实验碾米机性能测试

采用不同类别、不同粒型的稻谷试样对国内使用的实验碾米机进行实验测试,结果表明,不同仪器差异显著,同一样品用不同型号的碾米机,其整精米率差值,7个籼米的差值平均为11.05%.单一样品不同型号碾米机整精米率最大差值为9.23%,最小差为5.38%.说明不同型号碾米机对整精米率测定结果有较大影响.     

粳稻谷整精米率标准样品均匀性检验和定值中的数理统计方法

标准样品制备过程中,样品均匀性检验和定值检验是样品制备的关键。详细阐述了粮食行业标准样品——粳稻谷整精米率标准样品的制备过程中均匀性检验和定值中的数理统计方法,并通过实例对标准样品的标准值和不确定度进行计算。     

芝麻油脂肪酸成分标准物质的研制

选取当年产芝麻油作为标准物质的试验样品,对研制的芝麻油脂肪酸成分标准物质做了均匀性检验、稳定性监测和定值工作.选用的标准物质试验样品添加复配的BHA、BHT、TBHQ,混匀后充氮封装于2 mL安瓿中,室温条件下储存.芝麻油脂肪酸成分标准物质样品的均匀性检验结果经F检验以及16个月稳定性监测结果表明,单元内和单元间均匀程度以及标准物质样品的稳定性均达到国家一级标准物质的制备要求.芝麻油脂肪酸标准物质的定值结果为:C16:0(9.5±0.6)%,C18:0(5.2±1.0)%,C18:1(39.0±0.7)%,C18:2(44.9±1.0)%,C20:0(0.6±0.2)%.     

菜籽油脂肪酸成分标准物质的研制

选取当年产菜籽油作为标准物质的试验样品,对研制的菜籽油脂肪酸成分标准物质做了均匀性检验、稳定性监测和定值工作.选用的标准物质试验样品添加复配的BHA、BHT、TBHQ,混匀后充氮封装于2 mL安瓿中,室温条件下储存.菜籽油脂肪酸成分标准物质样品的均匀性检验结果经F检验以及16个月稳定性监测结果表明,单元内和单元间均匀程度以及标准物质样品的稳定性均达到国家一级标准物质的制备要求.菜籽油脂肪酸标准物质的定值结果为:C16:0(8.9±0.8)%,C18:0(2.8±0.2)%,C18:1(22.3±1.0)%,C18:2(40.1±2.2)%,C18:3(9.2±0.8)%,C20:0(0.5±0.1)%,C20:1(5.1±0.4)%,C22:1(10.0±1.6)%.     

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。     

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.     

淮安稻米品质研究

采集淮安市金湖、洪泽、盱眙、涟水、淮安区、淮阴区、清浦区七个粮食主产县(区)的粳稻谷样品63份,检测了稻谷的出糙率、整精米率、垩白粒率、垩白度、直链淀粉、食味品质、胶稠度指标。结果表明,出糙率、整精米率、胶稠度、食味品质都达到国家优质粳稻谷的要求,另外87.2%的样品的垩白粒率达到国家优质粳稻谷的要求;85.7%的样品的垩白度达到国家优质粳稻谷的要求;92%的样品的直链淀粉含量达到国家优质粳稻谷的要求。     

提高海南地区稻谷整精米率的工艺研究与应用

本实验以定安富硒稻谷为原料,研究稻谷水分、糙米加水调制工艺、多机碾米工艺对整精米率和能耗的影响。结合工厂实际生产需要和能耗要求,通过单因素实验得到最佳工艺条件为:稻谷水分14%,以1.2%的加湿量润糙60 min,在碾米过程中经由两道砂辊碾米机进行碾白,最后得到整精米率为52.56%,每吨米能耗为79.87 kW·h/t。     

对国标中关于整精米率的规定及检测方法的探讨

对国标中关于稻谷整精米率的有关规定提出看法，对影响稻谷整精米率的因素做了详细分析，并提出解决办法。重点对稻谷整精米率测定的操作方法(包括使用的实验碾米机型号、碾磨时间、试样用量)作了详细说明，希望能抛砖引玉，使国标中关于整精米率的规定更加完善，以利检验操作。     

同一试样检验稻谷“出糙率”与“整精米率”的探讨

新发布实施的GB/T 5495-2008《稻谷出糙率检验》标准,规定称取净稻谷试样20~25 g,对此我们做了大量实验,认为还应固定称取净稻谷量并确定为25 g。GB/T 21719-2008《稻谷整精米率检验》,规定试样用量(糙米)20 g左右的要求,须称取净稻谷量25 g才能满足。建议"出糙率"检验的总糙米量,用于检验"整精米率"所需糙米试样,由此简化了"整精米率"操作步骤,提高了稻谷质量检验速度。     

Effects of fluidized bed drying temperature and tempering time on quality of waxy rice

Waxy rice, which is soft and sticky in nature, can be used as a raw material to produce many food products. After being harvested, high-moisture waxy paddy must be dried to appropriate moisture content to prolong its storage life and to achieve higher head rice yield. Fluidized bed dryer could be used to dry waxy rice at high-temperature. However, due to the high heat and mass transfer rates during drying, stresses are generated in a rice kernel, leading to crack and low head rice yield. Tempering is thus recommended to reduce the moisture-induced stresses in the kernel after rapid drying. In this study, the effects of fluidized bed drying temperature (90, 110, 130 °C) and tempering time (30–120 min) on the quality of waxy rice, i.e., head rice yield, thermal properties, pasting properties, color, translucent kernel and microstructure, were investigated. The results showed that head rice yield of waxy rice after drying was significantly lower than that of the reference sample even when tempering was performed. Higher drying temperatures led to higher head rice yield while the tempering time did not have any effect on the head rice yield except when the drying temperature of 90 °C was used. Drying at higher temperatures also affected the starch granule morphology and the pasting properties. Waxy rice changed its appearance from opaque white to translucent when being dried at 130 °C.     

Physicochemical,milling and cooking quality of rice as affected by sowing and transplanting dates

The physicochemical, milling and cooking characteristics of three commercial varieties of paddy viz. Jaya, PR 106 and Pb. Basmati no. 1 as affected by different dates of sowing nursery and transplanting, were investigated. Grain yield was adversely affected with late sowing and transplanting dates. Significant differences were recorded on the yield of head rice and brokens in the three varieties grown under different sowing and transplanting dates. The effect of normal and late dates of sowing on 1000-kernel weight and grain dimensions was significant for both paddy and milled rice. Protein content of rice was not affected by sowing dates but late transplantings resulted in higher values. Free fatty acids in rice and bran were significantly increased with late sowing and transplanting dates, however, the amylose content decreased under these situations. Late transplanting dates decreased the minimum cooking time but increased the solid losses in gruel. The late transplantings deteriorated the organoleptic properties of cooked rice and had higher values for clearing and spreading.     

粳稻谷出米率与整精米率、出糙率相关性的研究

通过对2012年丹东质量调查的50个稻谷样品的检测,分析稻谷的出米率、整精米率、出糙率之间相关性,结果表明：稻谷的出米率与整精米率及出糙率之间存在相关性,且达到极显著水平,整精米率与出米率的相关水平要好于出糙率与出米率的相关水平,稻谷的出米率可以作为收购入库的定等指标之一。     

Parboiling of rice. Part II: Effect of hot soaking time on the degree of starch gelatinization

A differential scanning calorimetric study was done on raw and parboiled rice to determine the degree of gelatinization. Unparboiled rice absorbed the highest amount of endothermic heat, the enthalpy change gradually decreasing with increasing hot soaking time. The highest degree of gelatinization was achieved when the paddy was soaked for 120 min at 80 °C. With increasing degree of gelatinization, the yield point in a compression test also increased. During the parboiling process internal fissures were healed, resulting in higher head rice yield during milling.     

Effects of Combine Harvesting on Head Rice Yield and Chaff Content of Long and Short Grain Paddy Harvest in Sri Lanka

Paddy harvesting is the process of collecting the mature rice crop from the field which consists of activities such as cutting, handling, threshing and cleaning. Cutting, threshing and cleaning plays an important role to reduce postharvest losses. Lower performance of traditional harvesting process, labour shortage, reduced turn-around time and use of high yielding varieties have inevitably forced farmers to shift into mechanical grain harvesting in Sri Lanka. Rice milling is carried out to produce an edible polished or white rice product from harvested rough rice. Head rice yield is considered for marketing purposes because broken rice has low price in the market. Field survey was conducted in Polonnaruwa, Ampara and Hambanthota districts to identify most popular types of combine harvesters operating in the above districts. Paddy samples were collected from harvest of two most popular models of combine harvester in triplicate. Paddy sample of 1m² area from every paddy field were harvested separately by manual harvesting followed by manual threshing and cleaning in laboratory as control sample of relevant paddy field. Moisture content of the paddy grains were measured in the paddy field using digital moisture meter before harvesting. Paddy samples were subjected to sun drying until the moisture content come down to 14±1% before the quality analysis in the laboratory. Each paddy sample was analyzed for moisture content, chaff percentage and head rice yield percentage (HRY). Paddy was milled using laboratory scale rubber roll sheller and abrasive polisher. Chaff content percentage was measured by adding 100 ml of paddy to water and volume of chaff was measured using graduated cylinder. HRY was calculated dividing the weight of grain partials, which are larger than the ³/₄ of the grain, by weight of paddy sample. HRY between the two combine harvesting machine models evaluated were not significantly different at p<0.05 and also it was not significantly dependent on the harvesting methods such as combine harvesting and manual harvesting. The chaff content was significantly higher in model-2 in comparison to control sample for long grain paddy while model-1 was not significantly different with control sample for short grain paddy.     

烘干稻谷储藏过程中脂肪酸值变化规律研究与脂肪酸值预测模型的建立

为探究烘干稻谷在储藏过程中脂肪酸值的变化规律,将安徽、黑龙江2019年产的不同品种的稻谷样品以及辽宁地区2020年产的稻谷样品在烘干后进行实仓预埋储藏实验,对预埋样品进行跟踪检测,同时进行实验室模拟储藏实验。结果表明:随着储存时间的增加,稻谷脂肪酸值整体呈现上升趋势,温度越高,脂肪酸值上升越快,上升速率随着储存时间的增加有所放缓,脂肪酸值上升趋势更多受温度影响。初始脂肪酸值较高的样品在后续储藏中也较快的发展为不宜存;在实验室模拟储藏实验数据基础上建立脂肪酸值预测模型并进行实仓验证,拟合效果良好,为实际应用提供一定的参考价值。     

2014年湖北省中晚籼稻品质分析

为了解湖北省中晚籼稻品质性状、促进稻谷品质改良提供数据参考。选取湖北省2014年产115个中晚籼稻谷为样本，测定稻谷的碾米品质、化学特性、糊化特性以及蒸煮品质等指标，并利用数理统计分析的方法对其品质指标进行分析。结果表明，在所测定的19项指标中，多数（占77.8%）品质指标的变异系数大于10%，说明本研究收集的稻谷样品处于不同的品质水平，具有较好的代表性。其中分别有99.1%稻谷的出糙率和98.3%整精米率达国家稻谷标准三等的要求，直链淀粉含量、胶稠度、垩白度和垩白粒率分别有70.4%、96.5%、38.3%和21.7%达到国家优质稻谷标准三等的要求。采用主成分分析法对各品质指标进行分析，第一、第二、第三主成分的贡献值分别为37.11%、22.94%和15.37%，第一主成分将稻谷样品大致分为2类，以孝感产区样品为代表的I类稻谷，具有高直链淀粉、高回生值、低衰减值的特点，以荆门市、荆州市等产区样品为代表的II类稻谷，具有低直链淀粉、低回生值、高衰减值的特点。     

Effect of superheated-steam drying compared to conventional parboiling on chalkiness,head rice yield and quality of chalky rice kernels

Four rice cultivars (Ayutthaya 1, Khao Bahn Nah 432, Plai Ngahm Prachin Buri, and Prachin Buri 2) that usually have a major problem with chalkiness were processed by applying superheated-steam drying and conventional parboiling methods. The main objectives were: (1) to determine the possibility of applying superheated-steam drying to solve the chalkiness and low head rice yield problems and (2) to compare the properties of rice produced using superheated-steam drying and the conventional parboiling process. Both the initial moisture content and superheated-steam drying temperature significantly affected head rice yield. The higher moisture helped to increase starch gelatinization leading to a stronger rice structure and subsequently an increased head rice yield. The rice samples dried in the superheated-steam dryer using an initial moisture content of paddy at 32% w.b. for 6 h under a steam pressure of 1.2 bar and at three drying temperatures (120, 140, 160 °C) had higher milling quality than the conventionally parboiled rice samples. The darker color of the superheated-steam-dried samples was their main drawback. Both parboiling and superheated-steam drying could clearly lessen the percentage of chalky rice kernels compared to the raw paddy. The parboiled rice and superheated-steam-dried rice had more nutrients than normal white rice.