Effect of flaxseed and wheat flour blends on dough rheology and bread quality

The rheological and baking properties of flaxseed/wheat composite flours were studied. Flaxseed flour was used to replace 50, 100, 150 and 200 g kg^?1 of wheat flour in bread. Farinographic studies showed that water absorption, dough development time and mixing tolerance index increased as the amount of flaxseed flour increased, while dough stability decreased at 100, 150 and 200 g kg^?1 of flaxseed flour substitution. The extensographic energy of dough also decreased at 150 and 200 g kg^?1 flaxseed levels. The addition of increasing amounts of flaxseed flour caused a decrease in extensibility. Doughs containing 100, 150 and 200 g kg^?1 flaxseed flour showed resistance to extension comparable to that of control dough. The specific volume of flaxseed flour breads was similar to that of control bread. Crust L, a, b values of breads with flaxseed flour were lower than those of control bread. Breads with flaxseed flour gave lower crumb L and b values and higher a values than control bread. The sensory properties showed that an acceptable bread could be produced using flaxseed flour up to a level of 200 g kg^?1. Copyright © 2007 Society of Chemical Industry     

Microflora of the sour dough of wheat flour bread

Summary Wheat doughs elaborated with microbial mass fromSaccharomyces cerevisiae, Candida boidinii, Lactobacillus plantarum andStreptococcus faecium, individually and in up to 13 combinations have been investigated for: (a) changes during fermentation in short chain (C₃–C₆) volatile organic acids, and (b) headspace gas composition (alcohols, esters and carbonyl compounds) of fermented doughs. Lactic acid bacteria, when used individually, did not produce C₃–C₆ volatile organic acids, but when added to doughs with yeasts promoted an increase in propionic and isobutyric acids and a decrease in isovaleric acid concentration in relation to the amounts produced by the yeasts alone.n-Butyric andn-valeric acids were present in very low amounts that did not change during fermentation in any of the samples studied. The headspace gas from doughs with lactic acid bacteria contained very small amounts of volatile flavor compounds; diacetyl was the most relevant component. Yeasts had the same qualitative headspace composition, but they differed quantitatively.S. cerevisiae produced larger amounts of all the components thanC. boidinii. Ethanol was the most abundant compound followed by acetaldehyde,n-propanol, hexanal+isobutanol and isoamyl alcohol. In general, the addition of lactic acid bacteria to dough with yeasts did not significantly modify the head-space flavor fraction. Doughs with both yeasts and lactic acid bacteria produced more ethanol than expected from the proportion of each yeast. WhenC. boidinii was inoculated in higher concentration (70%) thanS, cerevisiae several components not detected in the other samples could be identified: isoamyl acetate,n-butanol, amyl acetate andn-pentanol.

---

Mikroflora der Sauerteiges von Weizenbrot XIV. Veränderungen der flüchtigen Verbindungen während der Gärung von Teigen mit reinen Mikroorganismen und ihren Mischungen

Zusammenfassung Es wurden Weizenteige mitS. cerevisiae, C. boidinii, L. plantarum und S. faecium, einzeln und in bis dreizehn Kombinationen, hergestellt und die Veränderungen der kurzkettigen (C₃–C₆), flüchtigen organischen Säuren während der Gärung und die Gaszusammensetzung im Kopfraum auf Alkohole, Ester und Carbonyl-Verbindungen der fermentierten Teige untersucht. Die Milchsäurebakterien, wenn einzel benutzt, bildeten keine (C₃–C₆) flüchtigen organischen Säuren, aber wenn sie zu hefehaltigen Teigen zugegeben wurden, verursachten sie eine Zunahme des Gehaltes an Propion- und Isobuttersäure und eine Abnahme des Gehaltes an Isovaleriansäure.n-Butter- undn-Valeriansäure waren in kleinen Mengen anwesend und veränderten sich nicht während der Gärung. Das Kopfraumgas von Teigen mit Milchsäurebakterien enthielt sehr kleine Mengen von flüchtigen Aromaverbindungen; Diacetyl war der wichtigste Bestandteil. Hefen ergaben eine ähnliche qualitative Zusammensetzung des Gases im Kopfraum, aber quantitativ unterschiedlich.S. cerevisiae bildete größere Mengen von allen Verbindungen alsC. bodinii. Der Gehalt an Ethylalkohol war am höchsten, gefolgt von Acetaldehyd,n-Propanol, Hexanal und Isobutylalkohol. Im Allgemeinen verursachte die Zugabe von Milchsäurebakterien zum Hefeteig keine tiefgreifende Veränderung der Aromafraktion im Kopfraum. Teige mit Hefen und Milchsäurebakterien bildeten mehr Ethylalkohol als erwartet. WennC. bodinii in höheren Mengen (70%) alsS. cerevisiae eingeimpft wurde, so konnten manche Bestandteile in den Proben nicht identifiziert werden: Isoamylacetate,n-Butanol, Amylacetat undn-Pentanol.

     

藜麦粉对小麦面团、面包质构特性及品质的影响

研究藜麦粉对小麦面团及面包质构特性的影响,为开发藜麦焙烤食品提供理论依据。在对藜麦粉中蛋白组分含量系统研究的基础上,利用质构仪的TPA模式测定添加藜麦粉对小麦面团硬度、弹性和黏性的影响,藜麦粉对面包硬度和弹性的影响。结果表明,随着藜麦粉添加量的增加,面团的硬度呈先减小后增加的趋势,添加量为15%时硬度最小;弹性呈先增大后减小的趋势,在藜麦粉添加量15%时达到最大值,黏性呈逐渐增大的趋势。随着藜麦粉添加量的增加,面包的硬度逐渐增大,弹性逐渐减小,感官评分先增大后减小,在15%时达到最大值。因此,藜麦粉的添加改变了小麦面团和面包的质构特性,且面团的质构特性与面包质构特性、面包感官品质间具有一定相关性。     

百合粉添加量对面团特性及面包品质的影响

为拓宽百合的应用渠道,提高面包的营养价值,研究了百合粉添加量(0%,5%,10%,15%,20%)对面团的微观结构、糊化特性、流变学特性以及面包品质的影响。结果表明:随着百合粉添加量增大,混合粉的持油性先降低后增加,持水性显著增加(P<0.05)。添加了百合粉后,面团的糊化温度升高,回生值和峰值黏度下降,面团的弹性模量和黏性模量均呈上升趋势。百合粉的添加,破坏了面筋蛋白原本均匀致密的微观结构;使面包的硬度显著增大(P<0.05),弹性、内聚性、胶黏性、咀嚼性、回复性、比容和感官评分显著降低(P<0.05);改变了小麦面团的特性和面包的品质,在小麦粉中添加5%～10%的百合粉,能保证面包较高的感官品质。     

脱皮率对小麦粉、面团及馒头品质的影响

对小麦籽粒进行脱皮处理,研究脱皮率对小麦粉、面团及馒头品质的影响。结果表明:随脱皮率的增加,小麦粉的蛋白质和可溶性膳食纤维含量呈先上升后下降的趋势,在脱皮率为6%时达到最高值;面团的黏度崩解值下降,回生值和蒸煮稳定性升高,扫描电镜图显示面筋网络的排列更均匀致密;馒头的综合感官评分增加,硬度、胶着性和咀嚼度下降,内聚性和回复性上升。脱皮率为0%～6%时面团和馒头的品质明显改善,在6%～12%时其品质提升幅度减缓。6%脱皮率能有效保留小麦粉的营养物质,改善馒头的品质,是较理想的脱皮程度。     

Effects of microencapsulated glucose oxidase on wheat flour dough properties and Chinese steamed bread quality

This study was to investigate the effects of microencapsulated glucose oxidase (MGO), in comparison with free glucose oxidase (GO), on wheat flour dough properties and Chinese steamed bread (CSB) quality. Effects on wet gluten (WG) content, farinograms and extensograms properties, dynamic rheological properties, microscopic structure, texture profile and sensory evaluation scores were studied. The results demonstrated that MGO catalysed the oxidation of dough at a much slower speed and exerted relatively great advantages in many aspects such as WG content, extensibility, G′ (Elastic modulus), G″ (viscous modulus), tan δ (equal to G′/G″), microstructure and texture properties and sensory evaluation scores of CSB, compared with free GO. The results suggested that slow oxidation of MGO was superior to free GO based on the improvements of wheat flour dough properties and subsequent CSB quality.     

小麦粉对馒头品质的影响

馒头品质的主要影响因素之一是小麦面粉品质。对小麦粉中的蛋白质含量、蛋白质质量、蛋白质组分及面团的流变学特性,淀粉含量、淀粉组成及小麦淀粉的黏度特性等各因素对馒头品质的影响进行了较为详细的论述。     

小麦及其面粉品质对馒头品质的影响

综合分析了小麦与面粉的蛋白质品质、淀粉品质、酶、脂类物质等对馒头品质的影响。     

Effect of waxy flour blends on dough rheology and bread quality

Although much research has been conducted on wheat flour dough rheology, the principal focus has been the role of the protein fraction. Starch is the main component of flour and plays a key role in dough dynamic properties, particularly during heating. This study assesses the effect of two different waxy flours, a durum and a bread wheat, and their blends with commercial bakers' flour on dough rheology during heating with a concurrent investigation into baking performance. Both waxy flour blends produced similar effects on dough rheological behaviour despite differences in protein content, acting to delay gelatinisation and reduce storage modulus. The main effects in bread were to increase loaf expansion during baking and reduce loaf firmness. It is postulated these effects are largely water mediated, with the higher swelling ability of the waxy starch granules reducing overall water availability and driving complete gelatinisation to higher temperatures.     

Effects of trypsin‐hydrolyzed wheat gluten peptide on wheat flour dough

BACKGROUND: Gluten peptide was prepared by trypsin hydrolysis and characterized by high‐performance liquid chromatographic analysis. The effects on non‐frozen and frozen doughs of trypsin‐hydrolyzed gluten peptide (THGP) and its combination with ascorbic acid or KBrO₃ were investigated. RESULTS: Molecular analysis of THGP showed a decrease in the high‐molecular‐weight and an increase in the low‐molecular‐weight sodium dodecyl sulfate‐soluble fractions, compared with those of control wheat gluten. The addition of 8% THGP decreased the mixing time and tolerance of the dough, both with and without ascorbic acid or KBrO₃. However, the maximum resistance and extensibility of the rested dough containing 8% THGP, with and without ascorbic acid or KBrO₃, were not significantly different from those of the control dough. The addition of 8% THGP significantly increased the loaf volume of bread baked from non‐frozen dough when combined with 60 ppm ascorbic acid or 30 ppm KBrO₃, but it had a significant effect both with and without ascorbic acid or KBrO₃ on frozen‐dough bread. A large difference in volume was observed between breads made with and without THGP at the oven‐spring, rather than at proofing. CONCLUSION: The addition of 8% THGP increased the loaf volume of bread made from freeze‐damaged dough and this effect increased when THGP was combined with 60 ppm ascorbic acid. Copyright © 2008 Society of Chemical Industry     

Influence of phosphorylated rice flour on the quality of gluten‐free bread

The chemical modification of rice flour by phosphorylation is an alternative to improve the technological quality of bakery products. The aim of this study was to investigate the effect of phosphorylation process of rice flour on technological properties (specific volume, crumb and crust colour) of gluten‐free breads and the hardening of these breads during two storage temperatures (21 °C and ?24 °C). Breads were made with native rice flour, with phosphorylated rice flour and with wheat flour, used as control. The phosphorylation causes significant reduction in the synaeresis of pastes and in retrogradation tendency of rice flours, varying from 258.7 cP (native rice flour) to 122 cP (phosphorylated rice flour). The breads prepared with phosphorylated rice flour showed reduction in the hardness in both storage temperatures studied and effect on rice bread volume, crumb appearance and colour, demonstrating the possibility of use of the phosphorylated rice flour in gluten‐free breads.     

Effects of pineapple pomace fibre on physicochemical properties of composite flour and dough,and consumer acceptance of fibre‐enriched wheat bread

Pineapple pomace fibre (PF, containing 70.2% total dietary fibre) can be added to increase dietary fibre of wheat bread. This study was performed to evaluate effects of PF added at 0, 5 or 10% (wheat flour‐basis) on physicochemical properties of the composite flour (wheat flour as the control, CPF‐5 and CPF‐10, respectively) and its dough, to evaluate consumer acceptance of CPF breads and to identify factors affecting willingness to purchase of CPF breads. Incorporating PF affected rheological and pasting properties of CPF. Water‐ and oil‐holding capacity of CPF increased (P < 0.05) as PF levels increased. Bread made with CPF‐5 was more acceptable than that with CPF‐10; however, it was not significantly different from the control, having similar specific volume and texture, but having about three times higher total dietary fibre than the control (4.4% vs. 1.5%). Product label and health benefit information potentially affected consumers' willingness to purchase of fibre‐enriched bread.     

Effect of heat treatment of rye flour on rye‐wheat steamed bread quality

To study the effect of heat treatment on rye flour quality, rye flour was treated by steaming, high temperature and high pressure (HTHP) and extrusion and then the pasting properties of rye flour and rye‐wheat blend, the dough rheological and steamed bread (respectively, fermented by yeast and Chinese traditional starter – Laomian) making properties of rye‐wheat blend were investigated. All three kinds of heat treatment increased the viscosity of rye flour, with the peak viscosity value followed the order 1744 cP (by steaming) >823.5 cP (by HTHP) >669 cP (by extrusion) > 626.5 cP (untreated). Dough and gluten made from mRFh (HTHP‐treated rye flour and wheat flour blend) had higher storage modulus (G′) and loss modulus (G″), which contributed to better extensibility and deformation capability. Steamed bread fermented by Laomian (LSB) made by mRFh had larger specific volume (2.26 mL g^?1), lower hardness (3510.93 g) and higher sensory scores (82.63), comparable to the quality of control samples, indicating the feasibility of adding rye flour into wheat flour for healthy product development without compromising the taste and texture.     

Characteristics and oil absorption of deep‐fat fried dough prepared from ball‐milled wheat flour

BACKGROUND: High levels of oil in fried products has been recognized as causing health problems. The formation of microstructure during frying is one factor that influences oil absorption. Above the glass transition temperature (T_g), the physical properties of a polymer influences the formation of structure. The ball‐milling process changes the physicochemical properties of wheat flour constituents. The present study investigated the effects of physicochemical changes in wheat flour by the ball‐milling process on structure formation and oil absorption in wheat flour dough model. RESULTS: Dough samples were made from wheat flour that had been ball‐milled for 0 to 10 h and then fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration, and textural properties of fried samples were evaluated. As compared with samples made of non‐milled flour, samples made from milled flour had smaller pores and higher oil absorption. The fracture force of a fried sample prepared from non‐milled flour was lower than that of a sample prepared from milled flour. CONCLUSION: Ball‐milling affected the microstructure formation in fried wheat flour dough, and subsequently oil absorption. The crispness of a sample prepared from non‐milled wheat flour is higher than that of a sample prepared from ball‐milled wheat flour. This may be due not only to a plasticization effect, but may also be dependent on microstructure. Copyright © 2008 Society of Chemical Industry     

燕麦全粉对面团特性及馒头品质的影响

以不同比例(0%~50%)的燕麦全粉替代小麦面粉,通过粉质、拉伸、快速黏度分析、旋转流变、F3-发酵流变、面团p H值的测定及质构分析等手段研究了混合面团的流变学特性、发酵特性及馒头的质构品质。结果表明:随着燕麦全粉替代比例的增加,混合粉的湿面筋含量显著降低,面团的吸水率增大,形成时间和稳定时间先增大后减小,弱化度逐渐增大,最大拉伸阻力和拉伸比例先降低后升高,延伸度逐渐降低;混合粉的峰值黏度、回生值、糊化温度及面团的弹性、黏性模量都随燕麦全粉的加入而逐渐增大;面团的持气性逐渐降低,漏气时间提前;燕麦全粉的加入使面团的p H值增大,使酵母及乳酸菌等的代谢受到了影响;燕麦全粉的替代比例小于20%时,混合粉仍具有较好的加工特性,更高含量燕麦全粉的加入将会导致馒头的比容和弹性显著降低,硬度明显增大。     

受热对小麦粉品质及其面团特性的影响

小麦粉在加工过程中会受到热的影响,导致小麦粉品质发生变化。该文研究不同受热条件下小麦粉品质及其面团特性的变化,以稳定或提高小麦粉品质。采用干热处理方式,在60~90℃分别对小麦粉加热10~50 s,测定小麦粉的水分含量、干面筋含量、面筋指数、蛋白质组分含量等理化特性,以及游离巯基含量、二硫键含量、面筋蛋白二级结构等结构组成和面团质构特性。研究结果表明,受热后小麦粉水分含量显著降低,在较长时间和较高温度时,随着温度升高和时间的延长,干面筋含量总体呈先升高后降低的趋势,当温度较高时,面筋指数均低于原粉,且随时间的延长先升高后降低;随着温度升高和时间延长,清蛋白和球蛋白含量降低,醇溶蛋白和麦谷蛋白含量先升高后降低;游离巯基和二硫键含量有显著变化,蛋白质的二级结构受温度影响显著,时间仅对β-转角含量有影响;面团质构特性在起始醒发时差异不大,但在醒发45 min后差异极显著,在温度高时,面团坚实度和黏弹性的值较大。     

Dynamic rheology of wheat flour dough. II. Assessment of dough strength and bread‐making quality

Controlled stress rheometry revealed that differences in wheat flour dough strengths could be observed by means of dynamic rheological measurements in the region of higher stress amplitude (ie >100 Pa). At lower stress amplitude (τ_o) the values of elastic modulus G′ for weak doughs were higher than those for strong doughs, but they decreased substantially beyond 100 Pa stress amplitude (τ_o), such that the G′ values for strong doughs crossed over the G′ values for weak doughs. Beyond a critical value of stress amplitude (ie 100 Pa), true differences in dough strengths could be seen on the basis of their elastic characteristics, because at large deformations protein–protein interactions played a more dominant role in the rheological behaviour of flour doughs. Dynamic rheological analysis demonstrated a very weak inverse relationship (R² = 0.16) between the G′ values of flour doughs and loaf volume data for 12 wheat cultivars of diverse bread‐making performance. However, the G′ values of glutens showed significant positive relationships with bread‐making performance, explaining 73% of the variation in loaf volume. © 2002 Society of Chemical Industry     

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