Flour treatment
A flour treatment (with flour treatment agents ) is used to standardize the processing properties of wheat and rye flours mainly from the production of bread and bakery products . The aim is usually to improve these properties with a flour treatment.
Due to the natural fluctuations in the raw material grain , the milled products made from it, especially flour , also have fluctuations in their properties that affect processing. In order to be able to offer the processors, primarily the bakers , flour with the lowest possible fluctuations, the mills cut different grain deliveries in such a way that the properties desired by the bakers can be kept constant for as long as possible.
If the target (specification) cannot be met in this way because the fluctuations in the grain properties are too great or no grain with the necessary properties is available, flour treatment agents can be used to compensate for these fluctuations and thus standardize the flour quality.
Flour maturation / oxidation
The most common flour treatment agent in Europe, ascorbic acid (vitamin C), is also used in particular to compensate for changes in the grain (here: especially wheat) and flour caused by storage by achieving effects such as faster flour ripening.
Due to the influence of oxygen, the stability of the doughs made with the flour increases during storage (both of the wheat and the flour) to reach a maximum after several months (wheat) or about 14 days (flour) is maintained for a long period of time. This effect is also known as flour ripening. If “young” wheat is milled (shortly after harvest), stability is lacking, as is the case when using flour within less than 10-14 days after milling.
From 1916 to the 1950s, oxidizing agents such as potassium bromate or ammonium persulphate were used almost exclusively to anticipate flour ripening. Because of the suspicion that has arisen in Japan that the breakdown products of bromate could be carcinogenic, alternatives were increasingly sought. As early as 1935, Jørgenson had discovered that ascorbic acid can stabilize dough. It was now possible to fall back on this (also because the relevant patents had expired and the production of vitamin C was meanwhile significant enough to make the price attractive enough for flour treatment). In the following years, the use of the very cheap and effective potassium bromate was banned in more and more countries, and in many places no other oxidizing agents may be used for flour maturation. Ascorbic acid is permitted everywhere for flour treatment, but not in all applications, e.g. B. "pain de tradition française". The mode of action of ascorbic acid, which is actually an antioxidant or reducing agent , has now been largely clarified: it is converted into dehydroascorbic acid by an enzyme present in the flour , which in turn has the oxidative effect required to stabilize the dough via a further enzymatic step.
The typical dosage of ascorbic acid for the treatment of wheat flour is 10 to 100 g per ton of flour (10-100 ppm ).
Enzymatic flour treatment
The fluctuations in the properties of the grain also affect the natural enzyme content. Various enzymes are formed by the grain to build up the reserves of the grain (especially starch and protein) and are largely broken down again in the course of ripening, provided this is not disturbed, e.g. B. by late frost. When the grain germinates, enzymes are formed again to mobilize the reserves. In order to be stable in storage and to have optimal processing properties, grain should be harvested and stored dry and germinated. However, if the natural enzyme content is very low, this can have a negative effect on the baking process and the baked goods. For example, if the enzyme α-amylase is absent, the doughs lack the leavening power (i.e. the baking volume remains small), the browning is poor, and breads made from them age very quickly, i. H. the crumb becomes firm and dry quickly.
To compensate for this lack of quality of the flour, an enzymatic flour treatment can be used. For this, enzymes from other sources are used, e.g. B. from malt or fungal and bacterial cultures. Enzyme preparations used for flour treatment often contain amylases , xylanases and lipases , occasionally also glucose oxidase and proteases .
The typical dosage of individual enzymes is 1 to 10 g per ton of wheat flour (1–10 ppm).
Emulsifiers
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Although they are approved for use in baked goods in Europe and other areas, emulsifiers such as lecithin , mono- and diglycerides of fatty acids , diacetyltartaric acid glycerides or sodium stearoyl-2-lactylate are hardly used for flour treatment in the mills, but are rather used in bakeries for technical purposes To compensate for deficits in the flour or to prepare flour for special uses. The dosage of emulsifiers is 100–1000 times higher than that of ascorbic acid and enzymes, but they are not required for many breads and baked goods. However , they are very important for the commercial production of cakes in order to simplify processing and enable consistently good baking results.
The typical dosage of individual emulsifiers is 1,000 to 10,000 g per ton of wheat flour (0.1–1%).
More reasons to treat flour
In addition to standardization, flour treatment can also take place in order to optimize the flour for special applications. Above all, a small number of available grain qualities, as is the case in remote areas mainly outside Europe, can make it necessary for a mill to use flour treatment agents in order to produce flours for various applications from a single raw material, e.g. B. for bread, croissants , pizza bases and biscuits , crackers or waffles .
Consumption quantities
Due to the low dosage of ascorbic acid and enzymes in particular, their absorption through baked goods is very low, especially since there is no technical need to treat all flours. With an average consumption of 85 kg of bread and baked goods per person per year, corresponding to around 50 kg of flour, and a very high treatment with 10 g of enzyme protein per ton of flour, this would result in consumption of 1 g of enzyme protein in 2 years - provided that all flour would be treated with enzymes.
The amount of ascorbic acid consumed is comparable. However, it is no longer active as vitamin C after the dough has been prepared. In addition, the daily intake from bakery products (around 3 mg per day - assuming all flours are treated) would be too low to significantly influence vitamin C intake (recommended: 100 mg per day).
Despite the higher dosage (than that of ascorbic acid and enzymes), the intake of emulsifiers via bread and baked goods is significantly less than 100 g per person per year - for lovers of industrially manufactured cakes, probably a little more.
Individual evidence
- ↑ CS Fitchett, PJ Frazier, 1986. Action of oxidants and other improvers . Ch.14 in: Chemistry and Physics of Baking Materials, Processes, and Products. JMV Blanshard, PJ Frazier, T. Galliard, (Eds.) Royal Soc. Chem., London, pp. 179-198.
- ↑ H. Jørgenson, 1935. A contribution to illuminating the inhibitory effect of oxidizing agents on proteolytic enzyme activity; on the nature of the effect of potassium bromate and analogous substances on the baking ability of wheat flour , I. / II. Biochem. Lines 280, 1-37 / 283, 134-145.
- ↑ H. Jørgenson, 1939. Process of improving the baking strength of flour . US patent 2149682.
- ↑ Werner Grosch, 1998. Mechanism of ascorbic acid . Grain, Flour, and Bread 52 (5), 267–269.
- ↑ Werner Grosch, H. Wieser: Redox Reactions in Wheat Dough as Affected by Ascorbic Acid . In: J. Cereal Sci. tape 29 , 1999, pp. 1-16 , doi : 10.1006 / jcrs.1998.0218 ( PDF ).
- ↑ Lutz Popper and a. (Ed.): The Future of Flour - A Compendium of Flour Improvement . AgriMedia Verlag, Hamburg, 2006, ISBN 978-3860373095
- ↑ proplanta: German bread consumption continues to grow
- ↑ DGE: The reference values for nutrient intake