糙米含水率对碾米性能影响的试验研究

通过加湿调质的方法适当提高糙米的含水率,分析糙米含水率与碾米能耗、整精米率、裂纹率、碎米率及力学指标之间的关系,以提高整精米率,降低碾米能耗、裂纹率及碎米率,确定最适碾米含水率。研究结果表明:糙米在加湿调质后的含水率与碾米能耗、整精米率、裂纹率及碎米率之间存在密切相关性,在试验参数范围内,稻谷碾米后的整精米率在含水率15.5%时精米率达到最大值70.78%,碎米率在含水率15.5%时达到最小值4.28%,稻谷最适宜的碾米加工的含水率为15.5%。研究结果可为糙米加湿调质工艺提供参考依据。     

润糙时间对糙米碾米性能影响的试验研究

通过加湿调质的方法适当提高糙米的含水率,分析润糙时间与碾米能耗及整精米率的关系,以提高糙米加湿调质后的整精米率,降低碾米能耗,确定较优的润糙时间。研究结果表明:糙米在加湿调质后的润糙时间与碾米能耗、整精米率及碎米率之间存在密切相关性,糙米加湿后60~90 min达到恰当水分梯度,碾米加工能耗最低,并且在加湿1.5%的条件下碾米加工时可以降低碾米能耗30%、裂纹及碎米率下降10%左右。研究结果可为糙米加湿调质工艺提供参考依据。     

糙米加湿调质参数对整精米率影响的研究

针对贮存后稻谷碾米后碎米率高的问题,研究糙米加湿调质工艺参数对整精米率的影响规律.以糙米的初始含水率、加湿量、均质时间为考察因素,以整精米率为评价指标,采用三因素五水平二次旋转正交组合试验设计,利用SAS软件建立整精米率的数学模型,分析各参数组合对整精米率的影响规律.结果表明:对糙米的加湿调质可以提高稻谷的整精米率,得到了低水分糙米加湿调质的最佳组合参数.     

低水分稻谷减碎加工的对策

探讨了低水分稻谷的加工特点，并以整精米率为评定指标，通过试验证明加工低水分稻谷时，采用多道碾白、糙米着水调质、低温升碾米并合理调整砻碾设备的工艺参数，可以减少出碎率，提高整精米率。     

稻谷水分对出糙率与整精米率的影响

稻谷水分是衡量稻谷质量的一项重要指标,又是稻谷入库质量检验和储藏期间的重要检验指标之一。分析了同一种稻谷、不同水分对出糙率及整精米率检验的影响。结果表明,在安全储粮的前提下,稻谷水分对出糙率和整精米率有直接的影响,将早籼稻谷、晚籼稻谷、粳稻谷入库水分分别控制在11.5%~12.5%、12.0%~13.0%、12.5%~13.0%,有助于提高稻谷的出糙率和整精米率,这对稻谷现场收购和建立统一的质量管理档案有着重要的指导意义。     

低温碾米工艺及设备的研究

针对加工优质稻如何保证其精度、降低碾米过程的增碎、提高整精米率和降低能耗等碾米工艺及设备研究方面的课题，从碾米工艺着手，分析了碾米过程中大米的温升与碾米机增碎的关系，探讨低温碾米工艺和研发新型低温碾米机及其碾米机的组合形式(碾米机组)。     

稻谷整精米率检验影响因素探讨

整精米率是反映稻谷品质的重要指标,对稻谷整精米率的检验影响因素进行了试验,探讨了不同水分的稻谷整精米率检验影响因素及影响程度。     

感官检测整精米率

稻谷整精米率的仪器检测过程比较复杂 ,从扦样、出糙、碾磨到计算约 30分钟左右 ,在收购旺季进行现场操作很不现实。因此 ,感观检测整精米率仍是较常用的办法。怎样在收购时快速感观检测整精米率呢 ?一是认品种。一般情况下优质稻比普通稻的整精米率要高。二是看粒形。同一品种 ,不同粒形整精米率不同 ,粒形短的高于粒形长的。三是观成色。仔细辨认稻谷新陈程度 ,稻谷储存期越长 ,整精米率越低。四是测水分。在标准水分左右 ,水分每高 1% ,整精米率提高 2个百分点左右。五是手碾磨。取约 10克稻谷于手磨砻或手掌心 ,均匀用力碾磨出糙 ,初略…     

稻谷干燥过程中整精米率的影响因素研究

该试验依据我国南方农村的稻谷干燥习惯,以大粒溪香优质稻品种为试材,对稻谷干燥过程中整精米率的影响因素进行研究。试验结果表明,稻谷干燥过程中不同处理对最终整精米率影响较大,不同处理之间整精米率最大相差6.8%。稻谷晾晒过程中采用篾席晾晒比水泥地直接晾晒所得整精米率高3.6%,晾晒过程中夜间存放于室外比存放于室内整精米率高2.2%,这些处理对稻谷最终含水量影响不大。     

稻谷整精米率标准样品研制

参照GB/T 15000.1-15000.9<标准样品工作导则>的要求进行了稻谷整精米率标准样品的研制.研究了颗粒类物质稻谷特定参数整精米率标准样品制备的原料选择、匀质(混匀)、均匀性试验、定值试验的过程.在本试验条件下,用人工和多级分样器混匀样品,可以得到均匀度合格的样本,经由多个实验室定值,分别得到籼稻整精米率标准样品理论真值为(45.8±1.4)%,粳稻理论真值为(74.6±1.2)%的结果.标准样品的制备为实验砻谷机、实验碾米机的校验和考核以及整精米率检验的质量控制提供了参照物.     

Rice degree of milling effects on hydration,texture, sensory and energy characteristics. Part 1. Cooking using excess water

The purpose was to assess the effect of degree of milling (DOM) on cooking kinetics, sensory attributes, and energy requirements when cooking rice in excess water. Commercial milling equipment was adjusted to produce parboiled and non-parboiled rice samples that were milled to varying DOMs, including brown rice lots having no milling. Surface lipid content (SLC) ranged from 0.15% to 0.55% for non-parboiled rice and from 0.40% to 0.95% for parboiled rice. The percentage gelatinized kernels, moisture content, peak force and sensory attributes were determined as a function of cooking duration for all samples. The cooking duration required to attain ‘well-cooked’ rice was determined, after which the energy required for cooking was measured. Within the SLC range tested, DOM did not affect cooking kinetics, texture and flavor of rice. Non-parboiled brown rice required the most energy, expressed as energy per unit mass of uncooked rice, to be cooked, followed by parboiled brown, parboiled milled and non-parboiled milled rice.     

糙米加湿调质过程中最佳一次加湿量的研究

本文以含水量12．5％的糙米为原料，采用不同一次加湿量将糙米加湿调质，并对试验样进行了碾米试验研究，测试了碾米加工的能耗、碎米率及裂纹率，研究证实糙米最佳一次加湿量在1．3％～I．5％之间可以避免加湿过程中产生的应力裂纹，而且可以降低碾米能耗30％左右、增加出米率、提高大米品质。     

干法、半干法和湿法磨粉工艺制备的糙米米线品质研究

采用干法、半干法和湿法3种方式将糙米磨粉制备糙米米线,干法粉碎强度10～40 Hz,半干法调节含水量为20%～35%及湿法料液比为1∶1、1∶2、1∶3、1∶4,研究了3种磨粉方式对糙米米线蒸煮品质和质构性质的影响,并分析了糙米磨粉颗粒细度及损伤淀粉含量与糙米米线蒸煮品质的相关性。结果表明,磨粉方式及磨粉工艺条件显著影响糙米米线的蒸煮、质构和感官品质,糙米磨粉颗粒细度与糙米米线最佳蒸煮时间显著正相关,与糙米米线断条率显著负相关。糙米磨粉损伤淀粉含量与糙米米线最佳蒸煮时间、硬度显著负相关,损伤淀粉含量与糙米米线断条率显著正相关。干法粉碎强度10、半干法水分调节含量20%、30%和35%、湿法粉碎料液比1∶3～1∶4时,糙米米线的品质较好。     

干法、半干法和湿法磨粉对糙米粉性质的影响

研究干法、半干法及湿法3种磨粉方式对糙米粉损伤淀粉含量、平均粒径、微观结构、水合特性、热焓特性和流变性质等的影响。结果表明,干法磨粉糙米粉损伤淀粉含量、吸水指数、水溶性和膨胀势显著高于湿法和半干法。但干法磨粉糙米粉平均粒径、凝胶最大弹性模量和最大黏性模量显著小于湿法和半干法。干法和半干法糙米粉糊化焓值低于湿法。干法磨粉糙米粉形成了许多不规则的颗粒碎片,而半干法和湿法的糙米粉淀粉颗粒较完整。磨粉方式和条件显著影响糙米粉的性质,应根据糙米制品品质的要求选择合适的磨粉方式和磨粉条件。     

Rice degree of milling effects on hydration,texture, sensory and energy characteristics. Part 2. Cooking using fixed,water-to-rice ratios

The purpose was to assess the effects of degree of milling on hydration and textural characteristics of rice cooked using a range of water-to-rice ratios, and to compare the energy requirements when using these fixed water-to-rice ratios to the energy required when cooking with excess-water. Surface lipid contents (SLCs) ranged from 0.15% to 0.55% for non-parboiled rice and from 0.40% to 0.95% for parboiled rice. Cooking degree was assessed by measuring cooked-rice peak force, moisture content and percentage gelatinized kernels. Milling degree had little to no effect on cooking characteristics of all milled samples. Differences in cooking characteristics between milled and brown rice were less pronounced for parboiled than non-parboiled rice. Non-parboiled milled rice required the least energy to be ‘well-cooked’, followed by parboiled milled rice, non-parboiled brown rice, and parboiled brown rice (there were no significant differences between non-parboiled and parboiled brown rice). In general, excess-water cooking required more energy than fixed water-to-rice ratio cooking.     

Characterisation of Brown and Milled Yellow Rice and Development of an Expanded Snack

Brown rice and yellow milled rice were characterised in relation to milling properties, cooking, processing quality and microbial testing, and utilised to develop an expanded snack. The extrusion process was done in a Mapimpianti single screw cooker-extruder. A flour sample feed rate of 70 g (dry matter) min⁻¹ was maintained by varying the force-feeder speed. A screw speed of 150 rev min⁻¹ and a die with 20 die-nozzle orifices (2 mm in dia) were used. The die zone was heated at 110°C by electrical resistance. Compressed air was circulate around the barrel to maintain precise control of the temperature. The moisture content of the samples was 120, 150 and 180 g kg⁻¹. The grains were classified as long-thin with an average size of 2·13 mm×6·79 mm. The milling yields obtained in the laboratory with paddy rice were 700 g kg⁻¹ brown rice and 600 g kg⁻¹ milled rice. Brown rice and yellow milled rice had similar amylose contents, 225 and 256 g kg⁻¹, respectively. Gel consistency was soft with low gelatinisation temperature (63–68°C) for both samples. Field fungi such as Helminthosporium oryzae and storage fungi as Aspergillus spp were present in paddy, yellow milled and commercial rice. Helminthosporium oryzae was not present in extruded products. The extruded products showed low density and a high degree of expansion, with the optimum degree of expansion obtained in flours processed with moisture at 150 g kg⁻¹ in both milled and brown rice. The highest values for water solubility index were obtained with flours from milled yellow rice and none of the extruded products showed significant differences on water absorption index. Sensory analyses carried out on the snack products showed them to be acceptable, with the bent acceptance for products made from milled yellow rice processed with 150 g kg⁻¹ moisture.     

大米表面颜色与碾削程度的相关性分析

以两优6393、蓉优3号、益禾8号3种稻谷为试验材料,研究大米表面颜色与糙出白率的关系。垄谷后,对每种糙米进行15、30、45、60和90 s的碾削,得到不同碾削程度的大米样本,测定出每个样本的糙出白率、明度(L)、红绿色调(a)和黄蓝色调(b)值,分析大米颜色特征随碾削时间的变化关系,通过回归分析的方法,分别建立大米表面明度(L)值、红绿色调(a)值和黄蓝色调(b)值与糙出白率关系的模型。结果显示,随着碾削时间的延长,大米的糙出白率显著降低,大米的表面明度明显增大,而红绿色调和黄蓝色调则逐渐减小;随着糙出白率的减少,大米表面的明度线性增大,红绿色调值和黄蓝色调值则线性降低;大米表面的L、a和b值与糙出白率的关系可以描述为简单的线性函数式。     

东北地区稻米碾磨品质区域变化规律研究

以生产水稻主栽品种碾磨品质和活动积温指标为依据 ,首次研究了我国东北全区域范围内稻米碾磨品质指标的区域变化规律。结果是 :不同地区和不同年际之间糙米率稳定性最大 ,整精米率稳定性最小 ,精米率介于两者之间。整精米率发生规律可以用直角三角形图示形象说明。针对其规律和特点提出了提高水稻碾磨品质的具体技术对策     

若干糙米及白米化学成分分析

对若干品种糙米和白米化学成分,如水分、蛋白质、脂肪酸值、粘度、不溶性直链淀粉含量等进行测定及分析,找出同品种糙米及白米化学成分特点,对糙米检测指标提供参考建议,证明糙米与白米相比在流通、储存及食用价值上具有优势。