Infant food applications of complex carbohydrates: Structure, synthesis, and function

Abstract

Professional health bodies such as the World Health Organization (WHO), the American Academy of Pediatrics (AAP), and the U.S. Department of Health and Human Services (HHS) recommend breast milk as the sole source of food during the first year of life. This position recognizes human milk as being uniquely suited for infant nutrition. Nonetheless, most neonates in the West are fed alternatives by 6 months of age. Although inferior to human milk in most aspects, infant formulas are able to promote effective growth and development. However, while breast-fed infants feature a microbiota dominated by bifidobacteria, the bacterial flora of formula-fed infants is usually heterogeneous with comparatively lower levels of bifidobacteria. Thus, the objective of any infant food manufacturer is to prepare a product that results in a formula-fed infant developing a breast-fed infant-like microbiota. The goal of this focused review is to discuss the structure, synthesis, and function of carbohydrate additives that play a role in governing the composition of the infant microbiome and have other health benefits.

Keywords: Carrageenans; Cellulose; Fructan; Fructooligosaccharide; Galactomannans; Galactooligosaccharide; Hemicellulose; Inulin; Lactitol; Lactose; Lactulose; Levan; Polydextrose; Xylooligosacharide.

Figure 1.

Structure of fructans and their common building blocks. Fructan type oligosaccharides are composed of sucrose and fructose residues.

Figure 2.

Enzymatic fructan production. The shaded circle in structure (6) represents a covalent linksage between the carbohydrate and the enzyme β-fructofuranosidase.

Figure 3.

Stucture of galactooligosaccharides (GOS) and GOS building blocks.

Figure 4.

Enzymatic GOS (12–14) production. The shaded circle in compound (15) represents β-galactosidase, the enzyme that facilitates the iterative glycosylation process.

Figure 5.

Uridine 5’-diphosphate galactose (UDP-galactose, 19) generation and lactose (11) biosynthesis.

Figure 6.

Lactitol (22) is produced through hydrogenation of Lactose (10).

Figure 7.

Lactulose (24) is synthesized from lactose (11) using either the Lobry de Bruyn-Alberda Ekenstein or Amadori rearrangements.

Figure 8.

Structure of glucose-based polymers. Each molecule differs significantly in terms of branching and the location and configuration of glycosidic linkages.

Figure 9.

Structures of the different subclasses of hemicellulose polymers.

Figure 10.

Structure of additional carbohydrate polymers that have been evaluated for prebiotic properties.