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  • REVIEW PAPER

    Possibilities to increase the quality in gluten-free breadproduction: an overview

    Andreas Houben Agnes Hochstotter

    Thomas Becker

    Received: 9 November 2011 / Revised: 16 March 2012 / Accepted: 21 March 2012 / Published online: 15 June 2012

    Springer-Verlag 2012

    Abstract The market for gluten-free products is

    increasing. Owing to better diagnostic methods, more and

    more people are identified to have coeliac diseases. Pro-

    duction of bakery products that do not harm these people is

    a big challenge for bakers and cereal scientists in the

    twenty-first century. The use of different cereals and flours

    makes it necessary to find possibilities to take over the task

    of gluten by other flour ingredients, by the addition of

    different components, by different flour and dough treat-

    ment or by changing the method of baking. The purpose of

    this review is to give an overview about the various pos-

    sibilities to increase the baking quality of gluten-free

    bakery products, increasing their water-binding capacity,

    uniform the crumb structure and increase the final bread

    volume. All the listed methods and ingredients are already

    in single use helpful to increase the quality in gluten-free

    bread production.

    Keywords Gluten-free Hydrocolloids Rheology Dough Bread Emulsifiers Sourdough Enzymes

    Introduction

    Baking without gluten is a big challenge for all bakers and

    cereal researchers. The task of gluten to form a three-

    dimensional protein network during dough preparation has

    to be taken over by other ingredients in gluten-free baking.

    In the recent years, owing to the increasing numbers of

    people with coeliac diseases, the market for gluten-free

    products has been increasing speedy. This haste is mostly

    based on the improvement in the diagnosis of coeliac dis-

    ease [1, 2]. The increasing market pushes the cereal

    industry to increase its output of high-class gluten-free

    products. To supply the market with high-quality products,

    new developments and knowledge have to be aimed in

    research and development [3, 4].

    The absence of gluten in dough production shows high

    influence on dough rheology, the production process and

    the quality of the final gluten-free product. The gluten-free

    doughs are much less cohesive and elastic than wheat

    dough. They are highly smooth and difficult to handle; they

    are more sticky, less elastic and pasty; and it is more like

    handling the batter of a cake [5]. In literature, these gluten-

    free doughs are often called batters instead of dough. The

    doughs are not really kneaded by a lot of energy input, but

    mostly mixed in mixing machines [6, 7].

    The final products show some deficits in quality when

    compared to French bread; their texture is crumble and

    their crumbs are lighter colour [8, 9], and because of their

    low carbon dioxide binding activity during raising, the

    volume of the products are mostly lesser [10]. Based on the

    missing interactions, the water molecules are not really

    stiffly bounded in the crumb and they diffuse much faster

    into the crust; this leads to a firmer crumb and softer crusts

    [9]. A short shelf life, particles detection in the mouth

    during consumption, a dry mouth feeling and a not really

    satisfying taste are also some of the disadvantages of glu-

    ten-free bread [11]. Development of new technologies and

    the use of gluten-free flours, starches, hydrocolloids and

    novel food ingredients will make it possible to find alter-

    natives for the traditional bakery products. Especially,

    changing the gas-binding capacity and the stabilization of

    the starch gel during baking is the most important aspect

    for being successful in reaching these aims [3]. The natural,

    A. Houben (&) A. Hochstotter T. BeckerLehrstuhl fur Brau- und Getranketechnologie, TU Munchen,

    Weihenstephaner Steig 20, 85354 Freising, Germany

    e-mail: houben@wzw.tum.de

    123

    Eur Food Res Technol (2012) 235:195208

    DOI 10.1007/s00217-012-1720-0

  • synthetic and biotechnological hydrocolloids, because of

    their high water-binding capacity and their structure-cre-

    ating behaviour, are mostly used in the different recipes for

    replacing the gluten network and its functionality. Other

    trials to replace the gluten are the use of other food proteins

    like the one from soybean, eggs or milk [1]. Also the use of

    enzymes can increase the gluten-free dough behaviour

    required for shelf life and quality [10]. Because most of the

    recipes are based on flours and starches that are by nature

    poor in their nutritional level, use of different fibres,

    wholemeal flour, addition of vitamins and minerals lead to

    an increase in the nutritional level of the gluten-free

    products [12].

    Positive is also the use of a very traditional bakery

    ingredient, of sourdough, because of it textural and sen-

    sorial advantages [13]. All these treatments and ingredients

    allow making gluten-free bakery products better in quality.

    The aim of all these changes is to reach a final product

    close to French bread quality [1].

    Gluten-free flours and starches

    Most non-gluten-free bakery products are based on wheat,

    rye, barley or even oats. Among these, oats should be

    gluten-free by nature but due to its planting and breeding

    procedure, in literature it is often counted as the non-glu-

    ten-free grains. So all these grains and flours are forbidden

    in the gluten-free bread production. Only gluten-free

    cereals and the so-called pseudocereals are allowed to be

    taken as raw materials.

    Gluten-free cereals are, for example, rice, maize and

    millet. Up to now, two different rice speciesOryza sati-

    va, originating from Asia, and Oryza glaberrima, culti-

    vated in Africa [14]and different subspecies of zea mays,

    millet species and Sorghum bicolor L. Moench [15], teff

    (Eragrostis tef (Zuccagni) Trotter), finger millet (Eleucine

    coracana L. Gaertn.), pearl millet (Pennisetum glaucum

    (L.) R. Br.) and foxtail millet (Setaria italica (L.)

    P. Beauv.), are used in the production of gluten-free bakery

    products [16]. Next to these grains and grasses, the

    pseudocereals amaranth, buckwheat and quinoa are often

    taken for gluten-free bakery products. The pseudocereals

    do not belong to the monocots, like the cereals do, but

    belong to the dicots. Some species used in human nutrition

    are buckwheat (Fagopyrum esculentum Moench), tartary

    buckwheat (Fagopyrum tataricum Gaertner), some ama-

    ranth spp. like Amaranthus caudatus L., Amaranthus

    cruentus L. and Amaranthus hypochondriacus and Che-

    nopodium quinoa [17].

    Next to gluten, pseudocereals are mainly taken as an

    ingredient in gluten-free products because of their nutri-

    tional level, high protein value, essential amino acids and

    fatty acids and high mineral content [18]. The functionality

    of the flours made from these grains and pseudocereals

    depends on their particle size, the particle distribution, the

    milling yield and the flour treatment. Also the growing

    conditions and the plant species influence the composition

    of the ingredients and by this the final product quality

    [17, 18].

    Next to gluten-free grains and pseudocereals, flours

    made from legumes like chickpea, field bean, soya bean

    and French bean, from cassava [1820], chestnut, coconut,

    linseed and from plantain are also used as starch additives

    because of their water-binding capacity in the recipes of

    gluten-free bakery products.

    There is mostly a mixture of different gluten-free flours

    and starches. Especially, the starches, the most important

    stored carbohydrates in plants, have a high influence on the

    dough parameters, the texture, the moisture retention and

    the final quality [21].

    The role of starch during baking is to bind the water and

    create a gas-permeable structure [22]. Commercial gluten-

    free starches are mostly obtained from rice, cassava,

    potatoes and maize [1, 7, 20, 23]. Since 2008, there is also

    a gluten-free wheat starch available on the market, whose

    gluten content is beyond 20 mg kg-1, the borderline given

    by the codex alimentarius; it does not harm most coeliac

    patients [24].

    The differences between the listed starches in their

    thermal behaviour, gelatinization process, gel-forming

    behaviour and final texture are based on individual com-

    position and chemical structures [21]. Its functionality is

    mostly influenced by its main components, the glucose

    polymers amylose (linear, 14 glycolysed a-D-glucoseunits) and amylopectin (complex bounded 14 and 16

    glycolysed a-D-glucose units). These components areassociated with hydrogen binding into crystal and form an

    insoluble kernel shape in cold water. By reaching a high

    temperature during baking, the starch kernels irreversibly

    swell by the uptake of water. The needed temperature, the

    so-called gelatinization temperature, is a characteristic

    parameter for every starch. The intermolecular hydrogen

    bonds are broken up, and the hydroxyl groups released are

    immediately hydrated. The special relation of the hydroxyl

    groups of water is the basis of gelatinization. A further

    increase in temperature leads to higher molecular activity

    and by this to par