Pasting properties of starch and protein in selected cereals and quality of their food products

In an attempt to improve intake of dietary fibre and antioxidants and quality of whole grain products, whole grain meals from barley, millet, rye and sorghum were evaluated individually and in blends with wheat flour in terms of starch pasting properties and protein heat damage, during cycles of heating and cooling in RVA tests. The whole grain meals were blended with either hard or soft wheat flour and processed into bread, cake, cookie or snack products. The products were then evaluated with regard to physical properties and acceptability. Significant differences were observed between cereals in starch peak, breakdown and setback viscosities as well as in protein peak viscosity. The results showed that RVA could be used to help formulate cereal blends with certain pasting properties. Substitution of wheat flour, with 15% of barley, rye, millet or sorghum whole grain, did not have significant detrimental effects on physical properties or acceptability of pita bread. Additionally, replacement of wheat flour with up to 30% of barley, rye, millet or sorghum whole grain meal had no significant effects on quality of cakes or cookies. A multigrain snack-like food was also developed as a healthy product and was highly acceptable in a sensory test. The developed product would help enhance consumption of whole grain foods, resulting in improved intake of fibre and health-enhancing components.     

Characterisation of flour, starch and fibre obtained from sweet potato (kumara) tubers, and their utilisation in biscuit production

Sweet potato (kumara) tubers of differing colours (orange, red and white) were used to produce tuber flour, a purified starch fraction and an isolated fibre extract. The fractions from each tuber colour were added into a biscuit mixture, and the effects of tuber source and fraction composition were observed in relation to the physico-chemical characteristics of biscuits. Addition of sweet potato flour and fibre fractions to white wheat flour significantly reduced the pasting properties (peak and final viscosity) of the resulting gels by up to seven-fold compared with the control wheat flour gel (as determined by the Rapid Visco Analyser). The addition of sweet potato starch affected the pasting properties of wheat flour–sweet potato starch mixes to a lesser extent. Biscuit texture (force required to cause a biscuit to fracture) was significantly reduced with the incorporation of sweet potato fibre into the biscuit dough preparation, this was linked to a reduction in biscuit thickness and spread ratio. However, the addition of sweet potato flour and starch resulted in biscuits of similar firmness as the control biscuits.     

Effect of grain hardness,fractionation and cultivars on protein,pasting and dough rheological properties of different wheat flours

Coarse flour fractions (CFFs) and fine flour fractions (FFFs) obtained from flour milled from twelve different wheat cultivars varying in grain hardness index (GHI) were evaluated for particle size distribution, pasting and protein characteristics. Cultivars with greater hardness produce flour with high protein content had more proportion of large size particles. FFF had higher unextractable polymeric protein, solvent retention capacity (SRC), sedimentation value (SV) and dough stability (DS) than their corresponding CFF. Both FFF and CFF from cultivars with lower hardness showed lower sodium SRC. CFF showed higher pasting viscosities than their corresponding FFF, and difference in these properties was greater amongst soft cultivars. DS increased with decrease in grain hardness, but medium hard cultivars showed exceptionally higher value. The concentration of HMW‐GS in the CFF was higher than FFF of hard wheat cultivars, whereas the concentration of LMW‐GS in the CFF and FFF was not influenced by the fractionation of flour.     

山农紫糯小麦粉理化性质分析及其馒头产品的开发

糯小麦粉由于直链淀粉含量很低而被赋予其独特的理化性质。本实验对山农新培育出的紫糯小麦品种制粉的理化和营养性质进行了测定,并与普通小麦粉配粉制作馒头,通过质构仪检测试验和感观评价相结合的方法对馒头品质进行了研究,从而确定了山东农业大学新培育紫糯小麦品种开发馒头产品的最佳工艺。试验结果表明:山农紫糯小麦粉的脂肪、蛋白质、灰分和蛋白质中清蛋白、醇溶蛋白、谷蛋白含量比普通面粉高,而淀粉和球蛋白含量比普通面低;其糊透明度、谷值黏度、最终黏度、糊化温度较低,但崩解值、峰值黏度、回生值高。添加15%的紫糯小麦粉可显著的改善馒头的表皮色泽,并且对馒头的弹性、黏着性、黏聚性和回复性影响最大,此时馒头的总评分达到最大值。     

Effect of Alkali Dipping on Dough and Final Product Quality

ABSTRACT: The effects of alkali dipping on starch, protein, and color changes in hard pretzel products have never been researched. Experiments were conducted to mimic reactions occurring on the pretzel dough surface. Dough was dipped in water or 1% sodium hydroxide solution at different temperatures between 50°C and 80°C. Protein and starch profile after dipping were analyzed. Color development on pretzel surface following the extraction of pigments from flour was investigated. Whole dough and pretzel samples were also made at pilot plant and the properties were analyzed. Only starch granules on the dough surface were gelatinized following dipping. Amylose-lipid complex dissociated at a lower temperature with alkali treatment but were not dissociated, even at high-temperature dipping in water. Treating the dough at 80°C in alkali solution resulted in the hydrolysis of proteins into smaller peptides that could be not precipitated by trichloroacetic acid (TCA). Dough surface color was different following pigment extraction from flour but not significantly different following baking. The results suggest that the color that developed on pretzel surface was not due to pigments present in the flour but was contributed by the reaction within or between the starch and protein hydrolysis derivatives during baking.     

青麦粉添加对馒头面团及面筋蛋白结构的影响

以馒头专用粉及青麦粉制作青麦馒头,利用激光共聚焦显微镜、黏度仪、红外光谱仪等分析仪器进行测定,探究不同青麦粉添加量(0%、5%、10%、15%、20%)对面团粉质特性、糊化特性、微观结构及面筋蛋白二级结构的影响。结果表明,随着青麦粉添加量的增加,混合粉湿面筋含量、面筋指数减少;糊化温度、峰值黏度降低,面团糊化时间缩短,面团稳定时间从6.18 min降至4.92 min、粉质质量指数减小了18,面筋强度变弱,承受力变差;面团拉伸面积、延伸度和最大拉伸阻力在135 min时显著减小;面筋网络结构逐渐出现孔洞,分布不均匀;面团面筋蛋白各吸收峰都发生了偏移,β-折叠和α-螺旋结构含量增加;综上所述,青麦粉的加入改变了面团特性和面筋蛋白结构,这些变化可能是导致青麦馒头品质下降的主要原因。     

Effect of wheat flour characteristics on sponge cake quality

BACKGROUND: To select the flour parameters that relate strongly to cake‐making performance, in this study the relationship between sponge cake quality, solvent retention capacity (SRC) profile and flour physicochemical characteristics was investigated using 38 soft wheat samples of different origins. Particle size average, protein, damaged starch, water‐soluble pentosans, total pentosans, SRC and pasting properties were analysed. Sponge cake volume and crumb texture were measured to evaluate cake quality. Cluster analysis was applied to assess differences in flour quality parameters among wheat lines based on the SRC profile. RESULTS: Cluster 1 showed significantly higher sponge cake volume and crumb softness, finer particle size and lower SRC sucrose, SRC carbonate, SRC water, damaged starch and protein content. Particle size, damaged starch, protein, thickening capacity and SRC parameters correlated negatively with sponge cake volume, while total pentosans and pasting temperature showed the opposite effect. CONCLUSION: The negative correlations between cake volume and SRC parameters along with the cluster analysis results indicated that flours with smaller particle size, lower absorption capacity and higher pasting temperature had better cake‐making performance. Some simple analyses, such as SRC, particle size distribution and pasting properties, may help to choose flours suitable for cake making. © 2012 Society of Chemical Industry     

Effects of Enzymatic Hydrolysis of Protein on the Pasting Properties of Different Types of Wheat Flour

Abstract: As one of the most effective methods to modify proteins, enzymatic hydrolysis is used widely in the preparation of wheat products in the food industry. During the same process, starch pasting occurs frequently. The effects of wheat protein hydrolysis with papain, pepsin, and trypsin on the pasting properties of 3 different kinds of flour were investigated in 5 concentrations. Results showed that the peak viscosity, trough, final, and integral area of pasting curve of these flours decreased with increasing enzymatic hydrolysis of protein, and decreased significantly with the increasing enzyme concentrations. Medium‐gluten flour was the least sensitive to enzymatic activity and weak‐gluten the most sensitive. Downtrends appeared with increasing papain and trypsin concentrations in the form of breakdown. Enzymes had no significant different effect on the peak times of strong‐ and medium‐gluten flour, but prolonged peak time slightly in weak‐gluten flour. The pasting time and temperature of strong‐ and medium‐gluten flour were significantly increased in a concentration‐dependent manner. However, there were no significant effects on the pasting times of weak‐gluten flour. These results could supply a basis for utilization of enzymatic hydrolysis of wheat protein in food industry and for further studies into the interactions between hydrolyzed protein and starch in food or processing industries. Practical Application: Illuminating the effects of enzymatic hydrolysis of protein on the pasting properties of different types of wheat flour is very important in food industry. Flour viscosity decreases after enzymatic hydrolysis of protein/gluten. Enzymes have different effects on peak time, pasting time, and pasting temperatures for different types of flour. These results could supply a basis for utilization of enzymatic hydrolysis of wheat protein in food industry and for further studies into the interactions between hydrolyzed protein and starch in food or processing industries.     

不同粉路小麦面粉理化性质与流变学特性分析

以15个不同出粉口小麦粉为样品,采用宏观理化表征与微观显微技术相结合的方法测定其特性。结果表明:M粉的前中路易糊化,其峰值黏度、低谷黏度、最终黏度、稀懈值、回生值比较高,其次是B粉的前路,而M粉的后路、B粉的后路、XF粉与T粉糊化指标相对较低,品质较差。面筋蛋白含量高的小麦面粉的吸水率、形成时间、稳定时间和粉质质量指数也相对较高,面筋蛋白含量对面团稳定时间影响很大,但相同筋力不同粉路的小麦面粉变化幅度不同。旨在为提高面粉品质分析与控制提供理论依据。     

IDENTIFICATION OF IMPORTANT PRODUCTION VARIABLES AFFECTING HARD PRETZEL QUALITY

The objective of this study was to determine the importance of raw material and processing variables that influence pretzel quality by utilizing a screening experiment design. Eleven variables were selected based on preliminary experiments, and a two‐level‐11‐factor (2 ¹¹ ) fractional factorial experimental design was used to screen the variables. Several responses were measured for dough before and after extrusion, for half‐baked and fully baked pretzels. These responses are important indicators of consistency and quality during pretzel processing. Results indicated that flour protein content, the amount of water added to make dough and dough mixing time were important variables influencing dough behavior. Caustic concentration affected brightness of half‐baked pretzels but did not influence the color of the final product. Baking time was the most important factor for both half‐baked product and final product qualities. The hardness of fully baked pretzels was influenced by baking time, temperature in baking oven zone 1, drying time and drying temperature. The color of final products was significantly influenced by baking time, while both baking time and drying temperature affected the moisture content of the final product. A key observation was that none of the raw material or dough processing parameters, within the range tested, influenced final pretzel quality as defined by pretzel moisture content, hardness or color.     

Wheat washing with ozonated water: effects on selected flour properties

Soft and hard wheat samples were washed using ozonated water (1.5 mg L⁻¹). Milling (rate of extraction), rheological (farinograph and extensograph characteristics), chemical (protein, falling number, sedimentation volume), colour (Hunter Laboratory values) and microbiological (total bacterial and yeast/moulds) properties of flours milled from the washed wheat were evaluated. Results indicated that washing with ozonated water did not significantly alter the chemical, physical or rheological properties of the flours from hard wheat samples. However, small but statistically significant ( P =0.05) differences were observed on extensograph values of flours milled from the soft wheat washed with ozonated water. A significant reduction ( P =0.05) in the total bacterial and yeast/mould counts was obtained after washing with ozonated water for both soft and hard wheat samples. Results suggest that ozonated water can be successfully used to wash hard wheat without affecting flour quality.     

湿热处理对发芽小麦粉品质影响的研究

小麦发芽过程中芽麦粉品质劣化,本文拟通过湿热处理或热液处理(heat moisture treatment,HMT)对芽麦粉进行处理,研究其对芽麦粉品质的影响。实验以郑麦366为原料,经过发芽处理后制粉,随后对其进行湿热处理,并测定湿热处理前后芽麦粉的品质变化。研究发现:发芽小麦经过湿热处理后白度和色泽变差;降落数值有明显的提升;蛋白质总含量轻微下降;损伤淀粉含量显著下降(p<0.05);糊化特性有明显的改善:峰值黏度有显著的提高(p<0.05),糊化温度升高明显;对湿热处理过的芽麦粉的热机械性质进行分析时发现,形成时间和稳定时间随水分含量、温度、时间增加呈现逐渐下降趋势,表明芽麦粉的蛋白质变性程度随着处理条件的加剧而增加。最佳处理条件为水分含量25%,处理温度100℃,处理时间60 min。结果表明,通过精确控制湿热处理条件,可显著改善芽麦粉中淀粉的糊黏度性质,同时避免热对蛋白质的激烈变性作用。      

Suitability of various australian wheats for chinese-style steamed bread

Three methods of preparation of steamed bread on a laboratory scale were evaluated to determine the one most suitable for discriminating between flour samples. The preferred method was then applied to a number of wheat varieties at different protein levels to select the most suitable ones for this product, and to determine the key analytical parameters of the most suitable flour. Flour colour and protein content appeared to be more important than other physical and chemical properties. Flour samples with high protein content (greater than 12%) and strong doughs gave bread with a wrinkled surface and dark colour, whereas low protein (less than 10%) soft wheat flours gave poor texture and eating quality, although the surface was smooth. It is suggested that flours of medium protein content (10–12%) and medium dough strength are the most suitable for steamed bread. Processing conditions affected steamed bread quality. Blending of high protein hard strong wheats with soft weak wheat could be practical for preparing flour for steamed bread.     

Dough and bread qualities of flours with whole waxy wheat flour substitution

Whole wheat flour has been developed as fiber-rich food for healthy bowel function. In this study, whole waxy wheat flour (WWF) was characterized and applied for breadmaking with the hope that breads made from WWF would improve the quality based on the superior properties of the waxy flour in retardation of bread staling. WWF had significantly higher protein, ash and dietary fiber contents (13.5%, 1.6% and 15.3%, respectively), but lower lipid content (0.8%) than commercial white flour (CWF). Amounts of soluble and insoluble dietary fiber in WWF were 4.1% and 11.2% (% total weight), respectively. WWF had lower pasting temperature and viscosities than CWF. Dough made from WWF increased water absorption and showed lower stability during mixing than that from CWF. The high amount of dietary fiber diluted the gluten protein in dough during mixing to form weak and inextensible dough. Bread made from whole waxy wheat flour had significantly low specific volume and big gal cell distribution as compared to that from CWF. Also, dark-brown color and bitter taste are weak points of whole waxy wheat bread. However, the WWF bread was significantly softer than CWF bread during storage. The qualities of breads were also improved using partial WWF substitution (10%, 30% or 50%) for CWF. As a result, whole waxy wheat flour can be used for breadmaking to improve nutritious quality of bread for health benefits.     

Wheat batter physical properties as influenced by starch/flour types and egg contents

Batter liquid–solid phase interactions can play a critical role in determining the functionality, including adherence, appearance and texture of end use coated product. Batter chemical composition is a key factor affecting batter characteristics. The effect of substituting wheat flour with fractions of rice flour, native corn starch, modified waxy corn starch, tapioca starch and lupine flour ranging from 26 to 56% of the solid phase and egg levels ranging from 6 to 35% of the liquid phase on the rheological properties of batter systems was studied. Results indicated that lupine flour had the greatest water holding capacity (WHC) ranging from 93.9 to 119.3% of various lupine flour percent to egg levels used. Flow behaviour index of batter flour treatments ranged from 0.91 to 1.87; values that were significantly (P?<?0.05) greater than a 100% control wheat flour. Consistency coefficient of treatments ranged from 0.01 to 0.37 mPa sⁿ; values that were significantly lower than wheat flour (i.e., 5 mPa sⁿ). Egg level used in this study had minimal effect on treatment rheological properties. The changes in WHC and viscoelastic properties of treatments were attributed to changes in protein and fibre contents and structure as a result of replacing wheat flour with starch/flour. Protein–starch–lipid matrix formation and variation in water absorption kinetics of treatments most probably wrought batter functionality. The increase in pasting properties with the increase in starch/flour contribution suggested an increased contribution of starch in forming a net effect of batter treatments pasting viscosities. Results of this study provide vital information for the potential use of starch types to enhance the rheological properties of coating applications including adhesion and water holding capacity of substituted batter treatment.     

Effect of Milling on the Starch Properties of Winter Wheat Genotypes

Fifteen winter wheat varieties (12 hard and 3 soft genotypes) produced in Martonvásár were selected to study the effect of milling on flour starch properties. Differences in protein and starch content, flour yield, water absorption, starch damage, particle size and pasting properties were studied. Significant difference was observed in the starch properties of the different wheat genotypes when milled with different laboratory mills (Chopin CD1, Brabender Junior, FQC‐109). Brabender Junior differed significantly from the other two mills for the properties of starch content, and final viscosity. That was Chopin CD1 which most differed from the other two mills, as it produces flour with the smallest particle size. It also produces flour with the lowest water absorption, and the highest breakdown‐ and lowest trough‐ viscosity parameters. The damage of starch was the smallest for Brabender Junior and the highest for FQC‐109 and they were statistically different. It was concluded that according to the purpose of the processing industry, starch properties can be varified by an appropriate wheat choice, grain preparation and mill‐choice, ‐setup and ‐adjustments.     

Use of wheat,triticale and rye flours in layer cake production

In this study, the capacity of obtaining high quality layer cakes from rye and triticale lines was analysed and compared to wheat lines. The samples were characterised considering grain hardness, flour composition and quality parameters as protein, pentosan, damaged starch, pasting viscosity and functional predictive test – solvent retention capacity test. Cakes were analysed in weight, symmetry, volume, volume index (VI) by measuring the height in different points of the cake, crust and crumb colour, crumb structure and texture. Wheat and triticale cakes showed similar characteristics. Rye cakes showed higher volume and lower weight than those with crumbs darker in colour, higher adhesiveness, springiness and resilience. The multiple regression analysis was used to develop an equation for cake volume index prediction. The best‐fit linear regression model was: VI = 14.75 – 0.14 × protein + 0.93 × water soluble pentosan – 0.27 × total pentosan. Despite the differences, high quality cakes can be elaborated with rye, triticale and soft wheat cultivars.     

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。     

Effect of partial substitution of wheat flour with resistant starch on physicochemical,sensorial and nutritional properties of breadsticks

This study determined the physicochemical, sensorial and nutritional properties of breadsticks to which a resistant starch (RS)-rich ingredient was incorporated by partial substitution, that is, 40%–70%, of hard wheat flour in the control recipe. Wheat flour substitution at the levels exceeding 50% lightened the colour while decreasing the moisture content and hardness of breadsticks, which was explainable by the microstructure. Changes in properties of breadsticks also affected the suitability of its sensory attributes, particularly colour and texture. Breadsticks, of which half of wheat flour was substituted, contained less protein and calories but higher carbohydrate than the control formula. Such flour substitution increased RS content closed to its effective dose of 15 g in a 45-g serving, which led to approximately 15% reduction in in vitro glycaemic index. Therefore, incorporating effective dose of RS in breadsticks could be performed, without causing substantial changes in product quality, by partial substitution of wheat flour.     

小米粉含量对小米小麦混合粉及其挂面品质特性的影响研究

将小米粉按照10%~80%的比例添加到小麦粉中,对小米小麦混合粉的粉质特性和糊化特性进行了分析,同时对由混合粉制作成的挂面的品质特性进行了分析研究。结果表明:1)随着小米粉添加量的增加,小米小麦混合粉的峰值黏度、最低黏度、最终黏度、回生值、衰减值和峰值时间都在降低,形成时间、稳定时间、粉质指数都是先降低再升高。2)挂面蒸煮损失率不断升高,干物质吸水率不断下降。小米添加量≤30%时,挂面品质比较好,添加量≤60%时,品质尚可,添加量60%时,挂面品质下降比较大。3)小米粉的添加量、小米小麦混合粉的RVA特性、粉质特性与混合粉挂面的蒸煮品质特性有非常高的相关性。