Effect of fungal α-amylase on the dough properties and bread quality of wheat flour substituted with polished flours

Whole grains of a hard-type wheat cultivar ‘1CW’ (No. 1 Canada Western Red Spring) were polished from the outer layer to the inner layer by 10% of the total grain weight using a modified rice-polisher. The polished flours of three fractions; C-1, C-5, and C-8 corresponding to 100–90%, 60–50% and 30–0% layer of the 1CW grain, respectively were used in this study. Effects of fungal α-amylase on polished flour substitution for the common wheat flour CW of 1CW on rheological or physicochemical dough properties and bread qualities were studied. When the polished flours were substituted for CW without fungal α-amylase, the mixing tolerance index of dough in a farinograph and all parameters of viscoelastic properties significantly increased rather than those of CW alone. As a result, baking qualities of breads made from the substituted flours were significantly inferior. But, the polished flours increased the total gas generation significantly during fermentation, as compared with CW alone. The addition of fungal α-amylase to polished flour substituted CW distinctly developed gluten matrix in the SEM images and produced large amounts of the generated gas during fermentation. Therefore, the loaf volume and firmness of breads were improved by the combined additions of polished flours and fungal α-amylase. Especially, the C-8 of the innermost fraction was more susceptible to affection of fungal α-amylase among all polished flours, and resulted in improvement of gas cell distribution and softness of breadcrumbs without lowering the loaf volume as compared with CW bread.     

Analysis of volatile compounds in Polished-graded wheat flours using headspace sorptive extraction

Headspace sorptive extraction method was used to determine the volatile flavor compounds of the Polished-graded wheat flours and commonly milled wheat flour (CW). The Polished-graded wheat flours of three fractions, C-1 (100-90%), C-5 (60-50%) and C-8 (30–0%), and CW obtained from a hard-type wheat cultivar ‘1CW’ (No. 1 Canada Western Red Spring) were used in the present study. A total of 48 volatile flavor compounds determined in all samples were common as in the wheat grain or flour. The major volatile compounds in C-1 included methoxybenzene (i.e. 1,4-dimethoxybenzene, 1,2,4-trimethoxybenzene, 1,2-dimethoxybenzene) associated with musty odors, and nitrogen compounds (i.e. trimethylamine, 3(4)-methyl pyridine, and 3-methoxy pyridine). The volatile flavor compounds identified in C-5 and C-8 were similar to those in CW. But, some compounds that have a connection with both oxidation products from unsaturated fatty acids and metabolites of a number of species associated with moldy grains, were more abundant in C-5 and C-8 than in CW. Furthermore, hexanal, methanol, ethanol, hexanol, 1-octen-3-ol, 3-octen-2-one, (E,Z)-3,5-octadien-2-one, (E,E)-3,5-octadien-2-one were considerably abundant in C-5 and C-8.     

马铃薯粉对面包烘焙特性与风味化合物的影响

以小麦面包为对照,研究马铃薯粉添加量为15%对面包烘焙特性的影响,并应用电子鼻以及顶空固相微萃取-气相色谱-质谱联用技术,分析马铃薯面包挥发性风味化合物的特征。结果表明,马铃薯粉的添加对面包的品质影响显著,马铃薯粉使面包的比容提高到4.12 mL/g,水分含量增加了7%,硬度减小了6 N,水分活度降低,面包的色泽和总体可接受程度明显提高,保质期和烘焙品质得到有效改善;对于风味,电子鼻主成分贡献率为97.3%,说明电子鼻能够很好地区分小麦面包和马铃薯面包的风味;顶空固相微萃取-气相色谱-质谱分析结果表明小麦面包和马铃薯面包的主要挥发性成分为酯类物质,添加马铃薯粉使各类风味化合物的相对含量发生变化,其中马铃薯面包中含有异薄荷酮、对薄荷-3-烯、1-甲基-4-(1-甲基亚乙基)-环己烯、丙二酸二乙酯等风味化合物,烯烃类物质相对含量和种类明显增多。     

Effects of flour from different barley varieties on barley sour dough bread

Twenty flours from 16 different barley varieties cultivated in 1990 and 1992, and a Swedish reference flour, were fermented by Lactobacillus plantarum A1 to sour doughs. Barley breads (40% barley/60% wheat flour) from each flour type were baked with and without an admixture of barley sour dough in order to investigate how the sour dough admixture would affect the baking properties. A trained panel carried out sensory evaluation by conventional profiling on breads made from three of the barley varieties and the Swedish reference flour, made with and without sour dough admixture.

The barley varieties influenced both the sour dough properties and the properties of the barley bread. The pH of bread with sour dough ranged from 4.6 to 4.8 as compared to 5.4 to 5.6 in bread without sour dough. The acidity of the breads with sour dough ranged from 4.1 to 5.0 ml NaOH/ 10 g bread crumb as compared to 2.4 to 3.6 in breads without sour dough. In 14 of the twenty bread types an addition of sour dough lowered the bread volume. Breads with a sour dough admixture scored higher for total taste and acidulous taste than breads without sour dough. The β-glucan content of the flours had no significant influence on the sour dough or the sensory characteristics of the bread, except for the breadcrumb colour.     

Effect of Rice, Corn and Soy Flour Addition on Characteristics of Bread Produced from Different Wheat Cultivars

Preparation and consumption of bread enriched with flours that contain appreciable amounts of protein, lysine, dietary fiber, and minerals will provide a healthy alternative to consumers and also a lowering of bread making cost in countries where wheat is not a major domestic crop. Addition of rice, corn, and soy flour to bread and durum wheat flours at 10, 20, 30, 40, 50% levels was carried out to examine the effects on the baking (specific volume, color, firmness) and sensory characteristics of bread. Dough rheological properties were also studied using Brabender Farinograph and Extensograph. Results of the present study suggest that incorporation of rice, corn, and soy in bread wheat flour up to a level of 10% (flour basis) and in durum wheat flour up to 20% produces bread without any negative effect in quality attributes such as color, hardness, and flavor and reasonable acceptance offering promising nutritious and healthy alternative to consumers. Increasing levels of substitution (30 and 50%) resulted in decreasing dough strength, extensibility, and loaf volume, due to the replacement of gluten by the added protein. Overall acceptability scores of these breads were found to be very low. The durum flour can be substituted with nongluten flours up to 10% more than the bread wheat flour because of its stronger gluten matrix and better dough rheological characteristics.     

BREAD MAKING OF DURUM WHEAT WITH CHICKPEA SOURDOUGH OR COMPRESSED BAKER'S YEAST

Two ways of improving durum wheat bread-making quality were evaluated.
First, durum wheat (cultivar "Papadakis") was blended with bread wheat flour of good (A-flour) or medium (B-flour) quality (70% durum and 30% bread wheat flour). Durum wheat flour displayed the γ-gliadin 45 electrophoretic band and acceptable bread-making quality. Breads from flour blends had better volume, particularly the durum and A-flour blend. The addition of ascorbic and citric acid and malt flour improved dough rheological properties and thus bread volume, as well as staling rate and sensory characteristics. These were more pronounced in the blend of durum with B-flour.
Second, durum wheat flour alone was used to prepare chickpea sourdough-leavened bread, as flavor is important for consumer acceptance. With the addition only of salt, the chickpea sourdough-leavened durum wheat bread displayed acceptable loaf volume, distinguished flavor and longer shelf life compared with bread prepared with compressed baker's yeast.

PRACTICAL APPLICATIONS

One of the practical applications of this study is the possibility of using a common durum wheat cultivar instead of local varieties as is the case with traditional breads. Results of this work may be useful for promoting greater acceptance of durum wheat breads as well as expansion of the use of a traditional Mediterranean chickpea sourdough-leavened durum wheat bread with distinguished flavor and taste.
This work may serve as a guide for determining the quality of flours suitable for production of "home made" or "village" bread (which has high market value as specialty bread) by blending durum and bread wheat flours. Best results are obtained with good-quality bread wheat flour, regardless of the good quality of durum wheat cultivar used, together with the use of the dough improvers implemented in this work.     

Flour quality tests for selected wheat cultivars and their relationship to Arabic bread quality

Analytical and rheological parameters were established for flours from nine selected wheat cultivars, each covering a range of protein contents. Arabic and pan breads were baked from these flours and baking quality was determined. Wheat cultivars were found to differ in their suitability for Arabic bread production. Within cultivars the relationship between protein content and Arabic bread score was best described by a quadratic equation. Traditional flour quality tests do not adequately describe the flour quality requirements for Arabic bread as clearly as for pan bread. Ranges and optimum values for a number of parameters can be set to describe flours most likely to be suited to the production of Arabic bread. However, for reliable evaluation of baking quality for Arabic bread, flours fitting the prescribed range must be test baked.     

Protein profile and sensorial properties of rye breads

The protein profile of four types of traditional rye breads formed on rye flours with the extraction rate of 100, 95, 85 and 70% and baked at 260 °C for 40 min was investigated as a nutritional quality indicator. A fractionation process was applied to discriminate high-molecular- (HMW >3 kDa) and low-molecular weight compounds (LMW <3 kDa) present in extracts of rye bread and its crumb and crust. The content of soluble proteins, available lysine, carbohydrates and total phenolic compounds was analysed before and after ultrafiltration in both retentates (HMW >3 kDa) and filtrates (LMW <3 kDa). The dependence between sensory quality of rye breads and composition on soluble proteins, available lysine, carbohydrates and total phenolic compounds was provided. Baking caused a decrease in rye bread protein content. The content of available lysine was the lowest in crusts and it was dependent on the rye flour extraction rate taken for rye bread making. The SDS-PAGE analysis showed that the primary structure of the rye bread proteins was modified in the highest extent in the crust’s bread of all types. The analyses of both retentates and filtrates after ultrafiltration demonstrated that the most of carbohydrates and phenolic compounds were incorporated into the HMW fraction suggesting their conjugation with proteins due to the Maillard reaction. Compounds able to react with Folin Ciocalteu reagent were also detected in filtrates of crust’s extracts (MW ≤3 kDa) from all breads indicating their distribution between LMW and HMW fractions. About 22.5, 27, 11.2 and 46.8% of the phenol compounds forming crusts of breads based on the flours with extraction rates of 100, 95, 85 and 70% were recovered in the corresponding LMW fractions.The sensory analysis of the four types of rye breads indicated for a high correlation between overall quality of breads and their content of carbohydrates. The highest correlation was noted for a rye bread formed on flour with extraction rate of 95%. This finding suggested that the content of carbohydrates as a substrate for Maillard reaction has had an influence on palatability by consumers of rye bread formed on flour with the extraction rate of 95% which had also the highest overall quality.     

顶空固相微萃取- 气质联用分析小麦馒头制作过程中的挥发性成分变化

为研究小麦挥发成分在加工过程的形成变化,选用具有代表性的3种不同筋力小麦品种--普冰143、晋麦47、西农9817,采用顶空固相微萃取技术萃取其小麦粉、发酵面团和馒头的挥发性成分并进行气相色谱-质谱分析鉴定。结果表明：普冰143、晋麦47、西农9817小麦粉检测出23种相同的挥发性成分,分别占总量的84.01%、77.82%和82.28%,其中主要成分为萘、1-甲基-萘、(Z)-2-丁烯二酸二甲酯、1,7-二甲基-萘、2-甲基-萘;发酵面团中检测出共同成分18种,分别占总量的80.99%、71.65%和70.44%,主要成分为乙醇、萘、1-甲基-萘、丁二酸乙基甲酯、苯乙醇;馒头中检出26种相同的挥发性成分,分别占总量的80.26%、75.99%和80.43%,主要成分为萘、1-甲基-萘、2-戊烷基-呋喃、乙醇、壬醛。不同筋力小麦制品之间的挥发性成分存在差异,但大部分主要成分相同。从小麦粉到馒头的制作过程中,挥发性成分发生明显变化,其中烃类物质相对含量明显减少而醇类物质种类和相对含量均增多。     

Release of free ferulic acid and changes in antioxidant properties during the wheat and rye bread making process

Changes in the free ferulic acid (FFA) contents and antioxidant properties during bread making processes were determined. Experimental breads were produced from whole meal and white wheat and rye flours, and fermented using either baker’s yeast or sourdough starter. Sourdough fermented bread contained the highest content of FFA. Release of occurred mainly during dough fermentation. A further increase in the ferulic acid content in the bread crumb and a decrease in the crust was observed. Total antioxidant properties of sourdough bread, defined as the sum of lipophilic and hydrophilic compound activities, were significantly (p<0.05) higher than for yeast bread. Sourdough bread contained more methanol soluble phenolic compounds, proteins, tocochromanols, and oxidized products of fatty acids than yeast bread. The equilibrium between the anti- and pro-oxidative compound contents resulted in similar antioxidant properties for bread using both types of fermentation, and to results observed for the flour used for baking.     

QUALITY OF BREAD SUPPLEMENTED WITH SILVER EAR

Silver ear ( Tremella fuciformis Berkeley) was used to substitute wheat flour to make bread. Bread quality including specific volume, color and sensory evaluation, and taste components including proximate composition, soluble sugars, free amino acids and 5'-nucleotides in bread supplemented with silver ear were analyzed and compared with those of white bread. White bread and 5% silver ear bread had a comparable proximate composition. Specific volumes of 2% and 5% silver ear breads and white bread were 4.02, 3.96 and 3.79 cm³/g, respectively. Both breads contained considerately low amounts of monosodium glutamate-like and sweet components of free amino acids and flavor 5'-nucleotides. The white bread looked lighter and whiter than 5% silver ear bread. All sensory results indicated that two breads were moderately acceptable. Overall, silver ear could be incorporated into bread to provide its beneficial health effects.

PRACTICAL APPLICATION

Silver ear mushroom ( Tremella fuciformis Berkeley) is commonly used as food in Oriental countries and is also a traditional Chinese medicine. The mushroom can be added to food as a supplement to extend and broaden its consumption and provide the beneficial health effects through various food products. Bread is consumed all over the world and many food ingredients have been included in bread formulation to increase its diversity, nutritional value and product appeal. Accordingly, the mushroom was used to substitute wheat flour to make bread. Bread quality including specific volume, color and sensory evaluation, and taste components including proximate composition, soluble sugars, free amino acids and 5'-nucleotides in silver ear bread were valuable information for its practical application. The present work showed that silver ear could be incorporated into bread to provide its beneficial health effects.     

Total phenolic and total flavonoid content,antioxidant activity and sensory evaluation of pseudocereal breads

The aim of the study was to investigate the effect of adding (in two different doses 15% and 30%) pseudocereal (buckwheat, amaranth and quinoa) flour on the antioxidant properties and sensory value of breads. Buckwheat flour had the highest phenolic content (7.25 ± 0.23 mg/g dw). The content of total flavonoids in flours was about 2–4 fold higher when compared to breads. The addition of buckwheat flour to wheat bread, particularly in higher dose, was more effective in enhancing antioxidant activity, as evaluated by means of FRAP and DPPH, which increased by 2.36 fold, and 3.64 fold respectively, in comparison with other pseudocereal flours (amaranth, quinoa), which caused, in higher doses, the changes of above parameters within the ranges 1.20–1.79 fold, and 0.60–1.71 fold. Analysis of sensory results of breads showed that addition of buckwheat flour to the dough might improve subjective properties of bread and increase acceptable quality attributes such as taste, colour or odour. All these observations suggest that addition of buckwheat flour into bread can improve antioxidant as well as sensory properties of bread. Bread fortified with pseudocereal flours, and especially with buckwheat flour, may be placed on the market as a functional food.     

Comparative study of phytic acid content,in-vitro protein digestibility and amino acid composition of different types of flat breads

Phytic acid content of eight different types of leavened and unleavened flat breads was determined. It was highest in unleavened and non-fermented whole wheat chapati and lowest in the leavened and fermented white wheat flat bread roghni nan. The effect of baking conditions, bread composition and phytic acid content on in-vitro digestibility of protein was measured using a pepsin multienzyme pH stat technique. The amino acids released were separated by ultrafiltration. The rate of protein digestibility of flat bread and amino acid released depended upon the type of flour used, baking conditions, phytic acid content and other antiproteolytic constituents of breads. Leavening and fermentation of breads resulted in an increase of protein digestibility and availability of amino acids. Addition of soya flour increases the protein digestibility of breads whereas millet flour decreases it.     

Significance of lipid binding on the functional and nutritional profiles of single and multigrain matrices

Lipid fractions and starch- and protein-lipid binding of single and blended oat, rye, buckwheat and wheat flour, dough and bread matrices were investigated, and results correlated with the functional and nutritional properties of the grain matrices during mixing and baking. Non-starch lipid was the most prominent fraction in terms of absolute content and as a percentage of total lipids. Free lipids, starch lipids and bound lipids were, respectively, the major, intermediate and minor lipid fractions in flours, doughs and breads. Great differences in total lipid content due to sampling result in divergences amongst lipid fraction content and distribution, especially for starch and bound lipid fractions. Lipids bound to proteins during dough mixing are translocated and bound to starch during baking. In blended samples, the higher fibre content seems to provoke a reduction of the lipid–protein and lipid–starch linkages due to interactions between fibres and endogenous biopolymers. Starch lipid showed the most significant correlations with parameters related to dough and bread performance during breadmaking, especially over the mixing step. Valuable fresh bread functional characteristics, such as high specific volume and high sensory score for softness and overall acceptability, correspond to a starch lipid’s increase due to mixing. The higher the free and starch lipids decrease by reason of temperature treatment—baking—the larger the starch hydrolysis and the higher β-glucans and total dietary fibre contents.     

Effects of fiber addition on antioxidant capacity and nutritional quality of wheat bread

Wholegrain and high fiber foods are recognized as nutritious and healthful products due to their content of dietary fiber, antioxidants and bioactive compounds. In this study, wheat, rye, barley, oat wholegrain flours and two fibers namely cellulose (insoluble fiber) and xanthan gum (soluble fiber) were used to replace a portion of wheat flour in pan bread to study effects of fibers on phenolic compounds, antioxidant capacity, dietary fiber fractions, and starch digestibility in vitro. Incorporation of wholegrain flours increased free and bound phenolics and antioxidant capacity of all the breads examined to various extent depending on the source of fiber. Additionally, soluble, insoluble and total dietary fiber fractions and total minerals increased with the addition of wholegrain flours or fibers. Rapidly and slowly digestible and resistant starches were not significantly influenced by adding wholegrain flours or fibers to breads. The study demonstrates the importance of enriching wheat bread with wholegrain flours to boost antioxidants and dietary fibers. On the other hand, more research is required to better understand impact of wholegrain flours or fiber on starch digestibility in vitro and glycemic response.     

Modification of appetite by bread consumption: A systematic review of randomized controlled trials

The inclusion of different ingredients or the use of different baking technologies may modify the satiety response to bread, and aid in the control of food intake. The aim of this study was to perform a systematic search of randomized clinical trials on the effect of bread consumption on appetite ratings in humans. The search equation was (“Bread”[MeSH]) AND (“Satiation”[MeSH] OR “Satiety response”[MeSH]), and the filter “clinical trials.” As a result of this procedure, 37 publications were selected. The satiety response was considered as the primary outcome. The studies were classified as follows: breads differing in their flour composition, breads differing in ingredients other than flours, breads with added organic acids, or breads made using different baking technologies. In addition, we have revised the data related to the influence of bread on glycemic index, insulinemic index and postprandial gastrointestinal hormones responses. The inclusion of appropriate ingredients such as fiber, proteins, legumes, seaweeds and acids into breads and the use of specific technologies may result in the development of healthier breads that increase satiety and satiation, which may aid in the control of weight gain and benefit postprandial glycemia. However, more well-designed randomized control trials are required to reach final conclusions.     

酵母菌对自然发酵酸面团面包中风味物质影响的研究

以添加不等量酵母菌（0，1，2，3g酵母菌／200g自然发酵剂）的自然发酵酸面团面包及非酸面团面包为研究对象，采用固相微萃取（SPME）技术分别提取样品中的挥发性风味物质，然后通过气相色谱-质谱（GC-MS）联用法进行鉴定：结果表明，44种挥发性物质存在于至少两种样品中，其中主要为醇类、酸类、醛类、酯类、烷烃类、酮类、烯类、芳香族化合物和杂环及含氮化合物。酸面团面包含一些独有的物质，如乙酸甲酯、4-丁酸丁交酯、1，2-苯二酸二乙酯和蚁酸丙酯等：酵母菌对自然发酵酸面团面包中主要挥发性风味物质有较大影响．如酸类物质的相对含量有所下降，醛类的含量增加，添加酵母菌的酸面团面包风味物质中酯类的比例低于不添加酵母菌的．     

面粉强筋剂复合品质改良的研究

将各种面粉强筋剂复合,以适当的比例添加到不同品种的小麦粉中,研究混合小麦粉的粉质特性及烘焙特性,并找出各种面粉强筋剂复合的最佳比例。结果表明：将种种面粉强筋剂按一定比例添加到小麦粉中并科学混合均质,要比单一使用发挥更好的改良效果。改良后的小麦粉各项指标均可达到面包专用粉的质量标准。     

Response Surface Methodology in the Development of Rice Flour Yeast Breads: Sensory Evaluation

Yeast breads were developed from rice flour (80%) and potato starch (20%). Using sensory measurement from a trained panel, response surface methodology (RSM) was applied to find carboxymethylcel-lulose (CMC), hydroxypropylmethylcellulose (HPMC), and water level combinations for gluten-free breads from three different rice flours. Formulations resulted in rice breads that met wheat bread reference standards for moistness, cohesiveness, yeasty flavor, adhesiveness, aftertaste, top crust and crumb color, cell size uniformity and predominant cell size. Medium grain rice flour breads met more sensory reference standards than long grain rice flour breads.     

Spontaneous sourdough processing of Chinese Northern-style steamed breads and their volatile compounds

The effect of amount of flour in the pre-fermented form (10%, 20%, and 30% flour in the pre-fermented form), fermentation time (12, 24, and 36 h), and amount of yeast (0.5%, 1.0%, and 1.5%) on acidity, specific volume, and crumb texture of Chinese Northern-style sourdough steamed breads were studied. Volatile compounds of the sourdough and non-sourdough steamed breads were also determined. The preferments were produced from spontaneous fermentation using all purpose (APF) and whole wheat flours (WWF). Specific volume was the highest at 20% preferment for APF sourdough steamed bread (ASSB) and 30% preferment for WWF sourdough steamed bread (WSSB). The softest texture was obtained with 20% preferment while at 30% preferment there was excessive gluten weakening due to high acidification. A total of 89 volatile compounds were identified in steamed breads with ethanol and 3-methyl-1-butanol being the most abundant compounds.