NL2015949B1 - Flour blends and the use thereof in bread baking processes. - Google Patents

Abstract

The invention relates to the field of bread making, in particular to flour blends, starter doughs and methods for preparing dough leavened bread products at an industrial scale. Provided is a flour blend for the preparation of a yeast leavened dough, the blend comprising (i) a patent wheat flour; (ii) a protein-enriched wheat flour fraction obtained by wind sifting a milled wheat flour; (iii) a starch-enriched wheat flour fraction obtained by wind sifting a milled wheat flour; and (iv) a heat treated wheat flour. Also provided is a starter dough, a dough and a baked product comprising or prepared using the flour blend.

Description

Title: Flour blends and the use thereof in bread baking processes.

The invention relates to the field of bread making. In particular, it relates to flour blends, starter doughs and methods for preparing dough leavened bread products at an industrial scale.

The two commonly used methods of dough mixing employed by the baking industry are the so-called straight dough and sponge dough methods.

The sponge dough method consists of two distinct steps, namely, the sponge stage and the dough stage. The sponge stage involves mixing part of the dough ingredients and allowing preliminary fermentation. The sponge usually comprises up to 50% to of the total flour of the complete dough, all the yeast and yeast nutrients, and sufficient water for a moderately stiff dough. If dough conditioners and malt are employed, these are also added at this stage. Fermentation time for the sponge is usually between 3 to 4 hours, and usually does not exceed 5 hours. At the dough stage, the fermented sponge (also referred to a starter dough) is returned to the mixer and additional ingredients are added, like the remaining flour, water and salt. Fermentation time from this point on, including final proofing, ranges from 1 to 2 hours.

The straight dough method is a single-step process, in which all the ingredients are mixed together in a single batch. Ordinarily, the fermentation time is about 4 to 5 hours, including that time required for the final proofing (raising of dough in baking pans). Within a given establishment, a standard fermentation time is followed closely, even though this may vary from one bakery to another due to such factors as character of flour, amount of yeast, temperature, formula ingredients, level of oxidation, etc. Variations in standard fermentation time within a given establishment not only reduce efficiency in operation but also jeopardize quality and uniformity of the end-product.

Since the sponge method of making doughs is more flexible in continuing operations and gives bread of greater volume and more desirable grain and texture, it is by far the most popular method in use in industrial bread making. The present invention is concerned with sponge dough methods only.

The industrial baking industry has come to rely on a whole host of additives to make a classic range of products, from crumpets to loaves. Over the past few years, the tide has been turning towards additive-free and "clean label” consumer products. Because consumers seem to equate naturalness, meaning no additives, with being better for them, the bread making industry is forced to respond to consumers' needs for more natural products with fewer additives. "Clean labeling” generally means removing ingredients with E-numbers like emulsifiers, flour treatment agents, such as ascorbic acid, and preservatives, which tend to be used by the larger industrial bakeries.

This is a challenging task since consumers don’t want to see any reduction in the quality of the bread and they don't want to see unacceptable cost being added onto the price of a loaf. In addition, the baking industry often restricts the variation in weight, volume and/or height of a loaf of bread in order to be sold, thereby further challenging replacing or removing the commonly used bread improvers. For example, in some countries the height of an industrial loaf bread produced in bread pans must be within the range of 16 ± 0.5 cm. A further challenge resides in the timing of producing an industrial bread. Traditionally, the manufacture of bread at night and at dawn to finish baking as soon as possible before being offered for sale of bread and to obtain a product which is accepted by the end of the day as fresh. In addition to unpleasant working hours for the personnel involved in the bread-making process, this procedure involves the problem that a day prior to the actual sale, the demand for bread must be predicted to bake the right amount or to order, so that on the one hand during the day no lack of bread produced and on the other hand remains no residual stock of bread at the end of the day.

To bake bread throughout the day and be able to adjust to changes in demand for bread and the demand for different types of bread, it has long been known to freeze dough and bake the bread from the predough. However, frozen doughs have several practical and economical drawbacks. These include long waiting times required to thaw the dough, and loss of yeast cell viability and fermentative capacity affected by dough freezing. More in particular, it is known that the overall quality of bread dough deteriorates gradually during storage at -18°C. This is typically by an increase in proofing time, a decrease in loaf volume and/or poor bread characteristics.

In attempt to overcome at least part of these problems, the present inventors set out to provide a high quality "clean label” bread product which can be produced at an industrial scale in an economically attractive fashion. More in particular, they set out to provide improved flour mixtures and starter doughs that allow for a highly reproducible, uniform bread that can be produced fresh (i.e. without freezing) and that can be labelled with flour, water, yeast and salt as the sole ingredients.

It was surprisingly found that at least some of these goals could be met the provision of a novel flour blend. The blend comprises a conventional patent flour, a protein-enriched wheat flour fraction, a starch-enriched wheat flour fraction and a heat treated wheat flour. Processing the flour blend together with yeast and water yielded a firm sponge dough that remained stable up to 6 days storage in the cold. The sponge (starter) dough was used to prepare a E-number free bread product with high quality (taste, structure, color) and uniformity.

Accordingly, in one embodiment the invention provides a flour blend for the preparation of a yeast leavened dough, the blend comprising (i) an (all-purpose) patent wheat flour (ii) a protein-enriched wheat flour fraction obtainable by wind sifting a milled wheat flour; (iii) a starch-enriched wheat flour fraction obtainable by wind sifting a milled wheat flour by; and (iv) a heat treated wheat flour.

The first, and major, component of the flour mixture is a patent wheat flour, which is generally considered the purest and highest-quality commercial wheat flour available. Preferably, the patent flour for use in the present invention is protein-rich, for example having a protein content of at least 11.5%, preferably at least 12.5%. Common flour additives like ascorbic acid (E300) are preferably not present.

The second and third components of the flour blend are, respectively, a protein-enriched and a starch-enriched (also referred to as protein-reduced) wheat flour fraction obtainable by wind sifting of a milled wheat flour.

Wind sifting (also referred to as air classification) is a technique used to separate particles according to size and density by means of air streams and centrifugation. The flour characteristics of fractions obtained from windsifting depends on the settings, e.g. the rotational speed of the classifier wheel and the air-flow pressure affecting the air streams used. The flour is fractioned into a coarse and a fine fraction. Since the size, shape and density differs between protein fragments (smaller) and starch granules (larger) in the flour, windsifting is very useful to separate flour into a protein- and starch-enriched fraction. More in particular, when separating wheat flour the fine fraction contains fragments of starchy endosperm protein and small starch granules. The coarse fraction contains mainly large starch granules and fragments of endosperm cells. The fraction yield and protein content vary with wheat varieties and hardness of the kernel. However, generally speaking the fine, protein-enriched fraction has a protein content of at least 18% and the coarse, starch-enriched fraction has a protein content of up to 14%. Preferably, 80% or more of the particles of (ii) and (iii) are less than 90 microns, preferably wherein the mean particle size is in the range of 20 to 60 microns.

Previous studies have shown that the protein rich windsifting fractions are suitable for yeast leavened bread, whereas low protein fractions are suitable for sponge cakes. DE10248160 relates to wheat flour mixtures for baking, and to air-classified flour to extract high-protein flour which is granulated in fluidized bed with water sprays. The wheat flour is air-classified into three fractions: graded flour, low-protein flour and high-protein flour. The high-protein flour is granulated in a fluidized bed, with sprayed-in water. The granules are introduced into flour or flour mixtures. Addition of high protein fractions from air-classified flour has been shown to increase the loaf volume of protein-poor flours. It has also been suggested that fortification of straight flour with high protein fractions yield doughs with greater elasticity, water absorption and bread volume. WO95/04462 discloses a Rye-flour fraction, obtained as the coarse-fraction of an air classification process, performed on a milled, ordinary Rye-flour. The Rye-flour fraction has a reduced protein content (less than 7 wt%), and a reduced dietary fibre content compared with ordinary Rye-flour. Also disclosed are flour blends, suitable for the production of Rye-containing products, wherein ordinary flour is blended with the protein-poor Rye-flour fraction, so that the weight ratio ordinary flour: Rye-flour fraction ranges from 95-5 : 5-95.

However, wheat flour blends as disclosed in the present invention comprising both the protein- and starch-enriched fractions of wheat flour have not been shown or suggested in the art.

Preferably, the total amount of the protein- (component (ii)) and starch-enriched fraction (component (iii)) in a flour blend of the invention is 10-25 parts by weight for each 100 parts by weight of component (i). More preferably, components (ii) and (iii) together make up 13-20 parts by weight for each 100 parts by weight of the patent wheat flour component (i).

This combination of windsifted fractions allows for a convenient adjustment of the protein/starch ratio. For example, the protein content can be increased without a concomitant increase in starch, and vice versa. The relative amounts of component (ii) and component (iii) can therefore vary according to specific needs. For example, they are present in the range of from 1.5:1 to 1:1.5 by weight. Good results are obtained in the range of from 1.3:1 to 1:1.3 by weight. In a preferred aspect, about equal amounts of the protein-enriched wheat flour fraction and the starch-enriched wheat flour fraction are used. In a specific aspect, the relative weight ratio is about 1:1.

The protein content of said protein-enriched (alternatively referred to as ‘”high-protein” or "low-starch”) wheat flour fraction is at least 17%, preferably in the range of 18-24%, more preferably 20-22%. For example, the high-protein wheat flour fraction contains 19, 20, 20.5, 21, 21.5, 22 or 22.5% protein. These wheat flour fractions are commercially obtainable. An exemplary protein-enriched wheat flour fraction for use in the present invention has a dry matter content of at least 86.5% (ICC 110/1), a moisture content of up to 13.5% (ICC 110/1), an ash content of maximally 0,45% (ICC 104/1) and a protein content of 21,0/22,0% (based on dry matter; ICC 167/1).

The protein content of said starch-enriched (alternatively referred to as "’high-starch” or "low-protein”) wheat flour fraction is up to 14%, preferably up to 12%, more preferably up to 11%. Good results are obtained when the protein content of the starch-enriched fraction is in the range of 9-12%, preferably 9-10.5%. These wheat flour fractions are commercially obtainable. An exemplary starch-enriched wheat flour fraction for use in the present invention is available from Meneba, The Netherlands, under the tradename Zeemax. For example, it has a dry matter content of about 88.5% (ICC 110/1), a moisture content of about 11,5 % (ICC 110/1); an ash content of maximally 0,45 % (ICC 104/1), a protein content (based on dry matter; ICC 167) of about 10,0%, a falling number of at least 275 sec (ICC 107/1), amylogram max. viscosity of ca. 800 AE (ICC 126/1) and amylogram temperature of maximally ca. 88° C (ICC 126/1).

The fourth component of a flour blend of the invention is a heat-treated wheat flour. The use of heat-treated flours in baking products is known in the art. For example, W02010/042825 relates to a method for heat-treating flour comprising the steps of dehydrating the flour to minimize or avoid gelatinization, and heat treating the dehydrated flour. The resulting flour was found to have increased moisture absorption, and dough and baked goods made from the heat-treated flour has improved performance and properties relative to dough and baked goods made from untreated flour. Heat treatment of flour or wheat has been carried out in the art for various purposes. For example, Japiske et al. (US 3,159,493) subjected flour to temperatures of about 125-155 °C in an atmosphere containing water vapor under elevated pressure for 1-10 minutes to eliminate microorganism contaminants in flour with a minimum irreversible change in the physiochemical properties of flour. At temperatures below this range microorganism contaminants were not completely eliminated, and temperatures above this range were likely to damage the flour. Heat-treated flours are also used in infant foods.

Preferably, the moisture content of the heat-treated wheat flour in a flour blend of the invention is 1.5% to 4.1%, more preferably 2.0- 3.5%. The water activity (Aw) of the heat-treated flour typically lies in the range of from 0.03 to 0.1. The heat-treated wheat flour is present in a relatively minor amount, e.g. less than about 15 parts, preferably less than 12 parts, more preferably less than 10 parts for each 100 parts by weight of the patent wheat flour. Very good results were obtained with a flour blend comprising 5-8 parts by weight the heat-treated wheat flour for each 100 parts by weight of the patent wheat flour. The protein content of the heat-treated wheat flour is not very critical, but typically lies in the in the range of about 10 to 13%. In one embodiment, the heat-treated flour has a protein content of 11 to 11.5%. In one embodiment, the particle size distribution of the heat-treated flour is such that greater than 80% of the flour particles are between 90 and 150 microns or greater than 80% of the flour particles are between 90 and 150 microns and greater than 7% of the flour particles are between 150 and 250 microns.

In a specific aspect, the heat treated flour has a protein content of at least 12%, preferably at least 13%. In one embodiment, the protein content is about 14 to 14.5%. Very good results were obtained with heat treated flour marketed by Meneba under the tradename Havik. For example, it has a dry matter content of minimally 95% (ICC 110/1), an ash content of maximally 0,60% (ICC 104/1) and a protein content (based on dry matter) of ca. 14% (ICC 167).

The heat-treated flour can be obtained by any of the methods recognized by those skilled in the art including batch and continuous flow methods. Useful apparatuses useful for preparing a heat-treated wheat flour for use in the present invention include industrial ovens, conventional ovens, microwave ovens, fluidized beds, dextrinizers, dryers, mixers and blenders equipped with heating devices, and other types of heaters, preferably wherein the apparatus is fitted with a vent to the atmosphere so that moisture does not accumulate and precipitate onto the flour. For example, a rotary drum dryer is used in a continuous flow configuration. Such dryers are commercially available. Preferably, a procedure which avoids gelatinization of the flour is used. See for example W02010/042825. A flour blend according to the present invention is advantageously used to make a dough. The dough may or may not be frozen. Preferably, the dough is not frozen. An example of a dough useful in the present invention includes flour, water, leavening agent which may be yeast or chemical leavening agent or both. Preferably, the dough is a so-called starter dough or sponge dough for use in the sponge dough method for (industrially) baking bread. Herewith, the invention provides a method for providing a starter dough for the manufacture of a yeast leavened dough, comprising mixing a flour blend according to the invention with water, baker’s yeast and salt, and processing the mixture into a homogeneous dough. In one embodiment, the method comprises mixing 100 parts of weight of the flour blend, from 40 to 60 parts, e.g. 50 parts, by weight of water, and 0.5 to 2 parts by weight of yeast. Good results are obtained using cooled water, e.g. water at 2 to 10°C, preferably about 5-6°C.

Any type of conventional baker’s yeast can be used, including liquid yeast, cream yeast and/or block yeast. By baker's yeast is meant a commercially or industrially produced S. cerevisiae strain. Liquid yeast is a suspension of baker's yeast cells with a yeast dry matter content usually between 5 and 25% (w/w). Cream yeast is a special form of liquid yeast. It is a product that is obtained directly after the fermentation step in the yeast production process, optionally after one or several washing steps. Cream yeast usually has a dry matter content between 17 and 23% (w/w). Alternatively, liquid yeast can be obtained by resuspending compressed yeast or dry yeast. In a preferred embodiment, block yeast is used.

After mixing the starter dough ingredients, the mixture may be gently kneaded into a loose dough. The resulting starter dough can then be stored to allow for fermentation, preferably at a temperature of about 2-10°C. Fermentation is preferably performed at a temperature of about 3-4°C. Surprisingly, despite the absence of any preservatives, additives and/or stabilizers, the starter dough of the invention remains stable without any signs of decay up until about 6 days storage in the cold. After about one day storage, the dough starts to show a shiny appearance and thereafter increases to produce a desirable aroma. The pH of the dough typically remains above 5. The fermentation time can be several days, e.g. up 6 days, thus allowing for an easy adjustable dough supply in an industrial baking setting.

Depending on the demand in bread, the starter dough can be taken from cold storage and processed into a yeast leavened dough for making a baked product. A further aspect of the invention thus relates to a method for providing a yeast leavened dough, comprising preparing a starter dough according to the invention, allowing fermentation at a temperature of about 2-10°C for a time period of at least 24 hours, and combining it together with water, flour, yeast and salt into a dough. For example, the starter dough is combined together with water, flour, yeast and salt into a dough. Good quality bread products can be obtained upon mixing 100 parts of flour, 30-35 parts of starter dough, about 2 parts salt, about 3-4 parts yeast and about 60 parts of water. Optionally, a dough may contain one or more additional ingredients including for example, iron, salt, stabilizer(s), flavored oils, enzymes, sugar, niacin, at least one fat source, riboflavin, corn meal, thiamine mononitrate, flavoring(s), and the like. However, in view of the desire to product "clean label” consumer products, the inclusion of additives that must be listed as E-number on the packed product are preferably minimized or completely avoided.

The resulting dough can be kneaded according to known protocols, e.g. slow kneading followed by fast kneading. Kneading is a process in the making of bread dough, used to mix the ingredients and add strength to the final product. Its importance lies in the mixing of flour with water. When these two ingredients are combined and kneaded, the gliadin and glutenin proteins in the flour expand and form strands of gluten, which gives bread its texture. The kneading process warms and stretches these gluten strands, eventually creating a springy and elastic dough. The dough can then be allowed to rise or "prove". Proofing (also called proving or more rarely blooming), as the term is used by professional bakers, is the final dough-rise step before baking.

The present invention also provides a baked product prepared from a dough comprising a flour blend of the invention. In one embodiment, the baked product is a bread. As will be understood, the baked product can be produced by any conventional baking procedure. For example, in one embodiment a method for providing a flour based baked product comprises preparing a yeast leavened dough according to the invention, optionally placing the dough in a bread pan, and baking the dough at the desired temperature, for example in a baking oven set at a starting temperature of 240°C and cooling to about 180°C during a baking time of about 30-40 minutes.

The invention is exemplified by the following non-limiting examples.

EXPERIMENTAL SECTION

Example 1: Preparation of a flour blend A flour blend was prepared according to the following mixture.

Basic wheat flour (13% protein)

Starch-enriched wheat flour obtained by windsifting (Zemax; Meneba, The Netherlands)

Protein-enriched wheat flour obtained by windsifting (Promax; Meneba, the Netherlands)

Heat treated wheat flour (Havik; Meneba, The Netherlands)

Example 2: Preparation of a starter dough

The flour blend of Example 1 was thoroughly mixed, and 6000 gram flour blend was added to half the amount by weight (3000 gram) of water (6 °C), and 0.8 wt% blocked yeast.

The resulting mixture was gently homogenized in a dough kneader until a loose dough was obtained (typically about 3 minutes). The dough was stored at 3 °C to allow for fermentation and swelling of the gluten to form a continuous network of fine strands. The initially firm, hardly kneaded mixture was found to gradually change into a starter supple dough by the mere storage in the cold. Suppling after 24 hours was sufficient for use in a baking process. Prolonged fermentation (3-4 days) resulted in a shiny, elastic and extensible dough that can be stretched up to a thin film without breaking it. The pH of the starter dough remained above 5, even after 4 days of fermentation. The temperature of the dough itself raised to about 9 °C, indicative of fermentation activity.

Example 3: Preparation of a baked product 5000 gram patent flour was mixed with 1600 gram of a starter dough according to Example 2. 93 gram (1.6w%) salt, 180 gram (3.1w%) yeast and 2920 gram water (20°C) were added to the mixture. The resulting dough was kneaded at ambient temperature during 7 minutes at a low speed followed by 5.5 minutes high speed kneading.

The dough was pre-shaped into loafs and allowed to rise at 30°C during 55 minutes. The dough loafs were placed in bread baking tins and allowed to proof for 70 minutes at 32°C. The tins were placed in an oven set at 240°C and the breads were baked while decreasing the oven temperature to 180°C during a total baking time of 33 minutes.

Example 4: Evaluation of a bread product

Ten breads prepared according to Example 3 were evaluated by a test panel of experienced members.

The height of all breads were within the range of 16 ± 0.5 cm. It was found that the bread had a richer aroma as compared to conventional industrial breads. The crumb appearance (visual texture) and bread quality are reviewed, with emphasis on the mechanical properties (physical texture) of the crumb. The crumbs were referred to as "woolly” and showed a superb consistency. The breads, even when freshly prepared, could be cut easily without mashing or flattening the whole loaf. Upon cooling of the loafs the bread crusts remained crunchy for a prolonged time period.

The breads also showed a surprisingly slow staling. Staling is the undesirable quality that baked products progressively undergo over time. These undesirable qualities include a more chewy crust, a more crumbly interior, and a loss of flavor. A bread of the invention was still perceived as "fresh” after 48 hours following baking.

The crusts also showed less browning as compared to conventional breads, which is desirable in view of the common belief that dark crusts contain increased levels of undesirable acrylamide.

In conclusion, the use of the unique flour blend of the present invention resulted in an E-number free dough and bread product showing desirable visual, structural and mechanical properties. The bread can be labeled with flour/grain, water, yeast and salt as sole ingredients.

Claims (17)

A flour mixture for the preparation of a yeast proofed dough, the mixture comprising (i) a patent wheat flour; (ii) a protein-enriched wheat flour fraction obtained by wind sieving a milled wheat flour; (iii) a starch-enriched wheat flour fraction obtained by wind sieving a milled wheat flour; and (iv) a heat-treated wheat flour. 2. Flour mixture according to claim 1, wherein the relative amount of (ii) and (iii) are in the range of 1.5: 1 to 1: 1.5 based on weight, and wherein the total amount of (ii) and (iii) 10 -25 parts is based on weight for every 100 parts based on weight of patent wheat flour. The flour blend of claim 2, wherein the relative amounts of (ii) and (iii) are in the range of 1.3: 1 to 1: 1.3 by weight, preferably about 1: 1. The flour mixture of any one of claims 1-3, wherein the total amount of (ii) and (iii) is 13-20 parts by weight for every 100 parts by weight of the patent wheat flour. The flour mixture according to any of the preceding claims, wherein about 80% of the particles of (ii) and (iii) are less than 90 microns, preferably wherein the average particle size is in the range of 20 to 60 microns. A flour mixture according to any one of the preceding claims, wherein the protein content of said protein-enriched wheat flour fraction is at least 18%, preferably at least 20%. A flour mixture according to any one of the preceding claims, wherein the protein content of said starch-enriched wheat flour fraction is up to 14%, preferably up to 12%. A flour mixture according to any one of the preceding claims, wherein the moisture content of said heat-treated wheat flour is 1.5% to 4.1%, preferably 2.0 to 3.5%. The flour mixture according to any one of the preceding claims, wherein the water activity (Aw) of the heat-treated flour is 0.03 to 0.1. The flour mixture according to any of the preceding claims, wherein said heat-treated wheat flour is present in an amount of 5-8 parts by weight for every 100 parts by weight or the patent wheat flour. A starter dough for the preparation of a yeast proofed dough, comprising a flour mixture according to any one of claims 1-10, water, yeast and salt. The starter dough of claim 11 comprising 100 parts by weight of the flour mixture, 40 to 60 parts by weight of water, and 0.5 to 2 parts by weight of yeast. A method for preparing a starter dough according to claim 11 or 12, comprising mixing a flour composition according to any one of claims 1-10 with water, yeast and salt, and processing the mixture into a homogeneous dough, and allowing ferment at a temperature of about 2-10 ° C for a period of at least 24 hours (up to 6 days). A method for providing a yeast proofed dough, comprising preparing a starter dough according to claim 11 or 12, and combining it together with water, flour, yeast and salt into a dough. A method for providing a flour-based baked product, comprising preparing a yeast proofed dough according to claim 14, optionally placing the dough in a bread pan, and baking the dough at the desired temperature. Baked product obtainable by a method according to claim 15. Baked product according to claim 16, being free from E numbers, in particular free from emulsifiers, flour treatment agents, such as ascorbic acid, and preservatives.