Compliance with these regulations ensures that confections meet the required quality and safety standards for consumption.
Soluble fibers are denominated as Resistant maltodextrin. Manufacturers must ensure that the levels of soluble corn fiber in confections meet FDA guidelines for dietary fiber content labeling.
