Flour Pedia

2. Enzyme-Active Soy Flour
One enzyme from soy flour, lipoxygenase, also has an oxidative effect on the protein of the gluten. During the oxidation of the lipids by lipoxygenase, peroxides are formed that have a cross-linking effect on thiol groups. However, the gluten-strengthening effect of soy flour is comparatively slight; its bleaching effect is more important. There are several types of lipoxygenases with different action patterns. While type I lipoxygenase only acts on free unsaturated fatty acids, types II and III also oxidize unsaturated fatty acid bound to the glycerol backbone. Bean flour contains mostly types II and III, which makes it an efficient agent for oxidizing all unsaturated lipids in flour. The use of lipoxygenase is limited because the enzyme creates a "green" flavour that is not desirable in this application.
3. Glucose Oxidase The enzyme glucose oxidase (GOD) is usually derived from the mould Aspergillus (in a similar manner to amylase) and sometimes …

The present necessity for oxidative treatment might be regarded as a disadvantage of the fast and gentle processing of grain into flour. Natural ageing of the flour by exposure to the atmosphere alone is no longer possible, so maturation has to be speeded up with oxidative preparations. Oxidation primarily affects sulphur containing amino acids that are constituents of the gluten. The oxidation of two adjacent hydrogen sulphide (thiol) groups results in the formation of a disulphide bridge between different sections of the long gluten molecule or between different gluten molecules. This causes a hardening of the protein.

1. Ascorbic Acid By far the most important substance for this purpose is ascorbic acid (AA). Using a complex biochemical method starting with starch as the raw material it is produced in a very pure form and sold as a fine or crystalline powder in various concentrations to facilitate dosing. Less often, AA of purely biological origin is used. The most common product is…

Flour Treatment is an Essential Part of the Industrial Production of Flour. Wheat is of increasing importance for feeding the world's population, whose growing number and changing food consumption habits require more and more wheat flour. At the same time the processing of wheat flour is changing; although small craft bakeries still predominate in many parts of the world, industrial bakeries are taking an increasing share of the market and thus of the raw material, flour. In these bread factories it is not uncommon to find engineers at the production line rather than bakers. The direct interaction of the raw material or dough with the person responsible has been reduced to a minimum, and this necessitates a minimum of fluctuation in the properties of the raw materials since the machines do not (yet) have a "feeling" for the dough. Consequently, the flour producer, the mill, is considered responsible for uniform flour quality. This goal of standardization is achieved by …

There is a huge demand for flour improvers these days, in the baking trade and in the food industry. In the past, fifty or sixty years ago, millers were not faced with this topic – except, perhaps, in the context of some very special sideline tasks such as the first attempts to vitaminize light-coloured flours (now generally known as "flour fortification"). After the hardship and privation of the war and the years that followed, the world's populations were satisfied with what grew on the soil, what farmers and cooperatives delivered to the mills and what could be shipped across the oceans in the context of world trade. And if the worst came to the worst one delved back into the past. Holger Jörgensen discovered it in 1935; P.R.A. Maltha confirmed it fifteen years later: ascorbic acid offers a reliable way of closing many a gap in quality (Jörgensen, 1935; Maltha, 1950). This, along with the intelligent use of malt flour, was the only possibility that existed for some l…

This chapter summarizes all the public standards for flour fortification in 70 countries, with the latest entries dating from September 2006. The adoption of flour fortification as a national standard and its modification is an ongoing process, and therefore the following information can only reflect the current situation.

Tab. 85 lists the nutrient standards of countries with mandatory or voluntary flour fortification. Whereas in North and Latin America the fortification of flour is implemented in nearly every state, there are still a lot of countries where fortification is not practised and people suffer from malnutrition. In South-East Asia and Africa, especially, more and more states are determined to start flour fortification and work on projects and plans to put guidelines into practice.

New legislation is coming into force in the Philippines (since November 2004), Peru (December 2004), Uruguay (February 2005), Yemen and Iran (March 2006). Vietnam will implement flour fortifica…

23. Detection As we have already said, detection is an important aspect of flour fortification. Overdosing flour with micronutrients is not only unnecessarily expensive but also undesirable. When fortification is carried out under US federal law, flour milling facilities are required to meet appropriate levels to fulfil their legal obligation. For all of these reasons it is important to conduct detection tests periodically. If the feeder discharge rate is monitored on a regular basis and the flour output does not change, then the dependence on the detection test is not as great. Over a prolonged period of time the consumption of the micronutrient premix and flour production quantities give a more accurate picture of the level of fortification used. Although this gives a more accurate figure of usage on average, it does not mean the rate of addition was consistently uniform over this period of time. In general, the possibility of overtreatment is unlikely, as no business entity would b…

22.3. Carriers and Physical Properties
Since micronutrients are added in minute quantities (ppm), they are difficult to feed accurately and uniformly through a feeder. This becomes even more challenging when the output of a flour production facility is very small. Therefore it is common practice to increase the bulk quantity of the premix containing the intended micronutrients by adding inert and free flowing material to help accomplish the uniform rate of addition.
In most premixes starch makes up the bulk of the material and is considered the carrier of choice. It is important for the premix colour to contrast as little as possible with the colour of the flour. Even though the addition rate may be only 125 to 150 grams per ton (1,000 kg) of flour its colour may still affect the appearance of the flour. Most premixes are either yellow or white. Particle size is also considered to be very important. In order to mix well with flour the particle size of the premix should be similar to t…

22.1. Powder Feeders
Powder feeders are the first and foremost critical step in the process of fortification technology. There are many types of feeders that are available from a number of firms including ingredient suppliers and milling equipment manufacturers. Different types of feeders include volumetric, gravimetric and loss-inweight feeders. Volumetric feeders are the most popular type of feeder used in North America.
One such feeder is described above (Fig. 103). As can be seen from the diagram, the float, indicating the level of the additive in the hopper, can be removed along with a lid that covers the top of the feeder. Additives are added from the top into the hopper. The sides of the hopper, along with built-in guide vanes, flex with an oscillating motion to provide a constant agitation. The powder flows to the feed rolls from the hopper. Stainless steel feed rolls are driven in opposite directions, facilitating discharge of the powder in a thin uniform layer over the width…

20. Quality Implications Millers planning to introduce a flour fortification programme may have concerns about whether some of the micronutrients added to the flour will have quality-related implications due to the nutrients' reactivity, or for any other reasons. For example, in order to fortify flour with calcium in the UK, calcium carbonate is added. This has been the case for many years and the industry has adapted well to the method of determining flour colour rather than flour ash as a measure of refinement. The industry has had to adapt because calcium carbonate increases the ash content of the flour appreciably, meaning that incremental small differences in ash content are less discernible. However, when the same calcium carbonate is added to flour in hot and humid environments it reacts and alters the pH of the dough, interfering with the baking process. In such situations calcium sulphate is used instead.
Likewise, reduced iron is a popular iron source although it is magn…

18. Cost of Fortification Estimated cost guidelines for fortification are available from suppliers of micronutrients and from the literature. Precise costs can be calculated when specific details are known. Such specific details include the geographic location of the milling plant and how many micronutrients have to be added in what amounts. Some markets may be more cost-sensitive than others. Like most other businesses, one may expect the milling community to be generally reluctant to embrace a voluntary fortification programme, even if it is a simple one. Much of the skepticism is due to the fact that the cost of this additional process is not known for certain. However, once it is recognized that the cost of fortification is quite reasonable and the technology very simple, then for many millers the resistance to the idea gradually disappears.
There are two main factors which determine cost of fortification per person and year: choice of the premix and per capita flour consumption. …

2.13. Technical Knowledge, Skills and Expertise of Millers Millers usually have a good educational and technical background. Their training prepares them to successfully overcome most technical challenges. Therefore, developing a system to incorporate flour fortification will be relatively easy for them when required.
Millers have the ability to analyze complex flow diagrams in order to understand and improve the quality of their production and implement any potential modification to expand and diversify production / quality requirements. Wheat flour milling is known tobe one of the most challenging cereal processing technologies, primarily due to the presence of crease, which complicates the clean separation of bran and germ from the endo-sperm. These must be separated to obtain optimum extraction of flour of high quality. Over the years millers have learned to meet this challenge, improving flour quality and flour extraction levels.
2.14. Familiarity with the Process of Dispensing Po…