Improving Carob Flour Performance for Making Gluten-Free Breads by Particle Size Fractionation and Jet Milling

Many different raw materials have been proposed for producing nutritious gluten-free breads, but rarely, there is a parallel analysis of the effect of physical treatment on those ingredients. The aim of this study was to incorporate carob flour fractions of varying particle size on rice gluten-free breads prepared with carob/rice (15:85) flour blends. Carob flour particle size was controlled by fractionation or jet milling application. Quality features of gluten-free breads containing carob flour and commercially available gluten-free breads were compared. Carob flour addition led to breads with improved colour parameters, crumb structure, retarded firming and lower moisture loss compared to rice bread. Further improvement in specific volume, crumb hardness, protein and ash content and estimated glycaemic index (eGI) could be obtained by a careful selection of the particle size distribution of the carob flour. Carob breads prepared either with the coarsest or the finest fraction prepared using jet milling led to end products with the highest specific volume (≈2.2 g/cm³) and the lowest crumb hardness (≈5.5 N), although they had lower specific volume and harder crumbs than breads from commercial blends (≈3–4 g/cm³, 0.6–3.8 N). Nevertheless, rice-based bread made with the finest carob flour was superior considering its slower firming, protein content and lower eGI. The incorporation of carob flour obtained by jet milling in rice-based gluten-free breads led to end products with quality characteristics and sensory acceptance resembling commercial breads and high nutritional value.     

大米发酵对米粉凝胶品质影响的研究

大米经发酵作用后会引起化学成分的变化。研究表明,大米在43℃条件下经12h发酵后,淀粉、蛋白质、脂肪、灰分含量都得到不同程度的降低。感官评价结果表明,采用发酵大米为原料制作米粉所得的产品的凝胶品质更好。     

Effect of Starch Substitution by Buckwheat Flour on Gluten-Free Bread Quality

The buckwheat flour was studied as a potential healthy ingredient for improving the nutritional and technological quality of gluten-free bread. The effect of exchange of gluten-free formulation mass by buckwheat flour in 10, 20, 30 and 40 % was investigated. The increase in loaf specific volume with rising buckwheat flour addition was observed. Compared with the control sample, decrease in whiteness and increase in redness and yellowness of crumb were noticed. The rising amount of buckwheat flour in gluten-free bread formulation caused a decrease in crumb hardness during storage. This was in agreement with the decrease in starch gelatinisation enthalpy with the increasing amount of buckwheat flour in gluten-free formula in comparison with the control sample. Buckwheat flour could be incorporated into gluten-free formula and have a positive influence on bread texture and delaying its staling.     

加工工艺对米粉凝胶品质影响的研究

阐述了加工工艺对米粉凝胶品质的影响,采用正交试验方法研究了粉坯含水量、温度、时间等工艺条件对米粉凝胶品质的影响。试验结果表明,粉坯含水量55％,时间30min,温度20℃是形成米粉良好凝胶品质的最佳方案。     

Effect of Different Extrusion Treatments and Particle Size Distribution on the Physicochemical Properties of Rice Flour

Rice flour is an interesting alternative for developing gluten free products, but its features do not always meet the process requirements. The objective of this study was to modify the functional properties of rice flour by combining extrusion and size fractionation. Different extrusion conditions (barrel temperature, feed moisture content and feed rate) were applied to vary the severity of the treatment on the flour constituents. Extrusion and mechanical fractionation of the rice flours modified their behavior affecting hydration, thermal and pasting features, besides their susceptibility to enzymatic hydrolysis. Specifically, onset and peak temperature increased and gelatinization enthalpy decreased when increasing barrel temperature of the extrusion. Fine flours with stronger extrusion (high temperature barrel) showed the highest susceptibility to enzymatic hydrolysis. Overall, the combination of both physical treatments maybe an attractive alternative for obtaining clean label rice flours with modified features.     

小麦粉粒度研究综述

小麦粉粒度是小麦粉的一个重要物理参数,它对小麦粉以及面制食品的品质产生很大的影响。小麦粉粒度的分布与小麦的品质和研磨方法有关。当小麦粉粒度变化时,小麦粉的组成成分以及物理特性也会发生变化,从而对面制品的品质产生影响。阐述了小麦粉粒度、小麦粉粒度分布以及当小麦粉粒度变化时,小麦粉的组成成分的变化等几个方面内容,同时介绍了小麦粉粒度的测定方法、小麦粉粒度在小麦硬度研究方面的应用和小麦粉粒度对面制品品质的影响。     

Impact of Legume Flours on Quality and In Vitro Digestibility of Starch and Protein from Gluten-Free Cakes

The aim of the study was to investigate the impact of incorporation of different legumes (chickpea, pea, lentil and bean) on quality, chemical composition and in vitro protein and starch digestibility of gluten-free layer cake (rice flour/legume flour, 50:50). The incorporation of legume flours increased the batter viscosity and, with exception of chickpea, resulted in higher specific cake volume than that in control. Chickpea and pea containing cakes had the brightest and the most yellowish crust. The legumes significantly increased the hardness and chewiness in the cakes, except with addition of lentil. Enriched cakes had higher total protein, available proteins, minerals, fat, as well as fiber content with except in the case of chickpeas. Legumes significantly affect the in vitro hydrolysis of starch fractions, decreasing the rapidly digestible starch yielding a reduction in the eGI, except chickpea containing samples. Overall, considering physicochemical properties and nutritional quality, lentil flour incorporation resulting in the best gluten-free cakes.     

Monitoring the Effects of Ingredients and Baking Methods on Quality of Gluten-Free Cakes by Time-Domain (TD) NMR Relaxometry

Gluten-free products exhibit some undesirable features due to the absence of the gluten network. Effects of ingredient interactions and baking type on the food matrix have not clearly been explored. The objective of this study was to investigate the effect of ingredient and baking types on the quality characteristics of cake by using nuclear magnetic resonance (NMR) relaxometry. Carob bean flour containing gluten-free cakes formulated either with hydroxypropyl methylcellulose (HPMC) or whey protein were baked in both conventional and microwave–infrared combination ovens. Specific gravity of batters was measured and cakes were analyzed in terms of weight loss, hardness, and specific volume. Microstructure of cakes was investigated by scanning electron microscopy (SEM). NMR relaxometry was used to support the information about water retention, and water–food matrix interactions. Cakes baked in microwave–infrared (MW-IR) combination oven had some undesirable characteristics due to higher weight loss and insufficient gelatinization of starch which was supported by SEM results. Compartments of relaxation data also indicated two specific proton pools for MW-IR-baked samples, which represented gelatinized and ungelatinized parts of the cakes. Spin–spin relaxation times (T₂) were found to be good indicators for explaining the physical state and distribution of water inside the samples, having Pearson correlation of 0.96, 0.86, and ??0.98 (p?<?0.05) between monoexponential T₂ values and hardness, specific volume, and moisture, respectively.     

不同实验磨研磨的小麦粉的粒度分布

采用4种不同型号的实验磨研磨不同硬度的小麦,通过激光粒度仪测试小麦粉的粒度。结果表明,不同小麦粉的粒度差异较大,尤其是细小粉粒的分布很不均衡。采用光辊心磨的实验磨磨制的小麦粉,其细粉比例高于齿辊实验磨,但低于生产线小麦粉的细粉比例。小麦硬度越高其细粉比例越低。     

小麦粉粒度变化与淀粉损伤程度

从小麦淀粉的原生态(粒径大小与分布)出发,首先拿等级粉的粗细度与之比较,分辨淀粉损伤的综合程度和倾向,进而对工艺中各研磨部位的面粉粒度、淀粉损伤程度进行分析研讨,以化验的量化结果,揭示淀粉损伤的真实面貌。紧紧抓住面粉粒度变化和淀粉损伤程度的同步因素,逐渐深入,诠释不被重视的等级粉淀粉损伤原因和专用粉能适应不同面制品要求的理论基础,提出了研究淀粉损伤和面粉粒度是制粉工艺研究的当务之急。     

Influence of Buckwheat Flour and Carboxymethyl Cellulose on Rheological Behaviour and Baking Performance of Gluten-Free Cookie Dough

In the present study, the influence of buckwheat flour and carboxymethyl cellulose (CMC) on the production of sheetable gluten-free cookie dough of acceptable rheological properties and subsequently their effect on the quality of gluten-free cookies was studied. The buckwheat flour was used to replace 10, 20 and 30 % of rice flour in gluten-free formulations. Cookie doughs of 100 % rice flour and 100 % wheat flour served as control samples. The impact of CMC addition was examined on formulation containing 20 % of buckwheat flour. Oscillatory and creep measurements were applied to test the effect of buckwheat flour and CMC on the viscoelasticity of gluten-free cookie dough. Frequency sweep results showed that all samples had solid elastic-like characteristics. An increase in the buckwheat flour addition led to a decrease in storage modulus and zero shear viscosity and an increase in tan δ and maximum creep compliance, while the addition of CMC led to an increase in dough tenacity and resistance to deformation. Cookie dough containing 30 % of buckwheat flour expressed the highest viscous properties, as revealed by relative viscous compliance value. The gluten-free dough containing CMC and buckwheat flour between 20 and 30 % replacement level showed similar strength and extensibility as wheat cookie dough. The results of the physical and sensory evaluation of gluten-free cookies showed that buckwheat addition led to a decrease in cookie hardness and fracturability and an increase in eccentricity (deformation from regular shape) as well as the overall acceptability, as evaluated by untrained panellists.     

添加挤压米糠粉对面包粉流变学特性影响的研究

米糠中含有多种营养成分,对人体具有重要的营养及保健功能,但其会影响食品的品质,需改性加工后方可适量添加到食品中。将挤压改性加工后的米糠粉以不同比例添加到面包粉中形成混合粉,并测试了混合粉的粉质及拉伸特性,以探讨米糠对面包粉品质的影响。结果表明:米糠的添加对面包粉的品质具有一定程度的影响,添加量越高影响越大,并通过米糠面包的物性测试对上述结果进行了验证,最终确定了适宜制作面包的挤压米糠粉添加量为15%。     

Effect of Carob Flour Addition on the Rheological Properties of Gluten-Free Breads

In this study, the rheological properties of gluten-free doughs from rice flour containing different amounts of carob flour were investigated. Water added changed in response to the carob amount. Dynamic oscillatory and creep tests were performed in order to gain knowledge on the rheological behaviour of doughs, which is essential for the control of the bread-making procedure and the production of high-quality bread. Simple power law mathematical models were developed in order to evaluate the effect of carob and water added in dough rheological behaviour. Creep data evaluation demonstrates that an increase in water content decreased the resistance of dough to deformation and, therefore, dough strength, whereas carob flour increased the elastic character and structure strength of the dough. This was also found in dynamic oscillatory tests. Increased amounts of carob flour led to an increase in bread dough elastic character since fibre addition elastifies and strengthens the dough structure. Moreover, doughs exhibited a solid-like viscoelastic character, with the storage modulus (G′) predominant over the loss modulus (G″). Dough rheological properties have an important effect on baking characteristics. Rheological experiments and applied mathematical models can provide us with good knowledge of rheological behaviour and dough viscoelasticity prediction. Therefore, dough samples containing carob-to-water ratios of 10:110 and 15:130 can be considered to possess a balance between the viscous and elastic properties compared to the other samples.     

Particle Size Fractionation of High-Amylose Rice (Goami 2) Flour as an Oil Barrier in a Batter-Coated Fried System

The particle size effects of high-amylose rice (Goami 2) flour on quality attributes of frying batters were characterized in terms of physicochemical, rheological, and oil-resisting properties. High-amylose rice flours were fractionated into four fractions (70, 198, 256, and 415 μm) of which morphology was also analyzed by scanning electron microscopy. Rice flour with smaller particle size exhibited a higher degree of starch gelatinization, giving rise to increased pasting parameters. When the rice flours were incorporated into frying batters, higher steady shear viscosity was observed in the batters with finer rice flour, which could be well characterized by the power law model. In addition, the dynamic viscoelastic properties of the batters were enhanced by the use of rice flour with smaller particle size, which also caused an increase in batter pickup. When subjected to deep fat frying, the batters with finer rice flour exhibited reduced moisture loss. Furthermore, the oil uptake was found to have a positive correlation with the particle size of rice flour (R ²?=?0.88), even showing the reduction of oil uptake by 15%. It could be synergistically attributed to the formation of outer starch granular layers, high batter viscosity/pickup, and reduced moisture loss by finer rice flour.     

Maize-Based Gluten-Free Bread: Influence of Processing Parameters on Sensory and Instrumental Quality

The performance of maize bread with spongy texture is still a technological challenge due to the absence of a natural network required for holding the carbon dioxide released during the fermentation process. The objective of this research was to investigate the influence of different maize varieties (regional and hybrid), milling process (electric and water mill), formulation and processing variables on the sensory and instrumental (specific volume, texture and colour) quality attributes of corn bread. For that purpose, the traditional breadmaking process applied to the development of the ethnic Portuguese bread (broa) obtained from composite maize–rye–wheat flour was modified to produce gluten-free broa. Significant differences (P < 0.05) between regional and hybrid maize were detected in terms of protein, amylose, and maximum, minimum and final viscosities as evaluated by Rapid Visco Analyser. Concerning the effect of milling process, the grinding in a water mill occurs at slower rate than it does in the electrical mill, in consequence the flour from water milling had lower ash content and higher maximum, minimum and final viscosities than the one obtained from electrical milling. An important point in the breadmaking process was the flour blanching that resulted in doughs with higher consistency, adhesiveness, springiness and stickiness as measured by texture analyser, due to the partial gelatinisation of the corn starch. Baking assays demonstrated sensory preference for regional in detriment of hybrid maize varieties for traditional broa production. Breadmaking technology could be satisfactorily applied to produce gluten-free broa.     

浅析清粉机筛船质量对走粉性能的影响

论述了清粉机筛船质量ｍ对其走粉性能的影响,提出了理论根据及解决措施。     

面粉品质参数对面制品品质的影响

作为面制品制作的基础原料,面粉具有不同的理化指标,这些指标的变化对面制品的品质有不同程度的影响。通过对面粉常规品质参数以及不同参数对面制品(如馒头、面条和面包等)影响的分析,对面粉品质和专用粉生产提供一定的参考,以制作优质的面粉来满足生产的需要。     

麦麸添加量和粒度对小麦淀粉糊化特性的影响

以强筋和中筋小麦粉为试验材料,添加2个强筋小麦和2个中筋小麦麸皮,并采用5个添加量(5%,10%,15%,20%,25%)、4个粒度(0.16～0.43 mm,0.43～1.0 mm,1.5～2 mm,2.5～3.0 mm)处理,分析麦麸添加量、粒度对小麦粉糊化特性的影响。随着麦麸添加量的增加,峰值黏度、低谷黏度、最终黏度、黏度面积、反弹值和峰值时间都呈现显著下降趋势,而淀粉糊化起始时间和糊化温度均呈现的Y=AX2-BX+C二次曲线增加趋势。峰值黏度、低谷黏度、最终黏度、黏度面积、反弹值平均值随着麸皮粒度的增大,均呈现升高趋势,而麦麸粒度对糊化温度和糊化起始时间没有影响。中筋小麦麸皮粒度在0.16～2 mm之间对峰值黏度和黏度面积的影响没有显著的差异,而超过1.5 mm的强筋小麦麸皮粒度对峰值黏度、低谷黏度、最终黏度和黏度面积的影响差异显著;小于2 mm的麸皮粒度对稀懈值的影响差异不显著,小于1 mm的麸皮粒度对反弹值的影响差异不显著。     

Production and Size Distribution of Rice Maitodextrins Hydrolyzed from Milled Rice Flour using Heat-Stable Alpha-Amylase

Maltodextrins were produced from milled rice flour in a single-step process using a heat-stable α-amylase preparation. The starting solids content was 30% (w/w), and processing temperatures and times were varied between 70–97°C and 15–75 min, respectively. Optimum liquefied starch yields, which accounted for virtually all of the starch present, were obtained at temperatures of 80°C and above, but reducing sugars and DE values were highest at 70°C. Low molecular weight saccharide concentrations (DP 1–10) were greatest at 80°C. Because processing at temperatures of 90–97°C resulted in decreased levels of reducing sugars and DP 1–10 concentrations without providing a substantial increase in solubilized starch yields, it was concluded that rice maltodextrins could be most effectively produced at a processing temperature of 80°C.