Importance of Starch Damage in Wheat and Milling Industry

By, Rabia Tiryaki, MSc, Bastak İnstruments , Turkey
Wheat, which is the most consumed nutrient among cereal products, has maintained its indispensable place and importance in human nutrition as a strategic product throughout the ages. Grain products, one of the indispensable basic needs of people living in all developed and developing countries, meet a large part of the daily energy required by the human body. In addition, wheat and flour production activities have once again revealed the economic value of the flour industry and the need of countries in terms of food security, shown with the food crisis that started in 2007 and the global economic crisis that started and continued in 2008.
At the beginning of the chemical and physicochemical properties sought in wheat and flour or semolina produced from wheat, the agricultural products that were the subject of the most international trade in history; amounts of water, ash, protein, gluten, gluten index, Zeleny sedimentation, starch and starch damage.
The amount of starch, which is the main component in wheat flour at the highest rate, has a very important effect on bakery products. Starch interacts with the other components and forms the dough structure. Water absorption, one of the most important functional parameters of starch, affects the quality and texture of bakery products. While intact starch granules have the ability to absorb approximately 0.33 times their weight in water, damaged starch granules can absorb water as much as their own weight.
Starch grains are found in a regular and organize structure between protein networks in the endosperm. However, they completely or partially lose their structure during the milling of wheat. The resulting flour contains damaged starch and undamaged starch granules in varying proportions. The the ratio and texture will vary depending on the grinding system and the adjustment of the rollers-,
The amount of starch damage has become an important quality parameter of interest to all sectors based on grain production, especially in recent years. After the inevitable effect of starch damage on the final product was revealed, it has become a routine analysis in many bread production industries and grain quality control laboratories.
In order to obtain dough of suitable consistency, the absorption of flours containing excessively damaged starch should be reduced.  Excess starch damage reduces the bread volume, affects the quality of the bread by spoiling the crumb properties. For a good bread making, the flour to be used must contain a certain level of damaged starch.  When there is not enough gluten to cover the large amount of surface area that occurs, an excessive increase in this ratio reduces its ability to hold gas and adversely affects the fermentation process.
The amount of damaged starch has an important place in the quality parameters for the pasta industry. During pasta making, damaged starch forms a substrate for amylase. They increase the amount of substance that passes into the cooking water by breaking down and cause turbidity. Semolina, which is a grinding product with low starch damage, is preferred in the pasta industry.
For the biscuit industry; Soft grain structure, lower protein and higher starch ratio form the appropriate quality feature. The amount of starch damage affects the cracking rate of biscuits. The amount of damaged starch is directly related to the enzyme activity. Alpha and beta amylase enzymes in wheat can only break down damaged starch. Considering that different products are obtained by using different properties of wheat fractions in different ways, it is essential to determine the optimum damaged starch property in order to produce the product under optimum conditions.