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Functional Replacements for Gluten
Abstract and Figures
Celiac disease (CD) is an immune-mediated disease triggered in genetically susceptible individuals by ingested gluten from wheat, rye, barley, and other closely related cereal grains. Currently, the only therapy able to normalize the clinical and histological manifestation of the disease is a strict and life-long gluten-free (GF) diet. The replacement of gluten presents a significant technological challenge, as it is an essential structure-building protein, which is necessary for formulating high-quality baked goods. The objective of this paper is to review some basics about CD, its current prevalence, and the recent advances in the preparation of high-quality GF breads using GF flours, starches, hydrocolloids, gums, and novel functional ingredients and technologies.
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... A schematic overview of these products is provided in Figure 3. The unique structure and texture of wheat-based breads and bread-type products is predominantly due to the ability of wheat flour to produce a workable viscoelastic dough when hydrated and kneaded [51]. Such a dough results from the formation of a protein network, the gluten, which aids in the incorporation and stabilization of air [52,53]. ...
... The unique structure and texture of wheat-based breads and bread-type products is predominantly due to the ability of wheat flour to produce a workable viscoelastic dough when hydrated and kneaded [51]. Such a dough results from the formation of a protein network, the gluten, which aids in the incorporation and stabilization of air [52,53]. ...
... As is evident, wheat largely dominates the production of bakery and bread-type products in SSA. Several approaches have been studied to create aerated bakery products based on alternative, non-wheat flours [51]. Those include the use of additives such as hydrocolloids as well as the modification of flours through bioprocessing technologies such as fermentation or physical treatments such as heat. ...
Massive urbanization and increasing disposable incomes favor a rapid transition in diets and lifestyle in sub-Saharan Africa (SSA). As a result, the SSA population is becoming increasingly vulnerable to the double burden of malnutrition and obesity. This, combined with the increasing pressure to produce sufficient food and provide employment for this growing population together with the threat of climate change-induced declining crop yields, requires urgent sustainable solutions. Can an increase in the cultivation of climate-resilient crops (CRCs) and their utilization to produce attractive, convenient and nutritious bread products contribute to climate change adaptation and healthy and sustainable diets? A food system analysis of the bread food value chain in SSA indicates that replacement of refined, mostly imported, wheat in attractive bread products could (1) improve food and nutrition security, (2) bring about a shift to more nutritionally balanced diets, (3) increase economic inclusiveness and equitable benefits, and (4) improve sustainability and resilience of the food system. The food system analysis also provided systematic insight into the challenges and hurdles that need to be overcome to increase the availability, affordability and uptake of CRCs. Proposed interventions include improving the agronomic yield of CRCs, food product technology, raising consumer awareness and directing policies. Overall, integrated programs involving all stakeholders in the food system are needed.
... Intake of proteins containing gluten from wheat, rye, barley, and other closely associated grains sources triggers immune-mediated celiac disease in genetically susceptible individuals and is the primary reason for the need of gluten-free diets (Zannini et al., 2012). Albumin and globulin are the main ingredients of amaranth seed protein, both of which are easily digestible and are considered important alternatives to glutencontaining foods (Singh et al., 2019). ...
Due to population and environmental concerns, more sustainable proteins are needed as alternatives to traditional proteins, including meat, milk, and soy proteins. Amaranth protein has been considered as a complete protein that is also gluten‐free and balanced in amino acid composition. Amaranth protein is rich in bioactive peptides, and its hydrolysis products have been demonstrated to be potential in preventing several diseases such as cardiovascular disease, cancer, and diabetes. Amaranth protein is high in albumin, glutenin, and globulin, whereas the variability in albumin and glutenin content is dependent on the geography and variety of amaranth. In the food industry, amaranth protein is currently used in nutritionally fortified foods, gluten‐free foods, and food protein‐based films. Due to its excellent nutritional and bifunctional properties, amaranth protein has shown a great potential in functional foods and meat analogues. This review provides an overview of several properties of amaranth protein, including nutrition, bioactivity, structure, as well as its applications in the food industry and prospects. By reviewing the above properties of amaranth protein, it is considered as one of the promising sustainable alternative protein sources for future foods.
... In addition, the wheat cultivars that used RNAi technology to down-regulate gliadin showed reduced dough ductility and viscosity (Gil-Humanes et al. 2014). At present, the common method to improve dough quality and restore gluten characteristics is to add functional components, including gluten-free flour (rice, sorghum, oats etc.) (Zannini et al. 2012), starch, hydrocolloids and proteins (Jnawali, Kumar, and Tanwar 2016). However, hydrocolloids can enhance the elasticity and viscosity of gluten-free dough, but they cannot replace the function of gluten completely (Mir et al. 2016). ...
Celiac disease (CD) is an autoimmune intestinal disease caused by intolerance of genetically susceptible individuals after intake of gluten-containing grains (including wheat, barley, etc.) and their products. Currently, CD, with "iceberg" characteristics, affects a large population and is distributed over a wide range of individuals. This present review summarizes the latest research progress on the relationship between CD and gluten. Furthermore, the structure and function of gluten peptides related to CD, gluten detection methods, the effects of processing on gluten and gluten-free diets are emphatically reviewed. In addition, the current limitations in CD research are also discussed. The present work facilitates a comprehensive understanding of CD as well as gluten, which can provide a theoretical reference for future research.
... Many gluten proteins contribute to the unique textural and organoleptic properties of the wheat grain and derived products (79)(80)(81). Their lack or reduced amount in the generated wheat DME and DRE2 mutants thus was expected to critically affect the end-use quality of derived products. ...
Wheat is a major source of energy and nutrition worldwide, but it is also a primary cause of frequent diet-induced health issues, specifically celiac disease, for which the only effective therapy so far is strict dietary abstinence from gluten-containing grains. Wheat gluten proteins are grouped into two major categories: high-molecular-weight glutenin subunits (HMWgs), vital for mixing and baking properties, and gliadins plus low-molecular-weight glutenin subunits (LMWgs) that contain the overwhelming majority of celiac-causing epitopes. We put forth a hypothesis that eliminating gliadins and LMWgs while retaining HMWgs might allow the development of reduced-immunogenicity wheat genotypes relevant to most gluten-sensitive individuals. This hypothesis stems from the knowledge that the molecular structures and regulatory mechanisms of the genes encoding the two groups of gluten proteins are quite different, and blocking one group's transcription, without affecting the other's, is possible. The genes for gliadins and LMWgs have to be de-methylated by 5-methylcytosine DNA glycosylase/lyase (DEMETER) and an iron-sulfur (Fe-S) cluster biogenesis enzyme (DRE2) early during endosperm development to permit their transcription. In this study, a TILLING (Targeting Induced Local Lesions IN Genomes) approach was undertaken to identify mutations in the homoeologous DEMETER ( DME ) and DRE2 genes in common and durum wheat. Lines with mutations in these genes were obtained that displayed reduced content of immunogenic gluten proteins while retaining essential baking properties. Although our data at first glance suggest new possibilities for treating celiac disease and are therefore of medical and agronomical interest, it also shows that inducing mutations in the DME and DRE2 genes analyzed here affected pollen viability and germination. Hence there is a need to develop other approaches in the future to overcome this undesired effect.
... This could also be responsible for softer crumb, increased bread volume, and retention of polyphenolic content. GF dough is less elastic and requires less mixing time, proofing, baking as compared to wheat dough (Zannini et al., 2012). Hence, it is necessary to add gums, stabilizing agent, foaming agents, and pre-gelatinized starch for the retention of gas during baking. ...
Use of additives in gluten-free breads is mainly to improve the properties vital to quality bread making as the alternative ingredients used could not mimic wheat gluten functionality. Incorporation of additives in dough, therefore improve the organoleptic properties by imitating some of the functions of wheat gluten. Most commonly used additives are hydrocolloids, enzymes, emulsifiers, dietary fibre, proteins, starch, salts, acids and minerals. These agents, in general help to retain carbon dioxide gas released from yeast fermentation during proving and accomplish binding of starch granules thereby improving dough cohesiveness. Hydrocolloids prevent staling of gluten-free bread and improve its sensory and structural characteristics. Emulsifiers have proven to be beneficial in improving texture and softness of bread crumb and crust and enhancing loaf volume. Dietary fibre enhances color and loaf volume in gluten-free bread. Enzymes increase the functionality of proteins and improve dough handling properties. The gluten-free breads are fortified with vitamins like B and D, and minerals (calcium, iron, zinc and magnesium) in wake of their low nutritional, vitamins and mineral content.
Lactic acid bacteria (LAB) synthesize exopolysaccharides (EPS), which are structurally diverse biopolymers with a broad range of technological properties and bioactivities. There is scientific evidence that these polymers have health-promoting properties. Most commercialized probiotic microorganisms for consumption by humans and farmed animals are LAB and some of them are EPS-producers indicating that some of their beneficial properties could be due to these polymers. Probiotic LAB are currently used to improve human health and for the prevention and treatment of specific pathologic conditions. They are also used in food-producing animal husbandry, mainly due to their abilities to promote growth and inhibit pathogens via different mechanisms, among which the production of EPS could be involved. Thus, the aim of this review is to discuss the current knowledge of the characteristics, usage and biological role of EPS from LAB, as well as their postbiotic action in humans and animals, and to predict the future contribution that they could have on the diet of food animals to improve productivity, animal health status and impact on public health.
Description of the Small millets and its genetic resources
Gluten-free bread making is a challenging task as the ingredients used could not mimic wheat gluten functionality. Gluten protein complex is considered vital for successful bread making. Commercially available gluten-free breads face both social and scientific challenges in comparison to conventional gluten-containing counterparts in terms of quality and acceptability. Doughs derived from gluten-free flours exhibit poor rheological properties and the resultant breads are characterized by sensory and nutritional defects. Addition of starches, hydrocolloids, proteins, enzymes, and emulsifiers to gluten-free flours are encouraged in order to counter the technological problems by enhancing dough rheological characteristics. Gluten-free bread (GFB) from nutritional point of view, lacks protein, vitamins and minerals and effective ways are required to be explored to enhance the fibre, protein, vitamin and mineral content of GFB while maintaining low glycaemic index. Fortification of GFB with alternate flours such as flours from pulses, gluten-free cereals like millet, rice, sunflour etc., bran or dietary fibre, nuts, pseudocereals or any oil seed is therefore recommended.
For successful bread making process gluten has an important role to play. But many of the individuals are susceptible to gluten and are associated with the development of gluten related disorders even on ingestion of small amount of gluten. The increasing incidence of gluten related disorders promotes worldwide interests for development of gluten free bread. However the exclusion of gluten from bread formulation has unfavourable effects on the bread making process and sensory attributes, and raises technological challenges in terms of making good quality bread. Gluten-free bread has poor visual, textural characteristics, low nutritional value, decreased mouth feel and flavour, as well as a shorter shelf-life. The low quality of gluten-free bread still remains a challenge in gluten-free bread making. In response to this, the use of novel alternative flours, functional and nutritional ingredients, processing aids, additives, innovative techniques, and their combinations are being used to improve the quality characteristics of gluten-free bread. This book chapter will present the main problems related to gluten-free bread making technology and to summarise the approaches which can be used to improve the technological, nutritional, and sensory properties of gluten-free bread.
Gluten free products do not resemble their gluten counterparts owing to lack of continuous three-dimensional protein-starch matrix that influences dough rheology and overall bread quality. It has become a prerequisite to adopt several approaches for altering gluten network structure and in turn ensure the quality acceptance by people consuming gluten free products. An ample range of functional ingredients and processing methods have being adopted to imitate gluten viscoelastic properties and consequently the overall final quality of gluten free product.
A simple bread making technique consisting of three steps (mixing, fermentation and baking) for producing gluten-free bread was developed. Wheat starch with bacterial protease, combined with various kind of gums, was used. The relative amounts of water, fat and sugar in the formulation were optimized and the mixing time was considered as the variable to be analyzed. Results showed that water, fat and sugar amounts do influence product quality. It was also found that Methocel was the most appropriate gum for the formulation of gluten-free bread.
Coeliac disease (CD) and other allergic reactions/intolerances to gluten are on the rise, largely due to improved diagnostic procedures and changes in eating habits. The worldwide incidence of coeliac disease has been predicted to increase by a factor of ten over the next number of years, and this has resulted in a growing market for high quality gluten-free cereal products. However, the removal of gluten presents major problems for bakers. Currently, many gluten-free products on the market are of low quality and short shelf life, exhibiting poor mouthfeel and flavour. This challenge to the cereal technologist and baker alike has led to the search for alternatives to gluten in the manufacture of gluten-free bakery products. This volume provides an overview for the food industry of issues related to the increasing prevalence of coeliac disease and gluten intolerance. The properties of gluten are discussed in relation to its classification and important functional characteristics, and the nutritional value of gluten-free products is also addressed. The book examines the diversity of ingredients that can be used to replace gluten and how the ingredient combinations and subsequent rheological and manufacturing properties of a range of gluten-free products, e.g. doughs, breads, biscuits and beer may be manipulated. Recommendations are given regarding the most suitable ingredients for different gluten-free products. The book is directed at ingredient manufacturers, bakers, cereal scientists and coeliac associations and societies. It will also be of interest to academic food science departments for assisting with undergraduate studies and postgraduate research.
The use of natural hydrocolloids or synergistic gum systems as film-forming and gelling agents for bakery and cereal products is discussed. Hydrocolloids are edible, biodegradable, high in soluble dietary fiber, and readily available in natural or unmodified versions. Benefits include cost reductions, improved functionality, low usage levels, and the ability to meet the requirements for kosher-certified ingredients.
In northern countries, the prevalence of coeliac disease is steadily increasing. One reason can be found certainly in the fact that new diagnostic methods have been introduced, such as serological tests. Still, the question remains whether the occurrence of coeliac disease is indeed increasing and if there is a connection to the increase in wheat consumption (Anonymous, 2004). Statistical data from the FAO show that production—and thus consumption—of wheat has increased worldwide over the last five decades. In Europe, the dominance of wheat within cereal-based foods is even more distinct. The share of wheat within all produced and consumed cereals has increased from 35% in the year 1961 to almost 50% today (FAOStat, 2007). However, it cannot be clearly stated that the increase in coeliac disease and the dominance of wheat are indeed correlated.
One of the countries with the highest stated prevalence for coeliac disease is the United States, where 1% of the population, i.e., about 3 million people, suffer from coeliac disease (Broz and Horne, 2007). In Europe, the figures are not much different. Based on serological diagnosis, the prevalence for coeliac disease ranges from 1:50 to 1:100 in Sweden (Carlsson et al., 2001) or 1:180 in Italy (Volta et al., 2001).
Because coeliac disease cannot be cured, affected people are dependent on a life-long gluten-free diet. Due to the increasing number of people suffering from coeliac disease, the need for gluten-free foods is becoming economically more and more relevant. Remarkably, a search in the product database “Productscan” revealed that the number of new gluten-free products per year increased from 28 in 1996 to 684 in 2006.