A Systematic Review on Gluten-Free Bread Formulations Using Specific Volume as a Quality Indicator

Effect of Adding Chestnut Inner Skin on Allergenic Protein, Antioxidant Properties, and Quality of Bread

Wheat-dependent, exercise-induced anaphylaxis has no fundamental cure and requires patients to refrain from wheat consumption or to rest after eating. Although hypoallergenic wheat production by enzymatic degradation or thioredoxin treatment has been investigated, challenges still exist in terms of labor and efficacy. We investigated a hypoallergenic wheat product manufacturing technology that takes advantage of the property of tannins to bind tightly to proteins. Commercially available bread wheat (BW) and hypoallergenic wheat (1BS-18 "Minaminokaori", 1BS-18M) were used. Chestnut inner skin (CIS) was selected as a tannin material based on the screening of breads with added unused parts of persimmon and chestnut. Hypoallergenicity was evaluated using Western blotting. The effect of CIS addition on the antioxidative properties of bread was also measured. For both BW and 1BS-18M, CIS addition reduced the immunoreactivity of wheat allergens. Antioxidant activities increased with increasing CIS substitution. However, 10% CIS-substituted breads were substantially less puffy. Five percent CIS substitution was optimal for achieving low allergenicity, while maintaining bread quality. The strategy investigated herein can reduce allergies related to wheat bread consumption. In this study, the evaluation of hypoallergenicity was limited to instrumental analysis. In the future, we will evaluate hypoallergenicity through clinical trials in humans.

Effect of sorghum pre-processing (roasting and germination) on the replacement level and quality of sorghum-wheat bread: bread characteristics, digestibility, consumer acceptability and microbiological analysis

Abstract

The present study was focused on the replacement of refined wheat flour (RWF) by control (CS) and processed sorghum flour [germinated (GS) and roasted (RS)] on the properties of flour/batter/dough (particle size, XRD, pasting, dynamic rheology, farinograph) and bread (physical, textural, digestibility, microbiological and sensory). Prominent variations adhered with sorghum processing, but decreasing patterns occurred for flour-water absorption, dough stability times, storage modulus, peak/final/breakdown viscosities, bread-moisture content, specific volume, porosity, and lightness. Flour's pasting temperature, dough development time, breadbulk density, hardness, gumminess, and bitterness increased. Composite flours mainly had weak nature compared to RWF. The baking loss was lower for 10-30% CS and GS incorporation than RS. Composite bread had higher in-vitro protein and starch digestibility (CS > GS > RS) than RWF. Three days storage life with acceptable quality scores was obtained for bread with CS and GS up to 20% and RS up to 30% incorporation.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05810-3.

Innovative Biobased and Sustainable Polymer Packaging Solutions for Extending Bread Shelf Life: A Review

Sustainable packaging has been steadily gaining prominence within the food industry, with biobased materials emerging as a promising substitute for conventional petroleum-derived plastics. This review is dedicated to the examination of innovative biobased materials in the context of bread packaging. It aims to furnish a comprehensive survey of recent discoveries, fundamental properties, and potential applications. Commencing with an examination of the challenges posed by various bread types and the imperative of extending shelf life, the review underscores the beneficial role of biopolymers as internal coatings or external layers in preserving product freshness while upholding structural integrity. Furthermore, the introduction of biocomposites, resulting from the amalgamation of biopolymers with active biomolecules, fortifies barrier properties, thus shielding bread from moisture, oxygen, and external influences. The review also addresses the associated challenges and opportunities in utilizing biobased materials for bread packaging, accentuating the ongoing requirement for research and innovation to create advanced materials that ensure product integrity while diminishing the environmental footprint.

Characterization of Lactic Acid Bacteria and Yeast from Grains as Starter Cultures for Gluten-Free Sourdough

With the increasing number of people affected by gluten consumption-related diseases, adhering to a gluten-free (GF) diet is the most effective preventive measure. Herein, we aimed to isolate and characterize the functional properties of autochthonous lactic acid bacteria (LAB) and yeast from various GF sourdoughs to determine their suitability in starter cultures for sourdough preparation. Three LAB, Weissella confusa BAQ2, Lactobacillus brevis AQ2, Leuconostoc citreum YC2, and Saccharomyces cerevisiae BW1, were identified. The isolated LAB exhibited greater TTA, faster acidification rates, and higher acid tolerance than commercial LAB. W. confusa BAQ2 exhibited the highest EPS production, W. confusa BAQ2 and L. brevis AQ2 showed high maltose utilization, and S. cerevisiae BW1 exhibited the highest CO2 production rate. Accordingly, all four microbial strains were mixed for the starter culture. The sourdough prepared with starter cultures exhibited differences in gas production depending on fermentation time, which influenced the volume of GF bread dough. GF bread prepared with fermented sourdough exhibited a 16% higher specific volume and enhanced crumb firmness and elasticity than that prepared using non-fermented sourdough. Thus, autochthonous LAB strains isolated from various GF sourdoughs can be used together to improve the quality of sourdough bread, demonstrating their potential for use in starter cultures for GF sourdough production.

Mapping the knowledge structure of a gluten-free diet: a global perspective

Background

A gluten-free diet (GFD) has become one of the most popular eating plans and is essential for managing gluten-related medical conditions, signs, and symptoms. Therefore, we performed a bibliometric analysis of the scientific literature on the GFD to describe the research landscape.

Methods

The Scopus database was searched for publications on the GFD from 1952 to 2021. A bibliometric analysis of the data was performed. VOSviewer software was used to perform visualization analysis, co-occurrence analysis, and publication trends in GFD.

Results

A total of 3,258 publications were retrieved. In terms of publications, Italy (n = 468, 14.36%) led in the number of publications, followed by the USA (n = 398, 12.22%) and Spain (n = 274, 8.41%). The retrieved documents earned an average of 22.89 citations per document, for a total of 74,560 citations. Since 2001, there has been a gradual growth in the number of articles published, going from 23 to more than 370 in 2021. Using the mapping terms in the title/abstract a minimum of 50 times, 291 terms were divided into two main clusters: ‘adherence to a gluten-free diet in celiac disease’ and ‘improvement of the nutritional and sensory quality of gluten-free products.’

Conclusions

Over the past six decades, there has been a growing need for gluten-free bakery products and a noticeable increase in related publications. This study indicates that the “improvement of the nutritional and sensory quality of gluten-free products” will remain a hotspot in this research field for upcoming years.

Development of Gluten-Free Bread Using Teosinte (Dioon mejiae) Flour in Combination with High-Protein Brown Rice Flour and High-Protein White Rice Flour

Gluten-free bread is an important product that is under development using different sources, such as rice and starchy plants. Teosinte seeds are utilized by ethnic groups in Honduras to produce gluten-free flour to prepare traditional baked goods and beverages. The quality of gluten-free products could vary depending on flour properties, such as amylose content, particle size, and water absorption capacity. A good strategy for developing baked goods is to mix different cereal grain sources to optimize their physicochemical properties. As a result, the current study aimed to develop bread from novel flours including teosinte (TF), high-protein brown rice (BRF), and high-protein white rice (WRF). Breads were analyzed for hardness, specific volume, and color utilizing a Simplex-Centroid mixture design coupled with the desirability function. Pasting, and rheological characteristics of the flours, were also analyzed. For flour characteristics, TF addition to BRF or WRF decreased the peak, trough, breakdown, setback, and final viscosities, which would result in a more stable bread and decrease the flow index of rice flour dispersions. BRF and WRF had similar pasting properties, except that BRF had a lower breakdown viscosity. For bread characteristics, TF addition to BRF or WRF increased the specific volume and hardness of the bread compared to rice flour alone. L* of the crust and crumb a* values were increased with greater TF in the mixture, whereas TF decreased the crust a*and b* values and crumb L* values when mixed with BRF or WRF compared to rice flours alone. WRF and BRF were similar in crumb color (L* and a*), except that BRF had greater crumb yellowness (b*). Teosinte flour can be used in combination with rice flour to produce bread with good quality.

Nutritional Composition of Breakfast in Children and Adolescents with and without Celiac Disease in Spain-Role of Gluten-Free Commercial Products

Eating a nutritionally balanced breakfast can be a challenge when following a gluten-free diet (GFD). We assessed the ingredients and nutrient composition of 364 gluten-free breakfast products (GFPs) and 348 gluten-containing counterparts (GCCs), and we analysed the nutritional quality of breakfast in a group of Spanish children and adolescents with celiac disease (CD) (n = 70), as compared to controls (n = 67). Food intakes were estimated using three 24 h dietary records. The composition of GFPs and GCCs was retrieved from the package labels of commercially available products. Most participants (98.5%) ate breakfast daily, and only one person in each group skipped breakfast once. The breakfast contribution of the total daily energy was 19% in participants with CD and 20% in controls. CD patients managed a balanced breakfast in terms of energy (54% from carbohydrates; 12% from proteins; 34% from lipids) and key food groups (cereals, dairy, fruits), but their intake of fruits needs improvement. Compared to controls, breakfast in the CD group provided less protein and saturated fat, a similar amount of carbohydrates and fibre, and more salt. Fibre is frequently added to GFPs, but these contain less protein because of the flours used in formulation. Gluten-free bread contains more fat and is more saturated than is GCC. Sugars, sweets, and confectionery contribute more to energy and nutrient intakes in participants with CD, while grain products do so in controls. Overall, breakfast on a GFD can be adequate, but can be improved by GFPs reformulation and a lower consumption of processed foods.

Assessing Gluten-Free Soy Bread Quality and Amino Acid Content

The nutritional and palatability relevance of bread prepared with soy flour was examined. There are a few effective nutritional measures that combine palatability, convenience, and functionality in the suppression of muscle loss (contributing to the improvement and prevention of sarcopenia). Therefore, in the present study, we attempted to produce bread using soybeans, which are rich in amino acids involved in the synthesis and degradation of skeletal muscle proteins. Rice flour was also used to avoid gluten intolerance. The bread was baked in an automatic bread maker, and the rheological properties of its breadcrumbs were determined using a creep meter. We found that a 70 g slice of soy bread satisfied approximately one-fifth of the daily nutritional requirement for leucine. Although soy decreased the specific volume of bread by preventing starch construction, the use of preprocessed rice flour recovered the volume, and corn starch improved the taste. We propose that the addition of soy bread to the daily diet may be an effective protein source.

Significance of different milling methods on white proso millet flour physicochemical, rheological, and baking properties

Proso millet is a nutritious, sustainable, and gluten free food which is currently underutilized. They can be incorporated into the grain industry and provide much needed healthy alternatives. Efficient grinding method should be adopted for easy incorporation. This study aimed to investigate the effect of three different methods of grinding namely, roller milling (RM), pin milling (PM), and hammer milling (HM) on proso millet flour rheology and baking properties for food application. The milling flow sheet was developed toward the production of the quality whole grain flour. The particle size distribution of all the flours showed bi-modal distribution except for the RM flour. The PM produced the flour with the finest particles with geometric mean diameter of 82 μm. The study also revealed that starch damage in the PM flour (4.64%) was higher than RM (2.46%) and HM flour (2.51%). The nutritional composition was not significantly affected by different grinding methods. Pasting properties of the flour were also affected by the grinding method applied. Rapid Visco Analysis profile showed pin mill flour to have a higher peak viscosity (PV) (2,295 cP) compared to HM (2,065 cP) and RM flour (2,130 cP). Finally, this study demonstrated that the production of bread from proso millet flour with desirable quality and texture is possible. The grinding method did not affect the specific volume of bread loaves and C-cell characteristics. The specific volume of the breads ranged from 2.40 to 2.52 cm³ /g. This study will help in promoting and producing value-added proso millet food products with enhanced nutritional quality.

Gluten-free grains: Importance, processing and its effect on quality of gluten-free products

Gluten-enteropathy affects a significant number of people, making gluten a major concern in the food industry. With medical advancements, the diagnosis of allergies is becoming easier, and people who are allergic to gluten are recommended a complete gluten-free diet. Since wheat provides a major part of the energy and nutrition in the diet, its elimination affects nutrition intake of allergic population. Food scientists are working to formulate products using protein-rich gluten-free grains with quality attributes at par with gluten-containing products. Focused research has been done to provide nutrition and a variety of food to people suffering from gluten-related disorders. Efforts are being made to remove the gluten from the wheat and other gluten-containing grains, while applying different processing/treatments to enhance the properties of gluten-free grains. Hence, the present review summarizes the importance, processing, and products of different gluten-free grains. It also highlights the digestibility of gluten-free grains with clinical trials and gluten elimination strategies for gluten-containing grains.

Rheological Properties of Corn Starch Gels With the Addition of Hydroxypropyl Methylcellulose of Different Viscosities

The objective of this study is to determine the effect of the addition of hydroxypropyl methylcellulose (HPMC) (from 0.5 to 2.0% w/w, starch basis) with three different viscosities (40–60, 80–120, and 2,600–5,600 mPa⋅s) to corn starch (30% w/w, total basis) gels. Average viscosimetric molecular weights (M_v) of tested HPMC were determined (from 27.2 × 10³ to 82.7 × 10³ g/mol). Water retention capacity of HPMC varied linearly with M_v. The formation and curation of gels were monitored by rheology employing consecutive steps such as heating ramp (25–90°C), time sweep (90°C), cooling ramp (90–25°C), time sweep (25°C), and frequency sweep. Additionally, creep-recovery tests were performed. HPMC above 1.5% w/w delayed the range of gelatinization temperature of starch up to 2°C. Viscoelasticity and stiffness of corn starch gels with HPMC depend on both the amount of polymer added and M_v of the HPMC. Finally, to achieve corn gels with mimetic viscoelastic properties to wheat gel (with constant total solids), HPMC with relatively low viscosity (low M_v) is necessary to be added at certain content.

Low-Carbohydrate, High-Protein, and Gluten-Free Bread Supplemented with Poppy Seed Flour: Physicochemical, Sensory, and Spectroscopic Properties

Background: This study aimed to determine the effect of poppy seed flour (PF) on the physicochemical and spectroscopic properties of low-carbohydrate, high-protein, and gluten-free bread. Methods: The changes at the molecular level were assessed in bread using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Bread prepared with buckwheat, flaxseed, and pea protein was enriched with PF at a concentration of 5–15%. Results: The results showed that the pasting parameters of dough supplemented with PF were significantly decreased compared to the control sample. The obtained bread samples were characterized by good quality and had 14.6% of carbohydrate, 16.3% of protein, 10.2% of fiber, and 4.0% of fat, with a caloric value of 177 kcal/100 g. The addition of PF had little influence on crumb mechanical properties. The ATR-FTIR analyses revealed spectral changes in the region related to protein and carbohydrate structures, as well as changes in band intensity characteristic of α-1,4-glycoside and α-1,6-glycoside bonds. The analyses showed that the main starch skeleton remained clearly visible. Conclusions: PF up to 10% can be potentially applied as a functional ingredient in the production of bread based on buckwheat and linseed flour. Such low-carbohydrate bread can be particularly useful to diabetics.

Pre-Gelatinisation of Rice Flour and Its Effect on the Properties of Gluten Free Rice Bread and Its Batter

In order to improve the quality of the gluten free rice bread (GFRB), pre-gelatinised rice flour (PGRF) was made and used to partially replace natural rice flour in the production of GFRB. The pre-gelatinisation parameters were optimised and the effects of PGRF on the quality of the GFRB and its batter were studied. The results showed that optimal PGRF was obtained when 50% total water was mixed with 1.0% rice flour and the mixture heated at 80 °C for 2 min. Supplementation with PGRF significantly improved the properties of GFRB by affecting its baking properties, textural properties, colour, and crumb grain features. Effects of PGRF on GFRB were mainly caused by the more closely packed gel structure of rice starch in the bread batter, the higher onset temperature during gelatinisation and the complex effect of PGRF on water-binding capacity in bread batter during the baking process. As the pre-gelatinisation parameters of flours and their effect on gluten-free baked products varied with grain variety, processing properties should be studied before using them, and emphasis should be placed on new techniques such as flour pre-gelatinisation to obtain gluten-free foods with improved quality.

Use of Oleogels to Replace Margarine in Steamed and Baked Buns

Bakery products are usually formulated with solid fats, like margarines and shortenings, which contain high levels of saturated and trans-fatty acids and have negative effects on human health. In this study, hydroxypropyl methylcellulose (HPMC) and xanthan gum (XG) were used as oleogelators to prepare oleogels, using sunflower and olive oil, as substitutes for margarine in baked or steamed buns. The effect of oleogels on the physical properties of the buns was evaluated by analyzing the crumb structure, specific volume, height, and texture. In addition, a triangular discriminatory sensory test was conducted, and lipid digestibility was assessed through in vitro digestion studies. Replacement of margarine with oleogels produced steamed buns with no differences in the crumb structure, volume, height, and texture; however, in baked buns, a less porous and harder structure was produced. No differences in texture were observed between the margarine buns and buns made with oleogels when the triangular test was conducted. The extent of lipolysis was not affected when margarine was replaced by oleogels in the baked and steamed buns. The results suggest that using oleogels instead of margarine in buns could represent an interesting strategy to prepare healthier bakery products.

Ancient and Modern Cereals as Ingredients of the Gluten-Free Diet: Are They Safe Enough for Celiac Consumers?

Celiac disease is an autoimmune disorder that occurs in genetically predisposed individuals after consuming prolamins from some cereals. Although the products available for celiac subjects have increased significantly in quality and quantity over the last few decades, research still focuses on identifying new ingredients to improve the nutritional, sensorial and functional qualities of gluten-free products. In terms of toxicity for people with celiac disease, there is a wide variability between ancient and modern grains. The most contradictory results are related to the role of oats in the gluten-free diet. In order to clarify the role of minor cereals (such as oat) and ancient grains in the diets of celiac patients, this review discusses recent in vitro and in vivo studies performed on those cereals for which the toxicity for celiac subjects is still controversial. According to in vivo studies, selected oat varieties could be tolerated by celiac patients. On the other hands, although some wheat-ancient grains (Triticum monococcum, Triticum aestivum ssp. spelta and Kamut^®) showed a reduced in vitro toxicity, to date, these grains are still considered toxic for celiac patients. Contradictory results underline the importance of studying the safety of "unusual" cereals in more detail.