Batter rheology and bread texture of sorghum‐based gluten‐free formulations modified with native or pregelatinised cassava starch and α‐amylase

The influence of α‐amylase (0–0.3 U g^?1) on the crumb properties of gluten‐free sorghum batter and bread, respectively, was investigated. The formulations were modified using native or pregelatinised cassava starch (i.e. batter A – 17% pregelatinised starch, 83% sorghum, 100% water fwb; batter B – 17% native starch, 83% sorghum, 100% water fwb; and batter C – 30% native starch, 70% sorghum, 80% water fwb). The batters had solid viscoelastic character with the storage modulus predominant over the loss modulus. Storage moduli of batter A decreased with increasing angular frequency, whereas the moduli of batters B and C were independent from the angular frequency. Increasing enzyme concentration did not affect the loss factors of the batters. Batters’ resistance to deformation, from highest to lowest, followed the order C > A > B. Increasing enzyme concentration decreased crumb firmness, cohesiveness, springiness, resilience and chewiness but increased adhesiveness. Overall, breads containing native starch had better crumb properties (i.e. springier and less firm, chewy and adhesive) than breads containing pregelatinised starch.     

Rheological and textural properties of sorghum-based formulations modified with variable amounts of native or pregelatinised cassava starch

Sorghum bread was made from native or pregelatinised cassava starch and sorghum flour in the ratio 10:90, 20:80, 30:70, 40:60 and 50:50. The other ingredients, measured on flour-weight-basis, were water (100%), sugar (6.7%), egg white (6%), fat (2%), salt (1.7%) and yeast (1.5%). The dynamic oscillatory behaviours of the batters were affected by the amount and type of starch. In the amplitude sweep measurements, increasing concentration of native starch decreased storage modulus, whereas increasing concentration of pregelatinised starch increased the linear viscoelastic range of the batters. In the frequency sweep measurements, the loss factor of batters treated with native starch declined with increasing frequency. Batters treated with 10 or 20% pregelatinised starch showed declining loss factors, whereas batters treated with 40 or 50% pregelatinised starch showed increasing loss factors with increasing frequency. Sorghum-based batters containing native starch gave bread with better crumb properties than batters containing pregelatinised starch. Crumb firmness and chewiness declined with increasing native or pregelatinised starch concentration. Crumb adhesiveness of breads containing pregelatinised starch increased with increasing starch content but was not affected by native starch. Cohesiveness, springiness and resilience increased with increasing native starch content, but were minimally affected by increasing pregelatinised starch content.     

Rheological and baking characteristics of batter and bread prepared from pregelatinised cassava starch and sorghum and modified using microbial transglutaminase

The effect of different concentrations (0, 0.5, 1 and 1.5 U/g) of microbial transglutaminase (MTG) on the creep-recovery properties of gluten-free batter prepared from pregelatinised cassava starch, sorghum and egg white was investigated. The test conducted in the rheometer had an instant loading of 80 Pa for 60 s and recovery of 0 Pa for 140 s. Increasing MTG concentration decreased the batters’ resistance to deformation and compliances but increased zero shear viscosity and elastic recovery. Changes in batter rheological properties were insignificant (P > 0.05) at MTG concentrations beyond 0.5 U/g. Crumb properties of gluten-free bread baked from the batter revealed that increasing MTG concentration increased (P < 0.05) crumb firmness and chewiness, whereas increasing incubation time decreased (P < 0.05) crumb cohesiveness, chewiness and resilience. There were no significant interaction effects (P > 0.05) between enzyme concentration and incubation time.     

大叶麻竹笋腌制过程中质地的变化

应用质构仪质地多面分析(TPA)试验方法,研究了大叶麻竹笋在不同食盐浓度腌制条件下及腌制过程中的质地变化。研究结果表明:大叶麻竹笋腌制过程中的硬度、咀嚼性、内聚性、弹性与回复性呈下降趋势,腌制食盐浓度越低,上述5个质地参数的数值降低的越多;黏着性呈上升趋势,腌制食盐浓度越低,其数值增加的越多。大叶麻竹笋TPA测试各质地参数间的相关性分析表明,硬度、咀嚼性、内聚性、弹性和回复性可用于更好地评价腌制大叶麻竹笋质地的变化。     

不同糠壳用量糟醅的质构特性与理化指标的相关性研究

该实验将不同比例糠壳添加到糟醅中进行窖外模拟发酵试验,分析了糟醅理化性质和质构特性的相关性。结果表明,糠壳含量对入窖糟醅的质构特性没有显著影响（P＞0.05）,不同糠壳含量糟醅在发酵期间的质构特性差异显著（P＜0.05）。随着发酵时间的延长,随着糠壳含量升高,糟醅的硬度、内聚性和回复性增大,黏着性减小,弹性变化不规律;发酵期间糟醅的水分和酸度均增大,淀粉含量降低。通过相关性分析发现,糟醅的水分和酸度与硬度、内聚性、回复性呈显著正相关（P＜0.01）,与黏着性呈显著负相关（P＜0.01）;而糟醅的淀粉浓度与硬度、回复性和内聚性呈显著负相关（P＜0.01）,与黏着性呈显著正相关（P＜0.01）,与弹性无明显相关性;得到入窖糟最佳质构范围：硬度为2 000～2 200 g,内聚性为22%～23%,黏着性为50%～55%,回复性为6%～7%。     

高粱超微全粉对面团流变学特性及馒头品质的影响

为研究高粱超微全粉对面团流变学特性及馒头品质的影响,将高粱超微粉碎后按一定比例添加到小麦面粉中,测定混合粉的流变学特性,并对混合粉馒头品质进行评价。结果表明:高粱超微全粉添加量较低时(5~10%),混合粉的各项粘度值和峰值时间增加;添加量增加到15~20%时,各项粘度值和峰值时间降低,糊化温度差异不显著。高粱全粉的添加使混合粉的吸水率有所增加。添加量达到10%及以上时,形成时间、稳定时间、粉质指数、拉伸曲线面积、拉伸阻力和延伸度均显著降低。混合粉馒头除色泽外的各项感官指标得分显著降低。馒头硬度和咀嚼性显著增加,粘附性和内聚性先增加后降低,弹性降低,回复性无明显变化规律。气孔延长度差异不大,其他图像分析指标差异显著。高粱超微全粉的添加改变了混合粉的主要成分特别是淀粉和蛋白质的构成与含量,对面团流变学特性及馒头品质均有较大影响。     

Prediction of sensory textural properties from rheological analysis for process cheeses varying in emulsifying salt,protein and moisture contents

Textural characteristics of process cheeses varying in emulsifying salt (disodium phosphate), protein and moisture contents were evaluated by rheological compression using texture profile analysis and by sensory evaluation. The primary objective of this study was to predict sensory textural parameters using instrumental rheological parameters. All sensory parameters correlated with one or more instrumental parameters, e.g. rheological firmness versus sensory firmness (R = 0.98, P < 0.001), rheological chewiness versus sensory rubbery (R = 0.92, P < 0.001) and rheological chewiness versus sensory chewy (R = 0.86, P < 0.001). Partial least squares calibration models were developed for each of nine sensory parameters using instrumental parameters. Principal component analysis of instrumental and sensory parameters illustrated relationships among parameters. It was shown that instrumental parameters could be used to supplement sensory evaluation of process cheese texture. Increasing emulsifying salt content increased firmness, springiness and chewiness and decreased adhesiveness, mouthcoating and mass formation. Increasing protein content resulted in increased fracture strain and stress and chewiness and decreased melting. Increasing moisture content increased cohesiveness and decreased firmness and chewiness. Copyright © 2007 Society of Chemical Industry     

甘薯淀粉对山药凝胶肠理化特性的影响

为研究甘薯淀粉对山药凝胶肠理化特性的影响,对不同甘薯淀粉添加量下山药凝胶肠的质构特性、色度、热特性、水分状态、微观结构以及结晶特性进行了测试。结果表明：甘薯淀粉的添加显著增强了山药凝胶肠的硬度、胶着性、咀嚼性、内聚性和回复性,但黏性、弹性和白度下降;当甘薯淀粉添加量达到20%时,凝胶肠硬度达到7 060.65 g,胶着性为5 263.38 g,咀嚼性为4 623.80 g,内聚性为0.75,回复性为0.42,接近市售火腿肠的质地。甘薯淀粉的添加降低了山药凝胶肠的含水量和水分子的自由度,导致淀粉分子运动受限从而使相对结晶度和回生焓降低,凝胶肠质地更为致密。     

The effect of par‐baking and frozen storage time on the quality of cup cake

The effects of frozen storage and initial baking time of par‐baked cake on baking loss, volume, moisture, colour and textural properties of cake obtained after thawing and rebaking were investigated. Cakes, par‐baked at 175 °C for 15, 20 and 25 min, were stored at ?18 °C for 3, 6 and 9 months. After storage, par‐baked cakes were thawed and rebaked at 175 °C for 10, 15 and 20 min. Baking loss, moisture content, L and +b colour values, firmness, gumminess and chewiness of the resulting full‐baked cakes were significantly affected by both par‐baking and frozen storage time, while specific volume, cohesiveness, springiness and resilience values were significantly affected by frozen storage time. The increase in the time of frozen storage of the par‐baked cake leads to a decrease in the quality of the rebaked cake, namely an increase of baking loss and cake crumb firmness, and a loss in the moisture content and specific volume. Moisture of cake crumb, L and +b colour values, firmness, gumminess and chewiness significantly increased as the par‐baking time increased. However, regarding baking loss, specific volume, moisture content and textural properties, 3‐month intermediate storage at ?18 °C and 20‐min initial baking time gave the best result among the cakes produced by using the two‐step baking procedure.     

木薯变性淀粉对猪肉肌原纤维蛋白凝胶质构、流变及热力学特性的影响

本实验研究了不同比例的木薯变性淀粉对猪肉肌原纤维蛋白(MP)凝胶特性的影响。分析了凝胶质构、静态流变和热力学特性的变化。结果显示:添加10%的木薯变性淀粉增加了蛋白凝胶的弹性,而凝胶的硬度、强度、内聚性、咀嚼性和胶黏性相对适中,从而改善凝胶的质构特性;通过差示扫描量热仪(Differential scanning calorimetry,DSC)分析发现木薯变性淀粉添加量为10%时,降低了蛋白的热相变温度和焓值,促进蛋白变性;另外,木薯变性淀粉的添加也改变了凝胶的表观粘度及触变环面积。当木薯淀粉添加量为10%时,凝胶的表观粘度和触变环面积最小,改善了凝胶的塑性能力及流变稳定性。     

5种豆类淀粉凝胶特性的比较研究

选取绿豆、豌豆、白芸豆、白豇豆、鹰嘴豆为原料,提取其淀粉,并制备及测定几种豆类淀粉凝胶的特性(凝胶强度及硬度、弹性、黏性等),比较分析各种豆类淀粉特性的差异。结果表明,不同淀粉浓度下,均以豌豆淀粉的凝胶强度最大,白豇豆淀粉的最小;5种淀粉的TPA质构结果显示,白芸豆淀粉凝胶在高浓度下(8%和10%)具有较大的硬度、弹性、咀嚼性和回复性;豌豆淀粉在中等浓度下具有较高的硬度、弹性、咀嚼性,但其回复性在3个浓度下均是最小的;白豇豆淀粉凝胶的硬度和咀嚼性小于其他4种豆类淀粉,但其弹性和回复性却较大;5种豆类淀粉中,豌豆淀粉的凝胶强度和TPA质构特性受浓度的影响最大,且适合在中等浓度(8%)下制作凝胶制品。相关性分析发现,豆类淀粉的凝胶强度与直链淀粉含量呈极显著正相关,而黏聚性呈极显著负相关,而其他质构参数与直链淀粉含量的关系因浓度不同而呈现差异。     

Response surface methodology study on the optimisation of effects of fat,wheat bran and salt on chemical,textural and sensory properties of patties

A three-factor Box-Behnken design was adopted for studying the simultaneous effects of processing variables such as fat (10–30%), wheat bran (5–15%) and NaCl (0–2%) on physicochemical, textural and sensory properties of cooked beef patties. In addition, the ridge analysis was conducted to find the values of processing variables that maximise and minimise the texture profile analysis (TPA) parameters (hardness, chewiness, gumminess, adhesiveness, springiness, resilience and cohesiveness) and sensory ratings. Experimental design allowed for evaluation of potential interactive and quadratic effects between these variables; fat wheat bran and NaCl. It was found that protein and fat contents of patties was decreased and increased, respectively as the amount of wheat bran increased. NaCl increased the ash content of patties. Fat and wheat bran had a notable influence on textural properties, which improved the textural properties at certain levels. Lower addition of wheat bran and NaCl into patty resulted in higher acceptable product with respect to firmness, juiciness and overall quality properties.     

不同粮食用量糟醅的质构特性和理化参数相关性研究

将不同比例粮粉添加到母糟中进行窖外模拟发酵,分析了发酵期间糟醅的酸度、水分、淀粉浓度等理化参数,通过物性测试仪对糟醅在发酵期间的硬度、弹性、粘着性、内聚性和回复性进行了检测,并分析了糟醅理化性质和质构特性的相关性。结果表明:不同粮食含量糟醅在发酵期间的质构特性差异显著(P<0.05),糟醅的初始粮粉含量越高,糟醅的硬度、弹性、内聚性和回复性呈减小的趋势,而粘着性呈现显著增大的的趋势;随着发酵时间的延长,糟醅的硬度、内聚性呈明显的增大的趋势,而黏着性呈减小的趋势,弹性和回复性的变化不规律。理化参数方面,发酵期间糟醅的水分和酸度均增大,淀粉浓度降低。通过相关性分析糟醅的水分和酸度与硬度、内聚性呈显著正相关(P<0.01),与粘着性呈显著负相关(P<0.01),而糟醅的淀粉浓度与硬度和内聚性呈显著负相关(P<0.01),与粘着性呈显著正相关(P<0.01),与弹性和回复性无明显的相关性,决定糟醅理化参数的主要质构特性是硬度、内聚性和粘着性。     

Response surface methodology study on the optimisation of effects of fat, wheat bran and salt on chemical, textural and sensory properties of patties

A three-factor Box-Behnken design was adopted for studying the simultaneous effects of processing variables such as fat (10–30%), wheat bran (5–15%) and NaCl (0–2%) on physicochemical, textural and sensory properties of cooked beef patties. In addition, the ridge analysis was conducted to find the values of processing variables that maximise and minimise the texture profile analysis (TPA) parameters (hardness, chewiness, gumminess, adhesiveness, springiness, resilience and cohesiveness) and sensory ratings. Experimental design allowed for evaluation of potential interactive and quadratic effects between these variables; fat wheat bran and NaCl. It was found that protein and fat contents of patties was decreased and increased, respectively as the amount of wheat bran increased. NaCl increased the ash content of patties. Fat and wheat bran had a notable influence on textural properties, which improved the textural properties at certain levels. Lower addition of wheat bran and NaCl into patty resulted in higher acceptable product with respect to firmness, juiciness and overall quality properties.     

Combined effects of inulin,pectin and guar gum on the quality and stability of partially baked frozen bread

Many attempts have been made to increase the nutritional value of bread by adding dietary fibre. However, fibre enrichment is usually associated with various technological problems. The aim of this study was to optimise the composition of a blend of inulin, pectin and guar gum to enrich the fibre content of partially baked frozen bread without impairing its technological quality. We prepared 20 formulations following a central composite design, together with 4 control breads. Bread enriched with inulin had higher crumb hardness, lower specific volume, shape, moisture content, and crumb cohesiveness than control bread, but improved flavour. Pectin and guar improved moisture content and crumb cohesiveness. There was no interaction between inulin and pectin for any of the bread attributes investigated, while interactions between inulin and guar were small. In contrast, guar and pectin significantly interacted to decrease volume and increase crumb hardness and chewiness. A desirability function method identified the optimised blend as containing 3% inulin, 0.9–1% pectin and 0.3–0.4% guar. Bread enriched with such blend had the following characteristics: specific volume, 4.06 cm³/g; shape, 0.63; crumb hardness, 189 g; resilience, 0.36; cohesiveness, 0.84; chewiness, 169 g; and flavour score, 4.6. Experimental values were close to the predicted ones, with prediction errors below 10% for all attributes tested. The specific volume, crumb hardness and chewiness of the enriched bread were superior to those of unenriched bread. However, undesirable textural changes occurred in the enriched bread during 12 weeks of frozen storage, and these changes strongly depended on the fibre blend composition.     

THE INFLUENCE OF FAT, ACID, AND SALT ON THE PERCEPTION OF SELECTED TASTE AND TEXTURE ATTRIBUTES OF CHEESE ANALOGS: A SCALAR STUDY

Twelve cheese analogs varying in amounts of fat (10 17.5, and 25%), sodium chloride (0.5 and 2.0%), and citric acid (0.1 and 1.2%) were prepared to determine the influence of the three constituents on taste and texture perception, as well as on the rheological behavior of the analogs. Sourness, saltiness, springiness, firmness, cohesiveness, and adhesiveness were rated by trained judges on a graphic scale. The Instron Universal Testing Machine was used for the rheological studies. Increasing the salt content in the cheese analogs resulted in an increased saltiness and sourness intensity and a decreased pH. Increasing the acid or salt content caused a significant decrease in cohesiveness and springiness and an increase in firmness. A higher fat content resulted in a softer, less springy, more cohesive and adhesive cheese analog.     

暂养环境因子对斑点叉尾鮰肌肉理化性质与质构特性的影响

以斑点叉尾鮰（Ictalurus punctatus）为研究对象，通过控制暂养温度（12、16、20、24 ℃）、氨氮质量浓度（0、5、10、20 mg/L）和暂养密度（1∶2、1∶3、1∶4、1∶5，m/V），考察不同环境因子对斑点叉尾鮰肌肉理化特性（水分含量、pH值和持水力）与质构特性的影响。结果表明：暂养温度24 ℃组鱼肉的水分含量与持水力显著低于其他温度组（P＜0.05）；12 ℃组鱼肉的水分含量、pH值和持水力较稳定，且肌肉弹性和咀嚼性显著高于其他温度组（P＜0.05）；水体氨氮质量浓度为0 mg/L时，鱼肉pH值稳定在7.12～7.15，持水力稳定在65%左右，随着暂养时间的延长，该组鱼肉硬度显著下降（P＜0.05），弹性和咀嚼性有所上升，回复性与凝聚性维持在稳定水平；暂养密度不低于1∶4（m/V）时，鮰鱼肌肉水分含量和持水力均随暂养密度的下降而显著上升（P＜0.05）；在整个暂养期间，1∶4（m/V）组鱼肉弹性大部分显著高于其他密度组（P＜0.05），且其鱼肉弹性和咀嚼性随着暂养时间的延长呈上升趋势，回复性和凝聚性随着暂养时间的延长呈下降趋势，而肌肉硬度与黏性无显著变化。综上，温度12 ℃、氨氮质量浓度0 mg/L、暂养密度1∶4（m/V）的暂养环境较有利于维持和提高斑点叉尾鮰肌肉品质。     

Effect of cellulose-derivatives and emulsifiers on creep-recovery and crumb properties of gluten-free bread prepared from sorghum and gelatinised cassava starch

The effect of cellulose-derivatives and emulsifiers on the creep-recovery behaviour of gluten-free dough prepared from gelatinised cassava starch and sorghum was studied. Cellulose treated doughs, except the treatment with 2.4% w/w fwb CMC, had lower resistances to deformation (range 10–33%) than emulsifier-treated doughs (range 3–13%). The higher elastic recovery of emulsifier-treated doughs corresponded to lower compliances and higher zero shear viscosities than for doughs treated with cellulose-derivatives. Addition of egg white powder (6.7% w/w fwb) eliminated several textural defects associated with gluten-free bread. Cellulose-derivatives did not decrease crumb firmness or staling rate when compared to the control. Though increasing emulsifier concentration (from 0.4% to 2.4% w/w fwb) decreased crumb firmness, crumbs treated with 2.4% w/w fwb emulsifiers, except diacetyl tartaric acid esters of mono- and diglycerides, were weak and difficult to handle after slicing. Nevertheless, all gluten-free breads treated with 2.4% w/w fwb emulsifiers staled at a slower rate than the control.     

基于质地多面分析法对不同苹果品种果肉质构特性的分析

为了细致研究"华红"苹果贮藏期间果肉质地变化和不同苹果品种质构特性差异,本实验以套袋和未套袋"华红"苹果为试材,应用质地多面分析法定期测定贮藏期间果肉质地参数;以及以不同熟期"华红"、"华苹"、"寒富"、"红星"、"嘎拉"、"津轻"为试材,比较不同苹果品种果肉质地品质差异,同时分析各质地参数之间相关性。"华红"套袋和未套袋果肉质地参数在常温贮藏过程中变化趋势基本一致,且未套袋果肉的各项质地参数稍高于套袋的。硬度呈下降趋势,在黏附性、内聚性、弹性、咀嚼性、回复性方面,贮藏0 d的果实与48 d相比稍有升高。"华红"果肉贮藏期间质地参数变化相关性和6个苹果品种之间质地参数相关性有相似处,内聚性与弹性、回复性、咀嚼性都呈正相关,弹性与回复性、咀嚼性都呈较好地正相关,回复性与咀嚼性呈较好的正相关。不同的是,"华红"果肉硬度与黏附性、内聚性呈负相关,而不同品种之间果肉硬度与内聚性、弹性、回复性、咀嚼性呈高度正相关。不同品种之间各质地参数也进行了量化比较。综上说明本实验选用的P5探头测定的果肉内聚性、弹性、回复性、咀嚼性能反映"华红"果肉质地变化规律,适用于苹果果肉质地品质的客观评价。硬度、内聚性、弹性、回复性、咀嚼性质地参数中的一项或多项可以作为评价"华红"果肉质地和比较这6个苹果品种果肉质地差异性的重要参数。     

木薯淀粉对栉孔扇贝闭壳肌凝胶特性的改善作用

为了解决扇贝产品单一,精深加工比例低的问题,以栉孔扇贝闭壳肌为研究对象,对其营养成分进行了测定,并研究了不同添加量的木薯淀粉对扇贝肉糜凝胶强度、质构特性、持水性、白度、蛋白组成及微观结构的影响。结果表明,栉孔扇贝闭壳肌中水分、粗蛋白、粗脂肪和灰分质量分数分别为82.15%、16.23%、2.05%和1.24%,除色氨酸外,16种水解氨基酸的总量为13.204%。随着木薯淀粉添加量的增加,扇贝闭壳肌肉糜的凝胶强度、持水性、硬度和咀嚼度呈现先升高后降低的趋势,但对其弹性、黏聚性和白度没有显著性影响。电泳图谱结果表明,添加质量分数为1%的木薯淀粉,贝糜凝胶蛋白中肌球蛋白重链的条带最窄,说明淀粉可促进贝糜蛋白的交联;光学显微镜和扫描电镜结果表明,木薯淀粉添加量为1%或2%时,贝糜凝胶的网络结构更为致密,孔洞更小。本研究表明,栉孔扇贝是一种高蛋白的水产资源,可用来生产贝肉糜凝胶,且1%的木薯淀粉添加量对贝糜凝胶品质具有较好的改善作用。希望本研究能为扇贝精深加工提供一定的理论依据。