Miller Magazine Issue 110 / February 2019

63 COVER STORY MILLER / FEBRUARY 2019 MEASUREMENT OF FLOUR QUALITY AND CHARACTERISTICS The composition of flour very much affects perfor- mance. Hard wheat and high protein flours are generally used for bread and leavened products. The strong gluten helps provide structure and stability. Soft wheat, and low protein flours are generally used for cakes, cookies, cra- ckers, noodles and some flat breads. But if it were only so simple … Knowing protein quantity – while important – is simply not enough. There are many additional factors which affect flour usage and performance. Some of these affect flour’s gluten and others affect the starch. There are many tests, analyzers, and techniques to elucidate flour properties. However, it all start with the wheat. MONITORING AND CONTROLLING WHEAT AT IN-TAKE Wheat comes in many varieties – each with differing characteristics. Additionally, the climate to which the wheat is subjected alters its characteristics so there can be significant variation from one crop year to another. Millers often contract with suppliers (farmers or large elevators) to deliver wheat with specific properties. It is important for the milling company to control its wheat supply and monitor it throughout the process chain. Processing wheat that is unknown or incompatible with standards does not always cause problems in mills, but a reduction in the quality of the flour can occur. There are several important wheat specifications including moistu- re, hectoliter weight, protein, falling number, hardness, and gluten content. When it rains at harvest, wheat can sprout. When it sprouts an enzyme called alpha-amylase is formed. Alp- ha-amylase breaks starches into their component sugars when flour has been mixed with water into dough. Too much enzyme can then cause real issues at ba- keries and other end users. The falling number method was de- signed to detect sprout damage and measure alpha-amylase acti- vity in wheat and flour. At mills, it is used to screen incoming grain to keep unknown sprouted grain from entering the mill, blending to meet optimal activity level, and for analyzing flour to ensure it meets specifications. It is important to note that alpha-amylase is not linear in its activity. Small changes in the amount of availab- le enzyme can have severe consequences at the bakery. Millers monitor falling number very closely. There are ICC, ISO, and AACCI approved instruments and metho- ds which help ensure the accuracy and precision of the falling number test. Perten Instruments offer the only validated instruments for these falling number approved methods and the new Falling Number® 1000 model is the fastest, safest and easiest to use falling number ins- trument ever. Gluten content and quality are key characteristics and need to be tested. The traditional method for determi- ning gluten quantity was handwashing. This has been replaced by the Perten Glutomatic System which is an internationally approved automated gluten washing met- hod, with much better reproducibility and repeatability. While gluten quantity is important, it alone is not suf- ficient to predict end-use suitability as flours with the same gluten quantity may still behave differently due to differences in gluten quality. Measurements like the Gluten Index parameter achieved from the Glutomatic System at the same time as gluten content is measured provide additional information which is highly useful for the miller and ultimately the baker. Moisture is always determined as wheat is sold either on a dry matter basis, or constant moisture content basis. Wheat is commonly bought and sold on protein content, so measurement is critical to milling companies to ensure they get what they pay for. Small inaccuracies can cost the milling company large amount of money since whe- at is purchased in bulk. Hectoliter weight is essentially a density measurement and provides an indication of mill yield by volume. Moisture and protein are typi- cally measured with near-infrared instruments (NIR). NIR replaces old oven, muffle furnace and wet chemical methods providing re- sults in less than a minute. New Perten NIR instruments, Inframa- tic 9500 and 9520, are nearly as accurate as the reference metho- ds with the added benefit of be- ing much faster, safer, and simp- ler to use. In addition to moisture and protein analysis, NIR instruments can give estimates for gluten and addi- tional parameters. The IM 9500 NIR instrument isequip- ped with a hectoliter weight module. In intensive harvesting periods, the purchase from the source of wheat provides significant advantages to flour industrialists and grain traders. However, it is not always FN1000 IM8800 GL2200 CT2016 GT2020