Effect of native and germinated finger millet flour on rheological and sensory characteristics of biscuits

Wheat flour was replaced with native finger millet flour (NFMF) and germinated finger millet flour (GFMF) at 30–50% levels to make soft dough biscuits. Dough rheological properties and baking characteristics of the blends were evaluated. Farinograph data of wheat flour replaced with NFMF and GFMF showed a decrease in water absorption, dough stability and an increase in mixing tolerance index as the level of replacement increased. Extensibility of dough decreased for both NFMF and GFMF as the levels increased. The hardness of biscuit dough measured by texture profile analysis increased from 125 to 234 N for NFMF and 118 to 126 N for GFMF. Scanning electron microscopic studies on the biscuit dough showed polygonal finger millet starch granules adhering to wheat starch granules and protein matrix. The results of the study indicated that the replacement level of 40% with either NFMF or GFMF produced biscuits with acceptable sensory attributes. Addition of sodium stearoyl‐2‐lactylate (SSL) showed further improvement in terms of spread ratio, surface characteristics and texture.     

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.     

Effects of endogenous flour lipids on the quality of short‐dough biscuits

Fractionation and reconstitution techniques were used to study the contribution of endogenous flour lipids to the quality of short‐dough (shortcake type) biscuits. Biscuit flour was defatted with chloroform and baked with bakery fat, but without endogenous lipid. Short‐dough biscuits baked from defatted flour had smaller diameters, and were flatter, denser and harder than control biscuits. Defatted flour shortcake doughs exhibited different rheological behaviour from the control samples, showing higher storage and loss moduli (G′ and G″ values), ie higher viscoelasticity. Functionality was restored when total non‐starch flour lipids were added back to defatted flour. The polar lipid fraction had a positive effect in restoring flour quality whereas the non‐polar lipid fraction had no effect. Both fractions were needed for complete restoration of both biscuit quality and dough rheological characteristics. A study of the microstructure of defatted biscuits revealed that their gluten protein was more hydrated and developed than the gluten of the control biscuits. This conclusion was supported by the higher water absorption of the defatted gluten. Copyright © 2004 Society of Chemical Industry     

Semi-Sweet Biscuits: 2. Alternatives to the Use of Sodium Metabisulphite in Semi-Sweet Biscuit Production

The influence of sodium metabisulphite (SMS) and other gluten-modifying agents on the performance of a commercial biscuit flour in the production of semi-sweet biscuits has been studied. Use of a proteolytic enzyme as a gluten-modifying agent resulted in a dough with a longer mixing time than other doughs, partly as a result of mixing to a higher temperature. The extrusion time of doughs containing the proteolytic enzyme was closest to the extrusion time of doughs containing SMS. Doughs containing SMS or proteolytic enzyme produced significantly shorter extrusion times than doughs containing l -cysteine hydrochloride. Dynamic oscillatory measurements showed that for doughs made at a constant water level the lowest elastic and viscous moduli were produced by doughs containing sodium metabisulphite. Doughs containing the other gluten-modifying agents produced stronger elastic properties than those containing SMS but weaker elastic properties than doughs containing no gluten-modifying agent. The hardness of the semi-sweet biscuits produced was found to be reduced by a weakening of the rheological properties of the dough. All gluten-modifying agents reduced dough piece contraction in length during processing, although SMS was the most effective. A decrease in dough piece length during processing caused an increase in dough piece thickness and width. Use of a proteolytic enzyme or the enzyme and l -cysteine hydrochloride in combination, as gluten-modifying agents, produced biscuits closest in quality to those produced from doughs containing SMS.     

Effect of emulsifiers,fat level and type on the rheological characteristics of biscuit dough and quality of biscuits

The effect of level and type of fat as well as emulsifiers on the rheological characteristics of biscuit dough and quality of biscuits has been studied. Increasing the level of fat from 150 to 250 g kg⁻¹ softened the dough, as indicated by a reduction in extrusion time from 108 to 18 s and an increase in compliance from 31.9 to 49.9%, while it reduced the development of gluten, as shown by a reduction in elastic recovery from 0.485 to 0.365 mm. Among the different types of fats used, hydrogenated fat produced the stiffest dough. Addition of any of the emulsifiers glycerol monostearate, lecithin or sodium stearoyl lactylate lowered the elastic recovery value, indicating their contribution to the shortening effect on gluten, and also resulted in a reduction in consistency and hardness and made the dough more cohesive. The maximum change was observed with sodium stearoyl lactylate. The density, breaking strength and compression strength of biscuits decreased, indicating an improvement in crispness, with increasing fat level. The thickness of biscuits was significantly higher when hydrogenated fat or oil was used in the formulation. Biscuits made with bakery shortening had better surface characteristics and higher crispness. Glycerol monostearate and lecithin brought about a greater improvement in the quality of biscuits when compared with sodium stearoyl lactylate. Studies indicated that emulsifiers in general had a greater beneficial effect, particularly in the case of biscuits made from medium hard wheat flour. © 1999 Society of Chemical Industry     

黑玉米全粉对小麦面团流变学特性及酥性饼干品质的影响

为了拓宽黑玉米全粉在烘焙食品领域的应用,将黑玉米全粉以0~50%的比例替代强中筋小麦粉,利用黏度仪、粉质及拉伸仪等研究黑玉米全粉替代对小麦粉理化特性及面团热机械特性的影响;利用质构仪、感官评价研究黑玉米全粉替代对酥性饼干品质特性的影响。结果表明,黑玉米全粉的加入对面筋网络结构起到阻隔和断裂作用,湿面筋含量及沉降值分别下降了73.2%、71.0%,面团筋度显著降低。黑玉米全粉替代显著改变了面团的流变学特性,面团形成时间、稳定时间下降,弱化度升高;拉伸能量、延伸度、最大拉伸阻力下降,面团强度、稳定性及耐搅拌性降低,加工性能劣化。黑玉米全粉替代小麦粉酥性饼干的延展因子、质构特性及感官评价指标综合分析结果显示,20%黑玉米全粉添加量的饼干延展因子最大,组织结构细密均匀,表面光滑无裂纹,咀嚼性及硬度最大,酥脆性最好,口感最佳。黑玉米全粉酥性饼干常温下6个月保质期内水分、酸价、过氧化值及菌群总数、大肠菌群、霉菌、致病菌指标都符合国家标准。20%的黑玉米全粉添加量使得小麦粉面团在筋度适当下降的同时获得具有黑玉米风味、口感较好的酥性饼干,该研究可为黑玉米全粉在食品加工行业的应用提供理论依据。     

Physicochemical properties of commercial semi-sweet biscuit

This study was performed to provide information about the physical and chemical characteristics of commercial semi-sweet biscuits and to ascertain the key characteristics of commercial semi-sweet biscuits (rich tea type), in terms of starch properties, such as gelatinisation, pasting, granule crystallinity and morphology, and to compare the magnitudes of changes of physical characteristics (diameter, thickness, weight and bulk density) for selected brands. A total of 10 rich tea biscuits from different brands were bought locally and were measured for physical and chemical characteristics. The three-point bend test showed that a biscuit with lower fat content was harder than a biscuit with normal fat content, except for sample B. Starch gelatinisation properties show that To, Tp and Tc were higher than for wheat flour whereas ΔH was lower than for wheat flour. X-ray results showed that commercial biscuits still retained their crystallinity but at lower intensities than native wheat flour. Microscopy observations revealed that some of the granule birefringence of commercial biscuits can still be observed under polarised light. Different brands of biscuits showed different physical and chemical characteristics.     

香菇粉对面团特性和酥性饼干品质的影响

目的 研究香菇粉对面团特性和酥性饼干品质的影响。方法 在面粉中添加不同浓度香菇粉, 对香菇面粉的白度、湿面筋含量、降落数值、粉质参数和拉伸参数等指标进行了测定。通过质构分析及感官品质评价, 研究了香菇粉对酥性饼干品质的影响。结果 在面粉中添加0%~25%的香菇粉, 增加了面粉的营养价值, 显著降低了面粉稳定时间、面团拉伸能量、面粉的白度和湿面筋含量(P＜0.05)。面粉降落数值随香菇粉添加量的增加呈先降低后增加趋势。质构分析表明, 香菇粉添加量为8%时, 酥性饼干的硬度和咀嚼性最低, 感官品质评分最高, 为73.5分, 接近满分75分。结论 在面粉中添加香菇粉, 有利于制作酥性饼干及需要低筋粉制作的食品。酥性饼干中香菇粉最佳添加量为8%, 此时该香菇酥性饼干不仅口感更酥脆, 而且增加了饼干中蛋白质、粗纤维等的含量, 降低了碳水化合物含量。     

麦麸对酥性饼干物理性质和淀粉消化性的影响

目的 研究麦麸对酥性饼干颜色、物理性质以及淀粉消化性的影响。方法 将麦麸按0～50%比例添加到面粉中制作饼干,测定混合粉的溶剂保持力,测定饼干颜色、延展度、硬度以及淀粉消化性。结果 添加麦麸导致混合粉的水和碳酸钠溶剂保持力值增加,乳酸溶剂保持力值和面筋性能指数降低(4.71%～33.20%和25.73%～34.11%),饼干颜色变暗。当麦麸添加量大于20%时,饼干的延展度和硬度增大(53.54%～64.31%和135.98%～408.53%)。此外,麦麸的添加在一定程度上降低了饼干淀粉消化性。麦麸添加量与饼干物理性质呈强正相关性,与消化终点葡萄糖含量呈负相关。通过主成分分析,提取了2个主成分,累计方差贡献率为85.3%。结论 适量添加麦麸有效改善了饼干酥脆性,并在一定程度上抑制了饼干淀粉的消化,增加了饼干的功能性质,可以为麦麸产品的进一步开发提供参考。     

荷叶粉对面粉理化性质及酥性饼干品质的影响

目的:探索酥性饼干中荷叶粗粉与荷叶超微粉适宜添加量。方法:采用粉质仪、拉伸仪、湿面筋仪、降落数值仪测定荷叶粗粉与荷叶超微粉对面粉理化指标的影响,采用质构仪测定面团的硬度和酥性饼干的剪切力,采用感官方法评价酥性饼干的感官品质,采用菌落总数测定方法测定原料与酥性饼干的细菌总数。结果:在面粉中添加0%~15%的荷叶粗粉与荷叶超微粉,能够增加面粉的吸水率、降落数值和面团的硬度,降低面粉的稳定时间、面团的拉伸能量和湿面筋含量,酥性饼干的酥松度和感官评分先增加后下降,当面粉中荷叶粗粉添加量为6%、荷叶超微粉添加量为9%时,酥性饼干酥松度和感官评分最大,此时与空白相比,酥性饼干的感官评分分别提高9.81% 和18.33%,荷叶超微粉添加量比荷叶粗粉高出3%。与空白相比,添加15%荷叶粗粉的酥性饼干其细菌总数下降41.18%,添加15%荷叶超微粉的酥性饼干其细菌总数下降62.94%。结论:荷叶粗粉与荷叶超微粉能够增加酥性饼干的营养价值和感官品质,超微粉效果比粗粉更好。     

鹰嘴豆全麦粉酥性饼干研制及品质分析表征

目的为开发一款低糖、低脂、富含氨基酸和膳食纤维的功能性饼干。方法以低筋粉、鹰嘴豆、全麦粉、玉米油等原料研制鹰嘴豆全麦粉酥性饼干,以感官评分为评定指标经单因素和正交试验优化得到最优配方。采用质构仪和低场核磁共振分析表征了不同组分条件下鹰嘴豆全麦粉酥性饼干的内在结构和水分分布情况。结果通过正交实验优化了鹰嘴豆全麦粉酥性饼干配方为：鹰嘴豆粉17.5%、全麦粉30%+低筋粉70%、木糖醇25%、玉米油22.5%。在此配方下制得的鹰嘴豆全麦粉酥性饼干感官评分最高且硬度、脆性、胶黏性和咀嚼性均高于其他试验组。结论本研究为膳食纤维功能饼干研发与生产提供理论参考。     

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。     

Correlation between the rheological and technological properties of biscuits with different levels of replacement of wheat flour by rice and azuki bean flour

A mixture design was used to evaluate the effect of replacing (0 to 100%) wheat flour (WF) with wholegrain azuki bean (WABF) and rice (RF) flours on the biscuits quality. High proportions of WABF increased diameter and decreased thickness, whereas WF affected inversely and RF intermediate. The WF biscuit specific volume was 17% greater than that of the dough, and the WABF and RF biscuits were 5 and 13% smaller, respectively. The WABF biscuit hardness was 26.25 N, close to WF (28.14 N), and higher than RF (7.6 N). The WABF increased the colour difference (ΔE) values for biscuits by up to 22.19 and the RF by 1.87. Peak viscosity, breakdown and setback of mixture flours showed positive correlations with the dough hardness and L*, a*, b* and Aw of biscuits and negatively with the radial expansion index and ΔE. The highest global desirability was for biscuits without WF, regardless of crust colour.     

Effects of Fat and Sugar on Dough and Biscuit Behaviours and their Relationship to Proton Mobility Characterized by TD-NMR

This study aimed to analyse the effect of large variations in fat and sucrose contents of biscuit formulation on dough rheology, biscuit quality and proton mobility. Control dough (full fat and sucrose) and 25 and 50% fat and sucrose-reduced doughs were elaborated. Rheological properties of dough were determined. Dough cooking behaviour and biscuit quality were evaluated. Fat reduction produced an increase in the consistency and elastic properties of the dough. The decrease in sucrose content affected to a lesser extent the rheological properties at room temperature, although it produced significant changes during dough baking. The biscuit quality decreased with fat and sucrose reductions. The reduction of fat or sucrose produced gluten hydration and extra interactions and subsequent cross-linking during baking, and a reduction of sucrose led to the swelling and partial gelatinization of starch during baking. A dipolar reversed eco NMR sequence was applied to determine changes in the amount and mobility of solid and mobile components both in dough and biscuits. TD-NMR results allowed corroborating the proposed hypotheses about the effects on dough and biscuit characteristics as a consequence of reduction of main ingredients, as fat and sucrose. The redistribution of water after baking can be correlated with biscuit factor and breaking force.     

小麦粉吸水速率对面团特性及馒头品质的影响

该文以不同吸水速率的小麦粉为基础,研究在相同的揉混条件下,其面团特性及馒头品质的变化。使用粉质仪将面团稠度达到最高时所用的加水量与消耗的时间的比值定义为吸水速率,测定不同吸水速率小麦粉其粉质特性、湿面筋含量、面筋指数、游离巯基与二硫键含量、面团质构特性、馒头比容与高径比、馒头的质构特性。研究结果表明,当小麦粉吸水速率从0.17 g/s增大到3.87 g/s时,面团的稳定时间及粉质质量指数显著下降。其湿面筋含量从38.81%下降到19.19%,二硫键含量从13.31μmol/g下降到9.05μmol/g。面团的质构特性在发酵0 min时呈先升高后降低趋势、在醒发45 min后整体呈下降趋势。馒头的比容从2.67 mL/g降低到2.27 mL/g、高径比从0.68降低到0.56,其硬度、胶着性、咀嚼性均成下降趋势。整体而言,吸水速率低的小麦粉其面团相对较硬且馒头较为筋道有嚼劲;吸水速率较高的小麦粉其面团硬度稍弱且馒头较为松软。     

Influence of gluten-free flour mixes and fat powders on the quality of gluten-free biscuits

Studies were conducted to develop gluten-free biscuits comparable in quality to wheat (W) biscuits and superior to those made from commercial gluten-free flour (Gf), suitable for coeliac sufferers. Three mixes of brown rice flour (R), corn starch (C), potato starch (P), soya flour (S), buckwheat flour (B) and millet flakes (M) were studied: RCPS in the percentage 70, 10, 10, 10, RPBM (50, 30, 10, 10) and RCPM (25, 25, 25, 25). Biscuits were tested for water activity, moisture, texture (snap test), diameter, thickness and colour (L* value), biscuit dough for hardness and stickiness. Various correlations >0.8 indicated for the three mixes, W and Gf that firm, non-sticky doughs yielded firm, thin, non-oval biscuits. Cluster analysis revealed that RCPS was most similar to W with regards to all parameters measured, and RCPS also showed best overall acceptability in sensory testing. Three fat powders were studied for use instead of palm oil: high and low fat dairy powder (HFP, LFP) and microencapsulated high fat powder based on vegetable fat (ME). HFP and ME yielded biscuits of comparable texture to palm oil, LFP resulted in much firmer biscuits, attributed to lower fat and higher protein and total sugar content.     

计算机辅助X光断层扫描对半甜韧性饼干的质构无损量化检测

采用X光计算断层扫描（X-ray computed tomography,CT）法研究了半甜韧性饼干（以下简称饼干）的 质构特征,并将CT参数与饼干常规物理参数进行了相关性研究。结果显示：CT测试所获得的组织重构可以直观再 现饼干的内部结构（二维及三维）;CT密度、孔隙率以及气泡截面积的平均值与饼干面团中蛋白酶或焦亚硫酸钠 （以下简称焦亚）的添加量、饼干厚度以及表观密度具有显著相关性（R＞0.9,P＜0.05）,反映出CT参数可以客 观地量化由于蛋白酶或焦亚添加量不同所导致的饼干组织结构变化。当蛋白酶或焦亚对面团产生程度相当的减弱面 筋（减筋）作用时,两种面团饼干的常规物理参数及CT参数均表现出显著性差异（P＜0.05）,并且饼干气泡截面 积的分布也表现出不同的特征,表明CT参数可以反映由于不同的减筋原理导致的饼干质构差异。结果表明,CT测 试可以应用于饼干质构的定性和定量测定,为饼干的生产与研究提供有益的信息。     

Effects of protein oxidation on the rheological behaviour of different wheat flour

Wheat flour proteins are subject to oxidation reactions during production, processing and storage. The quality of protein and the rheological properties of wheat are crucial for the flour industry. However, the impact and mechanism of protein oxidised on wheat flour quality remain unclear. In this study, ozone was used to oxidise wheat grains, the secondary structure of protein in flour and the rheological properties of dough were analysed by FTIR and Mixolab. The proportion of α-helix and β-folding of protein were decreased significantly, as were the development time (DDT), stability time (DST) and protein weakening (C2) value of dough. Meanwhile, starch gelatinisation (C3), amylase activity (C4) and retrogradation (C5) were increased significantly, along with the elastic modulus (G′) and viscous modulus (G″). Microstructure analysis indicated that protein oxidation destroyed the gluten network structure in the dough. In addition, the L* value of dough was decreased and a* and b* values were increased significantly. The results showed that the oxidation of protein reduced the stability of protein secondary structure, weakened the structure and stability of the gluten network in dough, and changed the viscoelasticity and colour of dough. Overall, these findings provide a better understanding of rheological behaviour in wheat flour.     

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。     

Wet-milling of wheat flour: industrial processes and small-scale test methods

Commercial manufacture of wheat starch and vital wheat gluten involves physical separation of starch granules and gluten particles formed in a neutral aqueous system. The wet-separation of gluten proteins and starch from wheat flour is based on their water insolubility, density, and particle size. Upon wetting, gluten proteins in wheat endosperm aggregate and form particles that are larger in size but less dense than starch granules. Wheat starch and vital gluten are currently produced industrially through wet-milling of wheat flour principally by four processes; the Martin, Alfa-Laval/Raisio, Hydrocyclone, and the High-Pressure Disintegration (HD) processes. The industrial processes differ mainly in the forms of the flour-water mixtures presented to the fractionation equipment (centrifuge, hydrocyclone, or screen) or in the initial separation practice of starch and gluten fractions from flour. However, the processes essentially merge into one as the intermediate starch and gluten-particle streams are purified to give >98% pure starch and ∼80% protein vital gluten. Handling of a second-grade starch stream, flour water-soluble, and fibrous residues may differ at various processing steps. Small-scale tests are available to assess the wet-milling quality of flours to be wet-processed by the Martin, Batter, Alfa-Laval/Raisio, and the HD processes. Yet, there are no laboratory tests reported for the Hydrocyclone process. Given the development of numerous new wheat varieties each year and of high-amylose and waxy wheats, it is important that small-scale wet-milling tests to assess the wet-milling quality and suitability of flour samples for the industrial processes be available.