Staling in Starch Breads: The Effect of Antistaling α-Amylase

A novel starch bread that contained no gluten was found to firm at a rate comparable to a normal standard bread made from wheat flour. Treatment of both the starch and the standard bread with Novamyl, an antistaling enzyme mix, inhibited firming. ¹³C CP/MAS NMR studies showed that the decreased firming of the Novamyl-treated starch bread was correlated with decreased starch retrogradation. For the Novamyl-treated bread the increase in retrograded starch over six days following baking was about 11% compared to an increase of over 200% for the untreated bread. These results suggests that starch retrogradation is sufficient to cause bread firming.     

Starch affecting anti-staling agents and their function in freestanding and pan-baked bread

Anti-staling agents with different mechanisms were added to a normal white wheat bread to investigate the relation between bread staling, amylopectin retrogradation and water-related properties (i.e. water content and distribution between crumb and crust). Bread was baked both as pan-baked and freestanding loaves. The anti-staling agents maltogenic α-amylase, distilled monoglyceride and lipase had a direct influence on starch retrogradation, whereas gluten and waxy wheat flour diluted the amylopectin content or changed the ratio between amylose and amylopectin. The degree of staling was measured as the firmness and springiness, together with two new methods, crumbliness and cutability. In addition, the degrees of amylopectin retrogradation and amylose–lipid complex formation were analyzed by differential scanning calorimetry, and the water content, water loss and water migration were measured. The addition of α-amylase improved most staling parameters, although the changes were not as large as expected. Furthermore, monoglyceride and lipase increased the formation of amylose–lipid complexes, but only lipase gave better results regarding the specific volume and firmness. Increased amylose–lipid complex formation was seen to increase water migration from crumb to crust. Adding 10% waxy wheat flour appeared to lead to a slight overall improvement i.e. lower water migration and better cutability. Adding gluten or 3% waxy wheat flour only improved the specific volume. The method of baking the loaves, i.e. freestanding or pan-baked, had a greater influence than the anti-staling agents, which shows that bread quality is not always improved by starch affecting anti-staling agents without process changes.     

Dough properties and breadmaking qualities of whole waxy wheat flour and effects of additional enzymes

BACKGROUND: Waxy wheat, a new kind of genetically back‐crossed wheat, was applied to make whole bread in this study. Dough properties and bread quality of the whole waxy wheat flour, which was milled from 100% whole grains containing bran and germ, were determined. RESULTS: Whole waxy wheat had lower protein and lipid contents but higher dietary fiber content than whole regular wheat flour. Pasting temperature and viscosity of the whole waxy wheat flour were significantly lower than those of the whole regular wheat. However, the white wheat flour milled from wheat grains with 48% recovery had significantly higher peak viscosity than the whole waxy wheat. Bread made from the whole waxy wheat flour was significantly softer than that from the whole regular wheat flour during storage. However, bread made from whole waxy wheat had significantly lower specific volume than that from the white waxy flour because of the high amount of dietary fiber. Addition of cellulase increased paste viscosity, lowered dough mixing properties and reduced the firmness of the bread. The addition of pentosanase also increased paste viscosity, lowered dough mixing properties, improved loaf volume of bread but increased the firmness of breadcrumbs, while the addition of α‐amylase only increased final viscosity of flour and did not affect dough properties and bread qualities of whole waxy wheat flour. CONCLUSION: As a result, waxy wheat shows superior properties for making whole breads. Additional enzymes are also necessary to improve bread quality and nutritive values of whole waxy bread. Copyright © 2007 Society of Chemical Industry     

大豆粉末磷脂对面团流变学特性和馒头品质的影响研究

将大豆粉末磷脂添加到小麦粉中,研究其对小麦粉面团流变学特性和馒头品质的影响.结果表明,在小麦粉中添加大豆粉末磷脂,可以明显地改善面团的稳定时间以及拉伸曲线面积和拉伸阻力,还可以提高馒头的品质,增加馒头的抗老化效果;当在小麦粉中添加0.8%的大豆粉末磷脂时,其对馒头品质有较好的改善作用.     

Effect of damaged starch levels on flour-thermal behaviour and bread staling

The effect of the amount of damaged starch in two different flours (wheat and triticale) on the bread quality and its behaviour during storage has been analysed. Two wheat and one triticale flour cultivars were milled in a disc mill to obtain different levels of damaged starch. Differential Scanning Calorimetry (DSC) and Rapid Visco Analyser (RVA) were used to characterize the flour properties and TA-XT2 textural analyses were made on breadcrumb. The effect of the damaged starch content on the bread firming, the amylopectin retrogradation and starch-pasting properties were studied in order to establish any relationship between damaged starch and bread staling. DSC analysis showed that the damaged starch content changed the thermal behaviour of flour–water mixtures: the higher the levels of damaged starch the lower the starch-gelatinization enthalpy and the higher the melting enthalpy of amylose–lipid complexes. The amount of amylopectin retrogradation and breadcrumb firming increased with the damaged starch content at the beginning of storage time; however, differences were decreasing at final storage time. The flour viscosity during pasting decreased as their damaged starch content increased.     

Increasing the health benefits of bread: Assessment of the physical and sensory qualities of bread formulated using a renin inhibitory Palmaria palmata protein hydrolysate

This study examined the textural and sensory effects of bread formulated using a Palmaria palmata protein hydrolysate with in vitro renin inhibitory properties. Four formulations were examined; a wheat flour control bread, a control bread containing 4% P. palmata protein hydrolysate, a buckwheat bread consisting of a blend of 70% wheat: 30% buckwheat, and a fourth formulation of the buckwheat bread containing 4% P. palmata hydrolysate. The volume, colour, texture profile, moisture, crumb structure, sensory attributes and renin inhibitory activity of all four baked breads are presented. Bright field light microscopy and confocal scanning laser microscopy images using a new triple labelling protocol were also obtained to visualise the main ingredients of the breads. It was observed that the addition of 4% P. palmata protein hydrolysate to the wheat bread control did not affect the texture or sensory properties of the bread to a large degree. Furthermore, when compared to the control, the bread containing the hydrolysate retained renin inhibitory bioactivity after the baking process. This study highlights that baked products may be a suitable delivery vehicle for bioactive compounds. The study demonstrates that the health value of bread was increased through the addition of a seaweed protein hydrolysate.     

Utilization of a Maltotetraose‐Producing Amylase as a Whole Wheat Bread Improver: Dough Rheology and Baking Performance

A maltotetraose‐producing enzyme (G4‐amylase) was utilized to improve the baking performance of whole‐grain wheat flour. Whole‐grain bread dough prepared with G4‐amylase showed reduced water absorption and increased development time, while the dough stability was not affected. Also, the G4‐amylase‐treated samples exhibited lower Mixolab torque values than the control upon heating and cooling. Rheological measurements showed the decreased ratio of R_max/E and increased tan δ, clearly demonstrating that the viscous characteristics of whole‐grain bread dough became dominant with increasing levels of G4‐amylase. The use of G4‐amylase produced whole‐grain wheat breads with a variety of maltooligosaccharides, primarily maltotetraose that positively contributed to the bread volume (1.2‐fold higher than the control). Moreover, G4‐amylase delayed the crumb firming of whole‐grain wheat bread during a 7‐d storage period, showing that it can function as an antiretrogradation agent to enhance the quality attributes of whole‐grain wheat bread.     

外源戊聚糖酶对国产小麦面包粉品质的影响

通过流变学试验、面包烘焙试验和面包芯质构测试,探讨了戊聚糖酶对国产小麦面包粉品质的影响。试验表明,与对照组相比较,在添加适量戊聚糖酶后,面团的流变学性质、面包品质都得到明显改善。质构测试显示,戊聚糖酶可以有效地延缓面包制品的老化现象。试验条件下,添加戊聚糖酶60μg/g(酶/小麦粉)为最适添加量。     

不同发酵基质的酸面团对酵母面团体系面包烘焙及老化特性的影响

应用分离自我国传统酸面团的区域特色乳酸菌--旧金山乳杆菌分别发酵小麦粉和小麦麸皮基质制成（小麦/麦麸）酸面团,研究了两种不同发酵基质的酸面团及其添加量对酵母面团体系面包烘焙及老化特性的影响。结果表明：与小麦粉制作的空白组面包相比,小麦酸面团可以明显改善面包的比容和感官品质;添加未发酵麦麸制作的非酸面团麦麸面包品质低于空白组,但引入麦麸酸面团（10%、20%、30%）后面包比容和感官评定得分均高于相对应的非酸面团麦麸面包。小麦酸面团和麦麸酸面团以及小麦麸皮均可以改善面包的老化特性,在相同贮藏期内,酸面团面包和麦麸面包的硬度增加量、水分迁移量和老化焓值都低于空白组,并且添加麦麸酸面团的面包其硬度和老化焓值都低于相对应的非酸面团麦麸面包。     

The use of normal and heat-treated barley flour and waxy barley starch as anti-staling agents in laboratory and industrial baking processes

Normal and heat-treated barley, both as flour and waxy starch, were added at a concentration of 3% to a white wheat bread. The effect not only of selected additives, but also of laboratory- and industrial baking processes on stalling was evaluated. Laboratory baked breads with heat-treated barley flour differed from control breads with regard to water content, firmness and amylopectin retrogradation. The influence of water content on firmness increased with storage time. All laboratory baked breads with barley additives, except normal barley flour, were less firm after 7 days of storage as compared to the control although amylopectin retrogradation tended to increase. Improved water absorption, and consequently, increased water content and/or different water binding capacities of the flour/starch could explain these results. Industrial baking caused higher water losses, especially in breads containing additives, thus reducing the effects on amylopectin retrogradation and firmness.     

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.     

木糖醇对面包粉回生特性影响

以面包专用粉为原料,添加不同质量浓度木糖醇,通过测定熟化后面包粉硬度、冻融稳定性及糊化特性研究木糖醇对面包粉回生特性影响。结果表明,添加木糖醇后,熟化后面包粉回生硬度明显降低,添加0.50 g/g木糖醇面包粉在4℃条件下回生5 d、7 d硬度较原面包粉分别降低37.31%、57.45%;面包粉冻融稳定性显著增强,原面包粉冻融循环4次失水率为47.39%,而添加0.20g/g木糖醇样品失水率为22.91%,比原面包粉减少24.48%;经RVA测定,添加0.20 g/g、0.50g/g木糖醇面粉与原面粉相比,峰值粘度显著增加;表明添加木糖醇对面包粉回生具有抑制作用。     

脱毒亚麻籽粕在面包中的应用研究

由于亚麻籽富含各种营养成分,目前正作为一种功能食品来源。本文将亚麻籽粕脱除毒性物质生氰糖苷后,将其添加到面粉中,以研究其对面团特性、面包烘焙品质以及面包贮存过程中老化程度的影响。结果表明,水煮法处理对除去生氰糖苷有较好的效果,通过正交实验确定以2%的比例添加可改善面团特性及面包烘焙品质,并增加面包的抗老化作用,延长了货架期。     

Emulsifiers: Effects on Quality of Fibre-Enriched Wheat Bread

Resistant starch (RS) is a nutritional ingredient commonly used in bread products as dietary fibre (DF). This ingredient presents similar physiological functions than those imparted by DF, promoting beneficial effects such as the reduction of cholesterol and/or glucose levels on blood. Quality improvement of bread containing RS, with an optimized combination of emulsifiers, will be useful in the development of new and healthy bakery products. The objective of this research was to analyse the effects of different emulsifiers on several quality parameters of dough and bread prepared with wheat flour partially substituted with resistant starch as a dietary fibre. A blend of wheat flour/maize-resistant starch (MRS; 87.5:12.5) with sodium chloride, ascorbic acid, α-amylase, compressed yeast and water was utilized. Emulsifiers were incorporated to formulations in different levels according to a simplex centroid design. The viscoelastic, textural and extensional properties of dough were analysed. Bread quality was evaluated throughout the gelatinization and retrogradation of starch, specific volume of loaves, and texture and firmness of bread crumb. The incorporation of 12.5% (w/w) of MRS to wheat flour caused an increase of 5% in water absorption. Stability decreases markedly (from 9.9 to 2.2 min) and the mixing tolerance index increased (from 79 to 35 UF). The sodium stearoyl lactylate (SSL)–diacetyl tartaric acid esters of monoglycerides (DATEM) mixture increased hardness and resistance to extension on dough, whilst dough containing Polysorbate 80 (PS80) was softer; nevertheless, both types of dough retained less CO₂. An optimized concentration of the three emulsifiers (0.24% SSL, 0.18% PS80, 0.08% DATEM, w/w) was obtained by surface response methodology. The bread prepared with this combination of emulsifiers presented a considerable specific volume with a very soft crumb.     

Bread quality of frozen dough substituted with modified tapioca starches

Rheological properties of dough and bread quality of frozen dough-bread containing 18.4% of hydroxypropylated (HTS), acetylated (ATS), and phosphorylated cross-linked (PTS) tapioca starch with different degrees of modification and 1.6% of dried powdered gluten were compared to the same amount of native tapioca starch (NTS) or wheat flour-bread. Doughs substituted with native or modified tapioca starches had the same mixing tolerance as 100% wheat flour. The dough was frozen and stored for 1 week at −18°C, and thawed (one freeze-cycle). The amount of freezable water in the dough substituted with native or modified tapioca starches was not significantly different from that of wheat flour. Frozen dough-bread substituted with highly modified HTS (degree of substitution; DS 0.09–0.11) retarded bread staling, while lowly modified HTS (DS 0.06–0.07) or ATS (DS 0.02–0.04), and PTS (0.004–0.020% phosphoryl content) substitution fastened bread staling as compared with frozen dough-bread baked from wheat flour. The breadcrumbs containing HTS and ATS felt tacky, whereas the bread containing PTS was dry feel. HTS and ATS swelled and collapsed easily during heating, while PTS was difficult to swell and disperse as compared with NTS, therefore the gelatinization properties seemed to affect the texture of bread. Breadcrumb containing HTS showed small firmness during storage, and highly modified HTS-h (DS 0.1) was the smallest. This means highly hydroxypropylated tapioca starch significantly retards bread staling. Staling properties and texture of frozen dough-bread with various tapioca starches were the same as conventional bread baked with the same amount of tapioca starches. These results suggest that a one freeze–thaw cycle and a 1-week frozen period do not change characteristics of starch, gelatinization and retrogradation properties as compared with the conventional method, and the highly modified HTS-h is prominent anti-staling food-stuff in frozen dough.     

中性木聚糖酶在面包制作中的应用

通过探讨不同浓度的中性木聚糖酶对面粉粉质、面包焙烤品质以及面包贮存过程中老化程度的影响 ,研究中性木聚糖酶作为焙烤添加剂的可行性。结果表明 ,中性木聚糖酶能显著地改善面粉的粉质 ,当添加量为 0 3mL/kg(面粉 )时 ,面团的形成时间可减少 5 0 %左右 ;能有效地改善面包焙烤品质 ,明显地增加面包的体积和比容 ,同时可以改善面包心的弹性和硬度 ,减小面包皮的硬度 ;酶添加范围为 0 0 5～ 0 48mL/kg(面粉 ) ,能增加面包的抗老化作用 ,贮藏 7d后 ,面包的硬度和弹性没有明显变化 ,延长了货架期     

糯小麦粉添加量对配粉流变学特性及馒头品质的影响

将糯小麦粉与普通小麦粉进行梯度配粉,研究不同糯小麦粉添加量对配粉糊化黏度、粉质特性和面团流变学特性的影响;采用质构和感官评价相结合的方法评价其对馒头品质的影响,确定合适的糯小麦配粉比。结果表明：随着糯小麦粉添加量的增加,配粉的糊化温度、峰值黏度、衰减度和回生值等快速黏度分析参数均呈现下降趋势,尤其是回生值降低显著。配粉的吸水量随糯小麦粉添加量的增加逐渐增大,面团的形成时间和稳定时间缩短,粉质指数降低;但当添加量增加至25.0%时,粉质特性各指标均产生显著性改变。不同配粉面团随着醒发时间的延长,面团拉伸曲线面积、拉伸阻力和拉伸比等指标均呈现一定的增大趋势,但延伸度却随醒发时间延长而降低。糯小麦粉配粉比例对馒头的质构和感官特性具有较大影响,适宜的糯小麦粉配粉比为20.0%～30.0%,25.0%配粉比使馒头具有较好的质构,感官总评分达到最大值。     

The anti-staling effect of pre-gelatinized flour and emulsifier in gluten-free bread

The use of gluten-free products is increasing since an increasing number of people (1–2 %) are suffering from Celiac disease and thereby need a gluten-free diet. Gluten-free bread tends to have shorter shelf life and quality compared with white wheat bread. In this study, 3 % (flour basis) of pre-gelatinized oat and barley flour as well as an emulsifier were added to a gluten-free mix to increase the water content by 1.5–2 %, affect the starch retrogradation and the formation of amylose lipid complex. The staling was followed measuring the firmness (texture analyzer), water content and distribution (nuclear magnetic resonance), amylopectin retrogradation and the formation of amylose–lipid complex (differential scanning calorimetry) in order to see the impact of both macroscopic and molecular changes on firmness. Both gluten-free bread and a white wheat bread were used as control loaves. Largest specific volume was found in the gluten-free control. The firmness varied with both the specific volume and the point of measurement. The amount of retrograded amylopectin increased the firmness, although this effect was dependent on the type of bread, in terms of distribution and availability of the water within the system. The proton relaxation time, which was representing movable water, decreased during storage and revealed that both the amylopectin retrogradation and the lipid complex formation were affecting the rigidity of the amorphous domain and not only the crystalline regions. In contrast to the other recipes, the use of emulsifier caused limited retrogradation and a low correlation between the texture properties and time-dependent events.     

木聚糖酶对馒头品质的影响及抑制回生的机理研究

本试验主要研究木聚糖酶对馒头品质的影响,结果表明:添加30 mg/kg(以小麦粉为基准)木聚糖酶对馒头的改善效果较好,馒头的综合评分最高,达93分;馒头的硬度为1 658 g,胶着性为1 439,咀嚼性为1 391,分别比对照降低了48%、46%和44%;RVA分析表明,与对照相比,馒头皮黏度降低了344cP,馒头芯部黏度降低168 cP,说明添加木聚糖酶增大了馒头表皮和芯部的糊化程度;馒头贮藏过程中DSC分析表明,馒头的结晶熔融焓值由对照的3.05 J/g降低为1.99 J/g,说明木聚糖酶可以抑制馒头回生。相关性分析表明,馒头芯部糊化程度与贮存期间馒头的回生性质呈负相关。而RVA和DSC研究结果表明,添加木聚糖酶后小麦粉糊化温度降低,热焓值降低,小麦粉更易糊化,阐明了木聚糖酶能够抑制馒头回生的机理。     

山药薏米芡实混合粉对小麦粉加工品质的影响

在小麦粉中加入山药、薏米、芡实混合粉,利用快速黏度分析仪、Mixolab混合实验仪和质构仪分析不同添加量的混合粉对小麦粉糊化特性、面团热机械学特性以及对馒头质构特性的影响.结果表明:随着混合粉添加量的增加,小麦粉的糊化黏度、崩解值、回生值、糊化温度、糊化时间、面团吸水率、形成时间和稳定时间逐渐降低,蒸煮稳定性和蛋白质弱...