不同粒径小米粉对面团流变特性及馒头质构特性的影响

为研究小米粉添加对面团流变特性和馒头制品质构特性的影响,分别选取不同粒径的粳性和糯性小米粉,利用损伤淀粉测定仪、快速黏度分析仪等对不同小米粉的损伤淀粉含量和糊化特性进行分析,通过流变仪测定小米面团的流变学特性,结合扫描电镜观察小米面团微观结构变化,并利用质构仪测定小米馒头的质构特性。结果表明：随着小米粉粒径的减小,多数品种小米粉（除冀谷39和汇华金米）损伤淀粉的碘吸收率增加;受直支比的影响,相同目数下,粳性小米粉的峰值黏度、谷值黏度、最终黏度和回生值较糯性小米粉大。流变学研究表明,除汇华金米和冀谷39,储能模量与损耗模量随角频率增加总体上升。扫描电镜观察发现小米粉的添加使面团结构更加松散。小米粉的添加会对馒头质构性质中硬度、咀嚼性和弹性等有一定程度的负面影响。主成分分析表明馒头咀嚼性、损伤淀粉、峰值黏度、谷值黏度、最终黏度、崩解值和回生值可作为区分粳糯品种和馒头品质特征的指标。     

Effect of dry- and wet-milled rice flours on the quality attributes of gluten-free dough and noodles

The rheological and cooking properties of gluten-free noodles prepared with dry- and wet-milled rice flours were characterized. Dry-milled rice flour with a higher degree of starch damage exhibited greater water hydration properties than wet-milled rice flour at room temperature. However, the pasting results of rice flour suspensions demonstrated that wet-milled rice flour showed a higher value of peak viscosity due to its great swelling power upon starch gelatinization. The similar thermo-mechanical tendency was observed in a rice dough system by Mixolab. In the planar extensional test, the noodle dough sample prepared with dry-milled rice flour exhibited higher elongational viscosity which could be favorably correlated to more resistance of dry-milled rice noodle strands to extension. When rice noodles were cooked, increased cooking loss was observed in dry-milled rice noodles which was attributed to great water solubility derived from a higher degree of starch damage.     

Physicochemical,antioxidant properties and in vitro digestibility of wheat–purple rice flour mixtures

The physicochemical characteristics, antioxidant properties and in vitro digestibility of high‐antioxidant content flours made from different combinations of Thai purple rice flour and refined wheat flour from 25%, 50% to 75% (w/w) were investigated and these were compared with whole flour from purple rice and refined wheat flour. The increase in substitution levels of purple rice flour affected all the functional properties of flours, at the same time the levels of dietary fibre, protein digestibility and antioxidant compositions were also changed. The purple rice flour exerted a particularly strong effect on starch digestibility as the purple rice increased to 50% in the mixture. Moreover, purple rice flour showed lower amounts of rapidly digested starch (RDS), whereas slowly digested starch (SDS) of whole flour from purple rice and 75% substitution purple rice flour was found to be the highest for all samples. The in vitro starch digestibility of all samples also showed a positive correlation between dietary fibre and antioxidant compounds. Overall, the addition of purple rice flour improved the final nutritional properties, notably a lower predicted glycaemic index, and a higher antioxidant potential, which are two important nutritional properties for human health.     

谷朊粉对糙米粉面团性质影响研究

研究了谷朊粉添加量对糙米粉面团性质的影响,主要包括粉质特性、热机械性质、流变学性质、微观结构等。结果表明:随着谷朊粉添加量增大,面团的吸水率、形成时间、稳定时间、淀粉衰减值和回生程度均在逐渐增长,蛋白弱化度在逐渐降低。糙米粉面团的弹性模量和粘性模量均在增大,且弹性模量大于粘性模量。扫描电镜结果显示:随着谷朊粉添加量增大,面团的网络结构越来越明显,淀粉颗粒镶嵌在蛋白形成的网络结构中,增加了面团的弹性及变形的阻力。     

用Mixolab分析马铃薯生全粉的流变学特性

采用Mixolab通过对热-机械性能的分析研究了马铃薯生全粉的流变学特性。以11个马铃薯生全粉为实验材料,探讨Mixolab检测马铃薯生全粉流变学特性的重复性,结果显示:各样品的2次测试曲线的重合度高,全曲线的平均变异系数小于5%;通过对比B01~B10这10个不同样品检测结果,可以看到不同马铃薯栽培品种流变学特性存在较大的差异,具体表现在面团形成、面团稳定、淀粉糊化和回生各阶段检测指标上的差异;通过对比B06和B10两个采用不同研磨方式制备的样品,发现不同马铃薯生全粉制作的研磨工艺将极大的影响样品的吸水率、各粘度指标,但对马铃薯生全粉面团的弱化后稠度(Cs和C2)影响不大;通过对比马铃薯生全粉、雪花粉和标准面粉的热-机械能能曲线,发现雪花粉在马铃薯主食化产品开发中所起到的作用主要为填充剂。马铃薯生全粉具有良好的加工性能,流变学特性还可以通过食品添加剂进一步改善,制造出无需添加小麦面粉的纯马铃薯主食化产品馒头、面条和面包是可能的。     

Effect of the shape of rice starch granules on flour characteristics and gluten‐free bread quality

The effect of three different rice varieties with different starch shapes (Seolgaeng (SG), round starch structure; Samkwang (SK), polygonal starch structure and Boramchan (BRC), polygonal starch structure) on rice flour characteristics and gluten‐free bread baking quality was investigated. Rice flours were produced by dry milling and passed through a 200 mesh sieve. Electron microscopy revealed that the structure of SG grains, with round starch granules, possessed larger void spaces than SK and BRC, composed of polygonal starch granules. For this reason, SG grain had low grain hardness and consequently, it was milled to a fine flour with low damaged starch content. The thermo‐mechanical properties were determined by Mixolab, which revealed that SG was gelatinised rapidly and maintained high viscosity after gelatinisation. These characteristics gave SG flour the ability to build up bread structure without gluten. Specific volume and crumb hardness of gluten‐free rice breads made of SG, SK and BRC flours were 3.37, 3.11 and 2.12 mL g^?1 and 2.61, 2.76 and 6.46 N, respectively. The SG flour with round starch structure is appropriate for making gluten‐free rice breads.     

The effects of extruded black rice flour on rheological and structural properties of wheat-based dough and bread quality

Addition of raw black rice flour leads to deficient processability on bread making quality. One of the effective methods to modify the functional properties of black rice flour (BRF) composite dough is to extrude black rice flour (EBRF) before incorporation. This study investigated and compared the effect of BRF and EBRF addition level of 10%–50% on the rheology, microstructure of dough and bread quality. The rheological properties of composite dough were recorded by Mixolab, stress relaxation and tensile test. The substitution of EBRF presented higher water absorption but lower development time, protein weakening, starch gelatinization, starch gel stability and starch retrogradation than wheat flour dough. Both the BRF and EBRF dough presented solid-like behaviour, while the EBRF dough showed more viscous, higher resistance and extensibility than BRF dough. The dough microstructure of dough was observed by SEM, and a more compact structure of EBRF dough could be seen than BRF dough. The incorporation of EBRF in bread quality presented higher specific volume, lower bake loss and firmness than BRF bread. These findings indicated the potential utilisation value of extruded black rice flour in bread making.     

糜米粉对面团特性及面包品质的影响

为研究糜米粉对面团特性及面包品质的影响,探究了糜米粉添加量(0、10%、20%、30%、40%和50%)对面团的微观结构、拉伸特性、动态流变学特性以及面包品质的影响。结果表明:随着糜米粉添加量的增加,面团的面筋网络出现了断层结构。添加糜米粉使得面团的拉伸强度和拉伸距离均呈下降趋势,面团的弹性模量和黏性模量均呈上升趋势。糜米粉的添加明显增加了面包的硬度和咀嚼度,降低了面包的弹性、粘聚性、回复性、比容和感官评分。因此,糜米粉的添加改变了小麦面团的特性和面包的品质,其添加量不宜超过30%。     

挤压膨化紫薯粉对小麦面团糊化特性和热机械学特性的影响

挤压膨化技术是一种高温、短时的加工方法,可以改变紫薯粉的特性,从而提高复合面团的品质。因此,本实验对紫薯粉进行挤压膨化,对比研究挤压膨化紫薯粉和紫薯生粉对小麦面团水分分布、糊化特性及热机械学特性的影响。结果发现,与紫薯生粉相比,挤压膨化紫薯粉显著缩短了横向弛豫时间T21（P＜0.05）,表明挤压膨化能够使水分与淀粉或面筋蛋白紧密结合;此外,与小麦粉相比,添加紫薯粉显著降低了面团的峰值黏度、谷值黏度、终点黏度、崩解值和回生值（P＜0.05）,尤其是挤压膨化紫薯粉。热机械学特性结果表明挤压膨化紫薯粉能够显著提高面团的吸水率、酶解速率和蒸煮稳定性（P＜0.05）,缩短面团形成时间,降低回生值和峰值扭矩（P＜0.05）。挤压膨化紫薯粉的添加不仅可以提高面制品的出品率,也有助于延缓面团的老化,延长保质期。本研究为挤压膨化紫薯粉在面制品中的应用提供了一定的理论依据。     

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.     

Comparative Study on Functional,Rheological, Thermal,and Morphological Properties of Native and Modified Cereal Flours

Effect of extrusion on the functional, rheological, thermal, and morphological properties of the modified cereal flours from different cereals was assessed. Rice flour, wheat flour, and flour, in combination (rice: wheat, 50:50) were passed through twin screw extruder to obtain modified cereal flours at variable conditions (barrel temperature: 175 and 190°C, feed moisture: 14 and 16% and screw speed: 500 rpm). Functional properties (water absorption index, water solubility index, swelling index, and viscosity) improved in modified cereal flours as compared to the unmodified flours. Modified flours showed lower paste viscosity as compared to unmodified flours, which was a desirable property for modified flours to be utilized as a functionality ingredient in food products. Processed flours recorded higher onset (T_o), peak (T_p), and endset (T_e) temperature and showed higher enthalpy change (?H) than the raw cereal flours. Degree of gelatinization was higher in flours processed at higher barrel temperature and feed moisture. The morphological pattern of modified flours was determined by scanning electron microscopy. The starch surface of cereal flours (modified and unmodified) differed from each other with respect to their morphological pattern.     

小麦面粉的3D打印特性

本实验以8种不同蛋白质量分数小麦面粉为研究对象,通过测定其理化特性、糊化特性、混合特性、流变特性及3D打印特性,研究小麦面粉不同品质特性与3D打印特性的关系。结果显示,蛋白质量分数对小麦面粉的3D打印特性有显著影响,蛋白质量分数在9%～10%时（ZY原味小麦粉、BN 4199小麦粉和XL中式面点粉）打印效果较好,制品整体形状规则、表面平整、纹路清晰,与模型的符合程度较高。面团的损耗模量（G’’）影响其挤出行为,而储能模量（G’）影响其支撑三维结构的能力,ZY原味小麦粉面团的损耗角正切值（tan δ）较大,有利于面团挤出成型;XL中式面点粉G’较大,有利于面团打印后保持自身的形状。在选用的8种小麦面粉中,XL中式面点粉的蛋白质量分数为9.33%,与设计的30 mm×30 mm×10 mm模型相比,其打印体积误差仅为0.26%。打印制品蒸制熟化后在X轴和Y轴方向上长度略有增加,但Z轴方向上长度略有减小,且发生一定程度的褐变。综上,小麦面粉作为3D打印材料是可行的,这有利于拓展3D打印技术在食品领域的应用。     

球磨改性对小米全粉理化特性及其面条品质特性的影响

小米兼具营养价值与药用价值,为提高小米的附加值和小米面条的加工品质,本实验利用球磨技术对小米全粉进行改性处理,探究不同球磨处理时间（0.5、1、2、4、6、8 h）对小米全粉营养成分、水合特性、糊化特性、流变特性、结晶结构及面条品质的影响,并分析部分理化性质与面条品质的相关性。结果表明,随着球磨时间延长,小米全粉的结晶结构破坏较明显,损伤淀粉质量分数显著增加,直链淀粉质量分数不断减少（除8 h外）,面粉亮度由77.27升至81.37。同时,球磨处理使小米全粉峰值黏度、谷值黏度和最终黏度均显著上升（P＜0.05）,分别由1 478、665 Pa·s和1 384 Pa·s提升至3 271（球磨1 h）、982 Pa·s（球磨2 h）和2 199 Pa·s（球磨2 h）,同时使水合特性（持水力、膨润力）显著提升（P＜0.05）。当球磨时间为4 h时,面团的凝胶网状结构愈发均匀致密,制作的小米面条质构、蒸煮品质均最佳。相关性分析结果表明,面条质构特性（弹性、胶黏性、咀嚼性）、感官品质（色泽、外观、黏性）与直链淀粉质量分数呈极显著负相关（P＜0.01）,与损伤淀粉和支链淀粉质量分数整体上呈极显著正相关（P＜0.01）。面条的蒸煮品质（断条率）与直链淀粉质量分数呈极显著正相关（P＜0.01）,与损伤淀粉和支链淀粉质量分数呈极显著负相关（P＜0.01）;且糊化黏度与面条品质相关性也较强。综合分析,球磨技术对小米全粉的改性处理可用于生产较高品质的小米面条。     

Improving Functional Properties of Rice Flours Through Phosphorylation

This research evaluated the chemical, technological, and thermal properties of rice flour modified chemically using phosphorus oxychloride (0.018; 0.030; 0.059; 0.088 and 0.100 g/100 g flour). The phosphorylated rice flours (PRF) obtained showed a decrease in viscosity, but the stability increased significantly as compared to the unmodified flour. The gel force and adhesiveness values decreased with the increase in phosphate groups incorporated. However, cohesiveness and thermal properties did not show significant differences among the native and modified rice flours, with exception for gelatinization enthalpy values. The phosphorylated flours obtained can be used as ingredient, especially in cream soups, salad dressing, and filling.     

Gluten‐free pasta: effect of green plantain flour addition and influence of starch modification on the functional properties and resistant starch content

Green plantain flour (GPF) is rich in indigestible carbohydrates, especially in resistant starch (RS). The objective of this study was to improve the functional pasta properties and RS content by producing gluten‐free (GF) pasta based on rice flour with different amounts of GPF addition (15–60% of total flour blend). Egg albumen (3.5–6.0% of total flour) and dough moisture (36–40%, dough humidity%), at constant emulsifier (0.5% of total flour) addition, were optimised in the first trials. The results showed that an addition up to 30% GPF with higher amount of egg albumen (6%) at dough moisture of 38% provided pasta with acceptable cooking quality and high RS content. Some qualities and/or RS content of GF pasta samples was further improved by adding 30% pregelatinised flours from the native GPF or drum‐dried green banana flour (DDGBF) in combination with applying varied steps of cooking and/or cooling, which were applied after pasta extrusion prior to drying them. The study suggests that GPF, in its native form, but particularly when pregelatinised, is a promising ingredient to be used for the production of GF pasta.     

小米挤压粉与小米生粉理化性质及营养品质的差异比较

为了全面分析挤压膨化处理对小米粉品质特征的影响,本文系统比较了小米挤压粉与小米生粉理化性质及营养品质的差异,结果发现:小米挤压粉的密度极显著低于小米生粉(P<0.01),而粒径(P<0.01)和静止角(P<0.01)极显著高于小米生粉。挤压膨化后,小米挤压粉亮度(L*)减小、色泽(a*)变暗、肉眼可观察到色泽的差异。挤压膨化过程中产生较多阈值较低,风味贡献较大的醛类、呋喃类和吡嗪类挥发性风味物质,使得小米挤压粉的风味明显优于小米生粉。醛类,尤其是己醛(其相对质量分数高达34.58%),是小米挤压粉的主要风味贡献物质。与小米生粉相比,小米挤压粉的干基脂肪含量和直链淀粉含量分别减少28.92%和28.21%,但多不饱和脂肪酸含量增加21.08%,其中亚油酸增加19.92%、亚麻酸增加63.40%。据此推测,适量添加小米挤压粉将有利于增强小米制品的风味、改善成品口感、提高成品质量。     

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.     

Effects of milling on functional properties of rice flour

ABSTRACT:  A commercial long-grain rice flour (CRF) and the flours made by using a pin mill and the Udy mill from the same batch of broken second-head white long-grain rice were evaluated for their particle size and functional properties. The purpose of this study was to compare the commercial rice flour milling method to the pin and Udy milling methods used in our laboratory and pilot plant. The results showed that pin milled flour had more uniform particle size than the other 2 milled flours. The chalky kernels found in broken white milled rice were pulverized more into fines in both Udy milled flour and CRF than in the pin milled flour. The excessive amount of fines in flours affected their functional properties, for example, WSI and their potential usage in the novel foods such as rice breads (RB). The RB made from CRF collapsed more than loaves made from pin milled Cypress long-grain flours.     

添加剂及储藏温度对糯性粉团抗老化的研究

研究了在不同储藏温度(-18、4、25和37℃)下的糯性粉团,通过分析储藏0-5 d中的水分含量、水分活度、质构特性和热力学特性的变化来研究老化性质,并对食品添加剂对其抗老化作用作了研究。研究表明:(1)在各个储藏温度条件下,食品添加剂的加入可以有效地抑制糯性粉团的老化回生,可使糯性粉团的硬度较小、水分含量较高、水分活度较低、DSC测定的ΔH较小。(2)在-18℃条件下储藏的糯性粉团的老化速率最慢,经过自然解冻后其品质接近于新鲜糯性粉团。当储藏温度位于冰点温度(0℃)以上时,在4℃储藏的糯性粉团的老化速率相比25℃和37℃要快很多,且37℃条件下储藏的糯性粉团的老化速率低于在25℃条件下储藏的糯性粉团。表明糯性粉团最适宜的储藏温度应是-18℃。而当储藏温度位于冰点温度(0℃)以上时,温度越低,糯性粉团的老化回生愈加显著。     

不同磨粉方法对荞麦面团流变学性质的影响

为研究不同磨粉方法对荞麦面团流变学性质的影响,分别采用石磨、高速万能粉碎机及湿磨三种磨粉方法制得荞麦粉。然后测定由上述荞麦粉制备的荞麦面团的热机械学特性、拉伸特性、质构特性及应力松弛行为。结果表明:与干磨荞麦面团相比,湿磨荞麦面团具有显著较低的面团形成时间和稳定时间以及显著较高的蛋白弱化度,但磨粉方法对淀粉糊化特性影响较小。湿磨荞麦面团的拉断距离低于干磨荞麦面团的拉断距离,但其硬度、黏着性、弹性和胶着性显著高于干磨荞麦面团。此外,湿磨荞麦面团与干磨荞麦面团相比具有显著较高的残余应力和显著较短的松弛时间。不同磨粉方法会导致荞麦面团流变学性质产生差异,面团流变学性质的差异将满足不同的加工需求。