pressure at each of five constant temperatures (10, 20, 25, 30, and 35°C) under 65%, 86%, and 100% RH, respectively. Three wide mouth glass bottles (250 mL) each containing 65 mL salt solution or distilled water were kept in one temperature controlled cabinet to maintain three groups of different RH levels ranging from 65% to 100%. Every relative humidity-temperature combination was conducted in triplicate totaling 45 bottles in the experiment for five sorption isotherms of a milledrice variety. Each sample of milledrice kernels (ca. 5.0000 g) was placed into a small copper wire gauze bucket (3 cm diameter × 4 cm length), and hung in the glass bottle on a copper wire pothook under the rubber plug, 2–3 cm above the saturated salt solutions. The rubber plug was placed tightly inside the mouth of the bottle. After exposing the samples to the saturated vapour, the copper wire buckets with samples were weighed every 2 h for 24 h, thereafter every 4 h until the change in mass between two successive readings was less than 2 mg. When the sample was exposed to a lower temperature, the sample was left longer to equilibrate. However, the rice kernels exposed over the saturated K 2 CrO 4
Abstract: He aim of his work is o determine the effect of different water sources on the cooking quality of an Abakaliki milledrice sample. A popular rice variety (306) was bought from Abakaliki rice mill in Ebonyi State and cooked with three different sources of water (tap, borehole and distilled). The cooked samples were analysed for their functional, proximate and sensory properties. The cooking time of the rice variety (306) was 15 minutes. The swelling capacity of the rice samples ranged from 107.8 to 190.0% with 306 DW having the highest value for both raw and cooked samples. The water absorption capacity of the rice samples
A b s t r a c t. The present investigation deals with analyzing the compressive strength properties of two varieties (Tarom and Fajr) of parboiled paddy and milledrice including: ultimate stress, modulus of elasticity, rupture force and rupture energy. Combined artificial neural network and genetic algorithm were also applied to model these properties. The parboiled samples were prepared with three soaking temperatures (25, 50 and 75 ° C) and three steaming times (10, 15 and 20 min). The samples were then dried to final moisture contents of 8, 10 and 12% (w.b.). In general, Tarom va- riety had higher compressive strength properties for paddy and milledrice than Fajr variety. With increase in steaming time from 10 to 20 min, all mentioned properties increased significantly, whereas these properties were decreased with increasing moisture content from 8 to 12% (w.b.). Coupled artificial neural network and genetic algorithm model with one hidden layer, three inputs (soaking temperature, steaming time and moisture content), was developed to predict the compressive strength properties as model outputs. Results indicated that this model could predict these pro- perties with high correlation and low mean squared error.
Abstract: The loss on drying method, which is regarded as the standard method of rice moisture content analysis, provides the most reliable results but is both labor intensive and time consuming. In order to improve the detection efficiency of the loss on drying method, this study investigated the drying characteristics of milledrice and developed an information fusion algorithm with which to predict milledrice moisture content based on the Weibull distribution and Levenberg-Marquardt (LM) algorithm. Application of the Weibull distribution model was investigated regarding its description of the drying kinetics of milledrice during infrared drying. An adaptive mechanism was applied to algorithm design, with the starting point of the estimation algorithm determined by calculating the drying rate at each measuring point, and the end-point distinguished using a two-level threshold algorithm. The calculated results were then compared with the measured data regarding the infrared drying of milledrice. For milledrice samples varying in moisture content from 14.44%-17.67% (dry basis), the relative error between predicted and observed values ranged 0.0037-0.0589, with a reduction in test time of 50.71%-67.87%.
The conventional process used to make rice noodles involves soaking the po- lished rice for several hours, followed by grinding, and steaming the rice slurry to gelatinize the rice starch in the flour . The uptake of water during soaking reduces the amount of damaged starch . The damaged starch content is cor- related with the water retention capacity, which is the primary factor that affects the quality of noodles    . Dry-milledrice flour has a marked tenden- cy to lose its viscosity and thicken capacity during cooking . Thus, chemi- cally modified starch and various chemical additives are used widely in the rice noodle industry. Alternative time-saving methods have been developed to im- prove and simplify the noodle-making process without the use of chemical addi- tives . Rice flour can be mixed with gums and transglutaminase to improve the noodle-making properties and cooking quality . The process used to produce instant rice noodles by pretreating rice flour with steam to partially ge- latinize the starch has been patented . Heat-moisture treatment of rice flour can also enhance the cooking and textural qualities of rice noodles . Modifica- tions based on heat-moisture treatment and annealing can facilitate the produc- tion of acceptable quality noodles from poor quality rice flour . Annealing or heat-moisture treatments have been used selectively to produce various qualities of rice noodle because of their different rheological effects on the noodle texture  . The objectives of the present study were to develop a method for the treatment of rice flour that reduces the cooking losses and improves the textural properties of cooked rice noodles without chemical additives.
variety in Nigeria are wholesomeness, rice length and stickiness when cooked but little consideration is given to rice nutritional value. It is reported that rice quality is influenced by variety, geographic location, degree of processing and storage conditions among others (Juliano, 1985; Zhout et al., 2001). Although Nigeria is leading producer of rice in Africa, however low quality rice occasioned by village-level processing, handling and storage techniques have ignited the crave for imported rice, the largest in Africa a trend which has negatively affected the country’s foreign exchange reserve since the 1990s exceeding one billion US dolar annually(Nextzon, 2017). Nigeria is one of the leading importers of rice in the world, mainly from Asia, where 92% of world rice is produced chiefly on irrigated production systems (Abbas et al., 2011). With reduced inflow of hard currency the government of Nigeria initiated a policy called agricultural transformation agenda which is directed at boosting production, handling and storage systems of key food crops of which rice is one. The impact of this policy is yet to be substantially felt as milledrice available in Nigerian markets are characterized by high level of broken rice, impurity and chalky grain. Rice is the source of dietary energy for more than half of the world’s population (Zhout et al., 2002; Ghadge and Prasad, 2012), constituting about 75% of calorie intake of some Asian countries (Roy et al., 2011). Paddy contains on average 77-87% carbohydrate, 7-16% protein, 1.5-9% fat (Kent, 1983), and after milling the carbohydrate content increased to 85-90%, other nutrients decreased; fat 1.5-1.79%, protein 6.5-8.5%, as well as minerals and beneficial phytochemicals. Further decreases occur if the kernels are polished, because the protein, fat
The 3K RGP 4.8mio SNP dataset was downloaded from the Rice SNP-Seek Database (http://snp-seek.irri.org/) (Alexandrov et al. 2015). The 2,994,907, 2,118,326, and 1,318,493 SNPs with minor allele frequencies > 5% and a missing data rate < 0.1 filtered by PLINK (Purcell et al. 2007) for the whole population, XI, and GJ panels, re- spectively, were used for the subsequent association ana- lyses (Additional file 3: Table S3). The single-locus GWAS was completed with EMMAX (Kang et al. 2010) to determine the associations between each SNP and the GNC, GCC, and C/N ratio of milledrice. A Balding– Nichols matrix based on the pruned subset of genome- wide SNP data (with the ‘indep-pairwise 50 10 0.1’ par- ameter in PLINK) was used to create the kinship matrix. We calculated the eigenvectors of the kinship matrix with GCTA (Yang et al. 2011) and then used the first three principal components as covariates to capture the variance due to the population structure. The effective number of independent markers (N) was calculated with the GEC software (Li et al. 2012) and suggestive P-value thresholds of association (1/N) were calculated (Add- itional file 3: Table S3). We identified the genes harbor- ing or flanking the suggestively associated SNPs and functionally annotated them based on the Nipponbare reference genome IRGSP 1.0 (Kawahara et al. 2013). The Manhattan and quantile-quantile plots for the GWAS results were created with the R package qqman (Turner 2014). To detect independently associated regions, mul- tiple suggestively associated SNPs located in one esti- mated LD block were clustered as one QTL region, and the SNP with the minimum P value in a cluster was con- sidered as the lead SNP. Each LD block containing the detected SNPs was estimated with the ‘--blocks’ com- mand in PLINK according to the block definition sug- gested by Gabriel et al. (2002).
The treatment of rice involved wetting in hot water for some time to reach the moisture content of about 30%. Water was then removed and the wetted paddy was cooked in steam (steam treat- ment) or heated in sand (dry heat process). The final effect of the treatment depends on the steam pressure and the duration of the steam treatment. After the treatment, rice was dried to the moisture content optimum for puffing (10.5–14%). Then rice was milled to some milling degree (minimum milling degree 6%). An increase of the expansion ratio was reached by salting or alcohol treatment. The salting can be done by wetting rice in the salt solution of specific concentration for a specific time followed by drying to the moisture convenient for puffing, or by a thorough mixing of saturated salt solution with treated milledrice. Puffing can be achieved with the treated rice by different proce- dures. In India, the most frequent way is puffing in hot sand (temperature of sand about 250°C). The second method is puffing in hot air (250–300°C) or in oil (200–220°C). Puffing of rice can also be done in the microwave field. Another method is puffing by means of the puffing gun.
Recent research shows that rice production in Uganda still faces many challenges not only in production, but also in post harvest handling and marketing. Kijima et al., (2006) found that many farmers did not have enough information on how to grow, harvest and dry rice, which negatively affected the harvested yield and milling rate. Absence of rice millers in nearby towns was cited as a major constraint to NERICA adoption by farmers in 2004. The common transportation means from the homestead to the rice mill was the bicycle, and a typical farmer had to travel 15 to 35 km by bicycle to take rice to the nearest rice mill (Kijima et al., 2006). These problems are not unique to Ugandan rice farmers. In Ethiopia, for example, poor post-harvest handling leads to high post harvest losses that arise from threshing and lack of proper storage facilities, which dents the quality of locally produced rice (inundated with gravel, uneven or broken grains) and renders it less desirable to consumers than imported rice. There are a few millers who directly buy rice from farmers, and these millers also double as traders (wholesalers and retailers) who dictate the prices (Asmelash, 2012). In the case of Uganda, however, a follow up study by Kijima et al. (2008) shows that the number of rice mills nearly doubled between 2004 and 2006 (from 360 to nearly 600), likely because of increasing demand for rice milling services by farmers. This is also reflected in the considerably shortened distance to rice mills from between 15 and 30 km in 2004 to between 6 and 11 km in 2006. This distance is believed to have reduced even further in recent years, with increased investments in rice milling services by the private sector. Despite this notable improvement in farmers’ access to milling services, some farmers still sell rice in unmilled form as paddy, which attracts a lower price than milledrice (Kijima, 2008). This paper
Radio frequency (RF) heating is considered as a potential postharvest technology for disinfesting agricultural products. Heating uniformity is one of the biggest problems in practical applications of RF technology. In this study, three different comparison experiments were conducted to evaluate the heating uniformity in a 6 kW, 27.12 MHz parallel plate RF heating system with a free-running oscillator. The three sample conditions in RF heating experiments include four different thicknesses milledrice placed in the container, the milledrice of 9% and 11% moisture content with 4 cm thickness, and milledrice and soybean with 4 cm thickness and 9% moisture content in the half section of the container. Finally the milledrice sample with low moisture in the corner and high moisture in the center of the container was used to evaluate the heating uniformity improvement. The results showed that the milledrice temperature increased with increasing thickness. Temperatures in corners and edges were higher than those in the center both in RF treated rice and soybeans. The samples of rice or with high moisture content were heated more than those of soybean or with low moisture content. The RF heating uniformity could be improved by placing the low moisture samples in the corner and high moisture ones in the center. This study should provide useful information for designing practical RF treatment processes as physical disinfesting methods.
DOI: 10.4236/oalib.1104833 2 Open Access Library Journal the desired sanitary quality. The rice storage problem usually occurs in a hot and humid climate when the population is unable to sell the offers to the market and the conditions of sale require a deposit of several months. Especially in areas where the relative humidity of the air and the heat are high, there is the birth of insects in the storage of rice. The noble objective of the seller to feed the popula- tion is distorted by a malice in the sales circuit caused by many factors: the at- mosphere in the storage chamber and the hygroscopicity of milledrice compete. The storage of white rice is fragile and often difficult to solve when an infection manages to become embedded in the mass. To preserve its quality, collectors and consumer households are looking for their own method of preservation . A good ventilation of the enclosure and storage in the shade in fresh medium are necessary conditions for the efficiency of its storage. Temperature and moisture are decisive factors to speed up or to delay grain deterioration. Bigger values ac- celerate insects and mould processing. According to the Burgess and Burrel dia- gram , a temperature of 15˚C and grain moisture above 10% are sufficient conditions to cause the formation of insects. Moulds are found at temperature of 10˚C (with the moisture of about 18%). As high temperature is favourable to in- sects, insects are born from 20˚C to 30˚C when the moisture in the bag is only 5% to 10%. Only, a temperature under 10˚C and the moisture of grain at 15˚C are good conditions for storage.
Rice is one of the most important cereals in the world. In recent years, with the emerging of large-scale rice processing production line, the most of them have realized the automation of production process. which has solved the rice processing line flow control and production process monitoring, improving production efficiency, and greatly reducing the labor intensity of workers. However, the operation of the rice whitening machine in the rice processing line is entirely dependent on skilled workers at present. The rice whitening machine, which determines the quality of processing, is the key milling equipment in the rice processing line. The control of whiteness (degree of milling) and percentage of broken kernels is done by skilled workers who adjust the pressure door in the outlet, according the color, translucent, temperature etc. of the milledrice. Due to the low cost of electricity at night, rice processing mills usually produce at night. It will make the workers who operated rice whitening machine very tired. All the facts together with the poor working environment (noisy and dusty) which may cause workers leave, will result in unstable production quality.
Milling and Cooking Parameters Parboiled and un-parboiled samples of each variety/line were cleaned with a seed blower. 1 kg of each treated and raw dried (less than 12% moisture content) paddy sam- ples of each line/variety were hulled with a testing husker (THU, 35H, Satake Engineering Co. Ltd., Japan). The moisture content of each sample was predetermined using a Steinlite Model 500 RC Electronic moisture tester. Then 500 g of brown rice of each sample obtained was whitened in a single pass friction rice pearler (BS08A, Satake Engineering Co. Ltd., Japan) with the degree of whiteness set between 'Low' and 'Medium' on the equipment. After milling, rice bran was removed with a 1.7 mm sieve. A cleaned sample of milledrice was weighed and used to determine milling recovery parameters inclu- ding total milling recovery percentage (TMR%), head rice recovery (HRR) and broken percentage. Head rice reco- very (HRR%) was calculated as perce- ntage of whole milled grains respect to the brown rice, then the average value was calculated (Bello et al., 2004). De-husked rice of both par- boiled and un-parboiled samples of each variety/line was cooked in ex- cess water. Twenty grains of each sample were cooked with a colander in a boiler placed on an electric heater
Fig. 2(a-f) summarizes the results of milling and cooking quality of raw milledrice (Pre-parboiled) and parboiled milledrice (post-parboiled). Significant variation was found among the studied genotypes for the traits. It can be concluded from the Fig. 2(b) that total milling recovery (TMR %) was increased in all the studied samples that showed significant variation among themselves. Highest TMR was obtained for line PK8649 followed by line PK7274 and PK8809 respectively. Minimum TMR was shown by line PK8892 (Fig. 2b). Likewise, among the lines tested maximum HRR (64.04%) was recorded for line PK8647 (fig 2c) while minimum (49.0) in case of PK7899. Maximum brown rice (81.27%) was recorded for PK8431, however, minimum in case of PK8647 (19.6%) as in Fig. 2(c). Almost all the lines showed significant increase in cooked grain length when subjected to parboiling. Cherati et al. (2012) also analyzed and studied the parboiling methods and the following impacts on waste reduction and yield increase in Iranian rice in paddy conversion phase and found fracture or broken percentage and bran percentage decrease while head rice recovery increase after parboiling. Fig. 2 (f) clearly emphasizes that bursting of cooked grain was reduced significantly for almost all the genotypes except for PK7274. Bursting of grains in all the parboiled samples was also found to be significantly low as compared to un-parboiled white rice (Fig. 2f). Rao and Juliano (1970) also showed increase in head rice recovery and cooking quality in parboiled rice. Kaddus Miah et al. (2002) also observed a large reduction in fissured grains in parboiled samples of rice as compared to non-parboiled. They further added that it is due to the fact that parboiling fills the void spaces in the endosperm and hence the cracks within the grains are cemented, making the grain harder leading it to less brokens. Insect infestation is also reduced due to the hardness.
Gal-ong, a traditional variety, still produced high brown rice and milledrice recoveries even at low or no fertilizer N application (organic fertilizers) indicating that it can be organically grown which would be more profitable to the farmers. It also had higher head rice recovery and total phenolic content than Burdagol-Laguna Type regardless of fertilizer treatment and season. The higher the total phenolic content in rice, the better since this compound may provide antioxidant and radical scavenging activity. Variations in the head rice recoveries and phenolic contents of the two varieties maybe due to their inherent characteristics.
The physical properties of the rice varieties are presented on Table 1. For the analyzed paddy Length, a significant difference between the vari- eties was observed at p<0.05. However, there was no significant difference in the width and thickness of the paddy of the varieties. Also, there was no significant difference (p>0.05) in the paddy length to width ratio of FARO 41, 52 and 61 expect for FARO 60. A similar trend was observed in the milledrice length, width, thickness and length-to-width ratio of the rice varieties as shown in table 2. The difference ob- served in the varieties could be traced to individ- ual properties. Different investigations also re- ported the wide range of grain dimensions while studying with different rice varieties (Correa, da Silva, Jaren, Afonso Junior, & Arana, 2007; Dan- baba et al., 2012; Shittu, Olaniyi, Oyekanmi, & Okeleye, 2012; Mir, Bosco, & Sunooj, 2013). The length, width and thickness of the varieties are important in designing and selecting sieve separators and in calculating power during rice milling (Varnamkhasti et al., 2008).
Rice is the most commonly consumed in the form of milledrice because of its softness and easy digestion. Brown rice is nutritionally superior to milledrice in terms of protein, dietary fiber, vitamin B, minerals, and even functional antioxidants which are mostly existed in external parts like hull and bran (Juliano, 2010); however, those nutrients are easily removed during the milling process. With increasing health concerns, the health promoting functions of brown rice have received the attention of consumers, and the demand for brown rice consumption has increased greatly. The bran in brown rice, however, restricts water diffusion during cooking, resulting in a harder texture and lower palatability than milledrice (Piggot et al., 1991).
Rice postharvest practices of farmers incur losses that limit supply and a ﬀ ect global production. Aside from physical losses, quality can be a ﬀ ected, leading to a possible accumulation of aflatoxin B1 (AFB1) that is harmful to humans when ingested. This is particularly important for countries like Cambodia that aim for both food security and rice exports. The objective of the research was to determine the e ﬀ ects of di ﬀ erent field drying and storage practices on AFB1 accumulation and milledrice quality in Cambodia. The study had four drying treatments and four storage treatments, in a randomized complete block (RCB) design. Tests were done for moisture content (MC), milling quality, germination rate, and AFB1 accumulation. High-performance liquid chromatography (HPLC) method was used to determine AFB1 contamination and one-way analysis of variance (ANOVA) was performed using CropStat 7.2. No significant AFB1 content was detected. Di ﬀ erent field drying treatments used, as well as duration and type of storage also had no significant e ﬀ ect on the accumulation of AFB1 in rice. Milledrice quality was higher with limited or no field drying (P < 0 . 01). Storing in IRRI-Superbag at 14 % MC resulted in higher germination (P < 0 . 01) than in other treatments. Storing in IRRI-Superbag at 16 % MC, however, resulted in lower head rice recovery than in the other three treatments. Reducing field drying and storing hermetically at 14 % MC could therefore potentially reduce rice postharvest losses. Field drying practices of 12 days or less can keep AFB1 contamination at bay.
Abstract - This study was conducted to develop rapid analytical methods to select suitable rice varieties with high stickiness for cracker production. Rice with low amylose is stickier than rice with high amylose. The study was designed to determine the two most important factors amylose and amylopectin. It was conducted to locally bred rice varieties AT 306, AT 405 and Samba. Amylose content was quantitatively determined using Juliano method. The amylopectin content was determined using a color card. It was developed by the reaction of several concentrations of pure amylopectin with 0.2% iodine to form respective colors. The particle size distribution of rice flour was analyzed. For this purpose, 100g of milledrice flour was placed on the sieve shaker and was operated for 12 minutes. The weight of flour retained on each sieve was weighed to identify passing through and retained on percentages. The results revealed that the amylose percentage of AT 306, AT 405 and samba were 19.6%, 12.2% and 25.87% respectively. The percentage of rice flour with larger particle size (>300µm) for Samba was above 95%, and for AT 306 and AT 405 it was 77%.
population, so almost all rice may vary considerably in the postprandial blood glucose (PPG) response to either low or intermediate level of GI at parboiled milledrice condition. Moreover, the post-harvest treatment of rice and the method of consumer preparation can also play a significant role in this variation. Starch comprises two glucose polymers: amylose and amylopectin. Amylose is a linear and relatively short polymer of glucose units linked by a (1 - 4) bonds. Amylopectin is a branched and longer polymer where glucose units are arranged linearly through a(1- 4), with branches emerging via a(1- 6) bonds occurring every twenty-four to thirty glucose units. It is well known that starches with a higher amount of amylose are more resistant to digestion. In addition to the variation in amylose content, cooking (and cooling) processes can influence starch digestibility via the degree of gelatinization and retrogradation of rice starch. Gelatinization is the collapse (disruption) of molecular order (breaking of H bonds) within the starch granule, manifested in irreversible changes in properties such as granular swelling, native crystallite melting, loss of birefringence and starch solubilization during hydrothermal treatment. This leads to the dissociation of crystalline regions in starch with associated hydration and swelling of starch granules, leading to higher starch availability to human digestive enzymes. Retrogradation is the re- crystallization of amorphous phases created by gelatinization and, in the case of amylose, results in the formation of type 3 resistant starch (RS3). RS3 is resistant to digestion, because it is heat stable and melts above 120 ◦ C. In contrast, retrograded amylopectin is thought to melt upon reheating (cooking) due to the low melting point