Physical properties of enzyme-supplemented doughs and relationship with bread quality parameters

The textural properties of wheat doughs made with different commercial amylases, xylanases/pentosanases, lipases and glucose-oxidase, singly and in mixed combinations, were investigated. Parameters from the texture profile analysis (TPA) and measurement of stickiness (Chen and Hoseney test) were determined after mixing the dough and after it had rested for 3.5 h. Resting of doughs led to softer and less cohesive doughs, with higher adhesive properties. Enzymes acted quickly and induced significant changes in the textural properties of doughs immediately after mixing. The influence of enzymes continued during resting. Xylanases/pentosanases substantially reduced dough consistency and increased stickiness, while addition of glucose-oxidase and specific lipases overcame these effects. Strong correlations could be established between different TPA parameters and stickiness and bread quality characteristics (i.e. volume, density and texture). Bread quality could be described by a single or multiple linear combination of textural variables.     

Interactive effects of flour, starter and enzyme on bread dough machinability

 Dough machinability of samples formulated with the enzyme principles glucose-oxidase, lipase, amylase and pentosanase/hemicellulase, and fermented with different microbial starters, was assessed by texture profile analysis and dough stickiness measurements. The individual and interactive effects of flour, enzyme and starter on the primary and secondary mechanical and surface-related parameters were evaluated, and the suitability of enzyme mixtures added to started doughs to improve dough handling characteristics and minimize adhesiveness and stickiness in flours was established. The general improving effect of the mixture of α-amylase, pentosanase and hemicellulase on most dough texture properties is particularly relevant when high-grade and/or sourer-started systems are used, because of their strong effect in decreasing hardness and adhesiveness respectively. Individual additions of glucose-oxidase and lipase cancelled out the excessive stickiness/adhesiveness of started and enzyme-supplemented doughs while the simultaneous presence of glucose-oxidase and lipase improved cohesiveness, chewiness and gumminess. The extent of the effects of this binary combination on dough mechanical characteristics was comparable to that obtained with the ternary mixture of α-amylase, pentosanase and hemicellulase, but avoided the deleterious effect of the latter enzyme combination on stickiness. In well-defined flour-starter systems, the enzyme supplementation of doughs constitutes a useful alternative to chemical improvers for enhancement of dough plasticity. Reveived: 16 February 1998     

Interactive effects of flour, starter and enzyme on bread dough machinability

 Dough machinability of samples formulated with the enzyme principles glucose-oxidase, lipase, amylase and pentosanase/hemicellulase, and fermented with different microbial starters, was assessed by texture profile analysis and dough stickiness measurements. The individual and interactive effects of flour, enzyme and starter on the primary and secondary mechanical and surface-related parameters were evaluated, and the suitability of enzyme mixtures added to started doughs to improve dough handling characteristics and minimize adhesiveness and stickiness in flours was established. The general improving effect of the mixture of α-amylase, pentosanase and hemicellulase on most dough texture properties is particularly relevant when high-grade and/or sourer-started systems are used, because of their strong effect in decreasing hardness and adhesiveness respectively. Individual additions of glucose-oxidase and lipase cancelled out the excessive stickiness/adhesiveness of started and enzyme-supplemented doughs while the simultaneous presence of glucose-oxidase and lipase improved cohesiveness, chewiness and gumminess. The extent of the effects of this binary combination on dough mechanical characteristics was comparable to that obtained with the ternary mixture of α-amylase, pentosanase and hemicellulase, but avoided the deleterious effect of the latter enzyme combination on stickiness. In well-defined flour-starter systems, the enzyme supplementation of doughs constitutes a useful alternative to chemical improvers for enhancement of dough plasticity. Reveived: 16 February 1998     

Bread quality and dough rheology of enzyme-supplemented wheat flour

The enzymatic treatment of wheat flours is an interesting alternative for improving their functional properties. Since enzymes with different biochemical activities could induce synergistic effects on dough behaviour or product quality, the individual and combined use of a wide range of enzymes (transglutaminase, glucose oxidase, laccase, α-amylase, pentosanase and protease) applied nowadays in bread-making processes were investigated. The blend of enzymes resulted in an improvement in the rheological behaviour of doughs and the quality of the final product. The simultaneous presence of transglutaminase (TG) and glucose oxidase (GO), as well as TG and protease (PROT) led to a synergistic effect on alveograph parameters. Polysaccharide-degrading enzymes exercised a significant effect on rheology only when used in combination with other enzymes, mainly affecting consistograph parameters. Analysis of bread-making data revealed significant interactions between TG and all the other enzymes except laccase (LAC). Significant synergistic effect on bread quality was observed by the combined use of GO and LAC, GO and pentosanase (PP), amylase (AMYL) and LAC, AMYL and PROT, and PP and PROT. Bread quality parameters showed greater correlations with alveograph parameters than with consistograph properties of dough. Tenacity (P) and extensibility (L) proved to be acceptable predictors of the height/width ratio of loaves. The duration of the alveograph test enhanced the prediction of bread quality parameters. Conversely, none of the rheological properties studied showed a high correlation with the specific volume of loaves.     

Effect of endoxylanases on dough properties and making performance of Chinese steamed bread

Two kinds of endoxylanase (XYL), one is a solid-phase enzyme (S-XYL) and the other a liquid-phase enzyme (L-XYL), were used to test their effect on the properties of dough and the quality of Chinese steamed bread (CSB). The textural properties of wheat dough made with the two enzymes were investigated. Parameters from the texture profile analysis (TPA) were determined after mixing the dough at 0th, 5th, 10th, 15th and 20th min, respectively. Both enzymes decreased farinograph parameters. They also influenced mixograms including decreasing time to peak and peak height. It was apparent that the decrease in hardness of the dough by adding S-XYL and L-XYL, respectively was more than that of the control sample and the sample with added yeast. It was found that the longer the time of fermentation, the lower the hardness of the dough. The mixing time was reduced by adding L-XYL by about 27.5%. The fermentation time was decreased by adding S-XYL or L-XYL. The addition of S-XYL and L-XYL on CSB resulted in increased specific volume, spread ratio and decreased crumb softness. A decreasing trend in L* value, a slightly increasing tendency in a* value and a slightly decreasing trend in b* value exist in crumb colour.     

Thermal properties of doughs formulated with enzymes and starters

 Thermal properties (gelatinization, amylose-lipid complex dissociation and amylopectin retrogradation) of bread samples formulated with two different quality wheat flours, two enzymes (α-amylase/pentosanase, lipase and their mixture), and three microbial sourdough starters were studied with a differential scanning calorimeter. The carbohydrases modified gelatinization temperature and enthalpy, whilst the lipase modified the amylose-lipid complex dissociation. The enthalpy of amylopectin retrogradation was significantly influenced only by the storage of breads. Second-order interactive effects of enzymes with flour or starter were found for gelatinization and/or amylose-lipid complex dissociation parameters. Some interesting relationships were observed between thermal and textural properties of fresh and stored breads. Received: 22 September 1998 / Revised version: 28 October 1998     

The effect of the use of hop additives and lactic acid bacteria starter in the preparation of dough on the properties of the resulting dough and bread

 In this research, the effects of lactic acid bacteria starter and hop additives, similar to yeast, on the quality of the resulting dough and bread, especially the development of staling, were investigated. In the experiments, a mixed culture containing Lactobacillus plantarum and L. fermentum was inoculated at the levels of 2% and 4% depending on the flour quantity. Hop additives were used at the levels of 0.025% and 0.05%. The effects of type-1, type-3 and type-5 flours were investigated with respect to their chemical composition, physical properties and bread experiment at three different periods, i. e. December 1993, March and June 1994. According to the results obtained, the best values for all three types of flours were found to occur in the second period, i. e. March 1994, whereas the lowest values were observed at the end of the third term. Almost all additives had an effect on dough and bread properties, pH and acidity development and, moreover, on the development of staling. The combined application of 0.05% hop and lactic acid bacteria starters at the levels of 2% and 4% was the most effective at delaying staling. Received: 10 December 1996     

The effect of the use of hop additives and lactic acid bacteria starter in the preparation of dough on the properties of the resulting dough and bread

 In this research, the effects of lactic acid bacteria starter and hop additives, similar to yeast, on the quality of the resulting dough and bread, especially the development of staling, were investigated. In the experiments, a mixed culture containing Lactobacillus plantarum and L. fermentum was inoculated at the levels of 2% and 4% depending on the flour quantity. Hop additives were used at the levels of 0.025% and 0.05%. The effects of type-1, type-3 and type-5 flours were investigated with respect to their chemical composition, physical properties and bread experiment at three different periods, i. e. December 1993, March and June 1994. According to the results obtained, the best values for all three types of flours were found to occur in the second period, i. e. March 1994, whereas the lowest values were observed at the end of the third term. Almost all additives had an effect on dough and bread properties, pH and acidity development and, moreover, on the development of staling. The combined application of 0.05% hop and lactic acid bacteria starters at the levels of 2% and 4% was the most effective at delaying staling. Received: 10 December 1996     

Incorporation of dairy ingredients into wheat bread: effects on dough rheology and bread quality

 Dairy ingredients are used in breadmaking for their nutritional benefits and functional properties. The effects of the traditionally-used whole and skimmed milk powder, sodium caseinate, casein hydrolysate and three whey protein concentrates on dough rheology and bread quality were studied. Whole and skimmed milk powders improved sensory characteristics. Sodium caseinate and hydrolysed casein displayed beneficial functional properties in breadmaking including low proof time, high volume and low firmness. Both ingredients increased dough height measured with the rheofermentometer. Bread with 2% or 4% sodium caseinate added was rated highly in sensory evaluation. Incorporation of whey protein concentrates generally increased proof time, decreased loaf volume and decreased dough height measured with the rheofermentometer. Received: 6 April 1999 / Revised version: 13 July 1999     

Impact of microbial transglutaminase on the viscoelastic profile of formulated bread doughs

The effects of microbial transglutaminase (TGM) on the viscoelastic profile of wheat flour doughs when added singly and in combination with hydrocolloids—hydroxypropylmethylcellulose (HPMC) and a high ester pectin (GENU pectin type BIG, or BIG)—, amylolytic (-amylase) and non amylolytic enzymes (xylanase) and an emulsifier [diacetyl tartaric acid ester of mono-diglycerides (DATEM)] have been investigated by applying response surface analysis to a Draper-Lin small composite design of formulated dough samples. In spite of the major effects on mixing, textural, extensional and viscometric parameters, which were provided by hydrocolloid/surfactant combinations, incorporation of TGM into dough formulas improved some viscoelastic properties. TGM, when added to DATEM and/or HPMC-containing doughs, induced synergistic effects on mixing parameters, resulting in increased water absorption, development time and stability. Highly cohesive doughs with improved water holding capacity and gluten strength during mixing and fermentation, and suitable pasting behaviour during cooking were achieved using TGM/BIG/DATEM mixtures, mainly associated with suitable interactions of the pairs TGM/DATEM and DATEM/BIG.     

Texture properties of formulated wheat doughs Relationships with dough and bread technological quality

Texture properties of wheat doughs were determined with a texturometer by using texture profile analysis (TPA) as well as Chen and Hoseney methodologies. The time elapsed between two compressions and strain were optimized so that meaningful values were obtained for TPA. Single effects and interactions between flour type, the breadmaking process and anti-staling additives (i.?e. monoglycerides, diacetyl tartaric ester of monoglycerides, sodium stearoyl lactylate, carboxymethylcellulose and hydroxypropylmethylcellulose) on dough texture properties (i.?e. springiness, resilience, hardness, cohesiveness, adhesiveness, chewiness, gumminess and stickiness) were estimated. The breadmaking process and addition of hydrocolloids had the most important effects and interactions on TPA. Hydrocolloids and α-amylase increased dough stickiness. Dough cohesiveness was a good predictive parameter of bread quality. Water content, acidity values and gluten quality were the main factors determining the texture properties of dough.     

食品酶制剂对冷冻面团流变学和微结构的影响

应用动态流变仪,Brabender拉伸仪,扫描电子显微镜(SEM)研究了葡萄糖氧化酶和谷氨酰胺转胺酶对冷冻面团粘弹模性量粘弹模量,抗拉伸阻力R5及微结构影响。空白面团(未加添加剂),含有葡萄糖氧化酶面团和含有谷氨酰胺转胺酶面团于-18℃冷冻贮藏7,21,35d,随冷冻贮藏时间延长,面团弹性模量(G′)降低。在同一冷冻贮藏时期内空白面团弹性模量最小,添加葡萄糖氧化酶面团弹性模量最大;含有葡萄糖氧化酶和含有谷氨酰胺转胺酶面团抗拉伸阻力R5大于空白面团。葡萄糖氧化酶和谷氨酰胺转胺酶使新鲜面团(未冷冻面团)面筋网络增强,淀粉颗粒镶嵌于交错的面筋网络之间,在-18℃经过35d冷冻贮藏,空白面团面筋网络不再连续,支离破碎,并与淀粉颗粒分离,而且面筋膜变薄。含有葡萄糖氧化酶和含有谷氨酰胺转胺酶面团依然有大量连续面筋网络存在。葡萄糖氧化酶和谷氨酰胺转胺酶抑制了面团弹性模量和抗拉伸阻力R5的恶化,而且抑制冰晶对面团中面筋三维网络结构的破坏。     

Effect of water content and storage time on white pan bread quality: instrumental evaluation

 The firmness of white pan bread was measured using compression and bending tests to determine the influence of the water content of the dough on bread quality and on the changes taking place with storage time. Three sample breads were prepared using different flours and three different water contents, and firmness was tested at 24, 48 and 72 h. For gluten-enriched flours, higher water contents tended to bring about a decrease in compression force and bending values, improving shelf-life by reducing the increase in firmness over time. Received: 24 March 1997     

Effect of water content and storage time on white pan bread quality: instrumental evaluation

 The firmness of white pan bread was measured using compression and bending tests to determine the influence of the water content of the dough on bread quality and on the changes taking place with storage time. Three sample breads were prepared using different flours and three different water contents, and firmness was tested at 24, 48 and 72 h. For gluten-enriched flours, higher water contents tended to bring about a decrease in compression force and bending values, improving shelf-life by reducing the increase in firmness over time. Received: 24 March 1997     

Quality of bread supplemented with mushroom mycelia

Mushroom mycelia of Antrodia camphorata, Agaricus blazei, Hericium erinaceus and Phellinus linteus were used to substitute 5% of wheat flour to make bread. Bread quality, including specific volume, colour property, equivalent umami concentration (EUC), texture profile analysis, sensory evaluation and functional components, was analysed. Mycelium-supplemented bread was smaller in loaf volume and coloured, and had lower lightness and white index values. White bread contained the lowest amounts of free umami amino acids and umami 5′-nucleotides and showed the lowest EUC value. Incorporating 5% mushroom mycelia into the bread formula did not adversely affect the texture profile of the bread. However, incorporating 5% mushroom mycelia into the bread formula did lower bread’s acceptability. After baking, mycelium-supplemented bread still contained substantial amounts of γ-aminobutyric acid and ergothioneine (0.23–0.86 and 0.79–2.10 mg/g dry matter, respectively). Overall, mushroom mycelium could be incorporated into bread to provide its beneficial health effects.     

Effect of flour fortification with haem liposome on bread and bread doughs

Slaughter blood haem was encapsulated in lecithin : cholesterol Liposomes. Wheat flour was fortified with this mixture at two levels (60 and 100 mg/100 g flour) using the haem liposomes as iron source. The effect of haem fortification on gluten and fat content of flours was determined, as were the effects of fortification on dough visco‐elastic characteristics (water absorption, development time, dough stability and breakdown time). The baking properties of the breads were also investigated. The addition of haem liposomes increased the fat content of flours, and had a positive effect on the stability and rheological characteristics of the dough. Loaf volume and crumb uniformity was improved. These results indicate a potential nutritional use for haem liposomes..     

Lipid binding of formula bread doughs Relationships with dough and bread technological performance

 Lipid binding of straight/soured started bread doughs treated with sodium carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC), fungal α-amylase and monoglycerides (MGL), diacetyl tartaric acid esters of mono-diglycerides (DATEM) and sodium stearoyl lactylate (SSL) was investigated and results correlated with dough and bread performance during breadmaking and storage. For doughs formulated with MGL or DATEM, free and bound lipids accounted, respectively, for 70% and 30% of the increase in non-starchy lipids, which preferentially bind to gluten (MGL) and to the outside part of the starch granules (DATEM). SSL mainly increased the pool of free lipids and preferentially bound to the inside part of the starch granules and loosely to the gluten. Hydrocolloids preferentially bound to the gluten (CMC) and to the outside part of the starch granules (HPMC) respectively; this was associated with a significant displacement of endogenous gluten-bounded lipids to the starchy fraction (CMC) and with a significant decrease in lipids bound to the outside part of the starch granules (HPMC). The addition of α-amylase promoted a release of endogenous, bound lipids, and the sourer starter induced the aggregation of the starch-lipid complexes, revealed by the respective decrease in the level of gluten bounded lipids (α-amylase) and increase in the level of starchy lipids. Desired trends in dough lipid parameters resulting in strengthened gluten, delayed starch gelatinization, softer bread and reduced/delayed bread staling corresponded to high values of both free and starchy lipids, achieved by the incorporation of SSL and/or CMC into doughs. Received: 22 January 1998     

Production of reduced-calorie grape juice jelly with gellan, xanthan and locust bean gums: sensory and objective analysis of texture

 The production of reduced-calorie grape juice jellies with gellan, xanthan and locust bean gums (LBG) was studied. Twenty formulations of grape juice jelly were prepared according to a second-order composite rotatable design (with six central points). Response surface methodology (RSM) was used to optimise jelly formulation using as independent variables: total sugar content, ranging from 14 to 46°Brix; and total gum concentration ranging from 0.30 to 0.70% (w/v), with the proportion of gums in the mixture xanthan:LBG:gellan ranging from 5:5:90 up to 45:45:10. The processing temperature used was 90°C for complete solubilisation of gums. The dependent variables were objective measures of texture and a parameter obtained from sensory analysis, the overall balance (B), which represents the overall evaluation of the jelly. The resulting polynomial equation (R ² = 0.929) revealed that a jelly produced with white grape juice, total sugar with sucrose equal to 39.3°Brix, and, 0.54% (w/v) of total gum added in the proportions of: 1:1:1.7 (gellan:xanthan:LBG) had a maximum value of B. The sensory-optimised jelly was objectively characterised for texture and the model was tested. The texture characteristics, i.e. gel hardness, cohesiveness and springiness, were found to be similar to those of a reference product, a previously developed reduced-calorie grape juice jelly with low methoxyl pectin. Received: 12 June 1997 / Revised version: 21 August 1997     

The effect of kefir addition on microstructure parameters and physical properties of porous white bread

The effect of kefir concentration on the quality of porous white bread has been investigated. Quality evaluation was done using flatbed scanning (FBS) for measuring crumb porosity, instrumental texture profile analysis (TPA), crust and crumb color (L ^* a ^* b ^*), moisture, specific volume, and density determination techniques. The correlations between porosity, brightness, and firmness were also investigated. Long fermentation time of the sourdough changed significantly (p<0.05) the cell mean area (mm²), cell mean perimeter (mm), firmness (N), chewiness (N), light reflectance, and specific volume (ml/g). A strong correlation was found between microstructure of porous white bread, brightness (L), and firmness from TPA test. Kefir prolonged the shelf life of bread.     

Improvers and functional ingredients in whole wheat bread: A review of their effects on dough properties and bread quality

BackgroundDespite the associated health benefits of whole grains, consumption of whole grain products remains far below recommended levels. Whole wheat bread is often associated with many distinctive attributes such as low loaf volume, firm and gritty texture, dark and rough crust and crumb appearance, bitter flavor, and reduced shelf-life. There is a need to improve its quality and sensory characteristics so as to increase consumer appeal and, ultimately, increase the intake of whole wheat bread. The inclusion of various ingredients improves dough and bread properties.Scope and approachThis review examines the effects of enzymes, emulsifiers, hydrocolloids, and oxidants on the properties of whole wheat bread and dough, with particular attention to effects on loaf volume and hardness. Wheat gluten and other plant materials are also discussed. Gaps in the research into whole wheat bread are identified, and future research needs are recommended.Key findings and conclusionsXylanase reduces the water absorption of whole wheat flour and increases loaf volume and crumb softness by hydrolyzing ararbinoxylans. α-amylase can be beneficial under certain conditions. Phytase may activate endogenous α-amylase. G4-amylase is promising but needs validation by further research on its effect on loaf volume, crumb hardness, and staling. Vital wheat gluten overcomes many of the challenges of whole wheat bread production and is found in the majority of commercial whole wheat breads. Emulsifiers DATEM and SSL can improve the volume, texture and staling profile of whole wheat bread. Several types of improvers are generally needed in combination to provide the greatest improvement to whole wheat dough and bread.