Protein vs. Texture: Breaking the “Glassy” Barrier in Extruded Snacks

High-protein extrusion has a “glass ceiling”; or rather, a glass wall. Pushing protein past 70% typically creates products with a vitreous, rock-hard texture that shatters rather than crunches. New patent applications from General Mills reveal a dual-strategy (flattened and puffed) to break this barrier, using sodium caseinate and matrix disruptors to achieve high loads without the jaw-breaking bite.

ByMaite Carricaburu

If you’ve worked with high-protein extrusion, you know the struggle: as you increase protein content (especially >50%), the melt viscosity drops, and the glass transition temperature (T_g) shifts.

The result?

Instead of a porous, expanded foam, you often get a dense, glassy structure. It’s the difference between a pleasant crunch and a hard shatter.

Two recent patent publications, US 2025/0134135 (Puffed) and US 2025/0134151 (Flattened), address this head-on.

They outline a method to stabilize high-protein (>70%) matrices while maintaining a consumer-acceptable texture in both cereal-like puffs and chip-like flattened pieces.

The Technical Core: Matrix Disruption

The innovation isn’t just in the equipment; it’s in the formulation engineering designed to interrupt the continuous protein phase.

  • The “Base Blend” Strategy: The patents suggest a specific ratio of Sodium Caseinate (10-60%) combined with other isolates (Milk Protein Isolate, Legume Protein Isolate).
    • Why Sodium Caseinate? Unlike many plant proteins that aggregate aggressively, sodium caseinate has unique film-forming and expansion properties. It acts as a “stretchy” scaffold that allows the bubble to expand before setting, preventing the collapse that leads to hardness.
  • Controlled Density:
    • Puffed (20250134135): Targets a lower density (approx. 0.1 – 0.3 g/cc) using expansion to create volume.
    • Flattened (20250134151): Targets a higher density but uses oil (1-8%) and moisture control (0.5-7%) as “plasticizers” or matrix disruptors. The oil likely prevents the protein chains from cross-linking too tightly, keeping the texture “short” (crisp) rather than tough.

Two Form Factors, One Goal

The separation of these patents highlights a nuance in snack architecture:

  1. The Flattened Approach (US ‘151):
    • Application: High-protein chips or crackers.
    • Challenge: Preventing curling and excessive hardness during the cooling phase.
    • Solution: A “base protein blend” that constitutes at least 60% of the total protein ingredients, ensuring the primary structural component is one with known expansion reliability (like caseinate), while fillers or “disruptive ingredients” break up the solidity.
  2. The Puffed Approach (US ‘135):
    • Application: Functional cereals or ball-shaped toppings.
    • Challenge: Uniform expansion without “blowouts” or large, hollow centers.
    • Solution: Balancing the hydration rate. Fast hydration in the mouth is desirable for flavor release but dangerous in the extruder barrel where it can lead to premature flashing. The specific protein ratios likely delay hydration just enough to allow full expansion at the die face.

😊 Thanks for reading!

Sources:

  • US Patent App. 20250134151 – “Extruded flattened high protein food pieces and methods of making” (General Mills, Inc.) Link
  • US Patent App. 20250134135 – “Extruded puffed high protein food pieces and methods of making” (General Mills, Inc.) Reference via PubChem
  • Coperion – “Challenges in Healthy Snacks Extrusion” Link
  • MDPI Foods – “Nitrogen Gas-Assisted Extrusion for Improving the Physical Quality of Pea Protein-Enriched Corn Puffs” Link