Rice is generally considered as semi aquatic annual plant that survives as perennial in the tropics or subtropics. The high cost of the available rice milling machine affects the production of rice in large quantity. Therefore, there is need for a low cost rice milling machine with high efficiency and reduced operating noise. A rice milling machine was developed consisting of the feeding unit, milling unit, cleaning unit, separating unit delivery unit and the frame. The rice milling machine has a capacity of 12 kg/hr and powered by a 3hp electric motor. The process of milling involves the interaction of machine and seed for the release of grains through blown air from impeller. The performance parameters include, percentage of broken rice, milling efficiency of paddy varieties, wholeness and machine efficiency which were evaluated at five different moisture content groups namely; A, 11.00-12.99%, B, 13.00-14.99%, C, 15.00-16.99%, D, 17.00-18.99% and E, 19.00-20.99%. Four varieties of paddy, NEL-42, NE 2, F55 and OFADA were used. The highest milling efficiency of 64 % was obtained for all varieties of paddy at A. The low percentage of broken rice and milling efficiency of 64% for paddy variety NEL-42 proved the effectiveness of the machine.
Paddy or rice grain consists of husk and brown rice. Brown rice, in turn, contains bran which comprises the outer layer and the edible portion. Rice milling is removal or separation of husk (dehusking) and bran to obtain the edible portion for consumption. The process has to be accomplished with care to prevent excessive breakage of the kernel and improve recovery of paddy or rice. The extent of recovery during milling depends on many factors like variety of paddy, degree of milling required, the quality of equipments used, the operators, etc. Milling is the process wherein the rice grain is transformed into a form suitable for human consumption, therefore, has to be done with utmost care to prevent breakage of the kernel and improve the recovery.Brown rice is milled further to create a more visually appealing white rice.After harvesting and drying, the paddy is subjected to the primary milling operation which includes de-husking as well as the removal of bran layers (polishing) before it is consumed. In this process the rice which is obtained after milling is called raw rice.An other process through which rice is obtained after milling is called "Parboiling Rice." Nearly 60% of the total rice produced in India is subjected to parboiling.Rice milling losses may be qualitative or quantitative in nature. Quantitative or physical losses are manifested by low milling recovery while low head rice recovery or high percentage of broken kernel reflects the qualitative loss in rice grains.
Sample Collection: The stratified sampling technique was applied for soil sample collection (Xie, 2001). Under this sampling technique, the sampling site was broken into four (4) stratums (small areas) north, south, east and west with respect to Kilema rice milling industry, Lafia. Each strata were further subdivided into four quadrants of equal size before five (5) samples were taken randomly by grab method within the depth of 0–15 cm in the individual quadrant (smaller area) making a total of twenty (20) samples per strata (small area) and a total of eighty (80) samples from the four stratums situated at the north, south, east and west of the industry were pooled together to form the composite sample labeled S1 to enable detailed representation of variability within the study area. The control soil sample for the industry was collected in a farmland within 1.2 km radius from the industry from site remote to possible sources of contamination associated with the industry.
Competition among firms is getting harder day by day due to many organizational and environmental reasons such as globalization, deregulation, increasing global and domestic competition, and new technologies. The rice milling industries in Kenya have faced a lot of changes in the environment that they operate in such as increasing costs of operations, proliferation of cheap imported rice, high inflation rates, lower consumer spending power and decreasing product margins due to a push for market share through products with a mass market appeal. Despite the challenges the rice milling factories in Kirinyaga County are making enormous progress. There has been a lot of innovation in processes and new product development in an aim to set each company apart from the competitors. Rice milling factories have branded and positioned themselves by capitalizing on the superior value of the unique physical features, products and services and thus enjoy more profits differentiating them from rivals to improve sales performance.
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The mathematical model was developed with an empirical approach, where the model was constructed from the results of measurement data in a series of studies. The best correlation between UV absorbance characteristic and DM value was investigated in the wavelength range whit different UV light absorption. The best correlation is expressed with the highest determination value of regression line between UV absorbance and DM of rice. The equation model used in the development of the model was selected based on the unique characteristics of agricultural materials which are usually in exponential form. In addition, the dissolving of fat content on the surface of rice to the inside of rice happens in the form of exponential , where in this case the fat content on the surface of rice was used as approach in determining the DM of rice or visual based optics.
orthogonal array optimization method was adopted. To achieve quantity, optimal parboiling conditions peaked in moisture content of 27% after soaking; steaming temperature of 90°C for 40 minutes; and drying at a temperature of 35°C. There was a significant increase in the milling rate from 70.48% of the control to 74.97% of the best experimental result. Minitab analysis showed drying temperature to be the most significant factor for milling yield. In qualitative analyses, there were varied optimal conditions, but the conditions for quantitative analyses can be adopted since nutrients optimized at the same conditions as stated above. Nutrient analysis showed a significant increase of 2% and 1.4% in protein and amylose contents respectively when compared with the control. Findings from this study show that only a right combination of all factors can guarantee a good outcome from the parboiling process; it is better to skip the process than to perform it improperly. The degree of combination of factors is dependent on the variety. Therefore, studies should always be carried out on new developed varieties before parboiling commences.
Rice milling typically involves harvesting, rying, milling and packaging. During milling, dried paddy undergoes de-husking, bran removal and whitening stages. In the de-husking stage, paddy is first fed into a sheller to remove its outer layer, i.e. the rice husk. The husks are separated from the brown rice (rough rice without husk) by aspiration. The brown rice is then conveyed to the whitening process to remove the rice bran. In general, the whitening process can be divided into two categories: the abrasive, and the friction type. The abrasive type functions by channelling rice through a moving rough surface and a stationary screen. In contrast, the friction type operates by contacting one kernel against another under slight pressure (Afzalinia et al., 2002). In the final stage, the milled rice is separated into the whole kernel and the broken kernel by its length by means of grading sieves. The length of the whole kernel is 75% or more of the full kernel. The remaining kernels are termed as broken rice (Webb, 1991). Two important indices of the milling process are the degree of milling and the head rice yield. The degree of milling refers to the extent in which the bran layers have been removed from rice during milling. The degree of milling affects the rice cooking time and texture (stickiness) as well as the properties of cooked rice (e.g. the starch content, the lipid as well as protein levels) (Lyon et al., 1999).
Thousand grain mass of rice grain is utilized in determi- ning the effective diameter which can be used in the theore- tical estimation of seed volume (Ogunjimi et al., 2002). Furthermore, this parameter is used for calculating the head rice yield (USDA, 1990). No rice variety can commercially successful unless it possesses high whole kernel (head) and total milled rice yield. Whole kernel (head) yield is the quantity of intact whole kernels (including broken kernels three-quarters or more in length) of well-milled obtainable from given quantities of rough rice (paddy). Total milled rice yield includes whole kernel (head) and other sizes of broken kernels obtainable from specified amounts of rough rice. The objective of rice milling is removal of hull, bran and germ, with minimum breakage of endosperms (Owens, 2001). Besides, the thousand grain mass of raw paddy is a use- ful index to milling outturn in measuring relative amount of dockage or foreign material in a given lot of paddy, and amount of shriveled of immature kernels (Luh, 1980).
Rice husk lifecycle involves three main processes, which are paddy production, rice milling, transportation and electricity generation as presented in Figure-1(a). The transportation of rice husk becomes the sub process of rice milling. A 1 tonne lorry is used to transport the paddy to mill, and a large truck is used to move the rice husk to the power plant. About 20-30% of paddy weight becomes rice husk after milling. In this analysis 20% conversion rate is used to estimate rice husk production from paddy, which is based on the experience from local mills (Zamil, 2010; Zulkifli, 2010). Equation 1 is used to calculate the rice husk availability in Malaysia. Q RH =P P ×0.2 (1)
Abstract— The purpose of this research is to develop the small rice milling machine in order to support the agricultural communities in Chiang Mai province and Ubon Ratchathani province using design of experiment technique. The experiment was designed by Response Surface Methodology (RSM) based on Central Composite Design (CCD). Type of rice: Thai Hom Mali rice 105 was chosen as testing rice. The two major factors including revolution per minute (RPM) and clearance between rubber and polishing cylinder were studied their effect on the percentage of broken rice after milling. In addition, the inverter system is also implemented in order to control the operation of the small rice milling.
An appropriate characterization of agronomic and quality traits is a fundamental tool for selecting stable genotypes suitable to be registered as new varieties. The objective of this work was to evaluate agronomic and quality traits of rice germplasm tested in two consecutive years for 23 advanced lines of Portuguese Rice Breeding Program and 3 commercial varieties. The influence of genotype, year and their interaction on grain yield and milling yield, grain uniformity and selected quality indicators for rice was assessed as well as the correlations between the agronomic, biometric and quality parameters. Results showed a generally dominant influence of the genotype, but with some quality parameters significantly affected by year conditions, and with some genotypes more stable than others. Some accessions have also shown better grain biometric uniformity within a year and between years. Significant correlations between quality and agronomic parameters that were observed may mark a plant pattern that can be used as predictor of the milling yield. These analyses provide objective tools for selecting most promising genotypes in rice breeding programs.
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Amylose content, gelatinization temperature and gel consistency are the important starch properties which influence cooking and eating characteristics. Gel consistency (GC) determines the softness or hardness of the cooked rice. GC of indica rice varies hard through medium and soft. Medium and soft gel consistency types of rice varieties/ hybrids are generally preferred. Among the 20 hybrids, only one hybrid IR 80154 A x IR 62037 (99.00) showed soft and eight hybrids (40.00 - 60.00 mm) showed medium gel consistency (Table 2). The hybrids with soft GC resulted from the crossing of either medium x soft or soft x medium or soft x soft GC types indicating the dominance of soft over medium (Dong et al., 1998). The highest GC was recorded in ‘Ghansal’ and lowest in ‘Pusa Basmati-1’. Kernel length after cooking (KLAC) ranged from 2.31-5.88 mm and the amylose content, starch, gel consistency and non-reducing sugar content decrease with elevated temperature (Shilpa, 2010).
of bran removed ,.Milling brings about considerable loss of nutrients and affects the edible properties of milled rice,. As most cereals, rice does not show a homogeneous structure from its outer (surface) to inner (central) . As a consequence, information on the distribution of nutrients will greatly help in understanding the effect of milling and aid in improving sensory properties of rice while retaining its essential nutrients as much as possible .Therefore, the aim of this study is to generate between rice of varieties and rice of moisture using Design of Experiment(DOE) by full factorial design in order to generate the suitable factors.
percentage of rough rice that remains greater than 75% of intact length throughout the milling process [3-9,10] . Improving HRY is a continuously targeted goal for rice growers. Weather conditions affect the moisture content of the rough rice at harvest thereby influencing HRY. Thompson and Mutters  studied the effect of weather and rice moisture at harvest on milling quality of California medium-grain rice. They found that harvesting under dry climate conditions produced a wide range of head rice quality. Dry windy conditions during harvest caused rapid reductions in rice moisture, predisposing rice to significant HRY loss and most of the loss occurred after rehydration conditions. Dilday  also stated that HRY generally decreased significantly as grain MC at harvest decreased. Moreover, Thompson and Mutters  concluded that harvesting rice under a combination of dry meteorological conditions and conditions of diurnal rehydration is considered as a main reason for the commercial variation in California medium-grain rice quality. To produce the highest quantity and quality of rice possible, the effects of the combine header and type over the entire range of rice harvesting conditions need to be investigated.
Thus, both additive and nonadditive gene effects were important for inheritance of almost all the characters studied. The use of population improvement concept may become an amenable solution in highly autogamous crop like rice. Biparental mating, recurrent selection and diallel selective mating system might be profitable in exploiting both additive and nonadditive gene action to obtain desirable recombinants for different quality characters.
In Uganda, efforts to promote rice production and marketing have been championed by the Office of the Vice President (OVP), National Agricultural Advisory Services (NAADS), and Non-Government Organizations (NGOs) such as Sasakawa Global 2000. Rice is grown mainly under three production systems, namely rain-fed upland; rain-fed lowland and irrigated. Of the three, rain-fed lowland is the most common system, covering 65,000 hectares of land, followed by rain-fed upland with 40,000 hectares and finally irrigated rice which covers 5,000 hectares of land (UNRDS, 2009). Most rice in Uganda is grown in eastern and western regions, due to the higher presence of lowlands and wetlands with sufficient soil moisture throughout the growing season (UNRDS, 2009). More than half of the rice produced by Ugandan farmers is sold for cash income (Sserunkuuma, 2008), meaning that rice is primarily grown as a cash crop; but the contribution of rice to smallholder farmers’ income is linked to the availability of functional milling services and markets for rice.
Alkali spreading score as a measure of GT revealed that of the 44 hybrids, 14 had medium, 5 low and remaining had high gelatinization temperature. In general, crosses involving HKR 241 and Basmati 385 as male parent and IR 58025A, PMS 10A , PMS 3A as female parent exhibited medium alkali spreading score. Gelatinization temperature, a physical property of starch is the range of temperature within which the starch granules start swelling irreversibly in hot water. Rices with high GT take longer time to cook and expand very little (Juliano et al., 1965). From consumers’ point of view rices with intermediate GT are preferred. In general, crosses involving restorers Basmati 385, HKR 241 and CMS lines IR 58025A, PMS 10A and PMS 3A as one of the parent had medium alkali spreading score hence, medium GT. Thus, in hybrid breeding programme select parents with intermediate GT to have intermediate basmati rice hybrids.
Figure 2 presents the oil concentration obtained from rice bran as a function of milling flow rate. Oil concentra- tion decreased as pilot scale mill setting increased, indicating that the highest concentration of rice bran oil is obtained in the outer bran layer. The oil concentration of bran in the outer layer (corresponding to the low mil- ling flow rate) is significantly higher than the oil concentration obtained in medium and high flow rates. Schramm et al.  stated that instead of treating the entire bran layer as a homogenous material, fractionating the bran layer and measuring component concentrations could result in a high value material for processing be- cause such bran material would contain a higher concentration of a component(s) of interest than the overall bran layer average, and that less bran would need to be processed to obtain those components of interest. These results show that the outer bran layer fraction of Jazzman results in a relatively oil rich fraction of 19.7%; if milled at the industrial scale, bran collected from Jazzman after the first milling break would be used for oil ex- traction.
GNY-50, GNY -53, LP-20 etc, Khushik et al. (2011). Some years before, farmers’ desire has been driving force behind the varietal spread, asking for seed of super quali- ty variety. Now a -days, he is confused by the seed hawk- ers hovering its farm. Farmers have also changed their mind set to market oriented varieties after the global rice crisis year 2008, FAO (2010). Basmati growers have slowly shifted from the most popular indigenous vari- ety Super basmati to the better quality Indian brands. As a result Punjab public sector has to registered Indi- an brand Kayaanat by name PS-2. Similarly, extra-long grain Indian varieties 1121 (kernel size 8.45 mm; yield 5000Kg/ha) and super seeder 1129 another represent- ative of Pusa rice category with higher yield 6000Kg/ ha and equal size (8.5mm) are promising replacing the indigenous basmati germplasms. Similarly, coarse rice packets of Sind province is replaced by Chinese hybrid rice as evident from the milled rice export status (Ta- ble 4). Year 2008–09 has been peak year of export when country earned USD 1.02 million against basmati rice export 924358 tons at the average unit record peak price USD 1102 per ton and value USD 1.03 million from 2.0 million MT of non-basmati export with average unit record peak price USD 511 per ton (Table 3). After that, slow down both in total of worth of rice export and average price value per unit MT particularly of basmati category can be seen in the Table 4. Besides higher yield perspective, there seems a holocaust change from other aspects including the habits of rice buying, cooking and eating in modem recipes and cuisines. Majority consum- ers are nontraditional street population whose number is far greater than the traditional rice consumers. Cooking quality of non-basmati rice even by traditional ways is at par or better than the Fine quality basmati rice when es- pecial skill is applied. Presently, bulk cooking is more common. Cooking of basmati rice in alkaline phase –addition of enough fresh lemon or dried plum has enough implications imparting spiciness, fluffiness,
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The results in Figure 7 show that cultivar Sazandegi became significantly whiter than the other two cultivars did, and it seems that under identical conditions, it will need smaller force for the separation of rice bran. Cultivar Tarom became less white than the other two cultivars did, indicating that greater pressure is needed in the whitener for further whitening. Figure 8 shows that, in total, the DOM of rice cultivars has increased as moisture content increased from 8 to 10%, and decreased as moisture content increased from 10 to 12 and 14%. Changes in the physical and mechanical properties of rice such as the friction coefficient and resistance to abrasion due to increased moisture content can be considered as the reasons for this issue. According to Figure 9, the mean DOM is higher in the blade whitener than in the abrasive whitener. The magnitude of frictional forces, the manner of exerting them, and the operation intensity in the blade whitener result in the separation of more bran, thus producing whiter rice. Figure 10 investigates the interaction effect of cultivar and moisture content on the DOM of rice. Accordingly, the highest mean values for the DOM of rice were obtained at 12% moisture content for cultivar Sazandegi, and 10% moisture content for cultivars Sorkheh and Tarom. The results in Figure 11 show the interaction effect of moisture content and type of whitener on the DOM of rice. According to these results, at all moisture contents, DOM is higher in the blade whitener than in the abrasive whitener. In the blade whitener, as moisture content exceeds 12% or falls below it, the mean DOM decreases. In the abrasive whitener, the mean DOM decreases as moisture content exceeds 8%. According to the results in Figure 12, in all cultivars, the blade whitener whitened rice to a significantly greater degree than the abrasive whitener did
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