###### Abstract  
The aim of the study was to evaluate wheat flour fractions and the relationships between the rheological properties of wheat flour mill streams with arabinoxylans content to predict flour functionality. The tested wheat variety was IS Laudis and an industrial milling station with several roll sections was employed to reach 30 passages of flour streams. Each mill stream fraction was analyzed separately. Several physiochemical (moisture, ash content, falling number, wet gluten content, gluten index, and damaged starch content) and rheological properties were evaluated by means of utilizing various test apparatus and techniques. The total content of non-starch polysaccharides and arabinoxylans, as well as soluble and insoluble fractions were investigated. Results showed significant differences between the mill streams in terms of the content of physicochemical parameters and rheological properties, as well as in soluble and insoluble fractions of non-starch polysaccharides and arabinoxylans. The relationships between the tested parameters and PCA analysis can be useful for millers who can then select and blend several flour streams to obtain a maximum amount of flour with specified characteristics. A better understanding of the origin and function of different fractions and the role of arabinoxylans and their fractions in the milling process will allow the development of wheat flour blends with the desired functionality. Flows from late reduction and sizing passages (C and R) as well as from sorting filter (V) streams showed high ash content as well as T-NSP and T-AX levels, so the final content of NSP in flour blends may be balanced by the application of the proper amount of C6-C7 and R5 stream flours. Keywords:wheat; mill stream; rheological properties; arabinoxylans; functionality +
Footnote †: journal: Applied Sciences  
a very high capacity. Roller milling is conducted on break rolls (which are designed to break and remove the endosperm and germ from the bran coat, and gradually grind endosperm into flour), sizing rolls (so as to generate'middling' with various particle sizes), and reduction rolls (which reduce the middling to flour). Each mill produces from a few to even dozens of flour streams, with large differences in the physicochemical properties of individual flours. These are mixed at the end of the process to produce so-called 'composite flours'. These stream mixes are dedicated to restaurants and bakeries for producing breads, cakes, and pizzas, or to various food plants for producing pasta, extruded products, or biscuits [5]. A wide range of wheat flour is produced, as a result of various combinations of flour stream mixing possibilities. Indeed, not every flour stream is equally useful for generating a composition of specialized wheat flour. Significant differences in the parameters of flour streams affect the difficulty in optimizing flour production. Therefore, it becomes very important to precisely test and predict the quality of flour streams, regardless of the ultimate applications of the final composed flour. Determining the distribution of beneficial and harmful components in mill streams is important for aspects such as assessing the quality of wheat milling [6], and the optimal combination of flour streams is of great importance to obtain the best baking quality [4]. Research on the differences between individual flour streams has been continuous. These differences concern such features as rheological properties [3; 4; 7; 8; 9; 10; 11], or physicochemical characteristics such as content and distribution of protein, protein composition or ash content [2; 3; 8; 9; 11; 12; 13; 14; 15], distribution, amount of enzymes [16; 17; 18; 19], fat content [2; 7; 20], starch damage degree [3; 11; 14], pentosans and its fractions [6; 21], or antioxidants content [22]. Apart from protein and starch, arabinoxylans (AX) are important components of wheat grain. These significantly affect the properties of flour.