Long-fermentation doughs: role of gluten structure and differences between strong flours and einkorn flours

Highlights

Long fermentations do not depend exclusively on flour “strength”
The idea that only strong flours are suitable is an operational simplification that does not capture the complexity of the gluten system.

Gluten is a dynamic system, not a static one
The gluten network forms and evolves over time through continuous processes of bond breaking and reorganization.

Dough stability depends on the continuity of the protein network
It is not only about “how much gluten,” but how it is organized into a connected three-dimensional structure.

There is a critical threshold of structural collapse
When network continuity is lost, the dough rapidly shifts from stable to unstable, with non-linear behavior.

Long fermentations modify the gluten network
Through:

• proteolysis

• thiol–disulfide exchange

• changes in redox state

Strong and weak flours differ in their distance from the critical threshold

• strong flours → more extended and stable network

• weak flours → more fragile network, closer to collapse

Einkorn represents a limiting model

• less organized and less elastic network

• higher sensitivity to degradation

• more plastic behavior

Collapse can be reversible or irreversible

• elastic → recoverable

• plastic → permanent loss of structure

Dough recovery is a reorganization, not a “reactivation”
Proteins do not regenerate: they restructure, temporarily increasing connectivity.

Key practical implication
Managing long fermentations requires control of network structural continuity, not just flour selection.

1️⃣ Introduction

In baking practice, it is widely believed that long fermentations necessarily require strong flours. Although this indication is often useful operationally, it does not account for the structural and dynamic nature of gluten.

“The quality of a dough does not depend exclusively on the quantity of proteins, but on their organization into a three-dimensional viscoelastic network, whose stability evolves over time under the influence of enzymatic and physicochemical phenomena (Wieser, 2007).”

2️⃣ Gluten as a dynamic system

Gluten is not a pre-formed structure, but a system that emerges during hydration and mixing. It is mainly composed of:

gliadins → provide extensibility
glutenins → provide elasticity
a very high molecular weight fraction called GMP (Glutenin Macropolymer) → the elastic backbone of the dough

GMP represents the fundamental structural component for the formation of a continuous network capable of retaining gas (Don et al., 2005).

The behavior of gluten is intrinsically dynamic: the protein network is subject to continuous processes of bond breaking and reformation, particularly disulfide bonds and non-covalent interactions (Wieser, 2007; Belton, 1999).

The gluten network progressively organizes into a three-dimensional matrix capable of retaining gas and water during mixing and fermentation. In this context, non-protein components such as arabinoxylans can also physically interact with the matrix, creating a secondary network that may strengthen the structure or, in some cases, hinder protein aggregation (Courtin & Delcour, 2002).

3️⃣ Evolution of the network during long fermentations

During long fermentations, three main phenomena are observed:

1. Proteolysis: endogenous and microbial enzymes reduce the length of protein chains (Thiele et al., 2002)

2. Thiol–disulfide exchange: covalent bonds between proteins are continuously reorganized

3. Changes in redox state: metabolites produced by microorganisms influence the oxidation–reduction balance (Grosch & Wieser, 1999)

These processes lead to a progressive modification of the connectivity of the gluten network.

4️⃣ The critical threshold of structural collapse

Dough stability can be interpreted in terms of continuity of the protein network. As long as a connected structure spans the entire system, the dough maintains its mechanical properties.

Below a certain critical threshold, this continuity is lost and the system collapses. This behavior is consistent with percolation models of polymer networks, in which emergent properties depend on the global connectivity of the system (Stauffer & Aharony, 1994).

As a result, the transition from a stable to an unstable state can occur suddenly and non-linearly.

5️⃣ Elastic collapse vs plastic collapse

From a rheological point of view, it is useful to distinguish between:

Elastic collapse (reversible)
soft but cohesive dough
ability to recover through mechanical handling
network still continuous but relaxed

Plastic collapse (irreversible)
incoherent and sticky dough
loss of gas retention capacity
absence of response to deformation

This distinction is consistent with rheological models of dough, which highlight the transition from viscoelastic to plastic behavior (Dobraszczyk & Morgenstern, 2003).

6️⃣ Strong flour vs weak flour: it’s not just “how much gluten”

The difference between flours does not lie solely in total protein content, but in structural parameters such as:

distribution of glutenin molecular weights
content of high molecular weight subunits
initial GMP density
stability of disulfide bonds
gliadin/glutenin ratio

Strong flours exhibit a more extended and stable initial network, placing them further from the critical collapse threshold. Weak flours, on the contrary, operate closer to this threshold and are therefore more sensitive to proteolysis and environmental variations (MacRitchie, 1999; Payne, 1987).

7️⃣ The case of einkorn (Triticum monococcum)

Einkorn represents a particularly useful system for analyzing dough behavior under conditions close to the critical threshold of structural collapse.

Compared to modern wheats, it is characterized by:

lower capacity to form Glutenin Macropolymer (GMP)
reduced presence of high molecular weight glutenin subunits
less extended and less elastic protein network
more plastic rheological behavior

These characteristics result in an intrinsically less stable structure, placing the dough near the critical threshold of continuity (Hidalgo & Brandolini, 2014).

Under long fermentation conditions, this configuration makes the system particularly sensitive to proteolytic phenomena and changes in redox state. As a result, the dough may show a marked loss of consistency, appearing macroscopically collapsed.

However, this state does not necessarily imply that the critical threshold has been exceeded.

If a continuous network is still present, even if highly weakened, moderate mechanical interventions can induce a reorganization of the structure, with partial recovery of rheological properties.

This behavior can be interpreted as a reorganization of the protein network, made possible by:

realignment of protein chains
reorganization of thiol–disulfide bonds
increase in local connectivity
partial restructuring of GMP

The observed recovery does not correspond to an increase in the intrinsic “strength” of the flour, but to a temporary restoration of structural continuity.

In this sense, einkorn constitutes an effective experimental model for making visible structural transition phenomena that are less evident in stronger flours.

Experimental case – structural recovery after long fermentation

In a test conducted on einkorn dough:

total maturation: 36 hours
12 hours at 18 °C
24 hours at 5 °C
subsequent rest at room temperature: 1–2 hours

The dough initially appeared highly degraded, with apparent loss of structure and behavior comparable to collapse.

However, the application of two light folds led to a significant recovery of shape and cohesion.

This result suggests that the system had not exceeded the critical threshold of structural continuity.

Mechanical handling likely promoted a reorganization of the protein network, temporarily increasing internal connectivity.

The described test is taken from: “Advanced methodology for producing bread doughs with flours of limited gluten development capacity”, available at www.glutenlight.eu

Scientific reference
Hidalgo, A., Brandolini, A. (2014). Nutritional properties of einkorn wheat. DOI: 10.1016/j.jcs.2014.04.005
Summary: einkorn exhibits a less organized protein structure and lower baking quality compared to modern wheats.

Complementary reference
Brandolini, A., Hidalgo, A. (2011). Einkorn wheat: a review
Summary: less elastic doughs, greater structural fragility, more plastic behavior.

8️⃣ Reorganization vs “reactivation”

It is important to distinguish between biological and physical phenomena. Gluten proteins do not regenerate or become “reactivated.”

The recovery observed in some doughs is attributable to a reorganization of the protein network, in which fractions initially not integrated into the GMP can progressively become involved (Belton, 1999).

A portion of proteins initially not fully integrated into the GMP may progressively be incorporated during:

maturation
handling
rest

This can temporarily increase network continuity. It is a physical phenomenon, not a biological one.

9️⃣ Practical implications

From a practical standpoint, evaluating dough condition can be reduced to its structural continuity:

cohesive but relaxed dough → potentially recoverable
incoherent dough → likely beyond the critical threshold

Mechanical operations (e.g., folds) are effective only if a continuous network is still present.

✅ Conclusions

Long fermentations do not necessarily require strong flours, but rather careful management of the parameters that regulate gluten network stability:

control of proteolysis
temperature management
redox state regulation
respect of the critical continuity threshold

The difference between strong and weak flours is mainly quantitative: the former operate far from the collapse threshold, the latter close to it. Under these conditions, system sensitivity becomes the determining factor.

Further insights

1 – Arabinoxylans
Non-starch polysaccharides that interact with the gluten matrix, influencing hydration, viscosity, and continuity of the protein network.
→ Further reading: Arabinoxylans

2 – Dough redox state
The oxidation–reduction balance regulates the formation and reorganization of disulfide bonds, directly affecting gluten network stability during fermentation.
→ Further reading: Redox

Essential references

• Belton, P.S. (1999). On the elasticity of wheat gluten. DOI: 10.1098/rstb.1999.0414

• Courtin, C.M., Delcour, J.A. (2002). Arabinoxylans and endoxylanases in wheat flour bread-making. DOI: 10.1016/S0733-5210(02)00011-1

• Dobraszczyk, B.J., Morgenstern, M.P. (2003). Rheology and the breadmaking process. DOI: 10.1016/S0268-005X(03)00059-6

• Don, C. et al. (2005). Glutenin macropolymer and dough properties. DOI: 10.1016/j.jcs.2004.07.001

• Hidalgo, A., Brandolini, A. (2014). Nutritional properties of einkorn wheat. DOI: 10.1016/j.jcs.2014.04.005

• MacRitchie, F. (1999). Wheat proteins and functionality

• Payne, P.I. (1987). Genetics of wheat storage proteins

• Shewry, P.R., Halford, N.G. (2002). DOI: 10.1093/jxb/53.370.947

• Stauffer, D., Aharony, A. (1994). Introduction to Percolation Theory

• Thiele, C. et al. (2002). DOI: 10.1128/AEM.68.3.1206-1213.2002

• Wieser, H. (2007). DOI: 10.1016/j.foodmicro.2006.07.004