Quality parameters and baking performance of commercial gluten flours

Commercial gluten which is labeled in different ways, i.e., gluten, gluten flour, glutinated flour, is sold without any specifications. Breadmaking potential of commercial gluten was assessed by adding them in different concentration levels (6 and 50 g/100 g) to wheat flour. This evaluation was done by physicochemical analyses and subjective characterization. Protein content of commercial glutens ranged from 15.2 g/100 g to 75.2 g/100 g. Diastatic activity of glutinated flours was around 30% lower than the values of wheat flour, while this activity in gluten flours was 24 - 79% lower than wheat flour values. Direct correlation was observed between protein content of blends and loaf volumes: breads volume value increased with the percentage of protein in blends (r_s=1). Furthermore as the percentage of protein in flour blends increased (up to 17.5 g/100 g) scores for smell, crumb color, crumb grain, crumb texture and eatability improved. Breads obtained by incorporating 6 g/100 g of gluten flour or 50 g/100 g of glutinated flour to a wheat flour had the best scores. Breads containing the highest protein content (50 g/100 g gluten flour) were refused by taste panelists, however, after being sliced and toasted they were rated acceptable.     

板栗淀粉、蛋白质及全粉的特性及在面包中应用研究

基于淀粉和蛋白质对面包品质至关重要,分析板栗粉、板栗淀粉及板栗蛋白的特性,并探索对面包品质的影响。板栗粉中淀粉（52.87%）、蛋白质（6.58%）均低于高筋小麦粉。与小麦淀粉相比,板栗淀粉更易溶胀、糊化,但热稳定性较差。与小麦蛋白相比,板栗蛋白的α-螺旋含量(10.6%)较低,无规卷曲（34.4%）较高。这些特性正好反映了,随着板栗粉的添加量提高,板栗粉-小麦粉混合粉粉质品质和面包比容均呈下降趋势。当板栗粉添加量为10%时,面包体积最大、气孔细密、评分最佳。     

Effect of defatted maize germ flour addition on the physical and sensory quality of wheat bread

Maize (Zea mays L.) processing produces large quantities of defatted maize germ (DMG) that is being used mainly for animal feed. The objective of this study was to exploit use of this nutrient-rich by-product in bread by replacing wheat flour at 5-20 g/100 g levels. Breads prepared with wheat-DMG flour blends were analyzed for loaf volume, density, instrumental dough hardness and bread firmness, Hunter color (“L”, “a”, “b”, chroma, and hue angle), and selected sensory attributes. Loaf volumes decreased significantly, from 318.8 ml to 216.3 ml, as the DMG flour supplementation was increased from 0 to 20 g/100 g; a similar effect was observed for bread specific volume. Increase in dough hardness (7.56-71.32 N) was directly related to increase in DMG flour levels. Instrumental firmness values were significantly higher for breads containing DMG flours, 61.58 N in 20 g/100 g DMG bread versus 32.84 N for the control bread, made with wheat flour only. The control bread was lighter in color, as shown by higher “L” values, than those having DMG flour, with chroma and hue angle values significantly higher in treatment breads. In general, no differences were observed for the sensory attributes of crumb color, cells uniformity, aroma, firmness, mouthfeel, and off-flavor in breads with up to 15 g/100 g DMG flour, while the overall acceptability scores showed a mixed pattern. The results of this study demonstrated that acceptable quality bread could be made with DMG flour addition at ≤15 g/100 g.     

Physicochemical and sensory properties of soy bread made with germinated,steamed, and roasted soy flour

For the development of healthful gluten-free soy bread acceptable to consumers, we evaluated the effects of various processing procedures for soy flour on bread quality, in terms of beany flavour and texture. We pretreated soy flour by both non-heating (raw:NS and germinated:GS) and heating (steamed:SS and roasted:RS) methods. In addition, to improve the loaf volume, we added 1% hydroxypropyl-methylcellulose (HPMC) to RS flour. Lipoxygenase activity was retained in the non-heat-treated flours (279 U/g for NS and 255 U/g for GS), but was significantly reduced in the heat-treated flours (106 U/g for SS and 69 U/g for RS). Moreover, heat-treated flour had higher isoflavone and ferric reducing antioxidant power than had non-heat-treated flour. However, RS flour had the lowest moisture content and lowest L^∗ value. The GS bread had the highest specific loaf volume (3.53 cm³/g), followed by NS (2.96 cm³/g), RS (2.25 cm³/g), and SS (1.81 cm³/g) bread. GS bread had the lowest hardness (1.53 N), followed by NS (1.65 N), RS (2.00 N), and SS (3.75 N) bread. The addition of 1% HPMC to RS increased the loaf volume (2.44 cm³/g), but decreased the bread’s hardness (1.80 N). As to the sensory properties, the bread with heat-treated flour was perceived to have a less beany odour and taste than was the bread with non-heat-treated flour. However, the latter had a better appearance than the former. These results indicated that soy flour pretreatment could enhance the loaf volume and reduce the beany flavour of whole soy bread.     

Phytochemicals and heavy metals content of hairless canary seed: A variety developed for food use

Canary seed is one of the top four specialty crops grown in Western Canada. Currently it is used entirely in food mixtures for caged birds but our previous studies have shown its unique composition and potential use in food and non-food applications. Through improvements by plant breeding a hairless variety was developed for human consumption and animal feeding. This study was aimed at investigating phytochemicals and heavy metals in hairless canary seed in comparison with the hairy variety and common wheat using three milling fractions (wholegrain, starchy flour and bran). The levels of bound and unbound phenolic acids, phytate, trypsin and amylase inhibitors tended to be similar in the three grains at a given level of processing. This was also true for most heavy metals tested although hairy canary seed exhibited a significantly higher concentration of copper while both canary seed varieties contained more nickel and zinc than wheat. Condensed tannins, alkaloids and deoxynivalenol (DON) were not detected in any of the crops while very low levels of aflatoxin were detected in all three grains. The results show that both hairless and hairy canary seed possess phytochemicals and heavy metals profile close to that of wheat demonstrating the potential of hairless canary seed as a food crop due to the absence of harmful hairs.     

Hard Red Spring wheat/C-TRIM 20 bread: Formulation,processing and texture analysis

C-TRIM, a β-glucan-rich fraction, was added to Hard Red Spring wheat (HRSW) flour to increase soluble fiber content of bread, and to obtain a minimum of 0.75 g/bread serving (0.75 g/30 g or 2.5%) required by FDA for health claim. Three treatments or blends FGT0 (100% wheat flour – control), FGT1 (58% flour, 25% gluten and 17% C-TRIM) and FGT2 (60% flour, 22.5% gluten, and 17% C-TRIM) were used in the study. The total amount of soluble fiber from C-TRIM in FGT1 and FGT2 was 4.07–4.17% which was more than the amount required by FDA. The presence of C-TRIM increased both, the Farinograph water absorption and the arrival time. The dough mixing tolerance index (MTI) was also increased by C-TRIM. The FGT1 had higher stability than FGT2, whereas, the loaf volume of FGT1-B was also significantly higher than FGT0-B control and FGT2-B bread. The DSC results indicated that the amount of freezable-water in C-TRIM treated bread (FGT1-B and FGT2-B) was significantly higher than the control wheat flour bread (FGT0-B). This may be attributed to the higher amount of water absorbed by C-TRIM during bread dough (FGT1-D and FGT2-D) preparation and trapped or bound within the bread matrix after baking as compared to the control. After storage of FGT0-B, FGT1-B, and FGT2-B breads 2, 5, and 7 days storage at 25 °C, 4 °C, and −20 °C, the texture of bread were measured with a Texture Analyzer and the data analyzed statistically. The FTG0-B control bread firmness was significantly higher than FGT1-B and FGT2-B C-TRIM treated breads after 7 days storage at 25 °C. The amount of 0.1 M acetic acid-extractable protein was lower in FGT1-B than the control wheat flour (FGT0-B) sample. In addition, more protein was extracted at pH 7.0 than pH 4.5 because of less charges at neutral pH than pH 4.5. The free zone capillary electrophoresis analysis showed obvious differences in the protein charge and size between the dough and bread.     

Effect of addition of protein concentrates from natural and yeast fermented rice bran on the rheological and technological properties of wheat bread

The effect of substituting wheat flour with 0%, 5%, 10% and 15% protein concentrates from natural and yeast fermented rice bran on the rheological properties of their dough and bread properties was studied. Rheological properties of wheat dough were influenced by addition of rice bran protein concentrates. Overall acceptability score and specific loaf volume of 100% wheat bread were not significantly different from composite bread up to 10% rice bran protein substitution, and therefore, the optimised level of substitution was established. The optimised composite bread contained higher total amino acid content, radical scavenging activity and ferric reducing ability power (43.04–48.87 g/100 g, 182.77–201.65   mmol TEAC/100 g and 613.29–637.81 mmol TE/100 g) than control (33.86 g/100 g, 109.43 mmol TEAC/100 g and 540.13 mmol TE/100 g). Springiness, cohesiveness and resilience values of wheat bread were not significantly different from composite bread. Scanning electron microscopy revealed that composite bread had surfaces with embedded granules like protein deposits with small spores.     

Influence of Tomato Seed Addition on the Quality of Wheat Flour Breads

Tomato seed, an abundant tomato processing waste product, contains high amounts of crude fat and protein. The protein is especially high in lysine, the limiting amino acid of cereal products. Dried, ground tomato seeds were added at 5, 10, 15, and 20% wheat flour replacement levels. The influence of tomato seed addition on amino acid content, loaf volume, and staling rate were studied. A sensory evaluation based on odor only was conducted to identify consumer attitudes towards “tomato seed bread.” The addition of tomato seed at a replacement level of 20% to a bread formula with shortening resulted in no significant change (P < 0.05) in staling rate, but showed an increase in specific loaf volume of 20.4%. No significant differences in specific loaf volume were found between bread with 3% shortening and the 10% tomato seed supplemental bread without shortening. Addition of fat extracted tomato seeds at the 20% level decreased specific loaf volume by 72%. The supplementation of wheat flour bread at the 10% and 20% replacement levels increased lysine by 40.2% and 69.0% respectively.     

Optimization of ingredients and baking process for improved wholemeal oat bread quality

Baking technology for tasty bread with high wholemeal oat content and good texture was developed. Bread was baked with a straight baking process using whole grain oat (51/100 g flour) and white wheat (49/100 g four). The effects of gluten and water content, dough mixing time, proofing temperature and time, and baking conditions on bread quality were investigated using response surface methodology with a central composite design. Response variables measured were specific volume, instrumental crumb hardness, and sensory texture, mouthfeel, and flavour. The concentration and molecular weight distribution of β-glucan were analysed both from the flours and the bread. Light microscopy was used to locate β-glucan in the bread. Proofing conditions, gluten, and water content had a major effect on specific volume and hardness of the oat bread. The sensory crumb properties were mainly affected by ingredients, whereas processing conditions exhibited their main effects on crust properties and richness of the crumb flavour. β-glucan content of oat bread was 1.3/100 g bread. The proportion of the highest molecular weight fraction of β-glucan was decreased as compared with the original β-glucan content of oat/wheat flour. A great part of β-glucan in bread was located in the large bran pieces.     

Selenium concentration and speciation in biofortified flour and bread: Retention of selenium during grain biofortification,processing and production of Se-enriched food

The retention and speciation of selenium in flour and bread was determined following experimental applications of selenium fertilisers to a high-yielding UK wheat crop. Flour and bread were produced using standard commercial practices. Total selenium was measured using inductively coupled plasma-mass spectrometry (ICP-MS) and the profile of selenium species in the flour and bread were determined using high performance liquid chromatography (HPLC) ICP-MS. The selenium concentration of flour ranged from 30 ng/g in white flour and 35 ng/g in wholemeal flour from untreated plots up to >1800 ng/g in white and >2200 ng/g in wholemeal flour processed from grain treated with selenium (as selenate) at the highest application rate of 100 g/ha. The relationship between the amount of selenium applied to the crop and the amount of selenium in flour and bread was approximately linear, indicating minimal loss of Se during grain processing and bread production. On average, application of selenium at 10 g/ha increased total selenium in white and wholemeal bread by 155 and 185 ng/g, respectively, equivalent to 6.4 and 7.1 μg selenium per average slice of white and wholemeal bread, respectively. Selenomethionine accounted for 65–87% of total extractable selenium species in Se-enriched flour and bread; selenocysteine, Se-methylselenocysteine selenite and selenate were also detected. Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.     

Effect of dietary fiber from sugarcane bagasse and sucrose ester on dough and bread properties

The suitability of an emulsifier, sucrose ester, to enhance the proportion of dietary fiber in white pan bread was examined. The substitution of dietary fiber from sugarcane bagasse and a commercial dietary fiber (Solka Floc^® 900) were varied from 0 to 15 g/100 g of wheat flour mass. Expansion and stickiness of dough, volume, specific volume, firmness and springiness of bread, including sensory evaluation all decreased as each of dietary fiber increased. Bread properties improved with sucrose ester addition. Bread made by 10 g/100 g of each dietary fiber substitution, was scored favorable by consumer when sugar ester was added at 1.5 g/100 g as wheat flour mass.     

Effects of barley flour and barley protein isolate on chemical, functional, nutritional and biological properties of Pita bread

This study was carried out to investigate the effects of fortification of wheat flour with barley flour (BF) and barley protein isolate (BPI) at three levels; 5, 10 and 15% levels on the chemical composition, nutritional evaluation and biological properties of pita bread. Proteins fractions such as globulin, prolamin, glutelin-1 and glutelin-2 as well as protein isolates were extracted from barley flour and evaluated for protein yield, chemical composition and nutritional quality. Highest yield and essential amino acids contents were obtained in barley protein isolate. SDS-PAGE gels electrophoresis indicated that fortified wheat flour with BPI and BF consists of proteins coming from wheat flour and barley proteins. The contents of essential limiting amino acids in bread were increased from 1.38 to 3.10 g/100 g for lysine and from 0.86 to 1.73 g/100 g for methionine as the ratio of fortification with BF and BPI increased from 0 to 15%. The highest content of total phenolics, antioxidant activity, and inhibitory activity for both angiotensin converting enzyme (ACE) and α-amylase were found in fortified bread with BPI at 15%. Results indicated that bread made from fortification of wheat flour with BF and BPI at 15% showed superior chemical, physico-chemical, nutritional and biological properties.     

Cooperation of phosphatidylcholine with endogenous lipids of wheat flour for an increase in dough volume

Phosphatidylcholine (PC) increases the gas-retaining ability of dough, the dough volume on fermentation and the loaf volume of bread. The cooperation of wheat flour endogenous lipids with PC was examined. More than 90% of the total wheat flour lipids were extracted with chloroform, the extracted lipids comprising glycolipids (33 wt%), non-polar lipids (56 wt%), and phospholipids (11 wt%). The increase in the specific volume of dough with delipidated wheat flour by the addition of PC was smaller than the increase in the specific volume of dough with native wheat flour. The addition of the extracted lipids to delipidated wheat flour restored the increase in dough volume by the addition of PC. The glycolipid fraction of the extracted lipids was most effective for enhancing the action of PC. The results suggest that interaction of PC with wheat flour glycolipids may synergistically increase foam stability to enhance the gas-retaining stability of dough.     

Yeast leavened banana-bread: Formulation,processing, colour and texture analysis

Banana powder (BP) was added to hard-red spring wheat (HRSW) flour intended for yeast-leavened bread formulation. Five different formulations containing 10%, 15%, 20%, 25%, and 30% BP were prepared with varying amounts of base flour, while vital gluten was maintained at 25% in all blends. Based on the added BP amounts only, the prepared bread could deliver 42.87–128.6 mg potassium/30 g of bread (one regular slice) and 0.33–1.00 g of fibre. Although the dough water absorption was increased, due to BP addition, the dough mixing tolerance (MTI) decreased. The bread loaf volume was significantly higher than the control except for the 30% blend, where the loaf volume was similar to the control. Bread staling increased with BP levels due to the high sugar content but, this effect was limited to the first two days of storage. Blends exhibited darker colour due to the high sugar and protein, while the 25% and 30% blends had the lowest percent of freezable water. The amounts of acetic acid extractable proteins from the dry blends and the dough decreased with increase in BP. The linear rheological properties of the control, 10%, and 30% blends exhibited similar viscoelastic solid behaviour, where both G′ and G′′ had plateaus (G′ > G′′) and they were parallel to each other over three decades of the frequency. Blends showed higher moduli values than the control.     

Bread improvers: Comparison of a range of lipases with a traditional emulsifier

This study compares three generations of lipase enzymes with the emulsifier, diacetyl tartaric esters of mono-glycerides (DATEM), on white wheat flour bread. Baking recipes with addition of DATEM (4500 ppm), Lipopan F-BG (15 ppm), Gryndamyl Exel-16 (115 ppm), Lipopan Xtra-BG (25 ppm) and Lipopan 50-BG (27.5 ppm) were test-baked after 60 and 150 min fermentations, to study their effects on the baking characteristics of volume, oven rise, crust colour, crumb texture and colour, shelf-life, flavour and aroma. The enzymes and emulsifier preparation caused significant increase in bread oven rise and specific volume with the exception of Lipopan 50-BG, which failed to improve loaf volume in the short fermentation method. There was no significant difference between other lipase enzymes and DATEM as a bread volume improver. Increase in fermentation time resulted in increase in volume in all samples, except for Lipopan-Xtra.     

A comparison of the ability of several small and large deformation rheological measurements of wheat dough to predict baking behaviour

The rheological characteristics of twenty wheat flour samples obtained from four organic flour blends and a non-organic control were compared in relation to their ability to predict subsequent loaf volume in the baked bread. The flour samples considered had protein contents that varied between 11–14 g/100 g. Four different rheological methods were employed. Oscillatory stress rheometry on the protein gel extracted from the wheat flour, oscillatory stress rheometry and creep measurement on undeveloped dough samples and biaxial extensional measurements on simple flour–water doughs. None of the fundamental rheological parameters correlated with loaf volume. There was a correlation between the storage modulus of the gel protein and storage modulus for the undeveloped dough (r = 0.85). There was a weak negative correlation between protein content and biaxial extensional viscosity (r = −0.62). Stepwise multiple regression related loaf volume to dough stability time (measured on the Farinograph) and tan (phase angle) for the undeveloped dough samples (overall model r² = 0.54). The results indicate that the four rheological tests considered could not be used as predictors of subsequent loaf volume when the bread is baked.     

In vitro starch hydrolysis and estimated glycaemic index of bread substituted with different percentage of chempedak (Artocarpus integer) seed flour

Chempedak (Artocarpus integer) seed flour (CSF) was substituted for wheat flour at different levels (0%, 10%, 20%, 30% w/w) in bread. Assessment on the in vitro starch hydrolysis was carried out to evaluate the hydrolysis index (HI) and estimated glycaemic index (EGI) of bread substituted with different levels of CSF. Kinetics of in vitro starch hydrolysis in all bread samples (with the exception for white bread) indicated a gradual increase with respect to time intervals. Bread of 30% CSF exhibited significantly lower (p < 0.05) in vitro starch hydrolysis, as compared with the other samples. Results showed that HI value decreased significantly (p < 0.05) as the levels of CSF substitution increased. Resistant starch (RS) content in bread samples was inversely related with HI value as CSF substitution levels increased, thus lowering the EGI value.     

Effects of Defatted Jack Bean Flour and Jack Bean Protein Concentrate on Physicochemical and Sensory Properties of Bread

This study evaluated the effects of substituting wheat flour with defatted Jack bean flour and Jack bean protein concentrate on bread quality. Jack bean flour milled from the seed nibs was defatted with n-hexane and part of the defatted flour (DJF) extracted in acid medium (pH; 4.5) for protein concentrate (JPC). Both the DJF and JPC were analysed for nutrient composition, and then used to fortify bread. Five bread samples with 0%, 10% and 20% of DJF or JPC were prepared using straight dough procedure, and then analysed for quality characteristics. The DJF and JPC had 28.8% and 49.47% protein, 46.44% and 30.22% carbohydrate, 0.61% and 1.00% crude fibre respectively; and were rich in Ca, Fe, Zn and P. Both DJF and JPC improved quality of bread but JPC conferred better quality. The 20% DJF and JPC respectively improved protein content of bread from 9.45% to 10. 97% and 11.16%, crude fibre from 2.39% to 5.20% and 5.32%, fat from 2.35% to 7.00% and 6.55%, and ash content from 1.35% to 2.05% and 2.10% but decreased carbohydrate content from 72.12% to 50.45% and 50.39% in the bread samples. All the fortified bread samples had acceptable crumb colour, crumb texture, flavour and loaf volume significantly comparable (p > 0.05) to those of 100% wheat bread. Thus, defatted Jack bean flour and Jack bean protein concentrate is recommended for use in fortifying bread for higher quality.     

Effect of Soybean 7S Protein Fractions, Obtained from Germinated and Nongerminated Seeds, on Dough Rheological Properties and Bread Quality

Germinated soybean flour has been proposed for use in bread making as a product to improve bread quality when small amounts are added to wheat flour. However, it is not clear which soybean components promote this action, and how these components may influence bread quality. The aim of this work was to evaluate the effect of the addition of soybean 7S protein fraction obtained from germinated and nongerminated seeds in dough rheological properties (farinographic and extensographic) and bread quality, including loaf volume, texture (firmness, compression force, resilience), colour (L*, a*, b*), crumb grain structure (cell density, mean cell area, shape factor), and consumer acceptance (sensory analysis). Results showed that this protein fraction just slightly affects bread quality, since no significant changes (P > 0.05) on bread volume and texture were obtained. Only crust and crumb colour were affected in a small amount, and a coarser crumb structure was also observed when adding 7S protein obtained from germinated soybean at its highest concentration. As the proportion of protein increased in the flour, both kinds of 7S fraction (germinated and nongerminated) were related to the increment in water absorption, as well as to the increment in extensographic maximum resistance to extension, specifically when adding 7S protein obtained from nongerminated soybean seeds. These results showed that the 7S soybean protein, as obtained in this work, is not related to the reported loaf bread quality improving effect of this legume when it is added in small quantities.     

Physicochemical and bread-making properties of air flow pulverized wheat and corn flours

The air flow pulverized grain flours were prepared from American wheat (AWF), Korean wheat (KWF), and corn (CRF) at 3 different grinding speeds, 9,000, 10,000, and 11,000 rpm. The effects of grinding speed on the physicochemical and bread making characteristics of resulting flours were investigated. Pulverization at low grinding speed produced the flour similar to those from conventional milling in particle size (80–100 μm). The higher speed grinding at 11,000 rpm produced grain flours with smaller particle sizes (20–30 μm) and higher amount of damaged starches. Accordingly, grinding speed increased water holding capacity, swelling power, and water solubility of the resulting grain flour, and also increased pasting properties. Gluten addition was needed for KWF (15% gluten) and CRF (30% gluten) to facilitate optimum bread making. The flour pulverized at high speed produced the KWF and CRF bread with the highest loaf volume and the lowest firmness.