Damaged Starch
.
.
.
Damaged Starch
In the bread and cereal industries, the concept of damaged starch plays a critical role in formulation and the final product’s quality. This type of starch refers to part of the cereal grain starch that loses its crystalline structure during the milling process. In this state, its water absorption capacity, enzymatic activity, and participation in dough structure are affected.
Characteristics of Damaged Starch
Damaged starch has the following characteristics:
Increased Water Absorption: The crystalline structure of starch is disrupted, causing its amorphous regions to readily absorb water.
Increased Amylase Activity: Damaged starch is more easily broken down by alpha-amylase and beta-amylase enzymes, producing fermentable sugars.
Facilitated Fermentation: The sugars released from damaged starch are utilized in the fermentation process by yeast.
However, one key point often overlooked is:
Excessive damaged starch content can negatively impact dough structure and the final quality of bread.
Why does this happen?
- Increased Surface Area: The more the starch is damaged, the more surface area is exposed to the environment, and it absorbs more water.
- Excessive Swelling: This swelling disrupts the three-dimensional structure of the gluten network.
- Reduced Gluten Integrity: Gluten attempts to trap starch granules and gas bubbles in its matrix; however, with excessive swollen starch, the gluten network becomes weak, thin, and unstable.
Consequences of Increased Damaged Starch in Dough:
Instability during fermentation
Reduced gas retention ability
Irregular loaf volume, texture, and internal pockets
Dough stickiness
Increased stickiness to industrial machinery
Optimal Amount of Damaged Starch
The optimal amount of damaged starch depends on the type of flour, production process, and final product. Generally:
For bread flour, a damaged starch content of 10-14% of the total starch is typically desirable.
For specific products like biscuits, this amount should be lower as less water absorption is needed.
Final Recommendations for Researchers and Bread Industry Professionals:
When assessing flour quality or optimizing the milling process, in addition to water absorption indices, attention should be paid to gluten’s structural parameters, including:
Integrity of the gluten network
Strength and elasticity of the protein network
Gas retention and flexibility
Paying attention to these factors can improve the final bread quality, reduce production waste, and enhance performance in industrial lines.
Source:
Delcour, J.A., & Hoseney, R.C. (2010). Principles of Cereal Science and Technology. AACC International
#Grainar