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Effect of HPMC on the Quality of Wheat-Free Bread Made from Carob Germ Flour-Starch Mixtures
Abstract
Unlabelled:
Carob germ proteins have been shown to have functional properties similar to wheat gluten enabling formulation and production of yeast leavened gluten-free baked goods from a true dough rather than a stiff batter. The purpose of this research was to optimize the production of wheat-free bread containing carob germ flour, corn starch, NaCl, sucrose, hydroxypropyl methylcellulose (HPMC), and H₂O. A key criterion was to formulate viscoelastic dough similar to wheat dough. To that end, response surface methodology (RSM) was used to determine optimal levels of carob germ flour, H₂O, and HPMC. Components varied as follows: 4.94%-15.05% for carob germ flour, 0.05%-3.75% HPMC, and 65.25%-83.75% H₂O (percents are on a flour basis, where carob germ flour in combination with maize starch equals 100%). Sucrose, NaCl, and yeast were held constant at 2%. Bread parameters evaluated were specific volume and crumb hardness, where the largest specific volume and the lowest value for crumb hardness were considered most desirable. The optimum formula as determined by RSM consisted of 7% carob germ flour, 93% maize starch, 2% HPMC, and 80% H₂O with predicted crumb hardness of ~200 g of force and a specific volume of ~3.5 cm³/g. When proof time was optimized, a specific volume of ~5.6 ml/g and crumb hardness value of ~156 g of force was observed. Carob germ flour may be used as an alternative to wheat flour in formulating viscoelastic dough and high quality gluten-free bread.
Practical application:
Celiac disease affects approximately 1% of the world's population. Sufferers of the disease must consume a gluten-free diet. Currently, gluten-free baked products are made from batters and lack the ability to be made from dough based systems which limits the overall processability and product variety. This research is aimed at the utilization of carob germ protein and its ability to form dough to produce an optimal gluten-free bread formulation. This will help to alleviate problems in processability and product variety associated with gluten-free baked goods.
... RSM was used as described by McCarthy et al. (2005), Schober et al. (2005), and Smith et al. (2012), with modifications for formula optimization and to determine the effects of tannin-containing sumac sorghum bran on a sorghumbased gluten-free (GF) bread system. Ingredient variables (factors) bran, gum, and water were used to optimize the GF bread formulation. ...
... Bread was sliced to a uniform thickness of 2.5 cm for analysis using a cutting jig, and crumb hardness was measured (g force) with a TA.XT plus (Stable Micro Systems Ltd., Godalming, Surrey, UK) texture analyzer as described by Smith et al. (2012). A 25 mm diameter cylindrical plastic probe and 30 kg load cell was used. ...
... These physical qualities are indicative of high-quality gluten-containing bread and thus generally favored by consumers. How-ever, associations can sometimes be misleading, such as high specific volume resulting from large holes in the crumb (Smith et al., 2012). Therefore, photographs of whole loaves and cross-sectioned slices are presented for visual inspection (Figure 1). ...
Ingredients used to enhance sensory quality of gluten-free (GF) bread often lack in nutrients. This presents nutritional challenges for celiac-positive individuals and fails to meet expectations of healthfulness for non-celiac GF consumers. Sorghum (Sorghum bicolor L. Moench) flour can provide acceptable GF bread properties, and tannin-containing varieties contain antioxidants concentrated in the bran along with dietary fiber. Using a central composite design, tannin-containing sumac sorghum bran, gum (xanthan + guar), and water levels were optimized in a GF sorghum-based bread formulation. Loaf specific volume and gas cells/cm2 were maximized while minimizing hardness and cell wall thickness. The optimum formulation containing 14.2% sorghum bran, 1% gum, and 145% water (flour basis) effectively increased dietary fiber in bread to 13.4% (considered “high fiber”) and showed oxygen radical absorbance capacity of 61.6 µmol TE/g. This optimum formulation did not differ from a sorghum flour-based control bread in consumers’ (N = 100) liking of color, texture, flavor, overall acceptability, nor willingness to buy (WTB). All mean hedonic scores (numbered 9-point scale) were above 5, whereas average WTB was 4.7 for the optimum formulation and 4.6 for the control (9-point Likert scale) among consumers varying in GF bread consumption habits. Perceived bread bitterness was low (averaging 2.85 on 9-point intensity scale), did not vary between samples despite marked differences in antioxidant capacity, and was not correlated with WTB. When utilizing effective optimization models with key functional ingredients, sumac sorghum bran addition can enhance dietary fiber and antioxidant potential in sorghum-based GF breads without compromising quality attributes.
... In fact, some approaches have been focused on the protein enrichment for enhancing their nutritional value (Krupa-Kozak, Baczek, & Rosell, 2013;Marco & Rosell, 2008). Later studies were focused in the addition of proteins as a structure and texture-forming agent to mimic the characteristics that gluten provides to bread and improve the texture, physical and sensorial properties of gluten-free breads (Aprodu, Alexandra Badiu, & Banu, 2016;Smith, Bean, Herald, & Aramouni, 2012;Ziobro, Witczak, Juszczak, & Korus, 2013). However, up to date only α-zeins, a fraction of the prolamins from corn (Lawton, 1992;Schober, Bean, Tilley, Smith, & Ioerger, 2011) and caroubin, found in the carob germ flour (Feillet & Roulland, 1998) presented gluten-like viscoelastic features but under specific conditions. ...
... Zeins proved to form a viscoelastic dough with corn starch but only when kneading was performed above its transition temperature (35°C) (Lawton, 1992), and with poor breadmaking performance (Andersson, Öhgren, Johansson, Kniola, & Stading, 2011). Likewise, carob germ flour led to the production of adequate gluten-free doughs and breads, but without completely imitating gluten functionality, being required the inclusion of hydroxypropyl methylcellulose (HPMC) (Smith et al., 2012). Therefore, up to date, gluten has not been fully replaced by any other protein. ...
... Therefore, βCC produced breads with higher volumes compared to vital gluten, likely due to better gas retention during yeast proofing. Higher volumes are related to a higher retention of carbon dioxide during proofing and are considered one of the most relevant quality indicator in bread (Houben et al., 2012;Smith et al., 2012). The hydration and protein concentration did not cause a significant effect in the area and perimeter of breads (Table 2). ...
Germination has been applied to different seeds to increase their nutritional values. Nevertheless, the potential impact of species has not been considered yet. This research evaluates the changes in the physiochemical and nutritional properties of A. quitensis (black specie) and A. caudatus (white specie) after germination. Hydration, thermal and rheological properties were evaluated. Also, starch and protein digestibility, phenolic compound, antioxidant activity and dietary fiber were determined. The reduction in pasting and viscoelastic properties as well as total and resistant starch content in A. quitensis, after being subjected to 24 h germination, were significantly higher (P <.05) than the reduction observed in these respective properties in A. caudatus. These results revealed that during germination the enzymatic degradation of starch is greater in A. quitensis than A. caudatus. In addition, A. quitensis showed a significant lower glycemic index and higher protein digestibility than A. caudatus (P <.05). The data in this study demonstrates the impact of species in the application of germination to improve physicochemical or nutritional properties of amaranth.
... In fact, some approaches have been focused on the protein enrichment for enhancing their nutritional value (Krupa-Kozak, Baczek, & Rosell, 2013;Marco & Rosell, 2008). Later studies were focused in the addition of proteins as a structure and texture-forming agent to mimic the characteristics that gluten provides to bread and improve the texture, physical and sensorial properties of gluten-free breads (Aprodu, Alexandra Badiu, & Banu, 2016;Smith, Bean, Herald, & Aramouni, 2012;Ziobro, Witczak, Juszczak, & Korus, 2013). However, up to date only α-zeins, a fraction of the prolamins from corn (Lawton, 1992;Schober, Bean, Tilley, Smith, & Ioerger, 2011) and caroubin, found in the carob germ flour (Feillet & Roulland, 1998) presented gluten-like viscoelastic features but under specific conditions. ...
... Zeins proved to form a viscoelastic dough with corn starch but only when kneading was performed above its transition temperature (35°C) (Lawton, 1992), and with poor breadmaking performance (Andersson, Öhgren, Johansson, Kniola, & Stading, 2011). Likewise, carob germ flour led to the production of adequate gluten-free doughs and breads, but without completely imitating gluten functionality, being required the inclusion of hydroxypropyl methylcellulose (HPMC) (Smith et al., 2012). Therefore, up to date, gluten has not been fully replaced by any other protein. ...
... Therefore, βCC produced breads with higher volumes compared to vital gluten, likely due to better gas retention during yeast proofing. Higher volumes are related to a higher retention of carbon dioxide during proofing and are considered one of the most relevant quality indicator in bread (Houben et al., 2012;Smith et al., 2012). The hydration and protein concentration did not cause a significant effect in the area and perimeter of breads (Table 2). ...
Fractionation of soy proteins has proved to produce protein concentrates with viscoelastic properties. In the present study, a β-conglycinin concentrate (βCC) obtained by a pH fractionation of soy flour was tested as structuring agent in gluten-free yeast-leavened bread model. A lean formulation with βCC and corn starch was used to produce gluten-free breads with two hydration conditions and three levels of protein (5%, 10% and 15%). Vital gluten was used to compare the functionality of βCC protein and its performance for breadmaking. Breads were characterized in moisture, color, textural parameters and image analysis. βCC presented lower hydration properties and higher emulsifying activity compared to vital gluten. Blends βCC:starch had higher water binding capacity compared to vital gluten blends. The hydration conditions tested affected the moisture, color and cell density of breads. Breads produced with βCC presented higher 2D area and height and presented higher crumb softness and cohesiveness, and did not present significant differences in springiness and resilience compared to vital gluten breads. The image analysis of crumbs showed higher cell density but lower porosity and mean cell areas in βCC breads. Thus, βCC proved to have potential as a structuring agent in gluten-free breads.
... Carob bean flour contains increased amounts of dietary fibers and proteins, and it is considered a safe substitute for gluten-free products. Carob germ proteins have been shown to have functional properties similar to wheat gluten, since they can form a true dough instead of a batter [9]. Commonly, gluten-free baked products are made from batters and not from dough-based systems, resulting in limited overall processability. ...
... On the other hand, breads made with carob fraction C contained approximately 4% carob germ (based on fraction C composition) (calculated on the protein content of fraction C). Carob germ protein addition in gluten-free formulations at low concentrations lowered the bread firmness values [9]. Except for the chemical composition of the different fractions, the particle size itself affected the texture of the produced breads. ...
In this study, gluten-free doughs with rice flour, substituted by 15% fractions of different carob seed flours, were prepared by varying their water content. The coarse carob fraction A (median particle size of flour, D50: 258.55 μm) was rich in fibers, fraction B (D50: 174.73 μm) was rich in protein, C (D50: 126.37 μm) was rich in germ protein, and fraction D (D50: 80.36 μm) was a mix, reconstituted from the other fractions and pulverized using a jet mill. Τhe experimental data of the dough’s volume over time were fitted to the Gompertz model for each carob fraction and water content. The calculated parameters of the model were the maximum relative volume expansion ratio (a), the maximum specific volume growth rate (μ), and the time lag of the leavening process (tlag). Gompertz’s equation adequately described the individual experimental curves. In the next step, a composite model was applied for each carob fraction where the parameters a and tlag were expressed as quadratic functions of water content levels (W), while μ was linearly dependent on W. Each carob fraction presented an optimum water content level for which dough height was maximized and time lag was minimized. Optimized dough volume could be predicted by the composite model; it was shifted to lower values as finer carob flour was used. In respect to baked products, softer breads were produced using finer carob flour and porosity values were higher at optimum water content levels. The investigated fermentation kinetics’ models provide significant information about the role of water and carob flour on gluten-free dough development and bread volume expansion.
... The 2.5 cm thick bread slices were scanned using a Ricoh Aficio MP C3002 copier (Ricoh, Tokyo, Japan) for pictures used in bread crumb structure analysis. Texture analysis was performed as described by Smith et al. (2012) with modification using a TA-XT2i texture analyzer (Stable MicroSystems) equipped with a 5-kg load cell. Each bread slice was subjected to 40% compression at a test speed of 1.7 mm/s. ...
... as pea flour increased, an increase in fiber, or a dilution of gluten as discussed previously. Prior studies have indicated that there is an inverse correlation between bread hardness and specific volume, where higher specific volumes are typically associated with softer crumb (Smith et al., 2012). As cells collapse and gas cells with thicker cell walls are formed, the bread crumb becomes more tightly packed and denser, increasing the hardness values for bread. ...
Background and objectives:
With growing trends in health-conscious consumers, pea flour has been investigated for incorporation into baked products. The objective of this study was to understand the effect of pea flour incorporation (0, 1, 2, 5, 10, and 20%) milled with a Miag Multomat mill into white pan bread. Bread and sensory quality were assessed.
Findings:
Bread loaf volume was reduced with higher levels of pea flour incorporation. Texture, specific volume, and height were not significantly different between treatments until ≥10% w/w pea flour addition. Bread crust color was not affected by pea flour incorporation. Bread crumb color was redder, more yellow and slightly darker with pea flour addition. Crumb gas cell structure was indicative of gas cell coalescence with larger cells and thicker cell walls. Bread quality was assessed with a consumer sensory panel comprised of 60 individuals. Consumers could perceive differences between the control and pea flour containing breads. However, there were no major differences in overall acceptability between pea flour containing treatments. Even with 20% pea flour addition, pea flour can be used in conjunction with wheat to make a sensorially acceptable bread.
Conclusions:
A high-quality pea flour containing wheat bread can be made. At 20% pea flour incorporation, quality as defined by instrumental analyses decrease, while sensory analysis showed few differences between treatments.
Significance and novelty:
Nutrient dense pea flour can be incorporated into wheat breads at a level of 20% with little effect on consumer acceptance.
... Carob fl our is rich in proteins, dietary fi bre, micronutrients, and polyphenols [Turfani et al., 2017]. Moreover, it contains caroubin, a water-insoluble protein able to form wheat-like dough due to disulphide bonded high molecular weight proteins, which makes carob an interesting ingredient in gluten-free breadmaking [Smith et al., 2012]. In fact, it was observed that carob germ fl our (7%), when mixed with corn starch (93%), HPMC (2%) and water (80%), was able to form viscoelastic dough similar to that of wheat, resulting in breads with both a higher specifi c volume and crumb softness [Smith et al., 2012]. ...
... Moreover, it contains caroubin, a water-insoluble protein able to form wheat-like dough due to disulphide bonded high molecular weight proteins, which makes carob an interesting ingredient in gluten-free breadmaking [Smith et al., 2012]. In fact, it was observed that carob germ fl our (7%), when mixed with corn starch (93%), HPMC (2%) and water (80%), was able to form viscoelastic dough similar to that of wheat, resulting in breads with both a higher specifi c volume and crumb softness [Smith et al., 2012]. Tsatsaragkou et al. [2014] used the Response Surface Methodology to optimise the levels of carob fl our, resistant starch and water in rice-based GFBs. ...
The presence of gluten is considered fundamental for successful breadmaking. However, the ingestion of gluten by susceptible individuals has been associated with the development of gluten-related disorders such as celiac disease, wheat allergy, and non-celiac gluten sensitivity. The elimination of gluten from cereal-based baked products has a detrimental effect on the breadmaking process and sensory properties, and raises technological challenges in terms of making good quality leavened bread. The use of non-gluten raw materials changes the rheological behaviour of the gluten-free dough, which may result in different processing performance and associated post-baking quality of the obtained bread. Gluten-free bread tends to have a poor visual texture characteristics, a low nutritional value, reduced mouthfeel and flavour, as well as a shorter shelf-life. The aim of this review is to present the main problems related to gluten-free breadmaking technology and to summarise recent findings in the improvement of the technological, nutritional, and sensory properties of gluten-free bread. A great deal of this review focuses on the development of novel and healthy gluten-free breads formulated with flours, starches, hydrocolloids, and alternative nutrient-dense raw materials, which should fulfil all quality requirements for bakery products as well as meet the needs of celiac consumers. © Copyright by Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences.
... Diff erences of use are slight, regardless of socioeconomic status or geographical location. Modern science is following traditional wisdom and many pharmacological discoveries about Carob were published, but the quest for healthier foods remains a top priority [110][111][112][113][114]. In this context, the search for gluten-free pastries found real support in the form of Carob fl our that is replacing conventional fl ours, but also being studied to improve it, for example, by addition of hydroxypropyl methyl cellulose [205]. ...
Carob has been used by humans since antiquity. Its major use is food, but traditional medicines
of many nations used it for treatments of various health disorders. The fruits (pods or kibbles)
were the main source for nutrition and medicinal uses, but decoctions and extracts were prepared
from other parts of the tree, especially leaves. Modern science has analyzed most of the chemical
compositions of the different parts, and among the phytochemicals that were found, antioxidants
play very important roles in Carob nutritional and medicinal activities. So, in addition to having strong
antioxidant activity and due to it, these natural products, their extracts, and foods that contain them,
have anticancer, neuroprotective, hepatoprotective, antiaging, skin care, antidiabetic, and others.
Phenolics and carbohydrates are the strongest antioxidants, but some volatile compounds have
the same activity, to some extent. However, this review will present Carob antioxidants, their major
nutritional and medicinal activities, and suggest future horizons for their use in human wellbeing.
... But the people who are lactose intolerant, incorporation of these dairy proteins need to be avoided. Carob germ and corn protein can be used with starch for improving the viscoelastic and cohesive property of the dough which could be helpful in holding the gas, resulting in soft crumb of the GFB (Smith et al., 2012). ...
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.
... But the people who are lactose intolerant, incorporation of these dairy proteins need to be avoided. Carob germ and corn protein can be used with starch for improving the viscoelastic and cohesive property of the dough which could be helpful in holding the gas, resulting in soft crumb of the GFB (Smith et al., 2012). ...
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.
... But the people who are lactose intolerant, incorporation of these dairy proteins need to be avoided. Carob germ and corn protein can be used with starch for improving the viscoelastic and cohesive property of the dough which could be helpful in holding the gas, resulting in soft crumb of the GFB (Smith et al., 2012). ...
There are various tests that can be used for evaluation of the quality of gluten-free doughs and breads. All such tests are related to certain parameters that determine the quality of these products. Chemical composition, color, texture, pasting, gelatinization, rheological and morphological properties are the major attributes determining the quality of the gluten-free breads. There is a great correlation between many of these parameters, for example, the visco-elastic properties of gluten-free doughs are closely related with their pasting and gelatinization properties. Therefore, rheological analysis also gives the information about the visco-elastic nature of gluten-free dough. Color directly influences the consumer acceptance of the finished product. Texture analysis gives the information about the degree of staling of gluten-free breads. A higher hardness generally indicates a higher staling of gluten-free breads. Sensory evaluation entails the consumer acceptance of the breads developed with gluten-free formulations.
... A variation of response surface methodology (RSM) used by Smith et al. (2019) and Smith et al. (2012) where Y is the response variable. When i = j, β 0 is the coefficient of intercept, β i is the coefficient for linear, β ij is the coefficient for quadratic, and when i ≠ j, β ij is the cross-product coefficient. ...
Peas are an underutilized crop that do not require allergen labeling and are rarely genetically modified. Peas contain less protein than soy and vary in protein composition. Because peas contain more starch than soy and less lipids, an alternative procedure for pea tofu production needs to be developed to prevent excessive starch gelatinization while promoting curd development. To accomplish this, a response surface model design was utilized to determine optimal oil addition, cook time, and salt concentration. Treatment ranges were from 0.0% to 4.2% for oil addition, 60–134 min for cook time, and 5.0%–9.2% for MgCl2 addition. Treatments had varying effects on tofu texture. Cook time was directly proportional to the hardness and could be used to match the soft, firm, and extra firm texture targets of conventional soy tofu. Protein secondary structure was not related to gel strength, indicating a system with synergies between multiple components other than protein. This research will help satisfy the growing demand for alternatives to soy‐based foods.
... Thus, a water level of 100% (specific loaf volume of 2.2 cm 3 /g) was selected as optimum for the zein-whole sorghum flour breads containing 3% HPMC (fwb). The effect of proof time was also tested with the new water level, with breads proofed for 30, 60, or 120 min; however, there was no effect of proof time on loaf volume, unlike what was reported for carob germ flour-based gluten-free bread (Smith et al., 2012). ...
Zein is known to able to form viscoelastic dough with wheat‐like properties under certain conditions. Several studies have been conducted to explain the mechanism behind this ability and to improve the functionality and end‐use quality of zein‐based dough systems. However, most of this research has been conducted using zein in combination with isolated starches or high‐starch flours. To investigate the production of additional zein–whole sorghum flour breads, experiments were conducted to determine factors impacting zein–whole sorghum flour dough and bread quality. Optimizing water levels, using defatted zein and/or sorghum flour, and increasing zein content in dough formulas were investigated as initial formulation steps. Of these factors, increasing zein content from 20% to 30% (flour weight basis) had the greatest impact, resulting in stronger zein‐based dough and improved bread quality. Additives and zein treatments shown to impact zein functionality were then investigated for their effect of zein–whole sorghum flour breads. Mixing zein and whole sorghum flour with 0.5% hydrogen peroxide, 5% ethanol, or 3% hydroxypropyl methylcellulose resulted in improved dough strength and bread quality. Breads made from whole white sorghum flour had improved quality compared to zein‐based breads made with black or high‐tannin whole sorghum flour.
Practical Application
Zein is known to be able to form wheat‐like dough when mixed under the right conditions. Most of the research on zein‐based dough and food products has used high‐starch flours. This project investigated optimizing the production of zein–whole sorghum flour dough and bread as an alternative. Increasing the zein content in the formula and using additives including ethanol and HPMC produced breads from zein–whole sorghum flour that were like those made with zein and pure starch.
... Black, red, and yellow dye addition levels were determined through preliminary experiments and based on initial color of bread made from HRW. Treatment levels were set to maximize variability in dye addition while maintaining a center point that provided L * , a * , and b * values close to that of the HRW. Model selection and optimization were adapted from previous work by (Smith, Bean, Herald, & Aramouni, 2012). Sequential determination of the model sum of squares was used to select a linear or quadratic model. ...
Consumer taste preference can be influenced by visual preference. To eliminate the influence of visual preference in the sensory evaluation of whole grain wheat, a reproducible method to eliminate color differences between Whole Grain breads prepared from hard white wheat (HWW) and hard red wheat (HRW) was evaluated. Response surface methodology (RSM) was used to match the color of HWW to HRW with the addition of commercially available dye solutions: McCormick black (red #40, yellow #5, blue #1), red (red #40, red #3, yellow #6), and yellow (yellow #5). Bread color was assessed by L * , a * , and b * color parameters according to the CIELAB international system of color measurement. Four replicates of the control and dye treated breads were analyzed. Initial color values for HRW were L * = 56.8 ± 0.40; a * = 8.04 ± 0.44; b * = 21.34 ± 0.46. RSM was used to predict dye addition levels to match color between HWW and HRW. With the addition of black (0.457 µL/mL), red (0.574 µL/mL), and yellow (1.165 µL/mL) dye to HWW, breads could be produced with L * , a * , and b * values of no statistical difference to the HRW ( P < 0.05). A timed storage trail demonstrated the need to standardize the time between bread production and feeding studies. Visual bias can hinder assessment of wheat varieties in sensory studies. A reproducible method of dying wheat was developed that can be used to reduce this bias in sensory studies.
Practical Applications
The ability to control color variability is a critical tool in determining perceived quality in sensory analysis of breads. In this study, a method to reduce or eliminate visual bias between breads made from different varieties of wheat was developed. This method is applicable to any foods where dye could be added to reduce or eliminate color bias in sensory studies.
... Some studies have investigated the use of locust bean gum (E-410) or carob germ flours to enhance the physicochemical properties of the extruded products or as an alternative protein source in breadmaking, respectively. 5,16,17 However, there is not much information available concerning the inclusion of carob fruit flours into cereal/legume formulations for the development of functional extruded products. ...
The consumers and the food industry are demanding healthier products. Expanded snacks with high nutritional value were developed from different rice, pea and carob flours blends. The proximate composition, starch (total and resistant), amylose and amylopectin, dietary fiber (soluble and insoluble) contents, and in vitro protein digestibility of the different rice-legumes formulations, were evaluated before and after extrusion process. Compared with the corresponding non-extruded blends (control), the extrusion treatment did not change the total protein content, however, it reduced the soluble protein (61-86%), the fat (69-92%) and the resistant starch contents (100%). The total starch content of all studied blends increased (2-19%) after extrusion. The processing increased the in vitro protein digestibility, reaching values around 88-95% after extrusion. Total dietary fiber was reduced around a 30%, and the insoluble fraction was affected in higher extent than the soluble fraction by the extrusion process. Because of its balanced nutritional composition, high dietary fiber content, as well as low energy density, these novel gluten-free snack-like foods could be considered functional foods and a healthier alternative to commercial available gluten-containing or gluten-free and low nutritional values snacks.
... In view of the current increasing incidence of celiac sufferers (due to improved diagnostic procedures), there is a major need for more research and development in the area of gluten-free cereal based products. In recent years, several studies were made on gluten-free products, including the use of rice and buckwheat flour (Ronda, Pérez-Quirce, Angioloni, & Collar, 2013;Torbica, Hadnađev, & Dapčević, 2010;Wronkowska, Haros, & Soral-Śmietana, 2013), chestnut flour (Demirkesen, Mert, Sumnu, & Sahin, 2010), carob germ and starch (Smith, Bean, Herald, & Aramouni, 2012), amaranth flour (Schoenlechner, Mandala, Kiskini, Kostaropoulos, & Berghofer, 2010), cassava, soy, chia, quinoa, potato (Capriles & Arêas, 2014) and hydrocolloids (Lorenzo, Zaritzky, & Califano, 2009). It was found that both the type and the lipid content affect the texture properties of non-fermented gluten-free dough (Lorenzo et al., 2009). ...
“Chipa” is a gluten-free bread made with cassava starch and cheese. Usually, the batter is baked immediately and the product is eaten warm. In this study, the effect of refrigeration and freezing of batter, and the role of cheese upon “chipas” prepared with cassava or corn starch were analyzed. This may offer alternatives to the storage of batter, and contribute to the knowledge of the effect of refrigeration and freezing of batter in gluten-free baking products. Texture and colour were analyzed in batter and baked products. Volume, sensory quality and in vitro starch digestibility of “chipas” were also determined. The refrigeration or freezing of batter turned darker mainly the baked products containing cheese, probably due to the Maillard reactions between proteins and products of lipid oxidation. The “chipa” made with cheese and cassava starch was bigger, softer and gummier than that prepared with corn starch, and these properties did not change when the batter was frozen. No differences were f...
... Model showed that levels higher than 9% produced a significant increment on the hardness. Miñarro et al. (2012) and Smith et al. (2012) found similar values in breads prepared using carob germ. An increase in water content diminished crumb firmness and led to an open cell structure. ...
An antioxidant gluten-free cracker snack was developed through the inclusion of carob by-products (germ and seed peel). The levels of formulation of these two novel ingredients were optimized through their effect on nutritional, physicochemical, sensory and antioxidant parameters of the final product. The results showed that both ingredients affected significantly (P≤0.05) the studied parameters. Based on the surface response models, germ content ranging 4-14% and seed peel lower than 9% were considered optimal formulation conditions of a protein and fiber-rich product with high antioxidant activity. The incorporation of both ingredients increased significantly the antioxidant activity of the snack. However, concentration outside the optimal range of germ and/or peel had modifications in the expected color, texture and flavour of the crackers.
... Model showed that levels higher than 9% produced a significant increment on the hardness. Miñarro et al. (2012) and Smith et al. (2012) found similar values in breads prepared using carob germ. An increase in water content diminished crumb firmness and led to an open cell structure. ...
ABSTRACT
An antioxidant gluten-free cracker snack was developed through the inclusion
of carob by-products (germ and seed peel). The levels of formulation of these
two novel ingredients were optimized through their effect on nutritional, physicochemical,
sensory and antioxidant parameters of the final product. The
results showed that both ingredients affected significantly (P�0.05) the studied
parameters. Based on the surface response models, germ content ranging 4–
14% and seed peel lower than 9% were considered optimal formulation conditions
of a protein and fiber-rich product with high antioxidant activity. The
incorporation of both ingredients increased significantly the antioxidant activity
of the snack. However, concentration outside the optimal range of germ
and/or peel had modifications in the expected color, texture and flavour of the
crackers.
PRACTICAL APPLICATIONS
The consumer demand for healthier food products is increasing. Snack food is
not beyond this trend; furthermore, because of its status of convenience food, it is
harder to find healthy alternatives to traditional snack food products. In this case,
a gluten-free snack with optimized bioactive properties (antioxidant activity) is
developed and proposed, and carob gum processing wastes are value-added by
being used as ingredients, adding an environmental benefit to its production.
Germ and seed peel from carob processing by-products provided protein and
antioxidant activity to the formulated food products. A formulation of a snack
with optimal physicochemical and antioxidant capacity was obtained.
... Concerning carob flour, a variety of studies reported the use of carob germ protein extracted from the seed germ in GF bread production, since carob germ protein is considered to have similar rheological properties to wheat gluten (Miñarro et al., 2012;Bengoechea et al., 2008;Smith et al., 2012). The rest of the seed contained increased amounts of soluble (locust bean gum from the endosperm) and insoluble dietary fibres, which could be used for GF bread production. ...
Dietary fibres can play a significant role in GF bread development. Besides their well documented health benefits, dietary fibres can improve the texture, sensory characteristics and shelf life of baked products, due to their water binding capacity, gel forming ability, fat mimetic, textural and thickening effects. Dietary fibres from different sources are discussed in this paper and their role in GF products' making is analysed. The sources of fibres vary: flours, fruit and vegetable processing by-products, isolated ingredients, seeds or mixtures of all of these can be used. Fibres improve the structure and result in dense crumb porosity. Tasty products with soft crumb can be produced, and there are many perspectives in further products development.
... In these group of protein preparation a special attention should be paid to carob germ proteins. As it was demonstrated by Smith et al. (2012) they improve viscoelastic properties of the dough and allow obtaining gluten-free bread with a high quality. Other proteins tested in the production of gluten-free include collagen and lupine proteins (Ziobro et al. 2013). ...
The study aimed to evaluate the effects of selected protein isolates and concentrates on quality and staling of gluten-free bread, in the absence of other structure-forming agents such as guar gum and pectin. The applied preparations included albumin, collagen, pea, lupine and soy. Their addition had various effects on rheological properties of the dough and volume of the bread. Volumes of the loaves baked with soy and pea protein were smaller, while those with albumin significantly larger than control. Presence of non-gluten protein caused changes in crumb structure (higher porosity, decrease in cell density, higher number of pores with a diameter above 5 mm) and its color, which was usually darker than of unsupplemented starch-based bread. The least consumer’s acceptance was found for bread baked with soy protein. The presence of pea and lupine preparations improved sensory parameters of the final product, providing more acceptable color and smell in comparison to control, while soy caused a decrease of all analyzed consumer’s scores. The addition of protein caused an increase in bread hardness and in enthalpy of retrograded amylopectin, during bread storage.
... results showed that soy flour pretreatment enhances whole soy bread quality. Impressive results were obtained by Smith and others (2012) who described the ability of carob germ flour to form viscoelastic dough when mixed with starch and water at room temperature due to its protein, named caroubin, that can mimic gluten's properties. The optimum formula results in an easily handled dough that can be used to produce bread without the aid of a baking pan. ...
The evidence that celiac disease is one of the commonest food intolerances in the world is driving an increasing demand for gluten-free foods. However, gluten is a structure-building protein essential for formulating leavened baked goods. Therefore, obtaining high-quality gluten-free bread (GFB) is a technological challenge. This review focuses on contemporary approaches in gluten-free baking that allow improvements at the structure, texture, acceptability, nutritive value, and shelf life of GFB. Gluten-free breadmaking is a relatively new, emerging research topic that is attracting worldwide attention in order to develop different kinds of GFB, including regional varieties. Several approaches have been used to understand and improve GFB systems by evaluating different flours and starch sources, ingredients added for nutritional purposes, additives, and technologies or a combination of these elements. Some studies aimed to assess or improve GFB's technological or nutritional properties, while others had multiple objectives. Several studies used food science tools in order to improve technological and sensory quality of GFB, together with nutritional value. Some GFBs are vehicles of nutrients and bioactive compounds. Furthermore, extensive research on interfacing food science, nutrition, and health is needed so that a GFB with both good technological and nutritional properties can be prepared and made more available to those with celiac disease, which will help them adhere to a strict gluten-free diet, increase social inclusion, and improve their quality of life.
http://onlinelibrary.wiley.com/doi/10.1111/1541-4337.12091/abstract
... high M w disulfide bonded proteins) (Smith et al., 2010). This makes zein unique in that it is capable of forming a gluten-like VEM from relatively small molecular weight proteins ($21-22 kDa) that are not dependent on disulfide linkages like caroubin and wheat gluten (Carceller & Aussenac, 2001;Lawton, 2002;Smith, Bean, Herald, & Aramouni, 2012;Smith et al., 2010). ...
Background: Celiac disease is an autoimmune disorder launched by gluten ingestion in genetically susceptible persons. This component leads to an inflammation of the small intestine which causes malabsorption of some important nutrients including calcium, iron, folic acid, and liposoluble vitamins. A gluten-free diet, that is strictly followed by affected patients throughout their whole lives, constitutes the unique effective treatment for celiac disease. Aims: Several gluten-free cereals, pseudo-cereals, legumes, starches (rice, corn, sorghum, millets, buckwheat, quinoa, teff, chestnuts, chia, potato starch, peas, etc.), and various gluten substitutes (xanthan and gum guar) were utilized to maintain the physical and sensory properties of gluten-free cereal products. This review examined recent advances in the formulation of gluten-free cereal-based products using innovative gluten-free flours. Conclusions: Consequently, this review presents and summarizes recent findings in the improvement of the technological, nutritional, and sensory properties of gluten-free cereal products. However, the preparation of cereal-based gluten-free products still remains a difficult process. Therefore, the diet must be not only exempt from gluten but also healthy to avoid nutrient, vitamins, and minerals deficiencies. Thus, a great deal of this review focuses on studying novel and healthy gluten-free ingredients which should fulfill all quality requirements for bakery and pastry products as well as satisfy the needs of celiac consumers. Keywords: gluten-free products, alternative flours, celiac disease.
Coeliac disease (CD), dermatitis herpetiformis (DH), non-coeliac gluten sensitivity (NCGS), and gluten ataxia (GA) are some of the most important problem, auto-immuno, and lifelong intolerance disorders in human. These disorders are found by the ingestion of gluten in our body. Gluten is mostly present in wheat, barley, rye, and other related grains. Replacement of gluten in our diet is the best method to reduce the chances the coeliac disease. Gluten replacement presents a major technological challenge, as it is an important protein that creates the structure required to formulate to bake the food of high quality. The functionality of non-gluten protein is the major limitation in the development of gluten free products. Finding of alternative protein is great demand in gluten free food markets. The selection of appropriate protein for gluten-free product is a great challenge for food industry. The current chapter focuses on the uses of alternative proteins to replace gluten. As well as studies related to the functionality and nutritional qualities of these alternative proteins are also discussed.
The protein composition, molecular weight distribution, and rheological properties of honey locust, mesquite, Kentucky coffee tree, and carob seed germs were compared against wheat gluten. Polymeric and Osborne fractionation protocols were used to assess biochemical properties. Dynamic oscillatory shear tests were performed to evaluate protein functionality. All samples had similar ratios of protein fractions as well as high molecular weight disulfide linked proteins except for the Kentucky coffee tree germ proteins, which were found to have lower molecular weight proteins with little disulfide polymerization. Samples were rich in acidic and polar amino acids (glutamic acid and arginine,). Rheological analyses showed that vital wheat gluten had the most stable network, while Kentucky coffee seed proteins had the weakest. High molecular weight disulfide linked glutenous proteins are a common, but not universal feature of pod bearing leguminous trees.
A sourdough combined with microwave heating method was adopted to make steamed cake (SSC), the dough yield, fermentation time and additive amount of sourdough were optimized by Response Surface Methodology (RSM) to obtain microwave‐steamed cake (MSSC) with high‐quality attributes and then the potential mechanism of sourdough on the improvement of the MSSC texture was investigated. The addition of sourdough with the optimized parameters could greatly improve the specific volume, porosity, hardness, and chewiness of MSSC, which was mainly related to changes in dielectric properties and water distribution. The results of dielectric properties confirmed that sourdough increased the dielectric properties of the system during microwave heating, affecting the microwave heating characteristics. And the changes of water states and distribution by T2 relaxation analysis showed that sourdough restricted water mobility during heating and facilitated the retention of water trapped in MSSC. Additionally, the scanning electron microscopy (SEM) images indicated that sourdough weakened the gluten network structure, and triggered a looser and smoother microstructure.
Practical Application
Steamed cake (SSC) is one of the most popular fermented foods in China, while its commercial development is greatly limited by the drawbacks of traditional steam heating. In recent years, the applications of microwave heating and sourdough in cereal‐based foods processing have gained more and more interest. However, there is little information about the application of sourdough combined with microwave heating in SSC production. This study revealed that sourdough addition increased the specific volume, porosity, texture, and consumer preference of MSSC, providing a natural, high‐efficiency, and easy‐to‐operate means for the fabrication of high‐quality fermented foods.
Consumers, food manufacturers and health professionals are uniquely influenced by the growing popularity of the gluten-free diet. Consumer expectations have urged the food industry to continuously adjust and improve the formulations and processing techniques used in gluten-free product manufacturing. Health experts have been interested in the nutritional adequacy of the diet, as well as its effectiveness in managing gluten-related disorders and other conditions. In this review, we aim to provide a clear picture of the current motivations behind the use of gluten-free diets, as well as the technological and nutritional challenges of the diet as a whole. Alternative starches and flours, hydrocolloids, and fiber sources were found to play a complex role in mimicking the functional and sensory effects of gluten in gluten-free products. However, the quality of gluten-free alternatives is often still inferior to the gluten-containing products. Furthermore, the gluten-free diet has demonstrated benefits in managing some gluten-related disorders, though nutritional imbalances have been reported. As there is limited evidence supporting the use of the gluten-free diet beyond its role in managing gluten-related disorders, consumers are urged to be mindful of the sensorial limitations and nutritional inadequacies of the diet despite ongoing strategies to improve them.
There are no reports of addition of carob fibre to gluten-free bread, as only carob germ flour was used. The research task was to determine what level of carob fibre can be used and how it influences the physical and sensorial properties of gluten-free bread. Especially, the knowledge of the antioxidant properties of such bread is very valuable. The gluten-free bread from rice, corn, and buckwheat flour (35:35:30%) was prepared after mixing (5 min), proofing (40 min, 30°C), and baking (45-50 min, 230°C) of dough. Carob fibre was added in the amounts of 1, 2, 3, 4, and 5% of the total flour content. The results showed that increased content of carob fibre induced significant and favourable changes in the volume, colour, and texture (hardness and springiness) of the bread crumb. Carob fibre enriched the breads with lipophilic compounds able to chelate metal ions. The activity of hydrophilic compounds was significantly higher in the case of control bread and bread with the lowest percentage of the additive. In conclusion, the highest increase in antioxidant activity was found for breads with 1 and 2% of carob fibre. The most acceptable gluten-free bread can be obtained by adding up to 2% of carob.
The gluten-free market currently offers a range of products which can be safely consumed by patients affected by celiac disease. Nevertheless, challenges for optimal formulation remain on the way in terms of appreciable texture, flavor, and adequate nutritional characteristics. Within that framework, legumes have recently attracted attention among scientists as structure- and texture-forming agents, as source of nutrients and bioactive compounds, and as a low-glycemic-index ingredient. This work aims at providing an updated and comprehensive overview of the advantages and disadvantages in the use of legumes in gluten-free breadmaking. It also shows how legumes can contribute to tackling the main technological, nutritional, and organoleptic challenges. From this critical analysis, it emerged that viscoelastic properties of gluten-free bread batter can be enhanced by the use of carob germ, chickpea, lupin, and soybean. Gluten-free bread organoleptic acceptability can be improved by incorporating leguminous flours, such as carob, chickpea, lupin, and soybean. Moreover, a better nutritional quality of gluten-free bread can be obtained by the addition of chickpea and soybean. Gaps and needs in the use of legumes in gluten-free breadmaking emerged and were gathered together to have a sound basis for future studies. The technological and nutritional potential of sourdough should be more extensively exploited. Moreover, in vitro and in vivo studies should be prompted to understand the health benefits of bread formulated with legumes. A holistic approach, interfacing food science, nutrition, and health might help to have, on the market, products with improved sensory properties and nutritional profile.
Development of viscoelastic doughs from non-wheat proteins allows for a wider range of gluten-free products. Little work has been completed to describe mechanisms of zein functionality in food systems. To identify factors responsible for dough development in zein–starch mixtures and their influence on zein bread quality, a mixture of 20% zein–80% maize starch was mixed with water and various reagents. Salts, NaSCN, NaCl, and Na2SO4 were evaluated at concentrations from 0 to 2M for their influence on the properties of zein–starch dough systems. NaSCN at low concentrations produced softer dough. Ethanol treatments produced softer more workable dough in the absence of salts. Increasing concentrations of NaCl and Na2SO4 resulted in coalescing of the proteins and no dough formation. The addition of β-ME had minimal softening effects on zein–starch dough. Specific volumes of zein–starch bread increased with decreasing NaCl addition in bread formulations. Likewise, including 5% ethanol (v/v) in the bread formula increased bread quality.
Nutritional therapy is currently the unique treatment for gluten intolerance. However, food technologists have been developing gluten free foods without having in mind both the nutritional status and nutrients' needs. It is important to consider that gluten intolerant patients do not have the same requirements when diagnosed than when they are fulfilling a long-life gluten free diet. Their needs are different at each stage, because of that diet might respond to their nutritional demands and be adapted. This chapter gives an overview of the nutritional pattern of gluten free intolerants at diagnosis, their requirements and how the currently marketed gluten free products meets those needs. In addition, this chapter reviews the tools that food technologist have for enriching the gluten free products, particularly bakery products, in macro-and micronutrients giving response to the consumers. It is also highlighted the role that nutritionist must play in this picture giving proper advice to consumers.
Carob (Ceratonia siliqua L.) is well known for its valuable locust bean gum obtained from the carob seeds. Separation of seeds from the pod leaves behind the carob kibble which is a good source of dietary fiber, sugars, and a range of bioactive compounds such as polyphenols and pinitol. Bioactive compounds present in carob kibble have been found to be beneficial in the control of many health problems such as diabetes, heart diseases, and colon cancer due to their antidiabetic, antioxidant, and anti-inflammatory activities. Carob kibble has substantial potential to be used as a food ingredient. This article focuses on the composition, health benefits, and food applications of carob kibble.
Research efforts on gluten-free bread making have rapidly increased during the last decade. A lot of different approaches are being used to improve the quality of these products. The techniques used in gluten-free bread making research vary widely. This review focuses on the methodological aspects of gluten-free bread making research and extracts relevant data from all Web of Science peer reviewed research articles on gluten-free bread published from 2010 to date. Recipes and methodologies are grouped by (main) starch source and list other ingredients, additives and treatments used. The focus lies on the experimental setups typically used to analyze batter/dough and end product. Small deformation rheological measurements are typically performed on gluten-free batter/dough, along with several other batter/dough properties, but there is no clear link between these characteristics and the bread quality which typically is determined by volume and texture analysis or sensory evaluation. Some more recent techniques that have already been used on wheat bread or other bakery products are discussed as well. Their application in gluten-free bread making research may help extend the current knowledge.
Celiac disease is an immune-mediated disease triggered in genetically susceptible individuals by ingested gluten from wheat, rye, barley, and other closely related cereal grains. The current treatment for celiac disease is life-long adherence to a strict gluten-exclusion 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. A major limitation in the production of gluten-free products is the lack of protein functionality in non-wheat cereals. Additionally, commercial gluten-free mixes usually contain only carbohydrates, which may significantly limit the amount of protein in the diet. In the recent past, various approaches are attempted to incorporate protein-based ingredients and to modify the functional properties for gluten-free product development. This review aims to the highlight functionality of the alternative protein-based ingredients, which can be utilized for gluten-free product development both functionally as well as nutritionally.
© The Author(s) 2014.
Background
Gluten free foodstuff development has attracted in the last decade great attention due to better diagnoses of coeliac disease and common chatters about the relationship of gluten free products with healthiness. The increasing interest has prompted an extensive research for developing gluten free foodstuff resembling gluten containing foods. This review aims to get some insights on dough functionality and process conditions regarding bread quality and to point out recent researches dealing with nutritional composition of those products.ResultsGluten free dough results from the combination of different ingredients, additives, processing aids, required for building up network structures responsible for bread quality. Some relationships between dough rheology and bread characteristics were established to identify possible predictor parameters. Regarding bread making process the impact of mixing, dough treatment and baking is stated. Nutritional quality is an important asset when developing gluten free breads, and different strategies for improving it are reviewed.Conclusion
Gluten free bread quality is dependent on ingredients and additives combination, but also processing can provide a way to improve bread quality. Nutritive value of the gluten free breads must be always in mind when setting up recipes, for obtaining nutritionally balanced bread with adequate glycaemic index.
Celiac disease (CD) is widespread and is often under diagnosed. It can affect a variety of genetically susceptible people from the young to the old. Presently, the only treatment for celiac patients is lifelong avoidance of any food, drink, sauce, or dressing containing gluten. Scientists and technologists continue in their quest to improve the quality of gluten-free products. Their main goal is to create a product of a similar standard to the gluten-containing products, currently on the market. However, the quality of these products still tends to be poor. Bread products have a low volume, pale crust, crumbly texture, bland flavor and a high rate of staling. Other gluten-free products contain minimal nutrition and substandard product characteristics, for example, pasta having an inferior texture, sauces which separate more easily. The main focus of this review is to discuss the most recent advances in gluten-free research which have arisen between the years 2011 and 2013. In particular, the manuscript focuses on ingredients and processing methods which have been documented to develop or improve the processing characteristics and nutritional properties of gluten-free products.
This study was focused on the analysis of the chemical composition of defatted carob germ flour and the protein isolate. The amino acid composition and the nature of the subunits that compose carob germ proteins were also studied. Isolate was obtained by alkaline extraction followed by isoelectric precipitation of proteins. Results showed that an isolate of 96.5% of protein content was obtained. A high amount of amino acids like glutamic acid, aspartic acid and arginine was detected. Carob proteins were found to be composed by aggregates formed by a 131 and 70kDa subunits linked by non-covalent bonds, and other peptides strongly bounded by disulfide interactions. Both, aggregates and subunits were formed mainly by 100 and 48kDa monomers linked by disulfide bonds. A considerable content of high molecular mass peptides (HMWP) strongly bounded were also found. Proteins became partially denatured and thermally stabilized at acid pH (pH 2). These results could be useful in the study of different functional properties of carob germ proteins, and the application of these proteins as nutritional ingredients in formulated food.
Cereal Chem. 82(5):609–615 The formulation of gluten-free (GF) bread of high quality presents a formidable challenge as it is the gluten fraction of flour that is responsible for an extensible dough with good gas-holding properties and baked bread with good crumb structure. As the use of wheat starch in GF formulations remains a controversial issue, naturally GF ingredients were utilized in this study. Response surface methodology was used to optimize a GF bread formulation primarily based on rice flour, potato starch, and skim milk powder. Hydroxypropylmethylcellulose (HPMC) and water were the predictor variables. Analyses of the treatments from the design were made 24 hr after baking. Specific volume and loaf height increased as water addition increased (P < 0.01). Crumb firmness decreased as water levels increased (P < 0.01). Significant interactions (P < 0.01) between HPMC and water were found for the number of cells/cm 2 . The number of large cells (>4 mm 2) decreased with increasing levels of HPMC and water. Optimal ingredient levels were determined from the data obtained. The optimized formulation contained 2.2% HPMC and 79% water flour/starch base (fsb) and measured responses compared favorably to predicted values. Shelf-life analysis of the optimized formulation over seven days revealed that, as crumb firmness increased, crust firmness and crumb moisture decreased.
Gluten-free breadmaking quality of 10 sorghum flours was compared using (relative basis) decorticated sorghum flour (70), corn starch (30), water (105), salt (1.75), sugar (1), and dried yeast (2). Batter consistency was standardized by varying water levels to achieve the same force during extrusion. Crumb properties were evaluated by digital image analysis and texture profile analysis (TPA). Significant differences (P < 0.001) in crumb grain were found among the hybrids with mean cell area ranging from 1.3 to 3.3 mm2 and total number of cells ranging from 13.5 to 27.8/cm2. TPA hardness values of the crumb also varied significantly (P < 0.001). Based on significant correlations (P < 0.01), starch damage, influenced by kernel hardness, was identified as a key element for these differences. Breads differed little in volume, height, bake loss, and water activity. Investigation of added ingredients on bread quality was conducted using response surface methodology (RSM) with two sorghum hybrids of opposite quality. Addition of xanthan gum (0.3-1.2% flour weight basis [fwb]) and skim milk powder (1.2-4.8% fwb) and varying water levels (100-115% fwb) were tested using a central composite design. Increasing water levels increased loaf specific volume, while increasing xanthan gum levels decreased the volume. As skim milk powder levels increased, loaf height decreased. Quality differences between the hybrids were maintained throughout the RSM.
The biochemical, physical and baking properties of caroubin, the main protein in the carob bean, were characterized. The biochemical properties of caroubin were analyzed using reversed-phase high performance liquid chromatography (RP-HPLC), size exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALS) and micro-fluidics analysis. The physical and baking properties of caroubin were characterized via SE-HPLC, laser scanning confocal microscopy, farinograph mixing, and texture profile analyzer analysis. Using a modified Osborne fractionation method, carob germ flour proteins were found to contain ~32% albumin and globulin and ~68% glutelin with no prolamins detected. When divided into soluble and insoluble protein fractions under non reducing conditions it was found that caroubin contained (~95%) soluble proteins and only (~5%) insoluble proteins. As in wheat, SEC-MALS analysis showed that the insoluble proteins had a greater Mw than the soluble proteins and ranged up to 8x107 Da. These polymeric proteins appeared to play a critical role in protein network formation. Analysis of the physical properties of carob germ protein-maize starch dough showed that the dough’s functionality was dependent on disulfide bonded protein networks, similar to what is found in wheat gluten. When baked into a bread these proteins were shown to have a possible improving affect by decreasing staling in gluten-free breads. This was evident when compared to a gluten-free batter bread, and a wheat bread over a five day period. United States Department of Agriculture grain marketing and production research center Master of Science Masters Food Science Institute - Animal Science & Industry Fadi M. Aramouni, Scott Bean (Agronomy)
Gluten Free Cereal Products and Beverages presents the latest work in the development of gluten free products, including the detection of gluten, exploring the raw materials and ingredients used to produce gluten free products, and the labeling of gluten free products.
The way a dough behaves when flour and water are initially mixed, and during further processing, are vitally important in determining the food quality of the end product. Rheology is the study of the flow of a material, which is deformed over time when a strain is applied. Dough is a viscoelastic polymer and hence its properties depend on how quickly the test is performed. Dough rheology has a major impact on the processing and quality of the end products such as bread, noodles and biscuits (cookies). Hence accurately defining dough rheology to predict end-product quality has been and continues to be a major challenge for the cereal chemist.
The rheological behaviour of a particular dough depends on the interaction of the genotype with the environment (G X E). The protein polypeptides, in particular the high-molecular-weight glutenin subunits (HMW-GS) and the low-molecular-weight glutenin subunits (LMW-GS), make a major contribution to the gluten macropolymer. The HMW-GS and LMW-GS are coded by the Glu-1 and Glu-3 genes, respectively. A wheat breeder-cereal chemist team can select for these six glutenin alleles and hence affect the genotype of a wheat variety. Environmental conditions, such as soil type, rainfall and temperature, can influence the proportion and amount of protein deposition in the developing wheat kernel. Hence, the environment modifies the genetic potential of a wheat variety. The grain received after harvest will have both G and E components. The G X E interactions affect the way the grain behaves during processing and hence the end-product quality of food. Cereal science has come a long way from the days when the total protein content was used as the main measure of processing quality. Not only is the total amount of protein important but also the percentage of different types of protein, such as the insoluble or unextractable polymeric protein (UPP), and the amount and type of the individual glutenin subunits. These affect the dough properties and hence the marketability of a wheat sample.
The rheological behaviour of a particular dough depends on the interaction of the genotype with the environment (G X E). The protein polypeptides, in particular the high-molecular-weight glutenin subunits (HMW-GS) and the low-molecular-weight glutenin subunits (LMW-GS), make a major contribution to the gluten macropolymer. The HMW-GS and LMW-GS are coded by the Glu-1 and Glu-3 genes, respectively. A wheat breeder-cereal chemist team can select for these six glutenin alleles and hence affect the genotype of a wheat variety. Environmental conditions, such as soil type, rainfall and temperature, can influence the proportion and amount of protein deposition in the developing wheat kernel. Hence, the environment modifies the genetic potential of a wheat variety. The grain received after harvest will have both G and E components. The G X E interactions affect the way the grain behaves during processing and hence the end-product quality of food. Cereal science has come a long way from the days when the total protein content was used as the main measure of processing quality. Not only is the total amount of protein important but also the percentage of different types of protein, such as the insoluble or unextractable polymeric protein (UPP), and the amount and type of the individual glutenin subunits. These affect the dough properties and hence the marketability of a wheat sample.
Gluten is an essential structure-building protein, contributing to the appearance, crumb structure, and consumer acceptability of many baked products. Therefore, the biggest challenge for food scientists and bakers in the area of gluten-free products is probably the production of high-quality gluten-free bread. Market research showed that the majority of breads currently on the market are of very poor quality. In wheat bread, gluten has such a wide range of functions that it is not possible to replace wheat flour with one single ingredient. Good-quality gluten-free bread can only be produced if a range of flours and polymeric substances, which mimic the viscoelastic properties of gluten, are included in the gluten-free formulation. It is recommended to use a range of gluten-free flours rather than just one flour to achieve products with good sensory and textural properties. The addition of a certain percentage of starch to a gluten-free formulation does certainly improve the overall quality of the gluten-free bread. Naturally gluten-free starches such as that from rice, potatoes, or tapioca, rather than wheat starch, should be used for this purpose. Hydrocolloids are an essential ingredient for gluten-free bread production, since they are able to mimic the viscoelastic properties of gluten to a certain extent. Research performed so far suggests that xanthan gum and HPMC are the most suitable hydrocolloids for gluten-free bread formulations. Protein-based ingredients are also essential in the improvement of gluten-free bread, and the most promising are probably the dairy-based ingredients. It is essential that only low lactose dairy ingredients be used. One of the most important ingredients in any gluten-free formulation is water, and therefore it is essential to optimize the water level for every formulation to achieve optimal results.
The possibility of forming dough from kafirin was investigated and laboratory prepared kafirin was formed into a viscoelastic dough system. Measurements with Contraction Flow showed that dough systems prepared from kafirin and from commercial zein had the required extensional rheological properties for baking of leavened bread. The extensional viscosity and strain hardening of the kafirin and zein dough systems were similar to those of gluten and wheat flour doughs. The kafirin dough system, however, unlike the zein dough system rapidly became very stiff. The stiffening behaviour of the kafirin dough system was presumed to be caused by cross-linking of kafirin monomers. SDS-PAGE showed that the kafirin essentially only contained α- and γ-kafirin, whereas the zein essentially only contained α-zein. Since γ-kafirin contains more cysteine residues than the α-prolamin it is more likely to form disulphide cross-links, which probably caused the differences in stiffening behaviour between kafirin and zein dough systems. Overall the kafirin dough system displayed rheological properties sufficient for baking of porous bread. Kafirin like zein appears to have promising properties for making non-gluten leavened doughs.
The effect of hydrocolloids on dough rheology and bread quality parameters in gluten-free formulations based on rice flour, corn starch, and sodium caseinate (control) was studied; the hydrocolloids added at 1% and 2% w/w (rice flour basis) were pectin, carboxymethylcellulose (CMC), agarose, xanthan and oat β-glucan. The study on rheological behavior of the doughs containing hydrocolloids, performed by farinography and rheometry, showed that xanthan had the most pronounced effect on viscoelastic properties yielding strengthened doughs; addition of xanthan to the gluten-free formulation resulted in a farinograph curve typical of wheat flour doughs. Moreover, among the preparations supplemented with hydrocolloids the elasticity and resistance to deformation of dough, as determined by oscillatory and creep measurements, followed the order of xanthan > CMC > pectin > agarose > β-glucan. The type and extent of influence on bread quality was also dependent on the specific hydrocolloid used and its supplementation level. Generally, the volume of breads increased with addition of hydrocolloids except for xanthan; with increasing level of hydrocolloids from 1% to 2% the loaf volume decreased except for pectin. Empirical methods were used for evaluation of porosity and elasticity of the crumb; high values of porosity were found for breads supplemented with CMC and β-glucans at 1% concentration, and pectin at 2%, whereas high crumb elasticity was exhibited by CMC, pectin and xanthan at 2%. An increase in lightness (L value) of crust was observed with the addition of β-glucan at 1%, whereas the whiteness of crumb was improved with inclusion of xanthan. Sensory evaluation by a consumer panel gave the highest score for overall acceptability to the gluten-free formulation supplemented with 2% CMC. In most cases, addition of hydrocolloids did not affect significantly the water activity (aw) values of crumb. During storage of breads a reduction in aw and an increase in firmness of crumb (compression tests) were observed. Compared to the control formulations, crumb firmness was not alter significantly with addition of pectin, CMC and agarose (at 1–2%), and of β-glucan (at 1%); instead, addition of xanthan (1–2%) as well as β-glucan (2%) resulted in crumb hardening.
The secondary structure of a dough-like zein polymer was compared to the structure present in a wheat viscoelastic system using FT-IR spectroscopy. When zein was mixed at 35 °C, which is above its glass transition temperature (Tg), changes in its secondary structure suggested that the protein loses its native structure, mainly composed of α-helices (∼68%), and a viscoelastic system is formed by a structural rearrangement that favors β-sheet structures. This rearrangement is very similar to the structural changes observed in gluten viscoelastic polymers. Upon removal of shear stress, the zein polymer showed a rapid decrease in the proportion of β-sheet structures (from ∼48% to ∼28% after the first 3 min) in favor of unordered structures. At the same time, the viscoelasticity of the polymer decreased rapidly. In contrast, gluten, in a similar viscoelastic system and held at the same temperature, showed a fairly constant high content of β-sheet structures (∼49%) coinciding with the slow relaxation time typical of gluten networks after the removal of shear. We speculate that the addition of a protein capable of causing extensive and stable β-sheet formation in the zein–starch viscoelastic polymer could increase the stability and relaxation time of the zein system and, thereby, create the possibility of a zein dough with similar functionality to a wheat viscoelastic system.
Gluten-free bread was prepared from commercial zein (20 g), maize starch (80 g), water (75 g), saccharose, NaCl and dry yeast by mixing above zein's glass transition temperature (Tg) at 40°C. Addition of hydroxypropyl methylcellulose (HPMC, 2 g) significantly improved quality, and the resulting bread resembled wheat bread having a regular, fine crumb grain, a round top and good aeration (specific volume 3.2 ml/g). In model studies, HPMC stabilized gas bubbles well. Additionally, laser scanning confocal microscopy (LSCM) revealed finer zein strands in the dough when HPMC was present, while dynamic oscillatory tests showed that HPMC rendered gluten-like hydrated zein above its Tg softer (i.e. |G*| was significantly lower). LSCM revealed that cooling below Tg alone did not destroy the zein strands; however, upon mechanical impact below Tg, they shattered into small pieces. When such dough was heated above Tg and then remixed, zein strands did not reform, and this dough lacked resistance in uniaxial extension tests. When within the breadmaking process, dough was cooled below Tg and subsequently reheated, breads had large void spaces under the crust. Likely, expanding gas bubbles broke zein strands below Tg resulting in structural weakness.
Maize prolamin (zein), together with starch, hydroxypropyl methylcellulose, sugar, salt, yeast and water can form wheat-like cohesive, extensible, viscoelastic dough when mixed above room temperature (e.g. 40 °C). This dough is capable of holding gas. However, it is excessively extensible, and when used for hearth-type rolls, it tends to become flat. Bench-scale defatting of zein with chloroform at room temperature significantly (P < 0.05) improved specific volume (4.5 ml/g vs. 3.3 ml/g) and shape of the rolls (width-to-height 2.0 vs. 3.9). The total lipid content determined by accelerated solvent extraction (100 °C, 69 bar, chloroform), however, only decreased from 8.0 to 6.6% due to this bench-scale defatting. Staining experiments with Naphthol Blue Black suggested that bench-scale defatting removed surface lipids from the zein particles, and thus facilitated their aggregation. Aggregation experiments with zein and water at 40 °C, and laser scanning confocal microscopy with zein-starch dough confirmed that zein particles aggregated more easily when surface-defatted. Dynamic oscillatory temperature sweeps demonstrated that surface-defatting lowered the temperature at which protein cross-linking occurred by 2 °C. This research can help to produce superior gluten-free bread and could also possibly contribute to the better understanding of wheat dough.
Biochemical properties of carob germ proteins were analyzed using a combination of selective extraction, reversed-phase high-performance liquid chromatography (RP-HPLC), size exclusion chromatography (SEC) coupled with multiangle laser light scattering (SEC-MALS), and electrophoretic analysis. Using a modified Osborne extraction procedure, carob germ flour proteins were found to contain approximately 32% albumin and globulin and approximately 68% glutelin with no prolamins detected. The albumin and globulin fraction was found to contain low amounts of disulfide-bonded polymers with relatively low M(w) ranging up to 5 x 10(6) Da. The glutelin fraction, however, was found to contain large amounts of high molecular weight disulfide-bonded polymers with M(w) up to 8 x 10(7) Da. When extracted under nonreducing conditions and divided into soluble and insoluble proteins as typically done for wheat gluten, carob germ proteins were found to be almost entirely ( approximately 95%) in the soluble fraction with only ( approximately 5%) in the insoluble fraction. As in wheat, SEC-MALS analysis showed that the insoluble proteins had a greater M(w) than the soluble proteins and ranged up to 8 x 10(7) Da. The lower M(w) distribution of the polymeric proteins of carob germ flour may account for differences in functionality between wheat and carob germ flour.
This study was conducted to improve the quality and theoretical understanding of gluten-free sorghum bread. The addition of 2% hydroxypropyl methylcellulose improved bread based on 105% water, 70% sorghum flour, and 30% potato starch. Nevertheless, a flat top and tendency toward a hole in the crumb remained. Sourdough fermentation of the total sorghum flour eliminated these problems. Size-exclusion high-performance liquid chromatography demonstrated that during sourdough fermentation, proteins from the dough liquid were degraded to peptides smaller than kafirin monomers (<19 kDa). Laser scanning confocal microscopy showed aggregated protein in bread crumb without sourdough fermentation, whereas with sourdough fermentation, only small isolated patches of protein bodies embedded in matrix protein remained. In oscillatory temperature sweeps, sourdough fermentation caused a significantly higher resistance to deformation (|G*|) after gelatinization of the above batter relative to batters without sourdough. Results suggest that a strong starch gel, without interference of aggregated protein, is desirable for this type of bread.
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