Polished Rice Research Articles

Influence of structural changes of brown rice by precise polishing on in vitro starch digestibility of cooked rice grain

The relationship between the tissue structure of rice grains prepared using stepwise degrees of polishing (DOP) and starch digestibility was investigated in this study. Brown rice grains (Oryza sativa L. cv. Koshihikari) was precisely polished to 1, 3, 5, 7, and 10% (w/w) of the original weight using a pressure-type rice polisher and then cooked using a standardized cooking procedure. Although the total starch content of cooked grains had a significant tendency to increase with an increase in the DOP (77.64–84.16% db), the resistant starch content was constant between the cooked grains with different DOP (0.32–0.43% db). Cooked brown rice grains had significantly lower starch hydrolysis (65.68 vs. 89.74–96.17%) and estimated glycemic index (72.50 vs. 84.95–92.90) than polished grains after in vitro gastro-small intestinal digestion. The results revealed that starch digestibility of cooked brown rice grains was not proportional to DOP. The bran layer remained intact and covered a smaller area of the endosperm as DOP increased. In conclusion, the starch digestibility of cooked stepwise polished rice grains was affected by the bran layer on the outermost surface, which was equivalent to 1% of the weight of the brown rice grains. However, it was not affected by the ratio of the bran layer remaining on the cooked grain surface. The results of this study could contribute to the development of new agricultural machinery products that solve problems related to the control of GI of rice and rice products.

Arsenic contamination in rice, radiation and chemical methods of measurement, and implications for food safety.

Rice products, including those given to infants, could be naturally polluted with arsenic. This issue for all age groups should be a top priority for the world food industry and the public. Food regulators assume incorrectly that infants' food and other rice products are safe, and health, agriculture and commerce authorities follow no clear guidelines. A common measure has been to place a ML on the amount of iAs in white rice and food intended for children and pregnant women. Although oAs is less toxic than iAs, it is still toxic; consequently, the ML of arsenic for the different age groups should be also specified. However, the ML of iAs in polished white rice for infants is very low (100μg/kg for infants and 200μg/kg for adults) and is difficult to measure. Using neutron activation for research is very useful in improving safety standards in the food industry. The second purpose of this review study is to report on the experimental results and methods used for measurements adopted at the Delft Reactor in the Netherlands with a colleague of the quantity of arsenic in 21 samples of different rice products from a variety of brands.

Feeding of vegetable waste silage to lambs by replacing maize silage

ABSTRACT The study examined the vegetable waste (VW) silage as feedstuff for lambs. Therefore, mechanically shredded VW was ensiled solely (T0) or by adding molasses (95:5 ratio; T1), or molasses and either wheat bran (T2) or rice polish (T3) or rice straw (T4) at an 85:5:10 ratio in 5 replicates for 45 days for evaluation. Then, the maize silage diet of two of the three groups of lambs (5 each) of 9.92 (±1.25) kg live weight (LW) was replaced with T4 silage at 50% and 100% on a fresh basis for 90 days and supplemented with a concentrated mixture at 1.5% of LWs. The significantly different pH (5.88, 5.21, 4.34, 4.33 and 4.23, respectively), lactic acid bacteria (not detected, 5.81, 6.51, 7.48 and 6.04 log10 cfu/g, respectively), and total volatile fatty acids (21.0, 29.2, 32.4, 36.0 and 32.0 mM/L, respectively) (P < .01) indicated that T2, T3 and T4 were of good quality silage. The dry matter intake and gain of lambs fed 100% T4 silage were significantly (P < .01) higher than others (2.30, 2.30 and 2.72% LW, respectively; 110, 128 and 141 g/d, respectively). It may be concluded that T4 silage may produce higher LW gain in lambs than maize silage.

쌀 가공 중 buprofezin의 잔류 특성

In this study, we aimed to analyze changes in the residual levels of buprofezin during milling, washing, cooking, and processing of rice to make porridge, rice cakes, and cookies. The pesticide residue levels in rice were analyzed using high-performance liquid chromatograph with UV detector. The residual buprofezin level in brown rice was 21.8 mg/kg, and after milling, that in polished rice was 1.73 mg/kg, with elimination of 92.1% of the pesticide residue. The rate of reduction in buprofezin levels during brown rice washing was 21.6-57.3%, and the residual level of buprofezin during polished rice washing decreased by 27.4-67.2%. When brown rice was cooked using an electric cooker and pressure cooker, buprofezin levels reduced by 51.7 and 55.5%, respectively. When washed polished rice was cooked using an electric cooker and pressure cooker, buprofezin levels reduced by 83.6 and 82.3%, respectively. When washed polished rice was soaked for 30 min and then cooked using an electric cooker and pressure cooker, buprofezin levels reduced by 87.1 and 88.0%, respectively. After processing polished rice into porridge, rice cakes, and cookies, the residue level of buprofezin decreased by 89.7, 82.0, and 79.4%, respectively, compared to the residual level in polished rice. In conclusion, various rice processing methods decrease the residue levels of buprofezin.

Occurrence and translocation of ustiloxins in rice false smut-occurred paddy fields, Hubei, China

Ustiloxin A (UA) and ustiloxin B (UB), two major mycotoxins produced by the pathogen of rice false smut (RFS) during rice cultivation, have attracted increasing attentions due to their potential health risks. However, limited data are available about their occurrence and fate in paddy fields and contamination profiles in rice. In this study, a field study was performed to investigate the occurrence and translocation of UA and UB in RFS-occurred paddies. For the first time to our knowledge, we reported a ubiquitous occurrence of the two ustiloxins in the paddy water (range: 0.01–3.46 μg/L for UA and <0.02–1.15 μg/L for UB) and brown rice (range: 0.09–154.08 μg/kg for UA and <0.09–23.57 μg/kg for UB). A significant positive correlation was observed between ustiloxin levels in paddy water and brown rice (rs = 0.48–0.79, p < 0.01). The occurrence of ustiloxin uptake in water-rice system was also evidenced by the rice exposure experiment, suggesting paddy water might be an important source for ustiloxin accumulation in rice. These results suggested that the contamination of ustiloxins in rice might occur widely, which was supported by the significantly high detection frequencies of UA (96.6%) and UB (62.4%) in polished rice (149 samples) from Hubei Province, China. The total concentrations of ustiloxins in the polished rice samples collected from Hubei Province ranged from <20.7 ng/kg (LOD) to 55.1 μg/kg (dry weight). Further studies are needed to evaluate the potential risks of ustiloxin exposure in the environment and humans.

Clinical profile of patients presenting with thiamine-responsive upper-gastrointestinal upset: A pointer toward gastric beriberi

ObjectivesAlthough beriberi is considered a forgotten disease in the West, Kashmir has a rice-eating population that has beriberi in endemic proportions. Patients with a thiamine deficiency (TD) occasionally present with gastrointestinal (GI) symptoms, including nausea, recurrent vomiting, loss of appetite, and abdominal discomfort. Together these often respond to thiamine, which points to gastric beriberi. MethodsPatients with GI symptoms suggestive of TD were recruited from the Department of Medicine at the Government Medical College and its associated hospital, SMHS, in Srinagar, India. Patients were evaluated for serum thiamine levels, serum lactate, biochemical parameters, and transabdominal ultrasonography after ruling out the usual causes of acute abdominal pain and vomiting. ResultsA total of 27 patients were recruited with a mean age of 47.28 ± 20.84 y. The mean lactate of patients at the time of admission was 6.43 ± 5.22 mmol/L, and the mean lactate at the time of discharge was 1.23 ± 0.50 mmol/L. All patients had a history of consuming polished rice, washed two to three times before cooking, as the staple diet. The most common GI symptoms were recurrent vomiting, nausea, and loss of appetite. All of the patients responded to the thiamine treatment, and showed improvement in their GI symptoms and decreased serum lactate levels within 2 to 6 h of their hospital stay. ConclusionsGastric beriberi is a rare presentation of TD that can lead to severe GI symptoms and lactic acidosis. Given the rapid response to thiamine, it is the standard-of-care treatment in such cases. Thus, clinicians should suspect TD when patients present with either mild or moderate-to-severe GI symptoms and raised blood lactate.

Trace Elements and Arsenic Speciation of Field and Market Rice Samples in contrasting Agro-climatic Zones in Sri Lanka

Rice is a major source for micro-elements for the Sri Lankan population, across all agro-climatic zones. This current study was conducted to investigate the variation of the metal(loid)s and As speciation in rice grains collected from wet, intermediate and dry zones of Sri Lanka. Field rice (brown rice) and market rice (polished rice) samples were analysed for total elemental profile and As speciation using ICP-MS and IC-ICP-MS, respectively. As, Cd, Co, Fe, Mn, Mo, Rb, Se, Sr and Zn in field grain samples varied across climatic zones. Highest median Cd, Cu, Mo, P, Rb, Se and Zn from wet zone; Co, Fe, Mn from intermediate zone; and As and Sr from dry zone were reported. Field rice (As, 0.3%; Cd, 1%) and market rice (As, 0%; Cd, 3%) samples exceeded maximum permissible levels of As and Cd. However, higher concentrations of both fields, 18% samples for As and 21% samples for Cd, and market, 7% samples for As and 38% samples for Cd, rice exceeded the recommended permissible levels of As and Cd in infant food according to EU regulations. The high per capita consumption and the chronic exposure to As and Cd through rice may cause adverse effects on Sri Lankan children and adults.

Effects of a Combined Processes of Low-Pressure Steam Enrichment and Low-Pressure Superheated Steam Drying on the γ-Aminobutyric Acid Content of Japonica Rice

In order to improve the content of GABA in japonica rice, so as to improve the nutritional composition and enhance the added value of rice, this study explored a combined process of low-pressure steam enrichment of γ-aminobutyric acid (GABA) content in japonica rice and low-pressure superheated steam (LPSS) drying of japonica rice. The low-pressure energy and the energy stored in rice grains were used to promote water absorption and activation of rice germs in a steam environment. Under the action of glutamate decarboxylase, the germ glutamate underwent an enzymatic reaction to generate GABA, which was transferred to and stored in the rice endosperm due to the concentration gradient and water gradient. After germination, LPSS was successively applied to dry the rice grains. The response surface method was used to optimize the parameters of low-pressure wet steam enrichment and LPSS drying of the rice grains. The experimental results showed that when the pressure was 0.026 MPa, the temperature was 60.66°C, the time was 5.01 h, and the flow rate was 0.31 L/h; the GABA content produced by low-pressure wet steam germination of japonica rice peaked at 94.1751 mg/100 g. When the germinated and enriched japonica rice was put through LPSS drying with a pressure of 0.021 MPa, a temperature of 66.55°C, a time of 1.57 h, and a flow rate of 0.28 L/h, the GABA content peaked at 104.161 mg/100 g. The results show that the combined process of low-pressure steam enrichment and drying continuously produced GABA in the soaking enrichment and drying stages, and the content of GABA in the drying stage accounted for 10% of the total content, which effectively increased the content of GABA in japonica rice and shortened the enrichment time. This study provides a technical reference for industrialized production of GABA-rich brown rice, embryonic rice, and polished rice.

Nutritional evaluation of different rice (Oryza sativa) straw of bio-fortified varieties, bio-fortified breeding lines and breeding lines

A total of 13 varieties of rice straw including eight biofortified varieties (BFV), two bio-fortified breeding lines (BBL), two breeding lines (BL) and one check variety of rice straw were subjected to straw quality evaluation. The Straw CP was negatively correlated with CF of straw and positively correlated with Iron and zinc content of brown rice and zinc content of polished rice. CF of rice straw was negatively correlated with important plant breeding parameters such as single plant dry weight, flag leaf length, iron content of brown rice, zinc content of both brown and polished rice. Improved bio-fortified breeding lines had more zinc than bio-fortified varieties indicating further scope of improvement of zinc content in straw. In vitro organic matter digestibility (IVOMD) ranged from 37.9 in DRR Dhan 45 to 49.6 in DRR Dhan49 with an average of 43.0 in different bio-fortified varieties. Thus, the straw obtained from different bio-fortified crops is valuable feed item which needs to be utilized in livestock rations.

Possibility for Prevention of Type 2 Diabetes Mellitus and Dementia Using Three Kinds of Brown Rice Blends after High-Pressure Treatment.

As it has been reported that type 2 diabetes mellitus increases the risk of Alzheimer’s disease, we investigated how to prevent type 2 diabetes and dementia using biofunctional boiled rice. We adopted unpolished super-hard rice (SHBR) for diabetes and wax-free unpolished black rice (WFBBR) for dementia and blended those with ordinary non-polished rice (KBR) (blending ratio 4:4:2), adding 2.5% waxy black rice bran (WBB) and 0.3% rice oil after high-pressure treatment (HPT) (WFBSK) to improve its palatability. This boiled rice is rich in dietary fiber, anthocyanin, free ferulic acid and β-secretase inhibitory activity. A randomized, parallel-group comparison study was conducted for 12 weeks with 24 subjects, using Cognitrax to evaluate their cognitive function primarily. Furthermore, as the secondary purpose, we performed a single-dose test for postprandial blood glucose and insulin secretion at the end of the human intervention test. After 12 weeks, consumers of the WFBSK rice exhibited significant improvement in language memory by cognitive test battery compared with those who consumed the control white rice (p < 0.05). Moreover, subjects who consumed the WFBSK rice had lower insulin secretion levels than those who consumed the control polished rice (p < 0.05).

Irrigation and phosphorous fertilization management to minimize rice grain arsenic content

This research sought to minimize inorganic arsenic levels in polished rice grain by using different irrigation and phosphorous fertilization practices while also maintaining crop yield and water productivity. Two experiments were conducted during seasons 2018–2019 and 2019–2020 using a split-plot design with three blocks, five irrigation treatments (main-plots) and two phosphorous levels (sub-plots). Irrigation treatments consisted of a traditional continuous flood (CF) control and four alternatives irrigation techniques with one or two drying events during the irrigation cycle. The phosphorous fertilization levels investigated were an unfertilized control (0 kg P2O5 ha−1) and the recommended fertilization level of 50 kg P2O5 ha−1. Soil pH and redox potentials were measured in each treatment. Strategically-timed, low severity drying events were effective at achieving aerobic soil conditions, resulting in Eh values over 50 mV. The alternative irrigation treatment with two drying events, implemented at panicle initiation and full flowering, was the most effective in reducing inorganic arsenic in grain without affecting grain yield or the amount of irrigation water applied. This irrigation technique could be considered as an alternative management to the traditional continuous flooded to reach minimal inorganic arsenic accumulation in grain in order to attend special quality standards or specific market requirements. Accumulated inorganic arsenic in grain was below international maximum levels in all analyzed samples, with an average value of 0.084 mg kg−1.

Widespread Occurrence of the Highly Toxic Dimethylated Monothioarsenate (DMMTA) in Rice Globally.

Arsenic (As) accumulation in rice is of global concern for human health and international trade. Rice is typically reported to contain inorganic As (iAs) and dimethylated arsenate (DMA), with current food guidelines limiting toxic iAs but not less-toxic DMA. Here, we show that the highly toxic dimethylated monothioarsenate (DMMTA) is also found in rice worldwide and has been unknowingly determined as less-toxic DMA by previous routine analytical methods. Using enzymatic extraction followed by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) analysis with a C18 column, DMMTA was detected in rice grains (n = 103) from a field survey from China and in polished rice grains (n = 140) from a global market-basket survey. Concentration ranged from <0.20 to 34.8 μg/kg (median 10.3 μg/kg), accounting for 0 to 21% of total As. A strong linear correlation was observed in all rice samples between DMA and DMMTA (being 30 ± 8% of DMA) concentrations. This robust relationship allows an estimation of DMMTA in rice grains from the DMA data reported in previous market-basket surveys, showing a general global geographical pattern with DMMTA concentration increasing from the equator toward high-latitude regions. Based on the global occurrence and potential high toxicity, DMMTA in rice should be considered in health risk assessments and for setting food regulations.

Starch Molecular Structural Features and Volatile Compounds Affecting the Sensory Properties of Polished Australian Wild Rice.

Cooked high-amylose rices, such as Australian wild rice (AWR) varieties, have slower digestion rates, which is nutritionally advantageous, but may have inferior eating qualities. Here, a comparison is made between sensory and starch molecular fine structure properties, and volatile compounds, of polished AWR varieties and some commercial rices (CRs). Starch structural parameters for amylopectin (Ap) and amylose (Am) were obtained using fluorophore-assisted capillary electrophoresis and size-exclusion chromatography. Volatile compounds were putatively using headspace solid-phase microextraction with gas chromatography-mass spectrometry. Sensory properties were evaluated by a trained panel. AWR had a disintegration texture similar to that of Doongara rice, while AWR had a resinous, plastic aroma different from those of commercial rice varieties. Disintegration texture was affected by the amounts of Ap short chains, resinous aroma by 2-heptenal, nonadecane, 2h-pyran, tetrahydro-2-(12-pentadecynyloxy)-, and estra-1,3,5(10)-trien-17β-ol, and plastic aroma by 2-myristynoyl pantetheine, cis-7-hexadecenoic acid, and estra-1,3,5(10)-trien-17β-ol. These findings suggest that sensory properties and starch structures of AWR varieties support their potential for commercialization.

Steaming retains more phenolics, dietary fiber, and antioxidant activities than cooking for rice with different milling processes

AbstractBackground and objectivesThe traditional heat processing methods, steaming and cooking treatment, can affect the nutrients in rice, such as phenolics, flavonoids, and dietary fiber. However, there is no systematic assessment that by which heat treatment method and conditions more nutrients in rice can be retained, especially in brown rice, two‐times milling rice, four‐times milling rice, polished rice, and color selection rice (from different milling processes with practical processing at rice milling factory). The aim of this study was to investigate the effect of steaming and cooking treatment on the changes in nutrients in rice with different milling processes, including dietary fiber and phenolic acids, flavonoids, anthocyanins, individual phenolic compounds, antioxidant activities (DPPH, ABTS, and T‐AOC) in the free, and bound extracts.FindingsCompared with unsteamed and uncooked rice, the total phenolic content (TPC), the total flavonoid content (TFC), and individual phenolic compounds in the free and bound fractions, total anthocyanin content (TAC), and antioxidant activity in the free fractions in brown rice, two‐times milling rice, four‐times milling rice, polished rice, and color selection rice were significantly reduced by steaming and cooking treatment (p &lt; .05). The TAC and antioxidant activity in the bound fractions, soluble dietary fiber (SDF), insoluble dietary fiber (IDF), and total dietary fiber (TDF) in the five rice samples were increased after steaming and cooking. However, it was very interesting that steaming treatment resulted in a less reduction in phenolics and antioxidant activities than cooking.ConclusionsFrom the view of retaining more nutrients, steaming treatment is more suitable for the white rice of the milling process with high milling degree, while cooking treatment is more suitable for the brown rice or rice of milling process with low milling degree. Generally, steaming treatment retains more phenolics, dietary fiber, and antioxidant activities than cooking rice with different milling processes.Significance and noveltyThis study may provide useful reference and offer a simple and practical method to retain more nutrients for preparation and consumption of rice. These results suggest that steaming treatment is an efficient method of daily processing to reduce the loss of nutrients in rice.

English

Dry matter digestibility (DMD), dry matter intake (DMI) and growth performance of concentrate- and forage-based diets were investigated using 24 growing Blended goats (12 males, 12 females) weighing 16.5&plusmn;1.2 kg (mean&plusmn;sd). Goats were blocked by sex and assigned randomly to three dietary treatments that were fed for 10 weeks, after two weeks of adaptation. Dietary treatments were MRG (40% maize bran, 40% rice bran, 20% Gliricidia leaf meal), BG (80% Brachiaria brizantha cv. Piat&atilde;, 20% Gliricidia leaf meal) and CG (80% Cenchrus ciliaris, 20% Gliricidia leaf meal). All diets contained sufficient nutrients to meet the requirements of growing goats. The MRG diet had lower DMI than CG, likely because MRG had small particle size and goats adapted slowly to that diet. Average daily weight gain was 10.7, 9.9 and 22.8 g/day for MRG, BG, and CG respectively, and did not differ among the diets. Goats fed MRG had lower overall live weight change than goats fed CG, while goats fed BG were intermediate. These findings indicate that B. brizantha cv. Piat&atilde; and C. ciliaris are equally useful as supplementary feedstuffs for growing goats during the dry season. Key words: Brachiaria brizantha cv. Piat&atilde;, Cenchrus ciliaris, maize bran, rice polish, Gliricidia sepium.

Effect of the varying inclusion levels of the egg yolk powder on growth, stress tolerance, and pigmentation of Guppy (Poecilia reticulata)

ABSTRACT The newly hatched nauplii of Artemia is extensively used as a live feed for ornamental fish hatchlings; however, its high cost and unbalanced nutrients necessitate exploring sustainable alternatives. An experiment was conducted to evaluate the effects of four formulated diets of 0%,5%, 10%, and 20% inclusion levels of egg yolk powder and other ingredients (fish meal, soybean meal, rice polish, corn) during the nursery stage of Guppy (Poecilia reticulata) compared to Artemia salina as a control. Results showed that survival did not differ (P > 0.05) among the diets. Weight gain, daily weight gain, and specific growth rate of the fry fed with 10% egg yolk-included diet containing 49.6% fish meal and 18.8% soybean meal were significantly higher (P < 0.05) than those of the other test diets and the A. salina. All the diets showed higher stress indexes (P < 0.05) than the control; the test diets did not affect pigmentation.

Deep learning based high-throughput phenotyping of chalkiness in rice exposed to high night temperature

BackgroundRice is a major staple food crop for more than half the world’s population. As the global population is expected to reach 9.7 billion by 2050, increasing the production of high-quality rice is needed to meet the anticipated increased demand. However, global environmental changes, especially increasing temperatures, can affect grain yield and quality. Heat stress is one of the major causes of an increased proportion of chalkiness in rice, which compromises quality and reduces the market value. Researchers have identified 140 quantitative trait loci linked to chalkiness mapped across 12 chromosomes of the rice genome. However, the available genetic information acquired by employing advances in genetics has not been adequately exploited due to a lack of a reliable, rapid and high-throughput phenotyping tool to capture chalkiness. To derive extensive benefit from the genetic progress achieved, tools that facilitate high-throughput phenotyping of rice chalkiness are needed.ResultsWe use a fully automated approach based on convolutional neural networks (CNNs) and Gradient-weighted Class Activation Mapping (Grad-CAM) to detect chalkiness in rice grain images. Specifically, we train a CNN model to distinguish between chalky and non-chalky grains and subsequently use Grad-CAM to identify the area of a grain that is indicative of the chalky class. The area identified by the Grad-CAM approach takes the form of a smooth heatmap that can be used to quantify the degree of chalkiness. Experimental results on both polished and unpolished rice grains using standard instance classification and segmentation metrics have shown that Grad-CAM can accurately identify chalky grains and detect the chalkiness area.ConclusionsWe have successfully demonstrated the application of a Grad-CAM based tool to accurately capture high night temperature induced chalkiness in rice. The models trained will be made publicly available. They are easy-to-use, scalable and can be readily incorporated into ongoing rice breeding programs, without rice researchers requiring computer science or machine learning expertise.

The promoted hydrolysis effect of cellulase with ultrasound treatment is reflected on the sonicated rather than native brown rice

Brown rice is nutritionally superior to polished white rice, as it maintains a large content of external bran that involves a series of bioactive compounds. However, the presence of bran also restricts water diffusion and results in adverse quality of brown rice. In this work, ultrasound conditions were optimized for cellulase to improve its hydrolysis effect on rice bran, and combinations of enzymatic and ultrasound treatment in different manners were conducted on brown rice, to improve the textural attributes. The results showed significant improvements in the catalytic activity and efficiency of cellulase after ultrasonication at the optimal intensity of 1.67 W cm−3 and duration of 30 min, with the conformational variation of cellulase observed from the fluorescence spectra and circular dichroism (CD). Despite the enhanced activity of ultrasonicated cellulase, it leaded to a similar rice surface morphology and a comparable amount of released glucose, and equivalent textural parameters of brown rice treated by native cellulase. However, for the pre-sonicated brown rice, the ultrasonicated cellulase showed a significantly higher hydrolysis capacity than the untreated enzyme, suggesting the important influence of ruptured bran surface on amplifying the hydrolysis effect of cellulase. Compared to the successive ultrasound stimulation on both cellulase and brown rice, ultrasound-assisted cellulase treatment on brown rice produced less glucose from rice bran, but induced similar textural properties of brown rice, possibly resulting from the simultaneously promoting effect of ultrasonication on cellulase and water diffusion. Ultimately, this study highlighted that the mild rice surface rupture is a crucial factor to display the promoted hydrolysis effect of ultrasonicated cellulase on brown rice. Ultrasound-assisted cellulase treatment potentially provides an effective strategy to improve the edible quality of brown rice.

Comparison Studies on Several Ligands Used in Determination of Cd(II) in Rice by Flame Atomic Absorption Spectrometry after Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction.

Ligands plays an important role in the extraction procedures for the determination of cadmium in rice samples by using flame atomic absorption spectrometry (FAAS). In the present study, comparative evaluation of 10 commercially available ligands for formation of Cd(II)-ligand complex and determination of cadmium in rice samples by ultrasound-assisted dispersive liquid–liquid microextraction (UADLLME) combined with FAAS was developed. Sodium diethyldithiocarbamate (DDTC) provided a high distribution coefficient as well as a good absorbance signal, therefore DDTC was used as a ligand in UADLLME. A low density and less toxic solvent, 1-heptanol, was used as the extraction solvent and ethanol was used as the disperser solvent. In addition, the experimental conditions of UADLLME were optimized in standard solution first and then applied in rice, such as the type and volume of extractant and dispersant, pH, extraction time, and temperature. Under the optimal experimental conditions, the detection limit (3σ) was 0.69 μg/L for Cd(II). The proposed method was applied for the determination of Cd(II) in three different rice samples (polished rice, brown rice, and glutinous rice), the recovery test was carried out, and the results ranged between 96.7 to 113.6%. The proposed method has the advantages of simplicity, low cost, and accurate and was successfully applied to analyze Cd(II) in rice.

Optimization of process parameters for quick cooking rice

Instant rice is prepared by soaking followed by precooking and dehydration. Instant rice is rice that has been fully cooked and then dried down to below 12% moisture. Instant rice can then be recooked by the consumer in 2-5min compared to 20min required to cook the polished raw rice. The present research is carried out with soaking time (5, 10, 15 and 20 min) and soaking temperature (45, 50, 55, 60, 65 and 70o C), cooking methods (electric cooker and pressure cooker), cooking duration (4, 8 and 12 min) and drying methods (microwave oven and hot air oven) on the three varieties of long-grain, medium-grain and short grain rice. The cooking is being carried out by pressure cooker, electric for 3, 5 and 8 min and dried by microwave oven. The cooked rice is dried by hot air oven and by microwave in such a way as to leave the desired degree of porosity and fissuring in the final product.It was observed that the rice samples of short grain variety (BPT 5204) were cooked for 8 min by both electric cooker and pressure cooker and the reconstitution time varying from 7 min- 8 min were found to be having good texture compared to other samples. The long grain rice cooked for 8 min was comparatively of better quality when compared to the rice samples at other cooking durations of 4 and 12 min. But the reconstitution time of instant rice was observed to be more compared to other two varieties. The best quality of instant rice was found in Short grain rice (BPT 5204) followed by Medium grain rice (Sona Masuri 1768) and then Long Grain rice (NLR 145).