How Is Damaged Starch Analysis Performed in Wheat Flour?

What is Damaged Starch?

Starch in the endosperm contains amylose and amylopectin molecules. These molecules exhibit a regular arrangement in the wheat endosperm. In this state, wheat has a semi-crystalline structure. One of the main factors forming the crystalline structure is the branching created by amylopectin. These molecules have short side chains. When these chains align parallel to each other, double (helical) structures appear. The crystalline layer is formed by these helices coming side by side. In the endosperm, there are structures formed by the regular arrangement of molecules as well as irregular structures. The areas where these irregular structures are present are called amorphous regions. The branched regions of the amylopectin molecule and the linear structures formed by the amylose molecule form the amorphous regions. When these structures are examined together at a microscopic level, they create interlaced structures. Since the rings form an interlaced structure, water has difficulty reaching the center of the rings. Therefore, a hydrophobic structure emerges. As a result, water struggles to reach the granule center.

When wheat enters milling, a large pressure occurs while moving between the rollers of the milling device. These pressures and forces transfer this energy to wheat granules during milling. With energy transfer to the granules, the bonds — hydrogen bonds — that hold the amylopectin helices together gradually start to separate. Therefore, the crystalline structure created by amylopectin dissolves, and the molecules move apart.

1.1 Breakage and Fragmentation in Starch Granules:

Starch granules can experience breakage due to light or bond rupture due to very severe mechanical effects.

Double Break Loss
Molecular Fragmentation

Double Break Loss: When starch granules come into contact with polarized light, they undergo breakage. As a result, the structure suffers degradation, and the crystalline structure formed by the molecules also degrades. As the degradation increases, the irregularity in the structure also rises.

Molecular Fragmentation: During wheat milling, wheat is not always exposed to a constant mechanical effect for various reasons. In some cases, milling can be very intense, and the resulting stress is not limited to intermolecular bonds but also causes the breaking of glycosidic bonds connecting glucose molecules, affecting the length of the chains as well.

When these deformations occur, they affect not only a single structure of the granule but also cause a geometric change in the whole granule. Granules subjected to high pressure between rollers flatten as a result. Consequently, surface area increases and volume decreases. Expansion and flattening events are observed. On the other hand, in some areas, granules break into separate pieces. This is important for flour flowability and rheology.

1.2 Post-Damage Contact with Water: Molecular Swelling

The disruption of the crystalline structure in the granules for various reasons causes the gaps to open. Therefore, the molecules in wheat become exposed to external influences. As a result, water molecules start attaching to -OH groups inside the crystals when entering. This attachment occurs easily because under normal conditions, heat is required for starch to absorb water. However, after starch granules are fragmented, molecules are already exposed, so even room-temperature water can easily penetrate this structure. Consequently, "cold gelatinization" occurs.

Uses and Importance of Damaged Starch Measurement in the Flour Industry

In the milling sector, the amount of damaged starch must be known for energy savings, machine control, and maintenance purposes. A high damaged starch value indicates excessive milling. Milling beyond normal values leads to overloading of the machines. Consequently, machines working harder bring rollers closer together. As this closeness increases, the pressure between rollers also increases. Increased pressure and fast operation can cause overheating in the machines. In the long term, this damages raw material, reduces product quality, and increases electricity consumption, leading to unnecessary expenses.

For the bread sector, the damaged starch amount directly affects product shelf life and efficiency. High damaged starch means the product absorbs too much water, but since gluten is weak, it later releases excess water, causing the bread interior to dry. This leads to rapid staling.

In biscuit and cake production, a low damaged starch amount is preferred because dough crispness is important. Too much damaged starch prevents proper dough spreading; the dough absorbs excess water, resulting in a hard final product.

Why Knowing Damaged Starch is Necessary for the Industry

Knowing damaged starch in the flour industry is essential for controlling the process from raw material to final product smoothly.

Water Absorption:
Insufficiently milled flour has fewer gaps between molecules, resulting in lower damaged starch. Low damaged starch means the flour struggles to absorb water. Flour that cannot absorb enough water yields less dough, reducing efficiency over time.

Over-milling causes control difficulties. In this case, a false water absorption occurs. Granules with more gaps absorb excess water initially but later release it.

Fermentation:
When damaged starch is low, the open starch area is insufficient for amylase enzymes, reducing their efficiency. Consequently, sugars needed for yeast are not released. Yeast cannot feed properly, and fermentation rate decreases. This leads to low gas production and insufficient bread volume.

Excess damaged starch makes enzymes more active, producing sugars for yeast. Yeast produces gas, but weak gluten cannot retain it, leading to dough collapse.

Figure 1: Relationship Between Damaged Starch Ratio and Gas Production Rate.

Crust Color:
Low inter-molecular gaps and enzyme inefficiency prevent sufficient sugar formation. The Maillard reaction does not occur, and bread crust appears pale. High damaged starch allows water to enter granules, enzymes release enough sugar, and crust darkens due to excess sugar.

Texture:
Low damaged starch cannot absorb enough water, leading to tough bread. Excess damaged starch initially absorbs more water but releases it later, causing sticky dough and potential machine adhesion.

Advantages of BASTAK SD CHEQ 15000 in Measuring Damaged Starch

4.1 Rapid Analysis, High Accuracy, and Economic Efficiency via Amperometric Method

Conventional enzymatic methods are slow and complex. The amperometric method provides highly accurate measurement of damaged starch. Bastak 15000 SD Cheq uses an electrochemical amperometric method to analyze starch granules’ iodine absorption with very small samples (1 g) in minutes. Based on the internationally recognized Chopin SD principle, the device measures damaged starch affecting water absorption and fermentation rate. SD Cheq 15000 visually maps damaged starch levels in C UCD units. It can measure damaged starch in commercial flour, wheat flour, whole wheat flour, durum flour, bulgur, vital gluten, vermicelli, and semolina within 7 minutes at international standards.

Analysis relies on iodine absorption into granule gaps. Faster iodine absorption indicates higher damaged starch. The device displays percentage damaged starch on the LCD as %Al. Values can also be converted to UCD, UCDc, AACC, and Farrand units.

The device reduces costs by eliminating expensive enzyme kits. Full automation reduces labor requirements. It also allows evaluation of dough fermentation, water absorption, rheology, baking performance, aroma formation, biscuit breakage, and pasta quality.

4.2 Data Traceability, Device Reliability, and Integrated Operation

The 5-inch high-resolution touchscreen allows easy monitoring and control. Memory storage enables comparison with past results. Reports can be digitally generated and accessed remotely.

Parameter Table:

Bastak milling samples analyzed with SD Cheq 15000 show consistent and highly precise results. Consecutive analyses demonstrate stability.

4.3 Cost Savings and Quality Control with BASTAK SD CHEQ 15000

Bastak SD Cheq 15000 provides cost savings and improved quality. Accurate, repeatable measurements enable optimization. Proper water absorption must be ensured to avoid losses. High damaged starch can lead to excessive water uptake and sticky dough. Early detection allows corrective action within 7 minutes without high chemical or labor costs, preventing production waste.

Appropriate Damaged Starch Levels by Protein Range

Figure 2: Relationship Between Protein (X-axis) and Damaged Starch (Y-axis) (Bastak Instruments, 2026).

Different products require different protein and starch levels:

• Pan bread: 11–14% protein, 19–23 UCD damaged starch

• Flat bread: 10.5–12.5% protein, 17–20 UCD damaged starch

• Crackers: 8–10.5% protein, 16–18 UCD

• Noodles: 8.5–10.5% protein, 14–17.5 UCD

• Biscuits: 7–9% protein, 14–16 UCD

• Snacks: 7–8.5% protein, 14–16.5 UCD

Protein and damaged starch optimization ensures proper fermentation, water absorption, dough texture, and final product quality.