浸泡对稻米粉体应用品质的影响

为了评价浸泡工艺对稻米粉体应用品质的影响,将糙米和白米在30℃下浸泡,评价不同浸泡时间(0.25,0.5,0.75,1,2,3,4,5,6,7,8 h)下糙米和大米的吸水率、微观结构、颗粒细度、损伤淀粉含量、蛋白质含量、微量元素含量及糊化特性。结果表明：白米在1 h内和糙米在2 h内吸水速率均快速增加,在2 h内糙米吸水速率显著低于白米,之后缓慢增加,在5h达到平衡。随着浸泡时间的延长,白米表面出现蜂窝状结构增多,蜂窝变大,截面中细胞壁与细胞壁之前出现分离,淀粉颗粒之间结构变得松散,蛋白质含量、锰、锌、钾含量均呈下降趋势,而糙米结构随时间的变化不明显;白米浸泡0.75 h内和糙米浸泡4 h内,颗粒细度不断降低;白米粉的损失淀粉含量随浸泡时间的增加而不断降低,而糙米粉无显著变化。总之,因糙米外层被果皮包裹,水分需要较长时间才能进入到糙米内部,吸水速率低于白米。随着浸泡时间的延长,白米的结构和营养变化显著,糙米粉的结构和营养变化程度低于白米粉。     

稻米蛋白提取工艺及其特性研究

以粳稻米为原料,分析其糙米、白米和米糠的营养成分及蛋白组成特点,研究提取条件对糙米、白米和米糠蛋白提取量的影响,并对这三种蛋白的溶解性及分子量分布特征进行比较。结果表明：糙米、白米中的蛋白均以谷蛋白为主,但糙米中谷蛋白含量比白米低4.78%,而清蛋白含量比白米高55.93%;糙米中清蛋白和球蛋白含量分别比米糠低77.22%、44.59%,但谷蛋白含量比米糠高47.00%。提取时间、温度及液料比对三种原料的蛋白提取量均有不同程度的影响,其中液料比是提取三种蛋白时最显著的影响因素 (p ＜ 0.01);温度对白米蛋白提取影响显著(p ＜ 0.05)、对米糠蛋白极显著(p ＜ 0.01),而对糙米蛋白不显著;时间仅对提取白米蛋白有显著影响(p ＜ 0.05),对其他两种蛋白的提取没有明显作用。采用响应面法对提取条件进行优化,得到三个回归模型,经验证,用该模型可以预测稻米蛋白的提取量。稻米蛋白溶解性与SDS-PAGE 电泳分析表明,糙米蛋白的溶解性及其蛋白分子量分布介于白米蛋白与米糠蛋白之间。     

白米、糙米和发芽糙米中氨基酸含量的研究

比较了白米、糙米、发芽糙米中游离氨基酸(FAA)和水解氨基酸(HAA)含量,结果表明,糙米和发芽糙米中HAA总量差异较小,二者中的HAA含量要略高于白米;除天门冬氨酸外,白米、糙米和发芽糙米中的FAA含量依次升高,糙米发芽能显著提高限制性氨基酸的含量。     

发芽糙米糊化特性研究

利用热差扫描仪(DSC)对发芽糙米,糙米和白米的糊化特性进行研究,结果表明糙米糊化起始温度(To)、峰值温度(Tp)、终止温度(Tc)最高;碾减率为16.7％白米糊化起始温度(To)、峰值温度(Tp)、终止温度(Tc)最低;发芽糙米糊化起始温度(To)、峰值温度(Tp)高于碾减率为16.7％白米,低于碾减率为8.3％白米。     

发芽糙米白米黑米软罐头米饭的研制

以发芽糙米黑米白米为原料开发研制比白米饭更具营养价值及食用方面性的软罐头米饭。通过研究3种米的比例、发芽糙米和黑米的预煮时间、蒸煮水的添加比例以及高温杀菌时间等单因素及多因素组合对软罐头米饭组织状态、口感及糊化度的影响,确定发芽糙米白米黑米的比例为2∶2∶1,把发芽糙米和黑米均分别预煮20 min和15 min,蒸煮水的添加比例为1∶1.4,再和白米一起蒸煮15 min,121℃高温杀菌30 min可得到呈淡紫色、有光泽、有米饭特有的天然香气、白米米粒完整、无软烂、口感爽滑、有嚼劲和弹性、软硬适宜的软罐头米饭。     

MCT-6型糙米调质器的研制与应用

阐述了糙米调质对提高成品白米的整米率，改善白米外观，提高米粒的光洁度及改善米饭食用品质的作用；介绍了MCT-6糙米调质器的结构，工作原理，性能指标和实际使用效果。     

浅谈糙米精选与调质

在碾米工艺中，增加糙米的精选分级，去谷、去未熟粒和细杂，保证进入碾米机的糙米是净糙米。此外增设糙米调质工序，加水量为0.2%～0.6%，糙米皮层的水分控制在16.5%～17%左右，可改善白米碾磨均匀度、降低白米龟裂、节约碾米电耗、降低碎米率。     

回添法糙米粉制备及其糊化与储藏特性研究

通过气流膨化与挤压膨化分别处理米糠,并研究米糠处理前后基本成分及其吸水性指数与脂肪氧化酶酶活的变化。选择挤压膨化处理的米糠回添到湿磨法制备的白米粉中,制得回添法糙米粉,将其与湿磨法制得的全粉碎糙米粉和白米粉的糊化特性及储藏特性进行比较。结果表明,3种米粉的糊化特性有显著性差异(P0.05),除糊化温度外,白米粉的峰值黏度、最低黏度、衰减值、最终黏度和回生值均最高,回添法糙米粉的峰值黏度、最低黏度、回生值和糊化温度均显著高于全粉碎糙米粉,更接近白米粉的糊化特性。在不同储藏温度期间,3种米粉的脂肪酸值均有明显的升高趋势,其中白米粉最低,全粉碎糙米粉最高,回添法糙米粉的脂肪酸值更接近于白米粉的脂肪酸值。因此用挤压膨化处理的米糠制得的回添法糙米粉的糊化特性及储藏特性优于全粉碎糙米粉,更接近于白米粉的糊化特性及储藏特性,用挤压膨化处理米糠并制备回添法糙米粉是一种糙米粉制备的较好方法。     

酶法降解糙米中植酸初探(一)——糙米中植酸提取或降解方式的选择

糙米是一种富含营养素的食品原料，它的营养价值已被越来越多的人所接受。和白米相比，糙米中含有的膳食纤维、谷维素、谷固醇及维生素等物质都对人体健康起着不同的促进作用［１］。但是，糙米中也存在着一些抗营养因子，如植酸会影响糙米营养效价的发挥，糙米口感差的问...     

大米及其制品中的RS3

测定了英国市场上销售的Basmati(白米,糙米)(长粒米),泰国香米(长粒米),日本大米(短粒米)样品中RS3的含量,比较长粒米和短粒米在熟化过程的稳定性以及不同米制品中含量的差异.结果表明,短粒大米RS3含量高于长粒大米;熟化过程对RS3含量的影响巨大,其中白米米粉在熟化过程中RS3含量下降的程度低于糙米米粉,长粒米米粉、短粒米米粉在熟化过程中RS3含量下降的程度差异不大;保鲜米饭与同品种大米制作熟化大米粉的RS3含量基本相当.     

糙米与精米的营养价值与质构特性比较研究

通过检测糙米和精米营养素,对比其营养素成分含量差异,结果发现糙米主要营养素含量远高于精米,糙米的营养价值高于精米。利用质构仪对糙米和精米质构特性进行分析,糙米的硬度高于精米。利用动态流变仪对糙米粉和精米粉凝胶特性进行分析,精米粉凝胶强度高于糙米粉。差示扫描量热仪测试糙米粉和精米粉的热特性,发现升温过程中糙米粉糊化温度68.6℃高于精米粉糊化温度62.4℃,糙米粉难糊化;降温过程,精米粉在20℃的G′为17210Pa,高于糙米粉11350Pa,精米粉回生变硬现象较为严重。     

应用近红外光谱技术快速测定粳稻品种的直链淀粉含量

应用近红外光谱法以稻谷、糙米、精米、糙米粉和精米粉为扫描材料分别建立了粳稻直链淀粉含量的预测模型。结果表明采用光谱预处理的校正效果比不采用预处理的好,用偏最小二乘法(PLS)获得的粳稻稻谷、糙米、精米、糙米粉、精米粉的回归模型和交叉验证结果为:最优校正决定系数(R2)和交叉检验均方误差(RMSECV)分别为0.8136、2.74,0.8864、2.56,0.8915、2.59,0.9261、2.26,0.9505、1.83,粉碎性样品的误差比整粒样品的误差小。育种实践中,低世代可选用糙米、高世代可选用糙米粉或精米粉作为扫描样本测定稻米直链淀粉含量。     

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.     

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。     

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.     

Interactions of Several Bile Acids with Hemicelluloses from Several Varieties of Rice

Purified and crude preparations of rice hemicellulose from rice bran, whole rice (brown rice), and milled rice were incubated with four bile acids (cholic, glycocholic, taurocholic, and glycotaurocholic acids) under in vitro conditions of pH, temperature, salinity, time for interaction and so forth to approximate conditions normally found in the intestinal tract. The amounts of bile acids bound gradually increased as the concentration of rice extract increased for all rice varieties, with whole rice extract or rice bran extract. Results suggest an effect of growing areas on the binding properties of rice bran and milled rice.     

转基因稻米DNA 提取方法的比较研究

目的：建立一种以水稻种子为原料,简便、快速、有效的基因组DNA 提取方法,作为转基因稻米的PCR 检测基础。方法：选择传统的CTAB 法、改良的碱处理法、高温水煮法,以转基因糙米、非转基因糙米、转基因精米为材料提取DNA,并对提取物进行检测。结果：改良的碱处理法提取的DNA 模板的完整性、纯度和PCR 反应方面与传统CTAB 法相近,且比CTAB 法的产率高、耗时短、成本低。结论：改良的碱处理法可以代替传统的CTAB 法用于转基因稻米检测中DNA 模板的制备。     

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.     

Germinated Brown Rice and Its Role in Human Health

Brown rice, unmilled or partly milled, contains more nutritional components than ordinary white rice. Despite its elevated content of bioactive components, brown rice is rarely consumed as a staple food for its dark appearance and hard texture. The germination of brown rice can be used to improve its taste and further enhance its nutritional value and health functions. Germinated brown rice is considered healthier than white rice, as it is not only richer in the basic nutritional components such as vitamins, minerals, dietary fibers, and essential amino acids, but also contains more bioactive components, such as ferulic acid, γ-oryzanol, and gamma aminobutyric acid. Moreover, germinated brown rice has been reported to exhibit many physiological effects, including antihyperlipidemia, antihypertension, and the reduction in the risk of some chronic diseases, such as cancer, diabetes, cardiovascular disease, and Alzheimer's disease. Therefore, it is likely that germinated brown rice will become a popular health food.     

Genotypic variation of mineral elements contents in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Mineral nutrition of potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are important for human health. The method of inductively coupled plasma mass spectrometry (ICP-MS) was employed to determinate the contents of K, Ca, Na, Mg, Fe, Zn, Cu and Mn in milled rice (Oryza sativa L.) of 274 rice genotypes. The results showed that the visible difference could be found for the contents of eight elements in milled rice among rice genotypes studied. It existed the possibility to select the genotype(s) with abundant of mineral nutrient from the genetic resource. Meanwhile, the contents of mineral elements in brown rice were significantly higher than those in milled rice. The averages of K, Mn and Cu contents of indica rice were significantly lower than those of japonica rice, while no significant difference was found for other five element contents between indica and japonica rice genotypes. The average contents of Na and Cu in non-glutinous rice genotypes were higher than those in glutinous ones, whereas the averages of K and Mn contents in non-glutinous rice genotypes were lower in present experiment. Additionally, the K, Ca and Mg contents of milled rice from white brown rice were significantly higher than those from red brown rice, and Ca content of milled rice from white brown rice was also visibly higher than that from black brown rice. For microelements, significant difference was observed for Zn content between milled rice from red and white brown rice, or between milled rice from red and black brown rice. Some genotypes with abundant mineral nutrient in milled rice had been selected and could be used in rice nutrient breeding.