معدل امتصاص الماء في الدقيق يُقصد به الحد الأقصى لحجم إضافة الماء عند تحويل أربعة إلى عجين, يشار إليها بنسبة مئوية (%). معدل امتصاص الماء له تأثير مباشر على معدل إنتاج المواد الغذائية. لمنتجات الدقيق مثل الكعك المطهو ​​على البخار والخبز, كلما زاد امتصاص الماء, العدد الأكبر من الكعك والخبز المطبوخ على البخار من نفس وزن الدقيق. هناك العديد من العوامل التي تؤثر على معدل امتصاص الماء للعجين: التخلص من حبيبات الدقيق بشكل رئيسي, محتوى البروتين, السكريات غير النشوية, أضرار النشا, محتوى الماء, إلخ. منها ثلاثة عوامل أهمها: محتوى البروتين, starch damage and non-starch polysaccharides.

The protein in flour is categorized as water soluble protein and water insoluble protein (gluten protein). Researches show that water soluble protein and water insoluble protein both absorb water, but the water absorption of water insoluble protein (gluten protein) is more important and has a great bearing on dough’s water absorption rate. When water insoluble protein absorbs water, it can form a viscoelastic network structure unique to dough. Starch damage means the damage of starch’s outer cell membrane caused by mechanical grinding and pressing during milling process. Damaged starch is decomposed into dextrin, maltose and glucose under the effect of acid and enzyme, which play an important role in water absorption during dough’s fermentation and baking periods. The water absorption rate of damaged starch can reach 200%, which is five times that of complete starch granules.

Obvious negative correlation exists between gluten content and dough’s water absorption rate; no correlation exists between water holdup rate and dough’s water absorption rate; while obvious positive correlation exists between damaged starch content and dough’s water absorption rate.

As damaged starch influences dough’s water absorption rate to great extent, damaged starch content is high and dough’s water absorption rate is high, and thus the production rate of flour products is high. لذلك, damaged starch content should be increased properly in order to improve the production rate of flour products. However, researches show that high starch damage rate will affect product quality, so damaged starch contents should be properly adjusted according to different usages of tailored flours.