香菇粉对小麦面团热机械学和动态流变学特性的影响研究

本试验通过测定不同比例的香菇粉和小麦粉混合粉的热机械学和动态流变学特性,研究香菇粉对小麦面团特性的影响。结果表明,香菇粉的添加使小麦面团的吸水率增大,面团的形成时间和稳定时间先下降后上升,相应的蛋白质弱化度先升高后降低。香菇粉的添加使小麦面团的峰值黏度和回生值均显著降低。动态流变学试验显示:香菇粉的添加使得小麦面团的黏弹特性发生了显著的变化,储能模量(G')与损失模量(G")均呈现先降低后升高的趋势。而tanδ随香菇粉比例的增大呈现了先略微升高后明显降低的趋势,表明了混合体系中分子交联的程度有所增加,弹性比例增大。     

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。     

小麦粉糊化特性与冷冻面团(馒头)品质关系研究

选取筋力各不相同的18种小麦粉为研究对象,测定其糊化特性,并进行冷冻面团馒头的制作实验,分析小麦粉糊化特性与冷冻面团馒头质构特性(TPA)和感官品质的关系。结果显示,两者关系密切。高中低三种不同筋力小麦粉表现出的糊化特性和冷冻面团馒头品质不同,高筋粉所制冷冻面团综合品质较好,低筋粉最差。峰值粘度与冷冻面团馒头的TPA硬度呈显著负相关;低谷粘度与回复性显著正相关;衰减值与TPA硬度显著正相关,与感官总得分、外观状况、柔软度呈极显著或显著负相关;糊化温度与TPA弹性和粘着性显著正相关,与冷冻面团馒头瓤的白度呈显著负相关;崩溃值与冷冻面团馒头比容呈负相关,关系接近显著。      

冷冻面团原料小麦粉的筛选及各指标的相关性分析

本实验选取了六种不同商业高筋小麦粉,采用粉质仪、拉伸仪和糊化仪对其进行基础成分和流变学特性的测定,并对所得指标数据进行相关性分析,同时对应用各小麦粉制作的冷冻面团的质构特性进行测定分析,筛选出北大荒高筋小麦粉适于制作冷冻面团。各特性指标进行相关性分析结果显示,吸水率与水分含量、蛋白质含量、最大拉伸阻力呈显著正相关(p<0.05),相关系数为0.849、0.789、0.828;形成时间与湿面筋含量、最大拉伸比例呈显著正相关(p<0.05),相关系数为0.900、0.885;形成时间与拉伸阻力、最大拉伸阻力、拉伸比例呈极显著正相关(p<0.01),相关系数为0.986、0.958、0.933;水分含量与最大拉伸阴力呈显著正相关(p<0.05),相关系数达到0.828;蛋白质含量与拉伸阻力、最大拉伸阻力、拉伸比例呈显著正相关(p<0.01),相关系数为0.986、0.958、0.933。      

面团熟化对面条品质影响研究进展

该文概述面条生产发展过程,并介绍面条熟化工艺,对熟化概念,面团熟化作用和要求及影响熟化因素进行详细阐述。     

Effects of plasma-activated water and heat moisture treatment on the properties of wheat flour and dough

Plasma-activated water (PAW) production and use is an emerging technology for enhancing product safety, extending shelf-life and quality retention, and promoting sustainable processing. At present, it has generated considerable attention for applications to starch and flour modification. This work presents an innovative approach to wheat flour (WF) modification using PAW and heat-moisture treatment (HMT), and compares this approach with distilled water (DW) treatment. As expected, PAW and HMT promoted flour granule clustering, increasing particle size. These treatments accelerated molecular interactions between wheat starch and non-starch components (e.g. proteins and lipids), which eventually increased resistant starch (RS) content. Addition of modified flour (30 g) to WF positively affected its rheological properties, and closely bound water content of the dough. The gluten protein network structure in the dough suffered varying degrees of damage. In conclusion, our results showed that PAW and HMT may provide a novel beneficial method for modifying wheat flour during food processing to obtain viscoelastic wheat flour products with nutritional functions.     

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     

维生素C对面团特性影响研究

通过研究Vc对面团特性影响表明,面粉中添加Vc能增加面团吸水率和形成时间,降低面团弱化度,增加面团拉伸面积、拉伸阻力和拉伸比值,降低面团延伸性;其最适添加范围为120～160ppm.     

The effect of different mixing processes on dough extensional rheology and baked attributes

BACKGROUND: Mixing is a significant part of the breadmaking process and is responsible for the development of the essential structure that will facilitate gas retention during proofing and the early stages of baking. The main objective of this study was to examine whether the dough extensional rheological and baking properties were affected from different mixers and energy inputs during mixing. RESULTS: It was found that extensional properties in uniaxial and biaxial extension were affected by the mixing equipment used and by the energy input used. Doughs mixed using a Farinograph had higher maximum resistance to uniaxial extension, higher P value and lower biaxial extensibility (Alveograph) and higher biaxial extensional viscosity than doughs mixed in a Stephan mixer (P < 0.01). The energy input was specific to each type mixing equipment and affected the biaxial extensional viscosity. Also, higher loaf volumes were achieved when higher energy inputs were used, whereas other baking properties were not affected. CONCLUSION: Altering the mixing equipment and the mixing speed affected the rheological properties of dough. Dough development during proofing as well as loaf volume was affected by the energy input levels and was increased by increasing the energy input and therefore the mixing time. Copyright © 2010 Society of Chemical Industry     

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.     

Small and large deformation rheology for hard wheat flour dough as influenced by mixing and resting

ABSTRACT:  The effects of mixing and resting on the physicochemical properties of doughs prepared with strong and weak hard wheat flours were investigated, specifically concerning aspects related to their rheological behavior and molecular mobility. Small deformation dynamic tests showed that, during the initial resting period, the complex modulus G * decreased and phase angle decreased for undermixed dough, whereas overmixed dough showed opposite trends. G * values for optimally mixed dough did not vary during the resting period investigated. This was more obvious for the strong dough. Large deformation tests more clearly showed differences among optimal, under-, and overmixed dough, and also between doughs prepared with strong and weak flour. Optimally mixed dough exhibited the highest peak stress and strain for both samples. In addition, the peak stress of dough prepared with the strong flour was higher than that of dough prepared with weak flour. Inconsistent results between small and large deformation tests implied that small and large deformation tests reflected different structural aspects of dough. NMR measurements were performed to estimate the relaxation properties of the sample upon resting. Decreased water mobility during resting, indicated by decreasing T ₁ relaxation time, was possibly attributed to increasing molecular interactions caused by continued hydration. Evidence of additional molecular interactions created by mixing was also observed.     

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。     

苦荞小麦混合粉面团的微观结构和粘弹性

采用扫描电子显微镜研究了苦荞小麦混合粉(30∶70)面团的微观结构,并用流变仪测试了加入酶制剂前后的面团粘弹性。结果表明,混合粉和成的面团,其面筋网络几乎不能形成。0.01%葡萄糖氧化酶、0.01%转谷氨酰胺酶能提高天然苦荞小麦混合粉面团的G'和G',降低其tanδ,但是对处理苦荞小麦混合粉面团的作用相反。0.002%戊聚糖淀粉酶能显著降低两种混合粉面团的G'和G',提高其tanδ。葡萄糖氧化酶和戊聚糖淀粉酶合用,处理苦荞小麦混合粉面团的G'和G'高于纯小麦粉面团,tanδ低于纯小麦粉面团。     

A farinograph study on the viscoelastic properties of sago/wheat flour dough systems

Doughs containing mixtures of sago and wheat flours of differing protein content at different levels of sago substitution (10, 15, 20, 25, 30, 40 and 50%) were prepared as follows: sago + high protein wheat (HPW) flour, sago + medium protein wheat (MPW) flour and sago + low ? protein wheat (LPW) flour. The viscoelasticity of doughs from control sago and wheat flours and sago/wheat flour mixtures was determined using a Braberder farinograph. It was found that arrival time increased with increasing protein content in the mixture. Peak time for control wheat flours and sago/wheat flour mixtures increased with increasing protein content. Dough stability, 20 min drop and water absorption were found to decrease as the sago proportion in the mixture decreased. The 50% sago/LPW mixture was unable to form a dough. Breakdown times for control HPW flour and HPW flour mixtures were the highest, followed by MPW flour and then LPW flour. However, breakdown time for control MPW flour was higher than that for HPW flour mixtures. The same trend was observed at all ratios of mixture over the whole experiment. Copyright © 2004 Society of Chemical Industry     

Effect of wheat bran dietary fibre on the rheological properties of dough during fermentation and Chinese steamed bread quality

The effects of wheat bran dietary fibre (WBDF) on the rheological properties of dough during fermentation and quality of Chinese steamed bun (CSB) were investigated. The study revealed that with the increase of the content of WBDF, the dough extensibility and time at which gas starts to escape from the dough significantly decreased but the dough firmness significantly increased (P < 0.05). The elastic modulus and viscous modulus showed an upward trend, probably due to the increased molecular weight of the viscoelastic body resulting from the presence of WBDF. Additionally, by changing the quality of the gluten network, the specific volume and L^* value significantly decreased from 2.52 to 1.31 mL g⁻¹, and from 87 to 51, respectively, these adverse effects on CSBs could be moderated by the fermentation process.     

发酵麦麸对面包面团生化特征及烘焙学特性的影响

采用马克斯克鲁维酵母(Marx Kluyveromyces)发酵麦麸,通过生化分析、流变特性测试及微观结构观察(Scanning electron microscope,SEM)等多种分析手段,研究其对面包面团生物化学特征和烘焙学特性的影响。结果表明:马克斯克鲁维酵母发酵麦麸中富含多种天然酶,主要包括纤维素酶、木聚糖酶和阿魏酸酯酶;水解酶在面包制作过程中持续作用,促进木聚糖溶解和酚类化合物释放,赋予面包较高的营养价值;与仅添加木聚糖酶的麦麸面包面团相比,马克斯克鲁维酵母发酵麦麸面包面团具有更好的持气性及连续的面筋网络结构,面包全质构特性和比容显著提升。研究结果显示,马克斯克鲁维酵母发酵麦麸可以作为一种天然面包功能配料。     

Effect of an enzyme preparation on wheat flour and dough color, mixing, and test baking

Bleaching flours with natural rather than chemical extracts is attractive because it reduces risks upon exposure and appeals to natural food consumers. This paper reports effects of a commercial proprietary blend of ‘natural’ bleaching enzymes on wheat flour and dough color, mixing behavior and test bake performance. Enzyme preparation did not improve whiteness (L*) and yellowness (b*) of flour system, but benzoyl peroxide sharply reduced b*. For whole wheat flour dough, L* increased for enzyme-treated dough after 2-h resting, ending higher than benzoyl peroxide and control dough. Yellowness increased in enzyme-treated dough. When enzyme application was during milling, resulting whole wheat flour dough had much higher L*. Mixograms of flours with increasing enzyme concentration showed severe dough weakness and rapid breakdown. Dialysis of the enzyme preparation in 3500 molecular weight cutoff (MWCO) tubes and freeze-drying prior to flour application recovered dough strength. l-cysteine in the enzyme mix was thought to adversely affect dough strength, and dialysis helped recover dough strength. However, pup loaf baking with dialyzed enzyme showed some loss of baking characteristics (loaf volume, loaf weight, and proof height) over the control. Although the natural enzyme extract addition enhanced whiteness for whole wheat dough, its effects on dough and baking properties were not favorable.     

Antioxidant activity of hard wheat flour, dough and bread prepared using various processes with the addition of different phenolic acids

BACKGROUND: The purpose of this study was to evaluate the effect of baking process on the antioxidant activity of different phenolic acids. Antioxidant potential was determined using the β‐carotene‐bleaching activity assay, and free phenolic acid levels were determined by high‐performance liquid chromatography. Four phenolic acids, caffeic acid, ferulic acid, syringic acid and gallic acid, were mixed with wheat flour at a concentration of 4.44 µmol/g of flour. RESULTS: Type of phenolic acid and processing affected antioxidant activity. Of the phenolic acids, caffeic acid had the most pronounced antioxidant effect. The ranking of phenolic acids in terms of their antioxidant activity in fermented dough and bread was similar to that before processing, i.e. syringic acid < gallic acid < ferulic acid < caffeic acid. The content of ferulic acid was greater than that of the other phenolic acids after baking. Antioxidant activity and free phenolic acid content were reduced by mixing but recovered after fermentation and baking. Phenolic acid recovery after baking was 74–80%. CONCLUSION: Phenolic acids retain their antioxidant activity after the baking process, which has potential health benefits for consumers. Elucidation of interactions between the baking process and phenolic acids is important for the development of functional foods. Copyright © 2010 Society of Chemical Industry