Potato flour as a functional ingredient in bread: evaluation of bread quality and starch characteristics

Potatoes have been added to bread for improvement of texture and moisture retention. The functional quality and starch digestibility in bread containing 5%, 10% or 15% potato flour were evaluated. Farinograph absorption of wheat and potato flour blends ranged from 59.0% to 77.7%. Bread with potato flour had significantly (P < 0.05) lower bread firmness during storage. There was a significant (P < 0.05) decrease in starch molecular weight as the level of potato flour increased. Inclusion of potato flour in these breads significantly (P < 0.05) increased the level of resistant starch (RS), while significantly (P < 0.05) decreasing the estimated glycemic index (eGI). Bread with no potato flour had 5.2% RS and an eGI of 95, while the bread with 15% potato flour had 11.3% RS and an eGI of 87. Overall, the addition of potato flour may reduce dough strength and loaf volume, but it reduced staling and increased resistant starch content of the bread.     

Effect of isomaltodextrin on dough rheology and bread quality

Isomaltodextrin (IMD) is a novel highly branched α-glucan ingredient that has potential applications in foods as a promising source of dietary fibre. In this study, we assessed the incorporation of IMD in baked products and its effect on dough rheology and physico-textural characteristics of wheat breads. IMD was added to wheat flour to reach the US FDA level of ‘good’ source of fibre (10% IMD). Use of the straight-dough method with IMD and regular dough mixing time (8 min) resulted in less elastic doughs and resulting breads displayed lower cohesiveness, springiness and chewiness compared to the control bread. A modified straight-dough method, with longer mixing time (36 min) and adjusted water level (70%), and a sponge-and-dough method were used to allow gluten structure to more fully hydrate and develop. With IMD addition, the modified straight-dough (36 min dough mixing time) and sponge-and-dough methods yielded enhanced dough elasticity compared to the original straight-dough method. Breadmaking methods were identified (improved straight-dough and sponge-and-dough) whereby IMD could be added at a 'good source' of fibre level with loaf appearance and texture similar to breads without IMD.     

Evaluation of viscoelastic properties and air-bubble structure of bread containing gelatinized rice

The impact of addition of gelatinized rice porridge to bread has been investigated on loaf volume, viscoelastic properties and air-bubble structure. We prepared four variety of bread: bread containing rice porridge (rice porridge bread), bread containing gelatinized rice flour (gelatinized rice flour bread), and wheat flour and rice flour breads for references. Instrumental analyses the bread samples were carried out by volume measurement of loaf samples, creep test and digital image analysis of crumb samples. Rice porridge bread showed the maximum specific volume of 4.51 cm³/g, and even gelatinized rice flour bread showed 4.30 cm³/g, which was larger than the reference bread samples (wheat and rice flour breads). The values of viscoelastic moduli of gelatinized rice flour bread and rice porridge bread were significantly smaller (p < 0.05) than those of wheat flour and rice flour breads, which indicates addition of gelatinized rice flour or rice porridge to bread dough encouraged breads softer. Bubble parameters such as mean air- bubble area, number of air-bubble, air-bubble area ratio (ratio of bubble area to whole area) were not significantly different among the bread crumb samples. Therefore, the bubble structures of the bread samples seemed to similar, which implied that difference of viscoelasticity was attributed to air-bubble wall (solid phase of bread crumb) rather than air-bubble. This study showed that addition of gelatinized rice to bread dough makes the bread with larger loaf volume and soft texture without additional agents such as gluten.     

Effect of dietary fibre on dough rheology and bread quality

Dietary fibre is a common and important ingredient of a new generation of healthy food products demanded more each day by customers. Dietary fibre increases the nutritional value of bread but usually at the same time alters rheological properties of dough and, finally, the quality and sensorial properties of bread. The present work investigates the effect of some purified dietary fibres from different origins (orange, pea, cocoa, coffee, wheat and microcrystalline cellulose) on the rheological properties of wheat flour dough and the final quality of breads. The study of the rheological behaviour of the dough was performed by means of a consistograph and an alveograph. Bread quality was determined by means of texture, colour and specific volume measurements after baking under controlled conditions. The influence of fibre on bread sensory evaluation was established. Dietary fibre additions, in general, had pronounced effects on dough properties yielding higher water absorption, mixing tolerance and tenacity, and smaller extensibility in comparison with those obtained without fibre addition (in the control bread). Regarding the effect on bread properties, the fibre always enhanced the shelf life, as textural studies revealed. Sensory evaluations revealed that dietary fibres, with the exception of those from coffee and cocoa, can be added to flour at the level of 2% without deterioration of the bread palatability in comparison with white flour bread. Additions of 5% could imply the use of some additives to correct the rheological properties of dough.     

Sensory and physical quality characteristics of bread fortified with apple pomace using fuzzy mathematical model

Apple pomace, after different processing procedures, was added into wheat flour in bread production to improve the dietary fibre content of breads. A fuzzy mathematical model was used in the sensory assessment of bread to improve the reliability of final conclusion. The addition of both apple pomace (AP) and skimmed apple pomace (SAP) reduced the extensibility and improved the resistance of wheat dough compared to the control sample. Wheat dough fortified with apple pomace of differing particle sizes did not have significant effects on either farinograph properties or extensograph properties. Sensory assessment of bread based on fuzzy mathematical model indicated that optimum concentration of apple pomace, both AP and SAP, added into wheat dough was 3%. Such results may be of importance when considering the use of apple pomace in bread production so as to enhance the dietary fibre intake, and also improve the sensory properties of bread.     

Bread fortified with dietary fibre extracted from culinary banana bract: its quality attributes and in vitro starch digestibility

The effect of fortification of dietary fibre (DF) on dough rheology, quality characteristics and in vitro starch digestibility of bread was studied. Bread was prepared incorporating DF (2–4 g per 100 g of flour mixture). Rheological study of dough showed an increase in dough stiffness and elasticity with higher incorporation of the DF. The results of chemical composition revealed that addition of DF increased total DF (19.65 g per 100 g) content of bread. However, incorporation of 2 g per 100 g DF of flour mixture with 66 g per 100 g moisture showed higher water retention and specific volume of 86.76% and 5.83 cm³ g⁻¹, respectively, which was close to control bread. Improved textural property with acceptable sensory attributes was observed for bread fortified with 2 g per 100 g DF of flour mixture and 66 g per 100 g moisture content. Incorporation of DF (2–4 g per 100 g of flour mixture) showed a decrease in rapidly digestible starch (RDS) and an increase in slowly digestible starch (SDS) content with lower predicted glycaemic index (pGI) than control bread.     

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.     

Effects of enzymes in fibre-enriched baking

The aim of the present study was to improve the quality of fibre-enriched wheat breads by enzymic treatment of the fibre fraction. The suitability of different enzymes in fibre-enriched baking and their effects on the dietary fibre content and the ratio of insoluble: soluble fibre content of the breads were studied. The enzyme preparations used were a hemicellulolytic culture filtrate of Trichoderma reesei, a specific (pI 9) xylanase of T reesei and Fermizyme, an α-amylase preparation containing a standardised level of hemicellulase activity. Rye bran was extracted in water (10% (w/w) suspension) to determine the solubilities of the β-glucans and pentosans. Addition of T reesei culture filtrate significantly increased the amount of extractable pentosan obtained from nonautoclaved rye bran. Rye bran supplementation (5%) of wheat flour increased the farinograph absorption and dough development time, but had little or no effect on stability and softening of the dough. The added enzymes decreased dough stability and increased softening. Addition of enzymes caused significant differences in the stickiness of the wheat doughs both with (P<0·003) and without (P<0·001) rye bran. Fermizyme significantly increased the stickiness of wheat doughs both with and without rye bran. The baking results of the fibre-enriched breads were improved by the added enzymes. Addition of T reesei culture filtrate increased the specific volume of the wheat breads both with and without rye bran by almost 20%. Enzyme mixtures were more efficient than individual xylanase in softening the bread crumb and reducing the staling rate of wheat breads both with and without rye bran. Incorporation of enzymes reduced the total dietary fibre content of the breads, but at least doubled the amount of soluble pentosan. The proportions of fluorescent cell walls in the breads were detected by microscopical image analysis. Enzyme addition caused the surface area of insoluble cell walls originating from wheat flours to decrease, suggesting that the enzymes exert more effects on wheat endorsperm cell walls than on bran particles. © 1998 SCI.     

IMPROVEMENT OF THE WHEAT AND CORN BRAN BREAD QUALITY BY USING GLUCOSE OXIDASE AND HEXOSE OXIDASE

The effects of addition of wheat (10, 20 and 30%) and corn bran (10 and 20%) on rheological and bread making properties of flour were examined. To improve dough and bread properties, glucose oxidase (GO) and hexose oxidase (HO) (15–30 and 45 mg/kg) were used separately in each bran-wheat flour formula with L-ascorbic acid at 75 mg/kg, glucose at 0.5% and vital gluten at 9.2%. Water absorption and development time increased as the amount of wheat and corn bran increased, while dough stability, maximum resistance to extension, extensibility, energy and loaf volume decreased. Corn bran was found to be more detrimental to dough rheology and bread characteristics than wheat bran. Corn bran and wheat bran could be used at bread making up to levels of 10 and 20%, respectively. Addition of 30 mg/kg of HO in combination with constant additives was most effective in improving dough and bread characteristics and GO with its 15 mg/kg usage level followed it. Further increasing of enzyme levels led to over oxidizing of doughs and breads.

PRACTICAL APPLICATIONS

Corn bran up to 10% and wheat bran up to 20% levels can be used in bread making. To improve dough and bread quality, besides L-ascorbic acid (75 mg/kg) and vital gluten (as a percentage of added bran weight), GO (15 mg/kg) or HO (30 mg/kg) could be incorporated into wheat flour-bran mixtures. However, the amount of enzyme should be carefully chosen because when they are used above the mentioned levels, they cause overoxidation of doughs and small loaf volumes are obtained. As a conclusion; by using the corn bran, which is a by-product of the starch industry, not only could it be possible to offer healthy alternative breads which contain high amounts of dietary fiber to consumers, but it could also be possible to obtain economical value by evaluating such a by-product in the bread industry.     

Utilization of germinated ancient wheat (Emmer and Einkorn) flours to improve functional and nutritional properties of bread

Germinated and untreated ancient (Einkorn and Emmer) and modern (Esperia) wheat flours (0, 5, 10, 15 and 20%) were used in bread dough to improve functional and nutritional properties of bread according to (3 × 2 × 5) x 2 factorial design. Utilization of wheat varieties in the germinated form increased the ash, total dietary fiber (TDF), total yellow pigment (TYP), total phenolic content (TPC), antioxidant activities, Ca, Fe and Mg content of bread, and also the most increments in those values (except TYP) were observed in Emmer flour usage. Germinated wheat flour decreased the mean phytic acid contents of bread samples from 313.32 mg/100 g to 291.81 mg/100 g compared to untreated wheat flour. The use of ancient wheat flour (einkorn and emmer) gave lower bread volume compared to modern bread wheat flour. The use of germinated wheat flour decreased the crust and crumb L* values of the breads but increased the a* and b* values. As a result, increasing ratios of germinated ancient wheat flour increased the functional component and nutritional value of the bread, and at the same time, its usage at low ratio contributed positively to the technological quality of the bread.     

Fibre, protein and mineral fortification of wheat bread through milled and fermented brewer’s spent grain enrichment

Brewer’s spent grain (BSG) represents 85?% of brewing industry by-products. Currently, BSG is underutilised as low-value animal fodder. The current study aims to expose additional nutritional and economic benefits of BSG as a food ingredient in wheat breads. The raw material properties were studied revealing that BSG by-product contains (on a w/w) 22.13?% protein (including exceptionally high levels of essential amino acids), 1.13?% minerals, 131.0?mg/L polyphenols, 28.22?% total fibre and 3.6?% essential fatty acids. Additionally, BSG was fermented (BSG SD), using the lactic acid bacteria, Lactobacillus plantarum FST 1.7, to elucidate the benefits of traditional sourdough for processing crude BSG. Fermentation resulted in softer breads with increased springiness. Farinograph results revealed that wheat flour incorporating BSG had increased water absorption. Rheological measurements showed a positively correlated increase in dough resistance in line with BSG or BSG SD incorporation. Supplemented breads had sensory acceptability up to levels of 10?% BSG or BSG SD, resulting in breads comparing favourably with wholemeal breads from a nutritional, technological and textural perspective. Using BSG as a main stream food ingredient would increase the market value of this by-product, thus enhancing its economic potential, a factor that is also discussed.     

籽粒苋保健面包的研制(II)——籽粒苋对赖氨酸和膳食纤维的营养强化作用

以 5%、10 %、15%、2 0 %、2 5%籽粒苋粉代替小麦粉 ,制成籽粒苋保健面包。对这类面包中赖氨酸、膳食纤维含量进行分析 ,结果表明籽粒苋粉能明显提高赖氨酸和膳食纤维的含量 ,特别是能改善可溶性膳食纤维与不溶性膳食纤维的配比。与全麦粉面包相比 ,籽粒苋面包中蛋白质的提高率为 0 .58%～ 6 .91% ,赖氨酸含量提高率为 13.50 %～ 56 .57% ,总膳食纤维提高 8.2 6 %～ 39.4 5% ,不溶性膳食纤维提高 7.91%～33.33% ,可溶性膳食纤维提高 9.76 %～ 6 5.85% ;而脂肪的含量则随籽粒苋粉的增加而减少。由于籽粒苋对赖氨酸和膳食纤维具有强化作用 ,使籽粒苋保健面包可以作为高脂血症、糖尿病和肥胖人群的理想食品     

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.     

Physiological Responses of Rats to High Fiber Bread Diets Containing Several Sources of Hulls or Bran

Fiber-supplemented breads, prepared by replacing 7.5% of the hard wheat flour with field pea, flax or sunflower hulls, wheat bran or microcrystalline cellulose, were evaluated for breadmaking characteristics and physiological effects on rats. Cellulose-supplemented dough and bread resembled the straight-grade wheat bread while pea hull and wheat bran breads were similar to whole wheat bread. Flax and sunflower hulls had adverse effects on dough mixograph properties, loaf volume and crumb characteristics while sunflower hulls also contributed grittiness and aftertaste in taste panel evaluations. The fiber-supplemented breads, when fed to weanling rats, gave similar feed consumptions, weight gains and serum cholesterol levels as rats fed the whole wheat bread. Pea hulls increased daily fecal weight and, with coarse sunflower hulls, decreased dry matter digestibility. Fine wheat bran and fine sunflower hulls in the bread diets were associated with low fecal weight, low fecal volume, high fecal density and high digestibility of dry matter.     

Techno‐functional properties of wheat flour‐resistant starch mixtures applied to breadmaking

Resistant starch can be used to reduce the availability of carbohydrates in baked products. In this study, the effect of type 4 resistant wheat starch (RS₄) on wheat flour dough and breads was evaluated. Wheat flour was substituted by RS₄ at 10%, 20% and 30% w/w (RS10, RS20 and RS30, respectively). Rheological and thermal behaviours of dough were evaluated. Besides, bread quality, starch digestibility and bread staling were analysed. All substituted dough exhibited viscoelastic behaviour but lower elastic and viscous moduli. Regarding to bread quality, specific volume and crumb texture were negatively affected in samples with RS₄. However, all samples were technologically acceptable. During storage, crumb hardening was observed in breads without and with RS₄ but amylopectin retrogradation was not particularly affected. The in vitro digestibility of bread with RS showed a lower release of reducing sugars and a lower estimated glycaemic index, suggesting a healthier profile for these breads.     

Effect of the addition of different fibres on wheat dough performance and bread quality

A good correlation has become evident between fibre consumption and the reduction of coronary heart-related diseases and diabetes incidence. However, fibre intake is commonly lower than recommended. In consequence, the development of foods with high fibre content should be desirable. The potential use of various commercial fibres (carob fibre, inulin and pea fibre), as fibre-enriching agents in breadmaking, is reported. The effects of the addition of these fibres to wheat flour on the viscoelastic properties of dough and both mixing and proofing behaviour is presented. Bread evaluation revealed that carob and pea fibre supplementation, although decreasing specific loaf volume (very slightly in the case of carob fibre), conferred softness to the bread crumbs. In addition, sensory evaluation showed that consumer panellists judged these fibre-enriched breads as acceptable. Therefore, their use, especially carob, allows an increase of the daily intake of fibre without promoting negative effects on the rheological properties of doughs or quality and overall acceptability of the resulting breads. The whole study indicates that these three fibres can be used as additives in breadmaking in order to fortify the diet.     

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.     

The effect of enzymic modification on the foaming, water absorption and baking quality of defatted soya flour

Defatted soya flour slurries were treated for 0,5,10,15 and 30 min with papain at 50°C and tested for whipability, water absorption and baking quality at replacement levels in wheat flour of 10,20 and 30% (w/w). When whipped, all modified suspensions showed volume increases exceeding 250% with lower stability ratings than the unmodified samples. The 30 min enzyme treated product exhibited excellent water absorption. Use in bread resulted in a depression of loaf volume, development of a granular texture, off-colour and flavour. As was expected, all favourable characteristics decreased upon increasing the percentage of soya product in the dough formulation. Loaf volumes of breads containing 10% modified soya flour (MSF) ranged from 444 to 527 cc; with 20% MSF between 374 and 428 cc, and with 30% MSF between 383 and 409 cc. Loaf volume of all wheat flour bread was 861cc. Hunter colour difference meter readings indicated samples at all replacement levels, regardless of the enzyme modification time, exhibited higher levels of visual lightness than all wheat flour bread. All experimental breads exhibited a higher level of yellow tones and lower level of green tones compared to the all wheat flour bread.     

EFFECT OF PENTOSANASE ON DOUGH AND BREAD PROPERTIES PRODUCED BY DIFFERENT TYPES OF FLOURS

ABSTRACT

The effects of pentosanase at different doses (20, 60 and 100 ppm) on physical dough properties and bread quality were studied using three types of wheat flours. Flour A was a regular bread flour, flour B had a high hardness ratio and protein content, and flour C was prepared from the same blend of flour A but had a high extraction ratio. Regarding farinograph data, water absorption values of the high extraction (86%) flour C and high hardness (65%) blend flour B increased with introduction of pentosanase. Extensibility values of the flours increased moderately with pentosanase addition, while resistance and energy values decreased. The volume of breads made with flours C and B decreased upon addition of pentosanase. But loaf volume of breads prepared with regular bread flour A with 50% hardness and 76% extraction rate increased with high levels of pentosanase addition. In conclusion, flour A as a regular bread flour gave satisfactory results with pentosanase supplementations, whereas the harder‐blend (65%) and higher‐extraction‐rate (85%) flours from the same cultivars did not.

PRACTICAL APPLICATIONS

Pentosanase addition was more effective on soluble pentosans than on insoluble ones. Because of these effects, it enhanced the bread‐making properties of regular flour more effectively than those of the high‐extraction and harder‐blend flours of the same cultivars.

     

Effects of hull-less barley flour and flakes on bread nutritional composition and sensory properties

Barley is a desirable food ingredient, with health benefits provided by a β-glucan fibre fraction. A hull-less barley flour and flakes were incorporated into white and wholegrain wheat bread in quantities usually applied in practice. The breads were evaluated for nutritional composition and sensory properties and compared to standard products as controls. The supplemented breads were high in fibre, zinc and selenium content. It was estimated that a 300-gram daily portion of such breads could meet up to 40% of dietary recommended intakes for selenium and 70–75% of recommended daily values for β-glucan. Regarding sensory quality, the only significant differences (p < 0.05) were higher taste and lower volume in the white supplemented breads and lower crumb elasticity in the white bread made with barley flour. Hull-less barley can substantially contribute to an adequate intake of selenium and β-glucan. In addition, supplemented breads were not found to pose a significant risk, with regard to excessive intakes of heavy elements (Pb, Cd, As).