Effect of the milling process on quality characteristics of rye flour

BACKGROUND: Most of rye flour is obtained by a gradual reduction system using roller flour mills, which generate different flour streams. The study of the different flour streams composition is necessary since it determines the flour quality and the flour uses. Four break streams and nine reduction streams were analysed for moisture, ash, starch, protein, damaged starch, falling number, amylose/amylopectin ratio, β‐glucans and colour. Mixing and pasting properties were also determined with a doughLAB and a Rapid Visco Analyser respectively. RESULTS: As the milling process advanced, moisture and starch content decreased but protein, ash, β‐glucans and damaged starch increased. The differences in composition are probably related to the effect of the roller mills and the increase in the contamination with bran. The absorption, development time, and pasting viscosity increased as the milling proceeded, in detriment of the peak time. The β‐glucan content was positively correlated to absorption, mixing tolerance index and pasting viscosity, and negatively correlated to peak time. CONCLUSION: Differences in composition, above all, in bran, showed different mixing and pasting properties in rye streams. The most different streams corresponded to the last streams in the break process, in the sizings and in the middlings. Copyright © 2008 Society of Chemical Industry     

小麦制粉系统各粉路面粉品质特性差异性分析

通过对小麦制粉系统各粉路面粉品质特性的研究,可为实现在线配粉、达成专用粉的开发提供技术支撑。本研究以小麦制粉过程中39个粉路面粉为研究对象,通过系统全面测定面粉白度、湿面筋含量、蛋白质含量、淀粉糊化特性、粉质参数和拉伸参数,比较不同粉路面粉品质差异性,运用主成分分析、因子分析和聚类分析方法分析不同粉路面粉间的品质变化规律。研究发现：前路心粉白度、淀粉糊化特性普遍高于其它粉路;后路心粉淀粉糊化特性、稳定时间、粉质质量指数普遍低于其它粉路;皮粉面团形成时间、稳定时间、粉质质量指数、拉伸面积、延伸度高于其它粉路;皮粉和重筛粉蛋白质含量、湿面筋含量普遍高于心粉。主成分分析发现前4个主成分累计方差贡献率达87.6321%,基本上能综合粉路面粉品质特性的大部分信息;根据面粉品质特性,利用聚类分析可以将39个粉路分为四类,第一类包括18个粉路,第二类包括12个粉路,第三类包含5个粉路,第四类包含4个粉路。检测结果可作为生产不同专用粉的参考和依据,同时为改进小麦粉加工企业制粉工艺提供参考。     

脱皮及超微粉碎对紫麦全麦粉加工品质的影响

以紫色小麦为原料,主要研究了0、4%、8%的脱皮程度及不同的超微粉碎工艺对全麦粉理化性质、流变学特性、糊化特性及曲奇饼干质构特性的影响。结果表明:随着脱皮率的增加,全麦粉中蛋白质、灰分、面筋含量都有所降低,但面筋指数增加。脱皮工艺显著改善了全麦粉的面团流变学特性、糊化特性及曲奇饼干的质构特性。与传统粉碎工艺相比,超微粉碎对全麦粉蛋白质及灰分含量的影响不大,而随着超微成分的增多,紫麦全麦粉的面筋含量、面筋指数、流变学特性、糊化黏度、曲奇饼干质构特性都有不同程度的提高。     

不同筋力小麦磨粉各出粉点小麦粉品质特性分析

采用布勒实验磨制粉,分别测定了强、中、弱筋3个小麦品种不同出粉点小麦粉的品质特性。结果表明,同一品种不同出粉点小麦粉的品质特性具有明显差异及变化规律,同一出粉点不同小麦品种的品质特性具有明显差异。在皮磨粉和心磨粉中,蛋白质含量、吸水率和PPO活性分别随出粉点后移而增大。三道心磨粉的小麦粉色泽a~*值和b~*值随出粉点后移均呈升高趋势;而小麦粉亮度L~*值、面团稳定时间、直链淀粉含量、峰值黏度、稀懈值和反弹值随出粉点后移有下降趋势。     

Original article: Influence of flour mill streams on cake quality

Wheat‐milling process generates different flour streams that differ in particle size, composition and functional and cake‐making properties. Particle size, composition and pasting properties of flour fractions (two from break and three from reduction system) obtained during milling of three wheats varying in protein content were determined. Shape, textural, colour and sensory analyses were performed on cakes prepared with the different mill streams. The final break and reduction streams had the highest protein and ash contents, pasting temperatures and the lowest starch percentage. Cakes prepared with the last streams showed higher batter density and lower volume. These results could indicate good air incorporation but deficient air distribution. Last streams cakes showed a darker, more reddish and yellowish crumb that was significantly related to flour colour characteristics. Because of these differences, such cakes obtained the lowest sensory scores. In this study, it has been verified that, to adapt flours to cake preparation, the final streams should be eliminated. The particle size of each stream is the most determinant parameter to obtain cakes with better volume and texture, being the flours with small particle size the most adequate.     

小麦籽粒不同部位蛋白质形貌与流变特性

目的:探索小麦籽粒不同部位蛋白质形貌和流变特性及其分布规律,为解释磨制所得不同粉路粉质量差异提供理论依据.方法:通过碾米机、三皮三心实验磨和六皮八心磨粉机制备参试粉,采用亮度值(L*)与灰分的比值定量表征籽粒的部位.参试粉在检测蛋白组分含量和质量指标的基础上,检测十二烷基硫酸钠可溶蛋白的形貌和谷蛋白大聚体动态流变学特性...     

干法、半干法和湿法磨粉对糙米粉性质的影响

研究干法、半干法及湿法3种磨粉方式对糙米粉损伤淀粉含量、平均粒径、微观结构、水合特性、热焓特性和流变性质等的影响。结果表明,干法磨粉糙米粉损伤淀粉含量、吸水指数、水溶性和膨胀势显著高于湿法和半干法。但干法磨粉糙米粉平均粒径、凝胶最大弹性模量和最大黏性模量显著小于湿法和半干法。干法和半干法糙米粉糊化焓值低于湿法。干法磨粉糙米粉形成了许多不规则的颗粒碎片,而半干法和湿法的糙米粉淀粉颗粒较完整。磨粉方式和条件显著影响糙米粉的性质,应根据糙米制品品质的要求选择合适的磨粉方式和磨粉条件。     

Industrial Roller Milling Process Characterisation for Targeted Bread Quality Optimization

Out of all satisfying and palatable foods, wheat and other cereals play an essential role in human nutrition. In recent years, customers demand for functionalized flours with engineered properties contributing to well-being. This fuels the need for deeper understanding of the milling process and establishment of relationships between flour properties and product characteristics. To address this shortcoming, structural and functional aspects of starch and protein were investigated in all 33 flour passages obtained during the standard roller milling process of the most widely produced bread flour. Starch and protein alterations were examined on flour, dough and bread levels. Repeated milling cycles and higher impact towards tail-end passages result in compositional differences and increase in damaged starch. This creates weakened gluten networks exhibiting reduced elasticity and extensibility. Decreased viscoelasticity and hence gas-holding capacity result in low loaf volume. With multiple multivariate linear regression, a model could be established allowing for a 95% precise prediction of the loaf volume of the passages and composite flour produced with the same mill settings. This quality prediction of bread quality based on easily measurable parameters on flour levels offers a straightforward approach for a targeted optimization of the milling process.     

高压射流磨处理对全组分燕麦浆的营养成分及理化性质影响

本文研究了不同压力下高压射流磨处理对全谷物燕麦营养成分及理化性质的影响。将经过湿法前处理的全谷物燕麦在5种不同压力(0、30、60、90、120 MPa)下经高压射流磨处理,以营养成分(燕麦β-葡聚糖、淀粉、损伤淀粉、可溶性蛋白、粗脂肪、多酚及黄酮含量)和理化性质(粒径大小、流变性质、不稳定分析指数)为评价指标,研究不同压力下高压射流磨对全谷物燕麦的影响。研究结果表明:随着高压射流磨的压力增大,燕麦浆的粒径明显降低,稳定性逐渐升高,相比未处理的样品,高压射流磨技术有效地改善了各项营养成分状态,经处理后,β-葡聚糖、可溶性蛋白、淀粉含量均有升高,脂肪含量先增大后减小,多酚、黄酮含量有稍微下降的趋势,损伤淀粉含量逐渐升高,黏度逐渐增大。这可为高压射流磨技术开发全谷物产品提供一定理论参考。     

Influence of damaged starch on cookie and bread-making quality

In this study two wheat and one triticale cultivars were milled in a disc mill to obtain different levels of damaged starch. The effects of the damaged starch content on physicochemical flour tests and cookie and bread-making quality were analyzed. The grain milling conditions in disc mill and grain hardness influenced the amount of damaged starch. The solvent absorption of flours, as measured by Solvent Retention Capacity Profile (SRC) and Alkaline Water Retention Capacity (AWRC), was significantly incremented by the damaged starch content. There was a consistent loss in cookie quality as the damaged starch content increased. In spite of the fact that the proteins were not affected by flour milling, bread quality decreased as the damaged starch content increased.     

Impact of endogenous constituents from different flour milling streams on dough rheology and semi-sweet biscuit making potential by partial substitution of a commercial soft wheat flour

A flour fractionation-reconstitution procedure was used to study the substitution of a commercial soft wheat flour with gluten, water extractables, prime starch and starch tailing fractions isolated from patent and clear flour streams on dough rheology and semi-sweet biscuit characteristics. Substitution of soft wheat flour with increasing levels of the native patent and clear flour streams raised the dough consistency, hardness and elastic properties as well as the biscuit textural attributes (density, hardness). The dough stickiness of the base flour was also reduced and the biscuits were free of cracks. Gluten isolated from the patent flour had a greater impact on dough consistency, hardness and elastic properties than gluten obtained from the clear flour, likely due to the superior protein quality of the former. Additionally, with increasing gluten levels in the fortified flour there were moderate increases in biscuit density, hardness, and lower crunchiness. The addition of starch tailings produced the largest impact on consistency and hardness of the dough. This fraction also exerted a pronounced effect on biscuit density and hardness, while it lowered crunchiness, presumably due to its higher pentosan content. Overall, the dough rheological properties and biscuit characteristics were controlled by the amount-nature of the fractions added; i.e., besides gluten (amount and quality), other constituents such as pentosans and the overall composition of the flour blends can largely affect the quality of the semi-sweet biscuits.     

Changes of chemical composition and dough rheology in two fractions of sieve‐classified Polish spring wheat flour

The study of chemical composition and dough rheology changes in sieve‐classified two fractions (up to 60 and 60–240 μm particles) of wheat flour was the subject of this study. The straight grade flours were obtained by the milling of three Polish varieties of spring wheat, differing in ?? abbreviation? (PSI) values. The flours were separated with the use of a SZ‐1 laboratory sifter. The yield of fine fraction was in the range 50.0–55.7%. The obtained fractions were assayed for the content and composition of free lipids, gluten proteins, damaged starch, ash, water absorption and amylograph viscosity. Dough rheology (extrusion in OTMS cell, alveograph and farinograph tests) and baking trials were also performed. The content of free lipids, including the non‐polar and phospholipids was lower and the content of glycolipids was higher in fine flours. Those fractions were more rich in linoleic acid but the lower content of oleic and linolenic acids resulted in a higher oxidizability index of free lipids. Fine flours contained less ash and significantly more damaged starch. At the same time, they were characterized by a higher content of wet gluten, water absorption, amylograph viscosity and better dough parameters. This was reflected in the bread volume, which was higher by 6.3–10.7%. The influence of the changes in composition and the content of free lipids upon the rheology of the dough after the 90 days flour storage has not been defined unambiguously and requires further research.     

Changes of chemical composition and dough rheology in two fractions of sieve-classified Polish spring wheat flour

The study of chemical composition and dough rheology changes in sieve-classified two fractions (up to 60 and 60-240 microm particles) of wheat flour was the subject of this study. The straight grade flours were obtained by the milling of three Polish varieties of spring wheat, differing in particle size index (PSI) values. The flours were separated with the use of an SZ-1 laboratory sifter. The yield of fine fraction was in the range 50.0-55.7%. The obtained fractions were assayed for the content and composition of free lipids, gluten proteins, damaged starch, ash, water absorption and amylograph viscosity. Dough rheology (extrusion in OTMS cell, alveograph and farinograph tests) and baking trials were also performed. The content of free lipids, including the non-polar and phospholipids was lower and the content of glycolipids was higher in fine flours. Those fractions were more rich in linoleic acid but the lower content of oleic and linolenic acids resulted in a higher oxidizability index of free lipids. Fine flours contained less ash and significantly more damaged starch. At the same time, they were characterized by a higher content of wet gluten, water absorption, amylograph viscosity and better dough parameters. This was reflected in the bread volume, which was higher by 6.3-10.7%. The influence of the changes in composition and the content of free lipids upon the rheology of the dough after the 90 days flour storage has not been defined unambiguously and requires further research.     

花生蛋白对面条品质的影响

通过在面粉中添加不同比例的花生蛋白,分析其对面粉湿面筋含量、面团流变学特性、面条蒸煮品质、感官品质和质构品质的影响。结果表明:在面粉中加入4%的花生蛋白,可显著提高面粉的蛋白质和湿面筋的含量,改善面团的流变学特性;制作的面条韧性和口感较好,增加了面条的营养价值,并且对面条加工特性没有太大影响。     

小麦制粉过程中水分状态分布及与品质特性关系研究

本研究以小麦制粉过程中的各系统粉为原料,研究各粉路小麦粉水分状态分布与品质特性的关系。采用核磁共振仪测定小麦粉的水分状态分布情况,并与其品质特性进行相关性分析。结果表明:皮磨粉蛋白含量最高,渣磨粉含量最低而白度最高,尾磨系统中损伤淀粉含量最高。各系统粉中,结合水弛豫时间T_(21)无显著差异,中间状态水弛豫时间T_(22),唯有尾磨粉具有显著性差异,自由水弛豫时间T_(23)差异性显著;前、后路粉中,T_(21)及其质子密度A21无显著差异,T_(22)、T_(23)及相对应的质子密度差异显著,且后路粉均值基本大于前路粉。3种状态水分中,结合含水量有越接近皮层越低的趋势,但降幅较小,而自由水含量则明显增加,中间状态水变化较小。各系统粉的水分状态与其品质特性具有内在相关性,该研究可为选择性配置小麦粉提供理论参考。     

小麦粉破损淀粉含量对面团发酵性能的影响

以中、高筋小麦粉为研究对象,分析破损淀粉含量对面团流变发酵特性和馒头品质的影响。结果表明,随着破损淀粉含量增加,面团流变发酵性能、馒头比容、亮度及感官评分均先上升后降低;中、高筋小麦粉破损淀粉含量分别为25.11,25.60时,面团发酵高度、总产气量和持气率最大;制作的馒头比容、亮度大,感官评分最高,外形挺立、表面光滑、内部结构均匀细密、口感好。因此,中、高筋小麦粉破损淀粉含量分别为21.65~25.11,23.56~25.60时,馒头品质较好。     

Enzymes as a Processing Aid in the Separation of Wheat Flour into Starch and Gluten

A pilot system for the separation of wheat flour into starch and gluten was used to study the effect of four enzyme preparations as processing aids. Technical enzyme preparations with hemicellulase, cellulase or protease activities appear to improve gluten yield, protein recovery in gluten and gluten coagulation in a flour with intermediate processing properties. With these enzymes similar results were obtained compared to a flour with good processing properties without the use of enzymes. The use of enzymes did not adversely affect protein content, baking quality and rheological properties of the gluten. The proportion of soluble proteins, however, increased when the protease was used. The yield of starch was slightly increased by the action of the cellulase and hemicellulase, but was significantly decreased with the protease. Starch purity as determined by its protein content was not affected. Based on these results it is concluded that some cellulases and hemicellulases can act as important processing aids for gluten/ starch separation.     

Laboratory‐scale Dry/Wet‐Milling Process for the Extraction of Starch and Gluten from Wheat

A laboratory‐scale process is presented for the manufacture of starch and gluten from wheat. Main feature of this process is that whole wheat kernels are crushed dry between smooth rolls prior to wet disintegration in excess water in such way that gluten formation is prevented and fibres can be removed by sieving. Centrifugation of the endosperm suspension yields a dough which can be separated into starch and gluten using an established batter process. The results suggest that starch recovery is increased in comparison to a conventional wheat flour process without a concomitant decrease in protein recovery. Although starch purification was omitted, a total starch with a low protein content is obtained. On the other hand, the protein content of the gluten fraction is rather low due to difficulties in removing the starch. Despite this, the effect on dough mechanical properties by the addition of gluten obtained from wet‐milled wheat is comparable to the effect of gluten from flour.     

臭氧处理对新收获小麦品质的影响

为了探讨臭氧处理应用于加速新收获小麦后熟的可行性,在室温、臭氧处理质量浓度为5mg/L、处理时间0.5~2.0h条件下分别处理新收获小麦,研究臭氧处理对新收获小麦基本成分、破损淀粉含量、湿面筋含量、面团流变学特性的影响。结果表明,与未处理组相比,臭氧处理对新收获小麦的粗蛋白含量无显著影响(P0.05),但对粗淀粉含量、破损淀粉含量、湿面筋含量、面团流变学特性有显著性影响(P0.05)。     

谷朊粉和小麦淀粉添加量对重组面团冻藏品质的影响

面团的冷冻保存品质无法满足鲜湿面条工业化生产的要求。为了研究面团主要组分（面筋蛋白和淀粉）对面团冷冻品质的影响,以高筋小麦面粉（50%）、谷朊粉和小麦淀粉（不同比例）为原料进行面团重组,-18℃冻藏20 d分析其水分分布、流变特性、糊化特性、凝胶强度、微观结构以及氢键强度,以100%原小麦面粉作为对照组。结果表明,随着谷朊粉:小麦淀粉比例从4:1减小至1:4,冷冻重组面团中的水分分布逐渐由结合水向自由水迁移,弹性模量从125900 Pa降低至73020 Pa;样品的各项糊化参数增大,凝胶硬度也由114.30 g增大到181.39 g。扫描电镜观察发现,谷朊粉:小麦淀粉比例越低越不利于面筋蛋白网络结构的均匀性。添加了谷朊粉和小麦淀粉后,重组面团中的氢键强度均大于对照组,且随着谷朊粉:小麦淀粉比例的减小不断增大。当谷朊粉:小麦淀粉为4:1时,冻藏20 d的重组面团的弹性模量值比对照组高49.95%,有效延缓了面团在冻藏过程中的品质劣变。将淀粉与面筋蛋白进行面团重组可以提高面团的黏弹性,进而有利于其冷冻保存品质。