Gummy manufacturing relies on a precise network of chemical bonds to achieve the desired texture, shelf stability, and shape retention. At KorNutra, we categorize these bonds into two groups: the essential bonds that form the structural backbone, and the transient or negligible bonds that affect processing but not the final shape.
Essential Bonds: The Structural Backbone
Three types of bonds are critical for a gummy to hold its shape over time:
- Hydrogen bonds - These are the primary stabilizers. Gelatin or pectin chains form extensive hydrogen bonding networks with water molecules and between polymer chains. In gelatin-based gummies, these bonds create a semi-crystalline "gel" network that traps water and sets the firm, chewy texture. For pectin-based gummies (common in vegan products), hydrogen bonds between galacturonic acid units provide the shape.
- Hydrophobic interactions - Especially important for gelatin, which contains hydrophobic amino acid regions. During cooling, these segments aggregate, driving gelation and providing additional structural integrity. This is a physical association, not a covalent bond, but it is essential for setting the shape.
- Covalent disulfide bonds - In gelatin, occasional residual crosslinks from collagen can reinforce the network, but these are minor compared to hydrogen bonds. For gummies using modified starches or gums, covalent bonds may be introduced during manufacturing (e.g., via crosslinking agents) to improve heat resistance.
Without these bonds forming properly during cooling or setting, the gummy will not maintain its shape and will weep liquid or collapse.
Transient or Negligible Bonds
Several other interactions occur during processing but do not contribute meaningfully to the final shape or stability:
- Ionic bonds - Often seen when calcium ions are added to pectin or alginate systems. While these can crosslink polymers during heating, they are typically transient in gummy candies. The calcium-pectin links break under shear during mixing and do not persist in the cooled gel unless carefully controlled. In most commercial gummies, they are negligible.
- Van der Waals forces - These weak attractions between adjacent polymer chains are present everywhere but contribute little to shape retention. They are overshadowed by the hydrogen bond network.
- Electrostatic interactions - In gummies with charged ingredients (e.g., some modified starches), temporary electrostatic repulsion or attraction can occur during processing. However, these are not stable enough to hold shape and are often neutralized by water or added salts.
- Hydrophobic interactions (in pectin-based gummies) - Pectin lacks hydrophobic regions, so these are absent in vegan formulations, making them negligible here.
In summary, for a gummy to hold its shape, the critical players are hydrogen bonds, hydrophobic interactions (for gelatin), and occasional covalent crosslinks. Ionic, van der Waals, and electrostatic bonds are either transient or contribute so little that they can be considered negligible. Proper control of these essential bonds is what allows KorNutra to deliver gummies with consistent texture and long shelf life.