γ-聚谷氨酸对全麦冷冻面团烘焙特性的影响

将γ-聚谷氨酸(γ-PGA)添加至全麦冷冻面团中,通过全麦粉持水率、酵母存活率研究γ-PGA的保水性和抗冻活性;以面包比容和质构等作为评价指标,研究γ-PGA对冷冻面团制作的全麦面包烘焙品质的影响。结果表明,添加γ-PGA可提高冷冻全麦面团的酵母存活率和发酵高度,增大全麦面包比容,减小面包硬度,促进面包芯中形成大气孔;贮藏3 d后,添加γ-PGA的全麦面包硬度和老化率显著降低(P<0.05),且γ-PGA的最佳添加量为1%。     

藜麦粉对冷冻面团特性及其面包品质的影响

将藜麦和小麦粉按一定比例混合,用快速粘度分析法测定混合粉糊化特性,流变仪测定了冻藏过程中小麦-藜麦冷冻面团的流变学特性,核磁共振法测定面团中水分迁移,并测定其发酵体积变化,最后分析了冷冻面团组织状态与产品品质的关系。结果表明：藜麦粉对冷冻面团及面包的品质均有改善。藜麦粉降低了混合粉体系的糊化粘度和崩解值。冻藏后,冷冻面团的弹性模量和粘性模量增加,小麦粉冷冻面团损耗角正切值增加了4.73%,添加量为5%时冷冻面团损耗角正切值仅增加0.41%;小麦冷冻面团自由水上升了3.90%,藜麦添加后仅上升2.40%,可见藜麦粉能冷冻面团降低水分迁移程度;同时,添加藜麦粉能维持面团面筋网络结构的完整性,发酵体积由26.42 mL/h增大到29.17 mL/h。不同添加量的藜麦粉对面团及面包的品质改善程度不同,最适添加量为10%,烘烤后面包比容为3.08 mL/g,硬度为2803.48 g。本研究可为开发藜麦冷冻面团提供理论基础,在藜麦新产品开发方面具有重要的指导意义。     

海藻酸丙二醇酯对全麦冷冻面团冻藏稳定性和烘焙特性的影响

本文研究了海藻酸丙二醇酯（Propylene glycol alginate,PGA）对全麦冷冻面团冻藏期间稳定性的影响,并探究了冷冻面团烘焙面包品质的变化。将0.3%的PGA加入全麦面团,通过测定冷冻面团冻藏1、2、3、4和5周后发酵特性、流变特性、蛋白质二级结构、微观结构以及面包的比容、质构特性、内部纹理结构和老化程度等,研究冷冻面团冻藏期间的稳定性。结果表明,随着冻藏时间的延长,添加PGA的冷冻面团在冻藏5周后具有较好的保水性,其发酵特性及流变特性相对于对照组均有所改善。冻藏5周后,对照组与PGA组其面包比容分别下降了19.872%和14.153%;面包硬度分别升高了64.186%和36.386%;气孔表面积分率分别下降了3.497%和2.300%;老化焓值分别上升了65.142%和42.416%。添加PGA能延缓冷冻面团冻藏期间β-折叠含量的上升和β-转角相对含量的下降。电镜扫描图（SEM）显示,随着冻藏时间的延长,PGA组的冷冻面团孔洞数目相比对照组明显减少且大小均匀,面筋网络结构完整性和连续性提高。研究结果表明PGA可以有效地延缓冷冻面团在冻藏期间的品质劣变,维持冷冻面团的稳定性并提高面包的烘焙特性。     

专用油脂对冷冻面团焙烤品质的影响

将以棕榈油和大豆油为原料制备的专用油脂应用于冷冻面团中,研究专用油脂对冷冻面团流变学特性影响及对冷冻面团焙烤面包品质的影响。结果表明：添加专用油脂制备的冷冻面团面包比容大、纹理细腻、口感柔和、品质良好;专用油脂可以有效地提高冷冻面团的筋力和延伸性,并能延缓冷冻面团因冻藏导致的焙烤品质下降,对延缓面包老化效果良好;确定专用油脂在冷冻面团中的添加量为配方中面粉质量的6%。     

糯麦粉对冷冻面团发酵流变特性和面包烘焙特性的影响

采用发酵流变测定仪和质构分析仪研究不同比例的糯麦粉对冷冻面团发酵流变学特性和面包烘焙特性的影响。结果表明：无论面团冷冻与否,随着糯麦比例增加,面团发展的最大高度(Hm)和持气率(R)逐渐下降,而气体释放曲线最大高度(H＇m)和CO2产气量(Vco2)在一定程度上增加。随着冻藏时间的延长,面团各种参数(Hm、H＇m、R等)逐渐降低,但是下降的幅度随糯麦粉添加量的增加而减小,如与冻藏7d相比,添加质量分数0%、10%、20%和30%的糯麦面团经冻藏60d后Hm分别下降了12.9%、9.6%、7.7%和7.5%,而R则分别下降了2.8%、2.1%、1.6%和1.7%。在冷冻贮藏过程中,面包品质虽有一定程度的下降,但添加糯麦粉的面包品质下降程度较慢,抗老化效果好,且由感官评定可知,冻藏不同天数后,添加10%糯麦粉的面包最易受人们喜爱。     

脱皮对紫糯小麦粉特性和面包焙烤品质的影响

研究了不同脱皮时间下制得紫糯小麦粉的理化特性和面团的流变特性,以及对面包焙烤品质和贮藏过程中老化程度的影响。紫糯小麦的脱皮时间分别设定为0、1、3、5、7 min,相当于约0%、1%、3%、5%、9%的皮层被去除。结果表明,随着紫糯小麦脱皮时间的延长,小麦粉的出粉率提高,蛋白质和灰分含量及面团的粉质和拉伸特性也发生改变。脱皮5 min后制得的紫糯小麦粉以15%比例添加到普通面包粉中,面包含水量显著增加,体积和质量呈增大趋势,并且面包结构变好,面包评分显著上升。此外,添加紫糯小麦粉的面包较长时间放置后仍然松软,能有效延迟贮藏期间面包的老化,在一定程度上延长了其货架期。     

Effects of wheat sourdough process on the quality of mixed oat-wheat bread

The aim of this work was to study the effects of sourdough fermentation of wheat flour with Lactobacillus plantarum, on the quality attributes of mixed oat-wheat bread (51 g whole grain oat flour and 49 g/100 g white wheat flour). Emphasis was laid both on β-glucan stability as well as bread structure and sensory quality. The variables of the sourdough process were: dough yield (DY), fermentation time, fermentation temperature, and amount of sourdough added to the bread dough. The sourdough process was shown to be a feasible method for mixed oat-wheat bread, and, when optimized, provided bread quality equal to straight dough baking. A small amount (10g/100 g dough) of slack sourdough fermented at high temperature for a long time resulted in the most optimal sourdough bread with the highest specific volume (3.5 cm³/g), the lowest firmness after 3 days storage (0.31 kg), and low sensory sourness with high intensity of the crumb flavour. Wheat sourdough parameters did not affect the content of oat β-glucan in the bread. Additionally, both straight dough and sourdough bread contained 1.4-1.6 g β-glucan/100 g fresh bread. The average molecular weight of β-glucan was 5.5 × 10⁵ in both types of bread, while that of oat flour was 10 × 10⁵. This indicates that a slight degradation of β-glucan occurred during proofing and baking, and it was not affected by variation in the acidity of the bread between pH 4.9-5.8.     

Enzymatic Reduction of Phytate in Whole Wheat Breads

The presence of phytate in flour may be responsible for reduced bioavailability of iron, magnesium, zinc, and calcium from bread. The effect of various concentrations of commercial phytase or phosphatase added to whole wheat flour-yeast doughs on their phytate and nonphytate phosphorus content has been investigated. By using 2.0% (flour basis) of phytase and 0.11% phosphatase the initial phytate phosphorus concentration of the dough was reduced to 1/8 and 1/12 of its initial values, respectively. Storage of the whole wheat breads for up to 96 hr at room temperature showed further significant reduction of phytate phosphorus. The phytate phosphorus content of yeast leavened whole wheat breads decreased during 2 hours of dough fermentation, baking and the subsequent 48 hours of storage at room temperature from 24 mg/100g dough (dry matter) to 1.7 mg/100g bread (dry matter); the phytate phosphorus continued to decrease and after 96 hours storage it was 0.6 mg/100g bread.     

Effect of Amino Acids and Peptides on Mixing and Frozen Dough Properties of Wheat Flour

Free amino acids, peptides, and vital wheat gluten were investigated to determine their effect on the mixing and frozen dough baking properties of wheat flour. Addition of 1% cysteine and aspartic acid decreased and glutamic acid, histidine, arginine, and lysine increased the mixing tolerance of flour. Cystine, methionine, tryptophan, and phenylalanine increased but isoleucine, histidine, glycine, arginine, glutamic acid, aspartic acid, and lysine decreased loaf volume of nonfrozen dough breads. However cystine, methionine, tryptophan, and phenylalanine did not increase loaf volume of bread prepared from frozen dough. Vital wheat gluten increased mixing tolerance and bread loaf volume only for the nonfrozen dough. However, wheat gluten hydrolysate, corn, and bonito peptides decreased mixing tolerance after optimum mixing time and were effective in increasing loaf volume for both frozen and nonfrozen dough. As the amount of corn and bonito peptide increased, specific loaf volumes also increased. Addition of 2.5% corn peptide was most effective in increasing loaf volume of frozen dough bread. Crust browning and crumb stickiness increased, whereas crumb softness decreased with addition of peptides. Addition of less than 1% peptide did not adversely affect the aftertaste and off‐flavor of bread. These results suggest that addition of peptides are effective for improving the baking quality of frozen dough, whereas amino acids and gluten have no effect.     

Utilization of sprout‐damaged wheat as raw material for sour dough pre‐ferments with mixed cultures of lactic and propionic acid bacteria

The utilization of sprout‐damaged wheat flour in pre‐fermentation for sour dough bread‐baking increased lactic acid formation and titratable acidity several fold in comparison to the use of baker's wheat flour, and also resulted in a lactic acid to acetic acid molar ratio acceptable for sour dough bread. Further, enzymic treatment of the sprout‐damaged wheat flour with malted grain flour appared to be necessary for a properly balanced acid formation although the α‐amylase activity of sprout‐damaged wheat flour was quite high. The accumulation of lactic acid in the pre‐ferment decreased in the presence of yeast, and thus the molar ratio of lactic to acetic acid could be adjusted suitable for sour bread‐baking even with homofermentative lactic acid bacteria. Finally, when using mixed culture pre‐ferments of Lactobacillus brevis and Propionibacterium jensenii, at least 0.1% of propionic acid (based on flour weight), sufficient to prevent mold growth in the final bread, was obtained.     

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     

Rheological and baking properties of cowpea and wheat flour blends

Effect of blending 50 to 250 g kg⁻¹ cowpea flour in wheat flour on rheological, baking and sensory characteristics of bread, chapati, cookies and muffins was studied. Farinograph water absorption, dough development time, mixing tolerance index and dough stability increased significantly with increased amount of cowpea flour. Incorporation of cowpea flour lowered gelatinisation time and peak viscosity. Loaf volume and overall acceptability scores of bread were reduced significantly beyond 150 g kg⁻¹ incorporation of cowpea flour. There were significant changes in specific volume and overall acceptability scores of muffins, registering an initial improvement up to 50 g kg⁻¹ and a significant decline thereafter. © 1999 Society of Chemical Industry     

Effect of the bread-making process on zearalenone levels

The effects of the bread-making process including fermentation with Saccharomyces cerevisiae and lactic acid bacteria (Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus acidophilus and Lactobacillus fermentum) and baking at 200°C on zearalenone (ZEA) levels were investigated. Standard solutions of ZEA were added to flour and then loaves of bread were prepared. Sourdough and three types of yeast including active dry yeast, instant dry yeast and compressed yeast were used for the fermentation of dough. ZEA levels in flour, dough and bread were determined by HPLC with fluorescence detection after extraction and clean-up on an immunoaffinity column. The highest reduction in levels of ZEA was found in the first fermentation (first proof), while the lowest reduction was observed in the baking stage. In addition, the results showed that compressed yeast had the maximum reduction potential on ZEA levels even at the baking stage.     

Acrylamide–asparagine relationship in baked/toasted wheat and rye breads

Acrylamide in baked and toasted wheat and rye bread was studied in relation to levels of asparagine in flour, dough, bread and toasts. Asparagine was consumed during bread preparation resulting in reduced acrylamide content in the products. In wheat bread, 12% of the asparagine initially present in the flour (0.14 g kg^?1) remained after yeast fermentation and baking; for rye bread, 82% of asparagine remained after sourdough fermentation and baking. Asparagine present in untoasted wheat bread had totally reacted after hard toasting. Toasted wheat and rye bread slices contained 11–161 and 27–205 µg kg^?1 acrylamide, respectively, compared to untoasted wheat and rye bread with <5 and 7–23 µg kg^?1 acrylamide, respectively. The dietary intake of acrylamide from bread (untoasted) of 2 µg day^?1 is relatively low; however, acrylamide exposure from bread increases several fold for people eating toasted bread.     

Effects of hydrophilic hydrocolloids on dough and bread performance of samples made from frozen doughs

ABSTRACT:  The objective of this study was to determine the effects of hydrocolloids in dough (xanthan 0.02%, 0.06%, and 0.1%; κ-carrageenan and carboxymethylcellulose 0.2%, 0.6%, and 1.0%) and duration of frozen storage on the quality of finished bakery product. Doughs were prepared with different concentrations of gums, stored at −18 °C and analyzed after 0, 7, 14, and 30 d for fermentation activity of yeast and rising time of dough. At the end of each frozen storage interval, bread was prepared and characterized for specific volume, crumb firmness, and crumb structure. The addition of the gums had significant effects on dough performance and quality of the final product. Gums at all tested concentrations reduced fermentation activity of yeast and prolonged the rising time of dough, which was similar to the effects of frozen storage. However, specific volume of bread for the control sample significantly decreased on the 30th d of frozen storage. Addition of hydrocolloids resulted in higher specific volume of loaves compared to the specific volume of control sample loaves. With the increase of the duration of frozen storage the specific volume of bread decreases in all analyzed samples. This decrease is less in the samples with hydrocolloids compared to the decrease in the control sample. The addition of 0.1% xanthan accomplished the same or higher values for specific fermentation activity, specific volume, and penetrometric's number compared to the values accomplished by the addition of 1% carboxymethylcellulose and κ-carrageenan, respectively.     

Exploitation of buckwheat sourdough for the production of wheat bread

This study investigates the exploitation of buckwheat sourdough for the production of wheat bread. The fermentation induced extensive hydrolysis of buckwheat main storage proteins, but did not influence the total protein, starch and polyphenols content of buckwheat. Buckwheat sourdough was incorporated at 10 and 20?% (w/w) in wheat dough, and control doughs were produced with the addition of a chemically acidified (CA) buckwheat batter. The addition of buckwheat sourdough greatly affected the rheological properties of the dough, by inducing a strengthening of the gluten network and decrease in elasticity. The acidification of wheat dough also stimulated the baker’s yeast activity during proofing, resulting in higher release of CO₂ in shorter times (volume of CO₂ released (ml), control dough, 1,671.5; dough with 10?% sourdough, 2,600; dough with 10?% chemically acidified dough, 2,715.5). The properties of wheat bread were enhanced by the addition of 10?% buckwheat sourdough, which led to higher specific volume (control, 3.41?ml/g; bread with 10?% sourdough, 4.03?ml/g) and softer crumb (crumb hardness, control, 5.28?N; bread with 10?% sourdough, 3.93?N). On the other hand, the higher acidification level did not influence the bread volume, but slightly hardened the crumb (crumb hardness, bread with 20?% sourdough, 7.41?N; bread with 20?% chemically acidified dough, 6.48?N). The fermentation positively influenced the nutritional properties of buckwheat flour and wheat bread, in terms of polyphenols (control bread, 8.84?mg GAE/100?g; bread with 10 and 20?% sourdough, 17.83 and 18.20?mg GAE/100?g, respectively) and phytic acid contents. Incorporation of buckwheat sourdough also led to an extension in the shelf life of wheat bread, which became more evident for the higher addition level. Overall, the results of this study suggest that buckwheat sourdough represents a suitable tool for enhancing the overall quality and nutritional properties of wheat bread.     

Evaluation of baking procedures for incorporation of barley roller milling fractions containing high levels of dietary fibre into bread

BACKGROUND: Roller milling of hull‐less barley generates fibre‐rich fractions (FRF) enriched in non‐starch polysaccharides from the endosperm cell walls (β‐glucans and arabinoxylans). This investigation was initiated to compare the suitability of different baking processes and to determine the optimal conditions for incorporation of barley FRF into pan bread. RESULTS: Addition of FRF from waxy and high‐amylose starch hull‐less barley genotypes was evaluated in pan bread prepared from Canada Western Red Spring (CWRS) and Canada Western Extra Strong (CWES) wheat flour. Three bread processes were used: Canadian short process (CSP), remix‐to‐peak, and sponge‐and‐dough. Addition of 20% FRF (equivalent to enrichment with 4.0 g of arabinoxylans and β‐glucans per 100 g of flour) disrupted dough properties and depressed loaf volume. CSP was not suitable for making FRF‐enriched bread because dough could not be properly developed. FRF‐enriched remix‐to‐peak bread was better, especially for the stronger CWES flour. The better bread quality compared to CSP was probably due to redistribution of water from non‐starch polysaccharides to gluten during fermentation prior to remixing and final proof. The sponge‐and‐dough process produced the best FRF‐enriched bread because of the positive effect of sponge fermentation on gluten development and hydration. FRF was added at the dough stage to fully developed dough. CONCLUSION: The method of bread production strongly influences bread quality. Pre‐hydration of FRF improved bread quality. CWRS and CWES flour produced comparable FRF‐enriched sponge‐and‐dough bread. Addition of xylanase to the sponge‐and‐dough formula improved the loaf volume, appearance, crumb structure and firmness of FRF‐enriched bread. Copyright © 2007 Society of Chemical Industry     

麦麸细粉营养成分分析及在面包烘焙中的应用

采用喷雾调质、研磨和筛选分离出小麦麸皮中的麦麸细粉,分析其营养成分,并通过流变特性测试及烘焙应用试验,研究其对面粉营养成分及面团烘焙特性的影响。结果表明,分离所得麦麸细粉的蛋白质和膳食纤维含量高达15.8%和33.6%,且富含钾、钙、铁等多种矿物质。随着麦麸细粉在面包专用粉中添加比例的增加,面包专用粉的灰分和湿面筋含量呈递增趋势;面筋指数、糊化黏度逐渐降低,面团吸水率、弱化度逐渐增加;稳定时间、延展性呈减小趋势;面包的搅拌时间、发酵时间延长,比容和品质评分降低。添加10%麦麸细粉的面包烘焙性能和感官品质较好,且营养价值得到了显著改善。     

EFFECT OF EMULSIFIERS AND FUNGAL α-AMYLASE ON RHEOLOGICAL CHARACTERISTICS OF WHEAT DOUGH AND QUALITY OF FLAT BREAD

Teftoon, a flat bread made of whole wheat flour, is prepared by hand sheeting of dough, followed by baking. Different emulsifiers, like lecithin, E471 (distilled monoglyceride) and E472 (diacetylated tartaric acid esters of mono- and digelycerid of fatty acids), were added to the flour at various levels ranging between 0.25 and 1.0% w/w, and it was observed that they improved the dough characteristics. Improvement in bread quality parameters, such as force to tear and sensory acceptability, were monitored. Fungal α -amylase was also incorporated into the flour at 5–20 g/100 kg flour basis alone and in combination with the emulsifier. The force required to tear the fresh bread was decreased with emulsifier and enzyme addition; however, E472 addition at 0.75% w/w of whole wheat flour gave the softest bread. The tear force of stored bread significantly increased with storage; however, bread containing E472 showed a less increase in tear force up to a period of 3 days. The sensory acceptability was found to be higher than that of the control bread for emulsifiers, and lower for enzyme at a concentration higher than 10 g/kg flour.

PRACTICAL APPLICATIONS

Flat bread is normally consumed fresh, but the staling phenomenon starts immediately after baking this kind of bread. Today, large-scale production and increased consumer demands for high-quality bread with long shelf life have created the need for functional food additives such as emulsifiers and α -amylase enzyme. Incorporation of emulsifiers and enzyme decreased the hardness of Taftoon bread. Emulsifiers and α -amylase enzyme enhanced the flat bread dough quality. The sensory acceptability also improved with the addition of emulsifiers. Optimizing the amount of emulsifiers and enzyme required for reduction of bread hardness is vital because the quality and price of the final product depend on this parameter.     

鲢鱼酶解产物和鱼胶原肽对冷冻面团品质的影响

通过对比分析经0～6次冻融循环处理后面团的酵母菌存活率、发酵力保存率、醒发时间以及焙烤性质研究了鲢鱼酶解产物和鱼胶原肽对冷冻面团品质的影响。结果表明:添加鲢鱼酶解产物和鱼胶原肽的面团经6次冻融循环后,酵母菌的存活率分别为78.95%和61.80%,发酵力保存率分别为59.06%和46.67%,面团醒发时间分别为330 min和318min,均明显优于空白组;冻融后的面团与新鲜面团相比,焙烤的面包比容和弹性减小,添加了鲢鱼酶解产物和胶原肽不仅可缓解冷冻面团这一缺陷,还可改善面包色泽。结果证明了鲢鱼酶解产物和鱼胶原肽具有良好的酵母菌抗冻保护活性。