The short answer is: when we talk about "gummy texture" in a consumer context, we are rarely, if ever, referring to a direct measurement of storage modulus (G') or loss modulus (G''). However, the physical properties measured by these moduli are what ultimately drive consumer preference. To be precise: storage modulus (G') is more closely correlated with the initial "chewiness" or "firmness" that consumers perceive, while loss modulus (G'') relates to "stickiness" or "mouthfeel" during chewing.
What these moduli actually measure
Storage modulus (G') represents the elastic, solid-like behavior of a gummy-its ability to return to shape after deformation. A higher G' means a firmer, more "bouncy" gummy. Loss modulus (G'') represents the viscous, liquid-like behavior-how much energy is dissipated as heat when the gummy is deformed, which correlates with stickiness and how it melts in the mouth.
In practice:
- G' (Storage Modulus): Governs the initial bite and chew resistance. A gummy with high G' feels "rubbery" or "hard"; low G' feels "soft" or "melt-in-the-mouth."
- G'' (Loss Modulus): Governs tackiness and how the gummy interacts with teeth and tongue. High G'' can indicate a sticky, tacky texture; low G'' feels smooth and cohesive.
Which correlates with consumer preference?
Consumer preference is complex, but data consistently shows that consumers prefer gummies with a balanced G'/G'' ratio-specifically, a relatively high G' (giving a satisfying chew) combined with a low-to-moderate G'' (avoiding excessive stickiness). A gummy that is too high in G' (too firm) is rejected as "hard" or "chalky." One too high in G'' (too sticky) is rejected as "gummy" (in an unpleasant sense) or "adhesive."
The industrial gold standard is a tan δ (G''/G') value typically between 0.2 and 0.5. This range indicates a viscoelastic solid that deforms cleanly without being brittle and releases from packages without leaving residue. For premium gummies, manufacturers often target a G' that is approximately 3-5 times higher than G''.
Practical implications for texture design
When a consumer says they want a "chewy" gummy, they are describing a product with:
- High G' - to provide that initial resistance and snap.
- Low G'' - to ensure it doesn't stick to the teeth.
Conversely, a "melt-in-the-mouth" gummy (like a pectin-based fruit snack) has a lower G' and a higher relative G'' (tan δ closer to 0.5-0.7). The gelatin-to-sugar ratio, humidity during storage, and type of gelling agent all directly alter these moduli.
Why we measure both objectively
While consumers don't think in terms of G' and G'', texture analysis (using a rheometer or texture analyzer) quantifies these precisely. At KorNutra, we use oscillatory shear rheology to track both moduli throughout product development. This allows us to:
- Reproduce a target texture batch-to-batch.
- Predict shelf-life changes (as G' typically increases, and G'' decreases, with moisture loss).
- Optimize for consumer preference-translating "chewy but not sticky" into specific G' and G'' targets.
So, when a client asks for a "gummy texture," we translate that into a measurable target: a G' of 2000-4000 Pa and a tan δ of 0.3-0.45, depending on the desired eating experience. You can think of G' as the skeleton of the gummy, and G'' as the adhesive-and the perfect texture is a matter of balancing the two.