The short answer is: when we talk about "gummy texture" in a consumer context, we are rarely referring to a direct measurement of storage modulus (G') or loss modulus (G''). The physical properties behind these moduli do shape what a consumer feels, but they are only part of the picture. To be precise: storage modulus (G') tracks the elastic, solid-like response behind perceived firmness and chew resistance, while loss modulus (G'') reflects the viscous, flow-like response behind melt and mouthfeel. Stickiness, which consumers also describe, is measured separately with a tack or adhesion test, not from G''.
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. That viscous response shapes how the gummy flows and melts in the mouth, but it is not the same thing as measured stickiness.
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 viscous flow and energy dissipation as the gummy deforms. High G'' means the gel melts and flows more readily; low G'' means it holds its structure. Stickiness to the teeth is measured separately, with a probe tack test.
Which correlates with consumer preference?
Consumer preference is complex, and it does not point in one direction. Excessive stickiness lowers liking: in a 2026 consumer test of fruit gum candies with 147 panelists, higher stickiness in starch- and pectin-based products reduced acceptance. Firmness is more conditional. In the same work, a harder texture improved acceptance of plant-based gummies, while gelatin-based products lost acceptance as hardness rose. A high G' is therefore not automatically better. The target depends on the gelling system and the eating experience the brand is designing for.
A finished gummy is a viscoelastic solid: G' exceeds G'' (tan δ below 1), so the gel holds its shape and deforms without flowing. How far below 1 the ratio should sit is a product decision, not a fixed industry number. The goal is a gel firm enough to release cleanly from packaging and hold its shape, yet soft enough not to read as hard or chalky. Those targets are set per SKU and then held constant batch to batch.
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'' so the gel holds together and flows less as it melts.
Conversely, a "melt-in-the-mouth" gummy (like a pectin-based fruit snack) runs the other way: lower G' for softness, with higher relative G'' so it gives way and melts quickly. The gelatin-to-sugar ratio, humidity during storage, and type of gelling agent all directly alter these moduli.
What G' and G'' don't measure
G' and G'' describe a gummy under small, non-destructive deformation, before anything breaks. Eating a gummy is a large-deformation event: the product gets bitten, fractured, and chewed, and that is where the attributes consumers describe live. DeMars and Ziegler's 2001 study of gelatin/pectin gummies found sensory texture followed strain at fracture (r = 0.90) and log stress at fracture (r = 0.87). Stickiness runs the same way: in soft candy work, sensory hardness, cohesiveness, and number of chews correlated with storage modulus and viscosity, while stickiness to the teeth correlated with probe tack force, and tack testing differentiated the formulations more effectively than oscillatory rheology alone. A complete spec therefore pairs oscillatory rheology with large-deformation and tack tests. G' and G'' give a repeatable read of the intact gel; fracture and tack tests describe how it behaves in the mouth.
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 climbs while the gummy loses moisture and firms.
- Optimize for consumer preference, translating "chewy but not sticky" into specific G' and G'' targets.
When a client asks for a "gummy texture," we translate that into a measurable target: a defined G' range (in Pa) plus a tan δ window, set for that product and held batch to batch. Think of G' as the skeleton of the gummy, and G'' as how much it gives and flows when you bite into it. The right texture balances the two.