Article

Cooking rice in excess water reduces both arsenic and enriched vitamins in the cooked grain

Taylor & Francis
Food Additives & Contaminants Part A
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Abstract

This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. Cooking rice in excess water efficiently reduces the amount of As in the cooked grain. Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice. Iron, folate, niacin and thiamin are reduced by 50-70% for enriched polished and parboiled rice, but significantly less so for brown rice, which is not enriched.

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... Reduction in iron content was similar in all the rice to water ratio. Increasing amount of reduction in vitamins was observed on increasing water in respect to rice Gray et al. (2016) Parboiling (husked and polished rice) Rice was parboiled in 1:10 rice to water ratio Parboiling resulted in significant reduction in amount of arsenic along with essential micro-and macronutrients Mwale et al. (2018) Washing and cooking Rice was cooked in two different rice to water ratios, i.e., 1:3 and 1:6 ...
... Pogoson et al. (2021) used easily available household food safe chemicals (citric acid and calcium carbonate) for pH-dependent soaking and found a 63% decrease in the level of As in cooked rice. During washing and cooking of rice in different rice-to-water ratios, approximately 6-80% lessening in grain As levels was observed by different research groups (Atiaga et al., 2020;Gray et al., 2016;Halder et al., 2014;Mandal et al., 2019;Mihucz et al., 2007;Mwale et al., 2018;Raab et al., 2009;Sharafi et al., 2019). The different studies showing specific As removal treatments and their effect on rice grain are summarized in Table 1. ...
... Washing in different rice-to-water ratios, before cooking, significantly decreased the levels of K (50%), Mg (22%), and Ca (15%), along with micronutrients such as Mn (17-29%), Zn (8-30%), Fe (4-93%), Cu (0.2-29%), Mo (39%), Se (12%), Co (21-32%), and Ni (45-54%), in rice grain. Gray et al. (2016) noticed that the removal of Fe in brown long grain rice was significantly lower (4-10%) than that in white and parboiled rice (35-93%) during washing and cooking. They also reported a significant decrease in the level of vitamins, viz., vitamins B 1 , B 3 , and B 9 from vitamin-enriched rice after washing. ...
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Rice (Oryza sativa L.) is particularly susceptible to arsenic (As) accumulation. Currently, to decrease the level of As accumulated in rice, various post-harvest methods, i.e., polishing, parboiling, pH-dependent soaking, washing, and cooking at different rice-to-water ratios (r/w), are being focused, because it removes significant amount of As from rice grain. Depending upon the rice variety and type, i.e., rough (with husk), husked (without husk/brown), or polished rice, these methods can remove 39–54% As by parboiling, 38–55% by polishing, 37–63% by soaking, and 6–80% by washing and cooking. Infants are highly vulnerable to As exposure; thus, these methods can be helpful for the production of rice-based infant foods. Although concern arises during the use of these methods that apart from decreasing the level of As in rice grain, they also lead to a significant loss of nutrients, such as macro- and micro-elements present in rice. Among these discussed methods, parboiling curtails 5–59%, polishing curtails 6–96%, soaking curtails 33–83%, and washing and cooking in different r/w reduce 8–81% of essential nutrients resulting in 2–90% reduction in contribution to the RDI of these nutrients through rice-based diet. Thus, these post-harvest arsenic removal methods, although reduce arsenic induced health hazard, but may also lead to malnutrition and compromised health in the population based on rice diet. There is a need to explore another way to reduce As from rice without compromising the nutrient availability or to supplement these nutrients through grain enrichment or by introducing additional dietary sources by changing eating habits; however, this may impose an extra economic burden on people. Graphical Abstract
... Likewise, Mandal et al. (2019) showed that washing rice thrice and then cooking in excess water having As contamination resulted in a 56 % increase in As level in cooked rice. However, using As-free water, an average 30 to 80 % reduction in As in cooked rice has been reported in several studies (Mihucz et al., 2007;Raab et al., 2009;Halder et al., 2014;Gray et al., 2016;Mwale et al., 2018;Mandal et al., 2019;Sharafi et al., 2019b;Atiaga et al., 2020) (Fig. 2). Washing rice thrice in 1:2 (r/ w) and cooking in 1:6 (r/w) reduced up to 45 % As in cooked rice (Mihucz et al., 2007;Mihucz et al., 2010). ...
... However, they found a negligible effect of washing on the level of As by using 1:6 (r/w). Gray et al. (2016) used a similar r/w (1:6) for washing and found a minimal effect on the As content in cooked rice. However, cooking at 1:2, 1:6 and 1:10 (r/w) removed up to 6 %, 35 % and 48 % of tAs in cooked rice, respectively. ...
... The rinse cooking method is traditionally followed in West Bengal and Bangladesh, where 3 to 4 times the amount of water is used. However, most of the studies have shown an average 30-35 % reduction in tAs by using 1:6 (r/w) for washing and cooking (Raab et al., 2009;Halder et al., 2014;Gray et al., 2016;Mwale et al., 2018), and up to 80 % As removal has been achieved by increasing the washing frequency (up to 5 times) and cooking in excess water (1:10) (Mandal et al., 2019;Sharafi et al., 2019b;Atiaga et al., 2020) (Fig. 2). ...
Article
Food-chain arsenic (As) contamination is a severe environmental and health problem worldwide, and its intake through rice affects billions of people. In this review, we have summarized the post harvest As removal methods from rice and their efficacy and feasibility. Rice grain subspecies (indica and japonica), size (short, medium and long), type (husked, parboiled or polished), soaking time, temperature and rice to water ratio (r/w) during washing and cooking are the major factors that affect the removal of total arsenic (tAs) from rice grain. The reduction in tAs was greater in japonica than indica rice and was directly proportional to As in husked rice. For the removal of As, a low water volume (1:2 r/w) was more effective during washing due to friction between rice grains, while high water (≥4 times water) during cooking was more effective. Up to 80 % As was removed by cooking in 1:10 (rice: water). Soaking rice in edible acids such as vinegar, acetic and ascorbic acid was not effective, except citric acid, which removes tAs up to 63 %. Human-health risk assessment showed that these post harvest and cooking methods reduce the non-carcinogenic and incremental lifetime cancer risk by up to 5-fold, as calculated on the basis of bioaccessible inorganic As. These pre harvest methods also remove nutrient elements and vitamins. The recommended dietary intake (RDI) of Zn and Cu was particularly affected (up to 40 and 83 %). The levels of P, Mo, Mn and Co were still sufficient to meet the RDI through the rice-based diet, while rice is already poor in the RDI of Ca, K, Fe and Se, and their levels were further reduced by 0.22-44 %. Thus, these post harvest and cooking methods may significantly reduce As induced health risks; however, other dietary sources of nutrients need to be carefully evaluated and supplemented.
... Another study reported that cooking rice with deionized water (1:6 ratio) can remove around 35% and 45% of total and inorganic As concentrations from long-grain and basmati rice, respectively [25]. Similarly, cooking of rice with excess water (1:10 rice: water ratio) removed inorganic As by 50%, 60%, and 40% in brown rice, parboiled, and long grain polished rice, respectively [26]. ...
... Atiaga, et al. [38] reported that cooking of white and brown rice with excess water (1:6 rice: water) can reduce inorganic As by 60% (range 29-90%). Similarly, a 40% and 50% reduction in inorganic As from long white and brown rice accordingly was reported by Gray, et al. [26], when rice grains were cooked with a high rice to water ratio (1:6-10). Carey, et al. [39] also found a 53% reduction in inorganic As from white rice when cooked with a larger amount of water (1:12 rice to water ratio). ...
... Very few studies have investigated the concentration of TEs and micronutrients in cooked rice [1,18,26]. The major concern was As removal from rice by various cooking procedures, but data on As speciation (inorganic and organic), Cd, and Pb, along with loss of essential nutrient elements are still lacking with regard to the suitable rice washing and cooking method for different rice grains. ...
Article
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This study determined the influence of different cooking procedures on the removal of toxic elements (TEs) including arsenic (As), cadmium (Cd), and lead (Pb) along with other nutrient elements from different commercially available rice brands sold in Bangladeshi markets. We observed 33%, 35%, and 27% average removal of As, Cd, and Pb accordingly from rice when cooked with a rice to water ratio of 1:6 after washing 5 times. We also found a significant reduction in essential elements: Zn (17%), Cu (10%), Mn (22%), Se (49%), and Mo (22%), when rice cooking was performed as in traditional practice. Daily dietary intakes were found to be between 0.36 and 1.67 µg/kgbw for As, 0.06 and 1.15 µg/kgbw for Cd, and 0.04 and 0.17 µg/kgbw for Pb when rice was cooked by the rice cooker method (rice:water 1:2), while in the traditional method (rice:water 1:6) daily intake rates ranged from 0.23 to 1.3 µg/kgbw for As, 0.04 to 0.88 µg/kgbw for Cd, and 0.03 to 0.15 µg/kgbw for Pb for adults. The HQ and ILCR for As, Cd, and Pb revealed that there is a possibility of noncarcinogenic and carcinogenic risk for As but no appreciable risk for Cd and Pb from consumption of rice.
... The traditional cooking method in which the high volume of water is used to boil rice and the excessive amount of water is discarded after the rice is cooked can significantly reduce the As concentration in the cooked grain. It was found that~15, 30, and 40-60% of As reduction in cooked rice was observed with water to rice ratio of 6 : 1 to 10 : 1 and 12 : 1 respectively (Gray et al. 2015;Carey et al. 2015). This may be caused by the release of easily mobile As species, As(III) in particular, into the surplus water which is discarded later (Raab et al. 2009). ...
... This method is popular due to being simple and easy. However, rice cooked by this method generally contained higher grain As than that of traditionally cooked ones (Raab et al. 2009;Gray et al. 2015;Liu et al. 2017;Liu et al. 2018). Cooking time and rice variety also affect the concentration of As in the cooked rice (Mandal et al. 2019). ...
... Cooking time and rice variety also affect the concentration of As in the cooked rice (Mandal et al. 2019). The choice of rice cooking also requires an optimum risk and benefit balanced decision as cooking rice with excessive water may result in the higher loss of nutritional values of rice (Gray et al. 2015;Shariatifar et al. 2020). ...
Article
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Widespread distribution, toxicity and exposure through rice and rice-based food products make arsenic (As) contamination of environment a serious issue. This review discusses various strategies that can be utilised to tackle the As problem in rice, and the socioeconomic impacts of the As problem. The countries of south and south-east Asia are renowned as hotspots of As contamination owing to occurrence and enrichment of As in soil and groundwater via natural biogeochemical weathering of rocks and As-enriched sediment. The irrigation of rice is mostly applied through the use of contaminated groundwater leading to high As accumulation in rice grains. The intensification of research to address the problem of As in rice has been seen in the past two decades. It has been realised that appropriate irrigation water management, which acts as a major driver of As chemistry in soil and As uptake and transport in plants, can be an easy and affordable solution. Further, balanced supplement of various nutrient elements like selenium (Se), silicon (Si), sulfur (S), nitrogen (N), iron (Fe) and zinc (Zn) has been found to impart dual benefits in terms of reduced As toxicity as well as enhance the nutritional quality of rice grains. Several other agronomic and biotechnological approaches, processing, and cooking methods of rice were found to have profound impacts on rice As and its speciation from farms to table.
... However, irrespective of the washing procedure, sequential washing with deionized water have shown to reduce the arsenic content in the washed rice grains (Jitaru et al., 2016;Liu et al., 2018). Therefore, washing of rice with low arsenic water may be beneficial and can be a modification at kitchen level to reduce arsenic in cooked rice, although maybe at the expenses of some loss of essential nutrients (Gray et al., 2016). ...
... However, when rice is cooked in excess water with low arsenic concentration, the inorganic arsenic is leached out of the rice during cooking at high temperature and efficiently decreases the total and inorganic arsenic content in cooked rice (Halder et al., 2014;Jitaru et al., 2016;Chowdhury et al., 2020). A relatively higher amount of cooking water (deionized water) has shown to reduce the inorganic arsenic content by 40%, 60%, and 50% in long-grain polished, parboiled, and brown rice respectively (Gray et al., 2016). Investigations involving an alternate method of cooking in a continual stream of percolating low arsenic water near boiling have shown 59% and 69% removal of inorganic arsenic in cooked rice compared to uncooked polished and whole grain rice, respectively (Carey et al., 2015) and 96% of inorganic arsenic in cooked bran (Signes-Pastor et al., 2017). ...
... Overall, the habit of cooking with excess water with low arsenic concentration rice can be considered as a decontamination process with the eventual decrease in cooked rice arsenic content, then the raw rice (Sengupta et al., 2006;Gray et al., 2016;Jitaru et al., 2016;Mandal et al., 2019;Chowdhury et al., 2020).Use of filtered water for cooking results in 61% tAs load in cooked rice from its raw counterpart whereas, the same for contaminated water is 73% (Basu et al., 2015). Therefore, the traditional method of rice cooking with low arsenic water and gruel discarded can be an interim intervention strategy to reduce the exposure of arsenic from the consumption of rice. ...
Article
Arsenic (As) contamination and its adverse consequences on rice agroecosystem are well known. Rice has the credit to feed more than 50% of the world population but concurrently, rice accumulates a substantial amount of As, thereby compromising food security. The gravity of the situation lays in the fact that the population in theAs uncontaminated areas may be accidentally exposed to toxic levels of As from rice consumption. In this review, we are trying to summarize the documents on the impact of As contamination and phytotoxicity in past two decades. The unique feature of this attempt is wide spectrum coverages of topics, and that makes it truly an interdisciplinary review. Aprat from the behaviour of As in rice field soil, we have documented the cellular and molecular response of rice plant upon exposure to As. The potential of various mitigation strategies with particular emphasis on using biochar, seed priming technology, irrigation management, transgenic variety development and other agronomic methods have been critically explored. The review attempts to give a comprehensive and multidiciplinary insight into the behaviour of As in Paddy –Water – Soil – Plate prospective from molecular to post-harvest phase. From the comprehensive literature review, we may conclude that considerable emphasis on rice grain, nutritional and anti-nutritional components, and grain quality traits under arsenic stress condition is yet to be given. Besides these, some emerging mitigation options like seed priming technology, adoption of nanotechnological strategies, applications of biochar should be fortified in large scale without interfering with the proper use of biodiversity.
... Though there are many investigations on this topic, only a few of them reported iAs data. For instance, washing or rinsing rice in cold water was found to reduce iAs in white rice by 10-40% (Atiaga et al., 2020;Gray et al., 2015;Naito et al., 2015;Raab et al., 2009). Others have reported~5% reduction in total As (tAs, which the sum of iAs and oAs) upon washing 3-5 times (Mandal et al., 2019;Sharafi et al., 2019). ...
... For example, a recent study (Atiaga et al., 2020) used both white and brown rice and cooked with excess water (1:6 rice to water ratio); this treatment reduced iAs 60% (mean), with variation (range: 29-90%) observed between the rice types. Similarly, Gray et al. (2015) reported that rice cooked with excess water cooking (1:6-10 rice to water ratio) reduced iAs by 40% from long white rice and 50% from brown rice. Carey et al. (2015) used percolating cooking water to remove arsenic and found that iAs removal effectiveness is linearly related to the amount of water used in cooking and found that highest water ratio (1:12 rice to water ratio) removed 53 ± 5% from white rice and 61 ± 3% from brown rice. ...
... There are only a few studies that investigated the micronutrient concentrations along with As in cooked rice. In their study, Gray et al. (2015) reported that rinsing brown rice does not significantly reduce Fe, Mn or vitamin (folate, niacin and thiamine) contents whereas the same treatment for white rice removed 90% of Fe and 80% of the vitamins. When brown and white rice was cooked with excess water, the loss of Fe was not significant for brown rice whereas both moderate and high volume excess water cooking (1:6-10 rice to water ratio) removed as much as 70% Fe and on average 50% reduction of vitamins from white rice. ...
Article
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Inorganic arsenic (iAs) is a group 1 carcinogen, and consumption of rice can be a significant pathway of iAs exposure in the food chain. Although there are regulations in place to control iAs for marketed rice in some countries, additional measures are explored to remove arsenic from rice. Due to the surface-bound and soluble nature of iAs, previous studies have shown that it can be removed to a significant extent using different cooking methods. Towards this goal we modified and tested the absorption method in combination with four home-friendly cooking treatments (UA = unwashed and absorbed, WA = washed and absorbed, PSA = pre-soaked and absorbed, and PBA = parboiled and absorbed) using both brown and white rice (3 types each). The nutrient elements were measured using ICP-MS and arsenic speciation was carried out using LC-ICP-MS. Overall, our results show that PBA was the optimum approach assessed, removing 54% and 73% of inorganic arsenic (iAs) for brown and white rice respectively, raising the margin of exposure (MOE) by 3.7 for white rice and 2.2 times for brown rice, thus allowing the consumption of rice more safely for infants, children and adults. Other cooking treatments were effective in reducing the iAs concentration from white rice only. Here we also report changes in selected nutrient elements (P, K, Mg, Zn and Mn) which are relatively abundant in rice. In general, the treatments retained more nutrients in brown rice than white rice. No significant loss of Zn was observed from both rice types and the loss of other nutrients was similar or less than in comparison to reported losses from rice cooked in excess water in the literature. We conclude that PBA is a promising technique and further research is needed by including different regional rice types and water quality levels.
... Traditional East Asia rice cooking method consists of washing and cooking in low-volume (W/R 1.4-2) water to dryness. The same method is practiced in the United States (Gray, Conklin, Todorov, & Kasko, 2016). In these regions, programmable rice cookers are available that are designed for this preparation method. ...
... Cooking to dryness removes no As (Naito, Matsumoto, Shindoh, & Nishimura, 2015), so pretreatment is the only way to reduce As. Washing with W/R 6 for 180 s removed an average of 11% iAs from white and parboil rice, but fail to reduce iAs in whole-grain rice (Gray et al., 2016). Triple washing (W/R 1.33) with agitation reduced iAs by 17%-29% for a white rice with 90% degree of polishing (DP), but only by 3% for brown rice (Naito et al., 2015). ...
... Rinsing or soaking rice in water, or cooking rice in excess water inevitably reduces water-soluble nutrients to a significant degree. Reduction of vitamins including folate, thiamin, and niacin (Gray et al., 2016) and essential metals including Fe, Cu, Co, and Zn was investigated. Such undesirable effects are costs of water rinsing or soaking. ...
Article
Background and objectives Rice contains an order of magnitude higher inorganic arsenic (iAs), a class 1 non‐threshold carcinogen, than other terrestrial crops. To reduce iAs in cooked rice, several methods have been proposed such as washing until clear, cooking with high water‐to‐rice ratio (W/R) then discarding excess water, or continuously percolating near‐boiling water. The traditional method practiced by 1.6 billion East Asians, washing and cooking with low W/R until dry, removes only a small percentage of iAs. Effective approach is needed to reduce iAs in cooked rice. Findings Brief (10 min) soaking (W/R 10) at above‐gelatinization‐temperature (80 ℃) reduced iAs in rice by up to 48.4%. A soaking protocol was developed for public use that on average reduced 39.5±6.6% (n=12) iAs in non‐waxy white rice. Conclusions Brief above‐gelatinization‐temperature soaking effectively reduces iAs in cooked white rice. Significance and novelty Above‐gelatinization‐temperature soaking was applied for the first time to cut iAs in cooked rice; hopefully, rice consumers can reduce chronic iAs intake and cancer risks.
... Prolonged exposure to arsenic is associated with adverse health effects, including the development of skin, bladder and lung cancers. 4 In 2013, the US Food and Drug Administration conducted a comprehensive assessment of arsenic levels in 482 samples of rice and 1300 rice-containing products. 5 In addressing the issue of arsenic contamination in rice, Gray et al. 4 proposed a practical approach by advocating the rinsing of rice with excess water, resulting in a potential reduction of arsenic levels by up to 60%. ...
... 4 In 2013, the US Food and Drug Administration conducted a comprehensive assessment of arsenic levels in 482 samples of rice and 1300 rice-containing products. 5 In addressing the issue of arsenic contamination in rice, Gray et al. 4 proposed a practical approach by advocating the rinsing of rice with excess water, resulting in a potential reduction of arsenic levels by up to 60%. However, it is crucial to acknowledge that rice with high moisture content results in a limited shelf life due to biochemical and microbiological activities. ...
Article
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BACKGROUND In this work, water transition points (first transition: monolayer–multilayer water; and second transition: multilayer–free and solvent water) of different parts of jasmine rice including white rice, brown rice and bran were identified through the integration of sorption isotherm and dielectric properties data. Desorption isotherm data were fitted to four established models to select the optimal model for describing the sorption behaviors. Then, dielectric properties such as dielectric constant (ε′) and dielectric loss factor (ε″) were measured across various moisture content levels within the frequency range of 200–20 000 MHz. RESULTS A type III isotherm was observed for all samples and the Peleg model was the best fit with the experimental data. Monolayer moisture content of the samples, estimated using the GAB model, ranged from 3.25% to 4.17% dry basis. For dielectric properties, frequency and moisture dependencies were evident for all sample types. Moreover, the sorption isotherm models effectively described the relationship between water activity (aw) and dielectric properties as reflected by their goodness of fit, and their strong correlation through principal component analysis and Pearson's correlation results. CONCLUSION The first water transition occurs at aw values of 0.11, 0.12, and 0.22, while the second transition appears at aw values of 0.9, 0.9 and 0.75–0.85 for white rice, brown rice and bran, respectively. This knowledge will be useful for food processors, providing insights into the optimization of food processing and storage conditions to extend food products' shelf life. © 2024 Society of Chemical Industry.
... On the other hand, it allows for a significant (Al, 29-42% on average) or small (As, 5.3-9.3% on average) removal of non-essential/toxic elements from the rice grains. This agreed with the literature data, where washing the rice grains three or five times resulted in a transfer of up to 8% of their total As to water [18]. Therefore, it should be taken into account that the pre-washing/rinsing of rice can affect the original content of the elements in its grains and may change the quality of the prepared RWMs. ...
... Satisfactorily, it could be reduced by half (to~9 ng g −1 ) when BRs are selected for the RW preparation due to a much lower extraction percentage of As (~20%) for this type of rice. It is in agreement with already published results showing that when rice is three times rinsed and then cooked in a six-fold excess of water, As is removed in 31% [18]. A lower degree of the As transfer for BR (despite a higher As content in raw rice) compared to WR was also observed [27]. ...
Article
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Although rice is a well-known source of nutrients, it unfortunately accumulates As the most compared to other cereal plants. Due to the growing interest in rice-based cosmetics, the aim of the work was the multi-element analysis of various home-made (natural) rice waters and commercialized ready-to-use rice-based cosmetics for skin/hair. The total concentrations of Al, As Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn in raw rice and rice products were determined using inductively coupled optical emission spectrometry (ICP OES) after wet sample decomposition in the presence of concentrated HNO3. In the case of As, the hydride generation (HG) technique was used as a sample introduction system to the ICP OES instrument. Five different procedures, including washing/rinsing, soaking, boiling, and fermentation steps, and three rice types, i.e., white, brow, and jasmine, were used for this purpose. The effects of the water temperature, the contact time of rice grains with water, and the type of rice on the water-soluble concentrations of elements were examined and compared. A significant difference in the solubility of elements was observed depending on the type of rice, with the lowest percentage of extraction noted for brown rice. The best option was soaking unwashed rice grains in a six-fold excess of cold water for 30 min. The selection criterion was to preserve the highest content of essential elements (Ca (0.76–1.2 mg kg−1), Cu (9.2–43 ng k−1), Fe (0.096–0.30 mg kg−1), Mg (6.9–11 mg kg−1), Mn (0.16–10.32 mg kg−1), and Zn (0.083–0.25 mg kg−1)) with reduced to a minimum As level, i.e.
... Cooking in variable amounts of water lowers niacin contents with increasing water amounts. The loss is less expressed in brown rice but to the greatest extent in non-parboiled white rice [163]. Niacin is stable during baking of bread [415]. ...
... Alongside natural niacin sources, fortified foods provide an additional dietary supply of the vitamin [92,173,175,178,179,183,185,186,416,424,[533][534][535]. Fortification of wheat and maize flour, as well as rice, with niacin is in many countries mandatory [92,163,181,182,417,536]. Niacin is also added to bread, breakfast cereals, and pasta [174,416,443,449]. ...
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This review summarizes the current knowledge on essential vitamins B1, B2, B3, and B5. These B-complex vitamins must be taken from diet, with the exception of vitamin B3, that can also be synthetized from amino acid tryptophan. All of these vitamins are water soluble, which determines their main properties, namely: they are partly lost when food is washed or boiled since they migrate to the water; the requirement of membrane transporters for their permeation into the cells; and their safety since any excess is rapidly eliminated via the kidney. The therapeutic use of B-complex vitamins is mostly limited to hypovitaminoses or similar conditions, but, as they are generally very safe, they have also been examined in other pathological conditions. Nicotinic acid, a form of vitamin B3, is the only exception because it is a known hypolipidemic agent in gram doses. The article also sums up: (i) the current methods for detection of the vitamins of the B-complex in biological fluids; (ii) the food and other sources of these vitamins including the effect of common processing and storage methods on their content; and (iii) their physiological function.
... Also, high losses of thiamine (45%) were observed in the samples of rice fortified with thiamine and cooked in a microwave oven [42]. It was also found that the content of thiamine was reduced by 50-70% for enriched polished and parboiled rice [43]. ...
... On the sensory analysis it was found that all products with the addition of analyzed preparations were characterized by similar and high sensory desirability, independent of the variant of preparation added (p < 0.001). An earlier study has shown that bitter taste can decrease consumer acceptance of food products, particularly those for which this taste is not characteristic [43,[53][54][55]. Metallic taste is also an important problem in food technology, for example with sweeteners. ...
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The aim of the study is to explore the possibility of vegetables being used as carriers of thiamine. The influence of carrier type (thiamine hydrochloride—TCh and thiamine pyrophosphate—TP) for the thiamine stability were investigated. Two varieties of pumpkin, Muscat and Hokkaido, as well as Cauliflower and Broccoli, were used as a matrix for the thiamine applied. The impregnated and freeze-dried vegetables were stored (230 days) with changing access to light (access to and restriction of light) and temperature (21 °C and 40 °C). The analyzed carriers were also used in the production of gnocchi dumplings. The content of thiamine was analyzed using the thiochromium method. In the study, consumer tests (n = 199) and sensory profiling were used to assess the impact of thiamine carriers on the sensory quality of gnocchi dumplings. It was found that the introduction of dried vegetables at the level of 30% allows for high sensory desirability of analyzed products, as well as suggesting the possibility of their frequent consumption. Such a product could potentially become an alternative to pork meat as a good source of thiamine. However, it should be noted that the thiamine losses may occur during the storage of dried vegetables and their culinary preparation.
... An earlier study confirmed the relationship between a bitter taste and decreased consumer acceptance of food products, particularly those for which this taste is not characteristic [45,46]. Additionally, these earlier studies confirmed a negative correlation between a metallic taste and consumer acceptance. ...
Article
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Objectives: Flour products with iodine-fortified dried vegetables can be a good source of iodine. However, in addition to iodine stability, the sensory quality of these products is also important. Therefore, this study aimed to assess the effect of adding iodine-fortified dried vegetables to flour products (gnocchi and ciabatta) on their sensory quality and map consumers (vegan/omnivore diets) as potential consumers of fortified flour products with iodine-fortified dried vegetables. Methods: A quantitative analysis of the sensory desirability and profiling were used to achieve the work objective. Results: It was confirmed that there was no relationship between the form of iodine (without iodine/KIO3/KI) and the intensity of all definite descriptors of colour, aroma, and taste. We also confirmed the relationship between the vegetable type and the descriptors’ intensity. It was confirmed that the positive attribute with the highest impact was the pumpkin taste, and the attribute with the most negative impact was the cauliflower aroma. This was true for consumers on vegan and omnivore diets, and they confirmed the most positive attitude toward the taste of pumpkin. Conclusions: Introducing dried iodine-fortified vegetables (gnocchi dumplings 24%; ciabatta rolls 5%) allows for the high sensory desirability of designed products. Introduced iodine (gnocchi dumplings 30 mg I/100 g; ciabatta rolls 9–11 mg I/100 g) does not change products’ sensory profiles.
... Multiple studies addressed that the addition of excess water for cooking rice plays an important role in the reduction and removal of As by 15-63% [24][25][26]. However, the use of excess water for cooking may cause a loss of essential elements such as iron (Fe) by 40-75% according to the type of rice and the technique of cooking [27]. ...
Article
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Environmental, soil, and groundwater pollution from toxic heavy metals, as well as food safety are all global concerns nowadays. The effect of various processes viz. washing, soaking, and cooking of rice samples (ten rice varieties, 50 samples) on the concentration of essential elements and toxic heavy metals was determined using the inductively coupled plasma-mass spectrometry technique. The concentrations of As, Cd, Cu, and Ni were found to be below the maximum permissible levels. The range of mean concentrations of metals (mg/kg) was recorded as Al (15.495–8.151), Fe (10.358–7.499), Ni (0.399–0.176), Cu (4.518–2.615), Zn (28.635–12.880), As (0.152–0.042), Cd (0.233–0.038), Pb (0.713–0.417), Ti (2.157 > 0.521), Sn (1.406–0.016), and W (1.114–0.017) mg/kg. Pt and Ag metals were not found in all samples. Soaking rice for 2 h was one of the most successful techniques for lowering heavy metal concentrations, followed by overnight soaking, which aided in the elimination of Al, Cd, Pb, and Pb. Heavy metal exposure has a significant impact on human health. This study creates a promising view to use a simple and accurate detection method for minimizing the effect of different processing methods on the essential elements and heavy metal contents.
... Before cooking, rice grains are washed a few times for variable time periods in each wash. This washing step can also remove some of the nutrients and arsenic (in the range of about 1-20%) (Mihucz et al., 2010;Gray et al., 2016;Pedron et al., 2019). Rice grains may also be subjected to soaking in water for some time as a washing measure and it has been noted that soaking in warm water results in greater arsenic reduction in grains . ...
... The two major approaches to dietary modification include the reduction of losses of thiamine during the preparation and cooking of the meal and the reduction of the intake of anti-thiamine factors. The loss of thiamine during preparation is minimized by reducing the number of washes of the rice before cooking and cooking rice in two volumes of water only (257,258). Cooking losses of thiamine in vegetables can be decreased by washing vegetables before chopping them into small pieces, keeping cooking time to a minimum, consuming freshly prepared meals immediately, and cooking vegetables in a small amount of water and consuming the water (259). ...
Article
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During pregnancy, many physiologic changes occur in order to accommodate fetal growth. These changes require an increase in many of the nutritional needs to prevent long-term consequences for both mother and the offspring. One of the main vitamins that are needed throughout the pregnancy is thiamine (vitamin B1) which is a water-soluble vitamin that plays an important role in many metabolic and physiologic processes in the human body. Thiamine deficiency during pregnancy can cause can have many cardiac, neurologic, and psychological effects on the mother. It can also dispose the fetus to gastrointestinal, pulmonological, cardiac, and neurologic conditions. This paper reviews the recently published literature about thiamine and its physiologic roles, thiamine deficiency in pregnancy, its prevalence, its impact on infants and subsequent consequences in them. This review also highlights the knowledge gaps within these topics.
... In consistent with our findings they reported that the concentration of As, Cd, and Pb in raw green wheat is much higher than in cooked wheat. Another study suggested significant reductions in As and Cd may be achieved as a result of cooking rice in excess water (Gray et al. 2016). One of the main reasons for this finding is that by penetrating water into rice, metals are dissolved in water, and eventually, the water containing dissolved metals is discarded (Adibi et al. 2014). ...
Article
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Heavy metal exposure through rice consumption (Oryza sativa L.) is a human health concern. This systematic review and meta-analysis investigated the association between toxic metals exposure and rice cooking methods. Based on the inclusion and exclusion criteria, fifteen studies were selected as eligible for the meta-analysis. Our results showed a significant decrease in the content of arsenic, lead, and cadmium following the cooking rice (WMD= -0.04 mg/kg, 95% CI: -0.05, -0.03, P = 0.000), (WMD = -0.01 mg/kg, 95% CI: -0.01, -0.01, P = 0.000), and (WMD = -0.01 mg/kg, 95% CI: -0.01, -0.00, P = 0.000), respectively. Furthermore, based on the subgroup analysis the overall rank order of cooking methods in the rice was rinsed > parboiling > Kateh > high-pressure, microwave, and steaming. The findings of this meta-analysis indicate the beneficial effects of cooking on reducing arsenic, lead, and cadmium exposure via rice consumption.
... Generally, it has been shown that using excess As-safe water for rice cooking, considerable amount of As is expelled out during rinsing as well as in gruel and accounts for the comparatively less As content in cooked rice than raw rice grain (Mandal et al., 2019;Naito et al., 2015). However, along with As removal, a considerable amount of micronutrients are also expelled out during rinsing as well as draining/straining of gruel in traditional process of rice cooking (Gray et al., 2016;Mwale et al., 2018;Menon et al., 2021). As a result, irrespective of priming treatments and As stress introduced at different growth phases, a significant amount of micronutrients was lost from cooked rice, after cooking with distilled water. ...
... One study showed that rinsing rice before cooking had a minimal effect on arsenic concentration, while removing nutrients such as enriched iron, folate, thiamin, and niacin. Cooking rice in excess water proved to be more effective in reducing the iAs concentration in rice, removing 40-60% depending on the type of rice, while reducing those same nutrients by 50-70% [85]. Cooking the rice can also change the speciation of the arsenic to a form that is more toxic or less toxic, depending on the type of rice and its region of origin [43]. ...
Article
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In certain populations, rice is the main source of exposure to inorganic arsenic (iAs), which is associated with cancer and non-cancer effects. Although rice is a staple food in Brazil, there have been few studies about the health risks for the Brazilian population. The objective of this study was to assess the risks of exposure to iAs from white rice and brown rice in Brazil, in terms of the carcinogenic and non-carcinogenic effects, and to propose measures to mitigate those risks. The incremental lifetime cancer risk (ILCR) and hazard quotient (HQ) were calculated in a probabilistic framework. The mean ILCR was 1.5 × 10−4 for white rice and 6.0 × 10−6 for brown rice. The HQ for white and brown rice was under 1. The ILCR for white and brown rice was high, even though the iAs concentration in rice is below the maximum contaminant level. The risk for brown rice consumption was lower, which was not expected. Various mitigation measures discussed in this report are estimated to reduce the risk from rice consumption by 5–67%. With the support of public policies, measures to reduce these risks for the Brazilian population would have a positive impact on public health.
... Upon cooking, the excess water is drained to keep the cooked grains friable and to prevent from lumping. The draining also helps in reducing the anti-nutritional factors like heavy metals such as As, Pb and Cd (40). Another common method is pressure cooking, which uses minimal water usually 2 times the volume of rice grains and does not involve draining. ...
Article
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Background Antioxidants detain the development and proliferation of various non-communicable diseases (NCDs). γ-oryzanol, a group of steryl ferulates and caffeates, is a major antioxidant present in rice grain with proven health benefits. The present study evaluated the distribution and dynamics of γ-oryzanol and its components in spatial and temporal scales and also delineated the effect of processing and cooking on its retention. Methods Six rice varieties (four Basmati and two non-Basmati) belonging to indica group were analyzed at spatial scale in four different tissues (leaf blades, leaf sheaths, peduncle and spikelets) and temporal scale at three developmental stages (booting, milky and dough). Additionally, the matured grains were fractioned into husk, embryo, bran, and endosperm to assess differential accumulation in these tissues. Further, milling and cooking of the samples was done to assess the retention upon processing. After extraction of γ-oryzanol by solvent extraction method, individual components were identified by UPLC-QToF-ESI-MS and quantified by RP-HPLC. Results The non-seed tissues were significantly different from the seed tissues for composition and quantitative variation of γ-oryzanol. Cycloartenyl caffeate was predominant in all the non-seed tissues during the three developmental stages while it showed significant reduction during the growth progression toward maturity and was totally absent in the matured grains. In contrary, the 24-methylenecycloartanyl ferulate, campesteryl ferulate and β-sitosteryl ferulate showed significant increment toward the growth progression to maturity. Milling caused significant reduction, retaining only an average of 58.77% γ-oryzanol. Cooking of brown rice in excess water showed relatively lower average retention (43.31%) to samples cooked in minimal water (54.42%). Cooked milled rice showed least mean retention of 21.66%. Conclusion The results demonstrate prominent compositional variation of γ-oryzanol during different growth stages. For the first time, the study demonstrated that ferulate esters of γ-oryzanol were predominant in the seed tissues while caffeate esters were dominant in non-seed tissues. Basmati cultivars show differential expression of γ-oryzanol and its components compared to non-Basmati cultivars. Cooking in excess water causes maximum degradation of γ-oryzanol. Post-harvest losses due to milling and cooking indicate the necessity of biofortification for γ-oryzanol content in rice grain.
... Very few studies have been conducted on the fate of heavy metals under rice cooking conditions [20,63,65]. Gray et al. [66] noticed that metals are more easily removed from parboiled rice than brown rice. Liu et al. [67] reported that cadmium decreased by only 3%, whereas the lead content was decreased by 20% during rice cooking. ...
Article
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Rice has been a dietary staple for centuries, providing vital nutrients to the human body. Brown rice is well known for its nutrient-dense food profile. However, owing to multiple causes (anthropogenic and non-anthropogenic), it can also be a potential source of toxic heavy metals in the diet. Brown Hassawi rice samples were collected from the Al-Ahsa region and analyzed for its content of toxic metals. The results reveal that all the tested metals varied significantly in the brown rice samples, while As and Pb in all three samples exceeded their respective maximum allowable limits (MALs), followed by Cd, which nearly approached the MAL in two samples out of three. Brown rice samples were cooked in rice:water systems, viz., low rice:water ratios (1:2.5, 1:3.5) and high rice:water ratios (1:5, 1:6), along with soaking as a pre-treatment. Soaking was unproductive in removing the heavy metals from the rice, whereas cooking dissipated all metals from the rice, except for Cd, which was statistically non-significant. The high-water cooking of the rice was more effective in the dissipation of metals from the rice as compared to low-water cooking conditions. Through the consumption of rice, the estimated daily intake (EDI) of heavy metals is 162 g per person per day for As, which is above the provisional maximum tolerable daily intake (PMTDI) regardless of cooking circumstances. The hazard risk index (HRI) also highlighted the fact that As can be a potential health hazard to rice consumers in the Al-Ahsa region of Saudi Arabia. These results indicate the potential health risks caused by the consumption of this rice by humans. Regular monitoring is recommended to manage and control elevated concentrations and related health hazards as a result of the use of Hassawi rice contaminated by the accumulation of metals and metalloids.
... Very few studies have been conducted on the fate of heavy metals under rice cooking conditions [20,63,65]. Gray et al. [66] noticed that metals are more easily removed from parboiled rice than brown rice. Liu et al. [67] reported that cadmium decreased by only 3%, whereas the lead content was decreased by 20% during rice cooking. ...
Article
Full-text available
Rice has been a dietary staple for centuries, providing vital nutrients to the human body. Brown rice is well known for its nutrient-dense food profile. However, owing to multiple causes (anthropogenic and non-anthropogenic), it can also be a potential source of toxic heavy metals in the diet. Brown Hassawi rice samples were collected from the Al-Ahsa region and analyzed for its content of toxic metals. The results reveal that all the tested metals varied significantly in the brown rice samples, while As and Pb in all three samples exceeded their respective maximum allowable limits (MALs), followed by Cd, which nearly approached the MAL in two samples out of three. Brown rice samples were cooked in rice:water systems, viz., low rice:water ratios (1:2.5, 1:3.5) and high rice:water ratios (1:5, 1:6), along with soaking as a pre-treatment. Soaking was unproductive in removing the heavy metals from the rice, whereas cooking dissipated all metals from the rice, except for Cd, which was statistically non-significant. The high-water cooking of the rice was more effective in the dissipation of metals from the rice as compared to low-water cooking conditions. Through the consumption of rice, the estimated daily intake (EDI) of heavy metals is 162 g per person per day for As, which is above the provisional maximum tolerable daily intake (PMTDI) regardless of cooking circumstances. The hazard risk index (HRI) also highlighted the fact that As can be a potential health hazard to rice consumers in the Al-Ahsa region of Saudi Arabia. These results indicate the potential health risks caused by the consumption of this rice by humans. Regular monitoring is recommended to manage and control elevated concentrations and related health hazards as a result of the use of Hassawi rice contaminated by the accumulation of metals and metalloids.
... Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice''. 28 (Gray and Conklin 2016). This method may also remove some key nutrients. ...
Article
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 (100 μg/kg for infants and 200 μg/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.
... The percolation cooking method uses a continual stream of percolating water through a filter unit by a coffee maker machine, wherein the rice is placed in the filter unit instead of coffee and boiling water is passed through the filter unit continuously. A reduction in iAs has been reported in raw polished rice by 59% and wholegrain rice by 69%, respectively [187]. Various factors such as high washing, soaking, and cooking rice with arsenic-contaminated water affect the final dietary arsenic ingestion in meal preparation [188]. ...
Article
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Citation: Khan, M.I.; Ahmad, M.F.; Ahmad, I.; Ashfaq, F.; Wahab, S.; Alsayegh, A.A.; Kumar, S.; Hakeem, K.R. Arsenic Exposure through
... The percolation cooking method uses a continual stream of percolating water through a filter unit by a coffee maker machine, wherein the rice is placed in the filter unit instead of coffee and boiling water is passed through the filter unit continuously. A reduction in iAs has been reported in raw polished rice by 59% and wholegrain rice by 69%, respectively [187]. Various factors such as high washing, soaking, and cooking rice with arsenic-contaminated water affect the final dietary arsenic ingestion in meal preparation [188]. ...
Article
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Dietary arsenic (As) contamination is a major public health issue. In the Middle East, the food supply relies primarily on the import of food commodities. Among different age groups the main source of As exposure is grains and grain-based food products, particularly rice and rice-based dietary products. Rice and rice products are a rich source of core macronutrients and act as a chief energy source across the world. The rate of rice consumption ranges from 250 to 650 g per day per person in South East Asian countries. The source of carbohydrates through rice is one of the leading causes of human As exposure. The Gulf population consumes primarily rice and ready- to-eat cereals as a large proportion of their meals. Exposure to arsenic leads to an increased risk of non-communicable diseases such as dysbiosis, obesity, metabolic syndrome, diabetes, chronic kidney disease, chronic heart disease, cancer, and maternal and fetal complications. The impact of arsenic-containing food items and their exposure on health outcomes are different among different age groups. In the Middle East countries, neurological deficit disorder (NDD) and autism spectrum disorder (ASD) cases are alarming issues. Arsenic exposure might be a causative factor that should be assessed by screening the population and regulatory bodies rechecking the limits of As among all age groups. Our goals for this review are to outline the source and distribution of arsenic in various foods and water and summarize the health complications linked with arsenic toxicity along with identified modifiers that add heterogeneity in biological responses and suggest improvements for multi-disciplinary interventions to minimize the global influence of arsenic. The development and validation of diverse analytical techniques to evaluate the toxic levels of different As contaminants in our food products is the need of the hour. Furthermore, standard parameters and guidelines for As-containing foods should be developed and implemented.
... The percolation cooking method uses a continual stream of percolating water through a filter unit by a coffee maker machine, wherein the rice is placed in the filter unit instead of coffee and boiling water is passed through the filter unit continuously. A reduction in iAs has been reported in raw polished rice by 59% and wholegrain rice by 69%, respectively [187]. Various factors such as high washing, soaking, and cooking rice with arsenic-contaminated water affect the final dietary arsenic ingestion in meal preparation [188]. ...
Article
Full-text available
Citation: Khan, M.I.; Ahmad, M.F.; Ahmad, I.; Ashfaq, F.; Wahab, S.; Alsayegh, A.A.; Kumar, S.; Hakeem, K.R. Arsenic Exposure through
... Laparra et al (2005) explored the iAs and total As in cooked rice simulated gastrointestinal digestion. Gray et al (2016) demonstrated a decreasing trend of grain iAs accumulation while cooking As contaminated brown long-grain, white medium grain, and parboiled rice with deionized water at a ratio of 2:1, 6:1 and 10:1 (water:grains) with increasing the volume of water. They, however, concluded that since cooking with a low amount of water did not eliminate As content, increasing water volume reduced up to 45% of iAs. ...
Article
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The human body loading with arsenic (As) through rice consumption is a global health concern. There is a crucial need to limit As build-up in rice, either by remediating As accumulation in soils or reducing As levels in irrigation water. Several conventional approaches have been utilized to alleviate the As accumulation in rice. However, except for some irrigation practices, those approaches' success and the adoption rate are not remarkable. This review presents human health risks posed due to consumption of As contaminated rice, evaluates different biomarkers for tracing As loading in the human body, and discuss the latest advancement in As reducing technologies emphasizing the application of seed priming, nanotechnology, and biochar application for limiting As loading in rice grains. We also evaluated different irrigation techniques to reduce As accumulation in rice. Studies showed that the lifetime cancer risk rate ranges approximately 5-22 for the top rice-producing Asian nations. Human scalp hair and nails are commonly analyzed biomarkers to trace As in the human body. For decreasing As in rice, altering water management regimes significantly reduces grain As accumulation. Bio-and nano-priming of rice seeds improve germination and minimize As translocation in rice tissues by protecting cell membrane, building pool around seed coat, methylation and volatilization, or quenching harmful effects of reactive oxygen species. Nanoparticles application in the form of nano adsorbents or nanofertilizers facilitates nano-remediation of As through the formation of Fe plaque or sorption or oxidation process. Incorporating biochar in the rice fields significantly reduces As through immobilization, physical adsorption, or surface complexation. Again, As content in cooked rice was found to depend on irrigation source and raw rice As level.
... Because of its relatively high consumption rate, white rice has been widely studied, particularly when addressing toxic elements and related health issues. However, elemental data on brown rice is still limited in the literature when compared with white rice (Antoine, Fung, Grant, Dennis, & Lalor, 2012;Gray, Conklin, Todorov, & Kasko, 2016;Marr, Batten, & Lewin, 1999;Narukawa, Matsumoto, Nishimura, & Hioki, 2014;Ogiyama, Tagami, & Uchida, 2008;Zeng et al., 2009). More importantly, the literature still lacking investigations related to multi-element analysis and health risk assessment in brown rice. ...
Article
Twenty-two brown rice varieties available in the Qatari market were analyzed for essential and toxic elements by ICP-MS. Found concentrations (µg/kg) were: As: 171±78 (62-343), Cd: 42±60 (4-253), Cr: 515±69 (401-639), Pb: 6±7 (<MDL-26), and U: 0.1±0.5 (<MDL-2). One third of the samples contained high levels of arsenic. Significant differences (p<0.008) in concentrations were observed for many elements based on the grains’ country of origin and size. Calculated carcinogenic risk based on published speciation data of inorganic arsenic and chromium(VI) available in the literature for rice is >1 in million, may possibly be >1 in 10,000 based on conservatively high brown rice consumption rates of 200 g/d or 400 g/d in Qatar. These elevated risks may be applicable to specific population subgroups with diabetic conditions who consume only brown rice. Non-cancer risks are mainly derived from Mn, V, Se, and Cd with a hazard index >1 from some brown rice samples.
... Interestingly, both countries prefer parboiled rice and traditionally cook in excess water. There are many scientific papers on reducing arsenic through different cooking methods to reduce arsenic exposure through rice consumption (Atiaga et al., 2020;Gray et al., 2015;Menon et al., 2020b) and these findings could be easily be communicated to the affected communities through public media, and educational/awareness/public intervention routes. ...
... Moreover, the inorganic As content is also further found to be reduced during cooking operations. It has been found that cooking in excess water reduces inorganic As by 40% from long-grain polished rice (Gray et al. 2016). On the contrary, partial cooking methods such as parboiling are not substantially reducing the arsenic content from contaminated rice (Duxbury et al. 2003). ...
Article
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Milled rice is an essential part of the regular diet for approximately half of the world’s population. Its remarkable commercial value and consumer acceptance are mostly due to its promising cooking qualities, appealing sensory properties, and longer shelf life. However, the significant loss of the nutrient-rich bran layer during milling makes it less nutritious than the whole grain. Thus, enhancing the nutritive value of milled rice is vital in improving the health and wellbeing of rice consumers, particularly for those residing in the low-economic zones where rice is the primary source of calories and nutrition. This article provides a critical review on multiple frontiers of recent interventions, such as (1) infusing the genetic diversity to enrich amylose and resistant starch to reduce glycaemic index, (2) enhancing the minerals and vitamins through complementary fortification and biofortification as short and long-term interventions, and (3) developing transgenic solutions to improve the nutrient levels of milled rice. Additionally, the review highlights the benefits of functional ingredients of milled rice to human health and the potential of enhancing them in rice to address the triple burden of malnutrition. The potential merit of milled rice concerning food safety is also reviewed in this article.
... Despite both, nigiri and maki, contain rice, iAs levels in sushi were lower than those recently found in rice and rice-based products (González et al., 2020). It would be associated to the fact that the rice used for sushi preparation is rinsed with water several times and then boiled, thus decreasing the content of iAs up to 60% (Althobiti et al., 2018;Gray et al., 2015;Jitaru et al., 2016). Nigiri was the type of sushi with the highest mean levels of Ni, with a range between 1.10 and 1.74 μg/g (Fig. 2c). ...
Article
Although sushi is considered as a healthy food, it can also be a route of exposure to chemical contaminants such as potentially toxic trace elements. In this study, we analysed the concentration of Cd, I, Ni, Pb and total Hg, as well as iAs and MeHg in sushi samples. Iodine levels were higher in samples containing seaweed, while iAs concentrations were greater in rice-containing sushi. In turn, total Hg and MeHg were significantly higher in sushi samples with tuna. Health risks of sushi consumption were assessed for three population groups: children, adolescents and adults. Considering an average intake of 8 sushi pieces for adults and adolescents, and 3 sushi pieces for children, the estimated exposure to MeHg by adolescents exceeded the tolerable daily intake set by EFSA, while MeHg intake by children and adults was below, but close to that threshold. A relatively high daily exposure of Ni and Pb was also found, especially for adolescents. Since this study focused only on the consumption of sushi, the contribution of other food groups to the overall dietary exposure should not be disregarded. It might lead to an exposure to MeHg and other trace elements above the health-based guideline values.
... Interestingly, both countries prefer parboiled rice and traditionally cook in excess water. There are many scientific papers on reducing arsenic through different cooking methods to reduce arsenic exposure through rice consumption (Atiaga et al., 2020;Gray et al., 2015;Menon et al., 2020b) and these findings could be easily be communicated to the affected communities through public media, and educational/awareness/public intervention routes. ...
Article
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High levels of arsenic in drinking water and food materials continue to pose a global health challenge. Over 127 million people alone in Bangladesh (BD) and West Bengal (WB) state of India are exposed to elevated levels of arsenic in drinking water. Despite decades of research and outreach, arsenic awareness in communities continue to be low. Specifically, very few studies reported arsenic awareness among low-income farming communities. A comprehensive approach to assess arsenic awareness is a key step in identifying research and development priorities so that appropriate stakeholder engagement may be designed to tackle arsenic menace. In this study, we developed a comprehensive arsenic awareness index (CAAI) and identified key awareness drivers (KADs) of arsenic to help evaluate farmers' preferences in dealing with arsenic in the environment. The CAAI and KADs were developed using a questionnaire survey in conjunction with ten machine learning (ML) models coupled with a hybrid feature selection approach. Two questionnaire surveys comprising of 73 questions covering health, water and community, and food were conducted in arsenic-affected areas of WB and BD. Comparison of CAAIs showed that the BD farmers were generally more arsenic-aware (CAAI = 7.7) than WB farmers (CAAI = 6.8). Interestingly, the reverse was true for the awareness linked to arsenic in the food chain. Application of hybrid feature selection identified 15 KADs, which included factors related to stakeholder interventions and cropping practices instead of commonly perceived factors such as age, gender and income. Among ML algorithms, classification and regression trees and single C5.0 tree could estimate CAAIs with an average accuracy of 84%. Both communities agreed on policy changes on water testing and clean water supply. The CAAI and KADs combination revealed a contrasting arsenic awareness between the two farming communities, albeit their cultural similarities. Specifically, our study shows the need for increasing awareness of risks through the food chain in BD, whereas awareness campaigns should be strengthened to raise overall awareness in WB possibly through media channels as deemed effective in BD.
... Additionally, considering the climate change scenario in the near future, it is also predicted that at 38 • C, 850 ppm CO 2 , the concentration of pore water arsenite in the rhizosphere of rice will increase leading to augmented accumulation of inorganic arsenic in rice varieties along with a decrease in productivity (Muehe et al., 2019). On the other hand, rice cooking and rinsing with arsenic-free excess water can reduce more than 40% arsenic load in cooked-rice but at the cost of eliminating vitamins and minerals too (Gray et al., 2015). Thus, the development of low arsenic accumulating rice is the most viable option to reduce the dietary exposure of arsenic. ...
Article
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The development of low arsenic-accumulating varieties for the contaminated areas is one of the best options for reducing the dietary exposure of arsenic to human population through rice. In this study, grain-arsenic content in one hundred genotypes revealed a large variation ranging from 0.05 mg/kg to 0.49 mg/kg. Compared to high accumulating variety, Shatabdi, 6-8 times the transcript upregulation of Arsenic sequestering ATP binding cassette C1 type gene (ABCC1), was observed in first internode of low accumulating variety Gobindabhog when 5 mg/kg of arsenite was present in soil. A comparison of the genomic sequence of OsABCC1 identified 8 SNPs between the two genotypes; 5 in introns and 3 silent mutations in exons. We identified a PCR based co-dominant marker targeting an SNP (T/G) between the two genotypes, which clearly distinguished 100 genotypes into low (mean 0.14 mg/kg) and high (mean 0.35 mg/kg) accumulating groups. All aromatic genotypes, either long or small grain, carry the Gobindabhog-type ABCC1 allele and are low accumulators of arsenic. Gobindabhog allele carrying 62 RILs and NILs showed almost 40-50% less As-accumulation in grains relative to 84 RILs and NILs carrying Shatabdi type ABCC1-allele. The marker will be useful in introgression of low accumulating allele of OsABCC1 into high yielding photoperiod insensitive varietal backgrounds more easily and accurately.
... The addition of NaCl to the soaking water may promote solubilization of iAs, which is consistent with other research demonstrating that chloride ions can solubilize heavy metals (Abt and Robin 2020). Due to several other studies indicating that reduction of iAs in other foodstuffs can be obtained through rinsing/washing and boiling, this effect appears to be a robust phenomenon (Gray et al. 2016, Redan et al. 2019, Redan 2020. Together, these results may help in producing a product with As concentrations more likely to be within compendial standards or potential regulatory limits. ...
Article
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Edible algae products have increasingly become a larger component of diets worldwide. Algae can be a source of essential micronutrients and bioactive phytochemicals, although select varieties also often contain elevated concentrations of heavy metal contaminants. Due to the effects thermal processing of foodstuffs can have on levels of nutrients, phytochemicals, and contaminants, it is important to consider the role processing has on the levels of these components in algae food products. Here, we evaluate the literature covering how different types of processing, including commercial thermal application and in-home preparation, affect constituents such as vitamins, minerals, carotenoids, pigment compounds, and metal contaminants. Overall, the literature suggests that there are optimum processing conditions and specific cooking techniques that can be used to increase retention of important nutritional components while also reducing concentrations of metal contaminants. Although further research is needed on how thermal processing affects individual compounds in algae and their ultimate bioavailability, these data should be taken into consideration in order to inform design of product processing to both increase retention of nutritional components and limit metal contaminants.
... Various food-processing operations include sorting, trimming, cleaning, cooking, baking, frying, roasting, flaking, and extrusion that have variable effects on mycotoxins (Kaushik, 2015). Cooking rice in excess water efficiently reduces the amount of arsenic (As) in the cooked grain (Gray et al., 2016). ...
... Various food-processing operations include sorting, trimming, cleaning, cooking, baking, frying, roasting, flaking, and extrusion that have variable effects on mycotoxins [49]. Cooking rice in excess water efficiently reduces the amount of arsenic (As) in the cooked grain [50]. ...
... Another limitation in our assessment of the exposure of i-As through diet is that we used concentration data from the raw commodities, which mean that we do not take into account the effect of processing on the level of i-As in the foods consumed. It is known that i-As contamination of foods may occur via contaminated water, i.e. when boiling (Torres Escribano et al. 2008); however, it is also known that first the rinsing of rice in (uncontaminated) water, the boiling in and then discarding of excess water contribute to a lower level of contamination of the consumed rice (EFSA 2009;Gray et al. 2015). It is unknown whether the effects of processing will lead to an over-or underestimation of the disease burden. ...
Article
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Arsenic is a naturally occurring metalloid in soil, air, water and food in organic and inorganic forms. Several epidemiological studies have shown that inorganic arsenic (i-As) is carcinogenic to humans. Previous studies have raised concern about dietary i-As exposure from various sources, including brown rice. We estimated the burden of disease in terms of disability-adjusted life years (DALY) of lung, bladder and skin cancer caused by dietary exposure to i-As in Denmark. Moreover, we investigated the impact of different rice-consumption scenarios of white and brown rice. We combined exposure assessment with dose response relationships of i-As exposure and lifetime risk of each cancer type to estimate the annual incidence due to i-As exposure. Associated DALY was calculated based on national health statistics. We estimated 0.57 extra cancer cases and 4.5 DALY [95% UI 4.2–4.8] in the Danish population in 2018. Even though rice was found not to be the main contributor of i-As, substitution of white and parboiled rice by brown rice resulted in a 32.7% increase in DALY compared to the current consumption of rice. The estimated number of cancer cases due to dietary i-As equals 0.006% of the annual incidence of the three cancer types in Denmark. Our estimates exclude exposure to i-As from drinking water and other beverages, which should be accounted for in future estimates. Our study highlights the need for deriving national-specific estimates of food borne disease burden to allow for comparison and prioritization.
... Various foodprocessing operations include sorting, trimming, cleaning, cooking, baking, frying, roasting, flaking, and extrusion that have variable effects on mycotoxins [100]. Cooking rice in excess water efficiently reduces the amount of arsenic (As) in the cooked grain [101]. ...
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This chapter assesses human health risks of inorganic arsenic (As) from drinking well water and consumption of rice irrigated by high-As groundwater in the Mekong River Delta . Geogenic inorganic As (iAs) occurring at elevated levels in groundwater has been detected in more than 70 countries. Among mostly rural residents relying on groundwater for drinking, this exposure has resulted in negative health consequences including visible skin lesions, multiple internal organ cancers, numerous invisible non-cancer health effects such as cardiovascular diseases, and premature deaths. In the Mekong River Delta (MRD, defined by elevation <10 m above sea level in this book), As issues in groundwater have been documented as early as 1999 in Cambodia, with literature reporting its occurrence in Vietnam since 2005. Since the early 2000s, efforts have been made to test for As in about 100,000 wells from Cambodia, Laos, Vietnam and Thailand. Here, a combined dataset with a total of 94,768 unique As tests was analyzed to illustrate the spatial patterns and to assess the health risks of drinking well water As in Cambodia and in southern Vietnam. Although knowledge is far more limited, an attempt was also made to examine the potential health risks associated with iAs exposure from rice, a major staple for the MRD. Here, irrigation using highly As enriched groundwater for rice cultivation has expanded this environmental health problem from the hydrosphere (water) to the geosphere (soil) and, in turn, the biosphere (rice, and ultimately humans). Of 41,928 tests in Cambodia, 35.8% exceeded 10 μg/L, the WHO guideline value for drinking water As, while 21.5% exceeded 50 μg/L, the Cambodian drinking water standard. Of 52,858 tests in Vietnam, the exceedance rate for 10 μg/L, which is also the Vietnamese drinking water standard, is 10.0%. High As wells, regardless of whether it is relative to 10 or 50 μg/L, are located in proximity to the main course of the Mekong-Bassac Rivers, especially within a 5 km distance. The vast majority (>98%) of high-As wells are located in low-lying areas, i.e. <25 m elevation in Cambodia and <10 m elevation in Vietnam. High-As wells occur frequently at shallow depths (<70 m) across the MRD but also at deeper depths (300–500 m) in Vietnam. Due to the clustering of high As wells along the Mekong-Bassac Rivers, extreme human health tolls are identified in 11 districts of Cambodia and 3 districts of Vietnam with a population attributable fraction exceeding 0.1, meaning that >1 in every 10 adult deaths is solely due to drinking water As exposure. The annual excess deaths attributable to arsenic exposure alone is 1204 in Cambodia and 1486 in Vietnam, or 1 in every 27 adult deaths and 1 in every 78 adult deaths, respectively. In addition to uncertainties in bioavailability and toxicity of iAs in rice grains, soil and rice As data, especially rice As speciation data needed for risk assessment, are still limited in the MRD .
Chapter
Arsenic is a naturally occurring metalloid in the earth’s crust. Arsenic contaminates the environment through anthropogenic sources, industrial activities, and the use of pesticides. The main route of arsenic exposure is ingestion through food and water. The population in Bangladesh and West Bengal has been highly affected by arsenic exposure. Rice and other food crops grown and harvested in highly contaminated areas showed higher exposure. Irrigation with contaminated groundwater and flooding irrigation methods has contributed to high arsenic content in rice. Seafood and fish grown in contaminated water showed higher arsenic content. Ingested arsenic is absorbed into the gastrointestinal tract which is then delivered to the liver and kidneys and converted into dimethyl arsenic acid and excreted through urine. Arsenic can accumulate in organs which can lead to adverse situations. Chronic exposure to arsenic can lead to developing cancers in the lungs, kidneys, bladder, skin, and prostate. Though the molecular-level activity that causes cancers is unclear, exposure to arsenic can cause DNA damage, induce cell proliferation, obstruct nucleotide repair, and shut down cellular apoptotic pathways. These can lead to the unfortunate development of cancerous cells. Not only cancers, but arsenic can also lead to other diseases like skin lesions, neurotoxicity, diabetes, cardiovascular diseases, and stroke. Many technologies have been adopted to remove arsenic from contaminated soil and water. Coagulation and precipitation, activated alum, ion exchange resins and membrane filters, microbial bioremediation, and phytoremediation have been used to lower the arsenic content. Regulations are also established by WHO on recommended arsenic levels in drinking water (10 μg/L) to ensure the safety of the population.
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Dietary arsenic (As) contamination is a major public health issue. In the Middle East, the food supply relies primarily on the import of food commodities. Among different age groups the main source of As exposure is grains and grain-based food products, particularly rice and rice-based dietary products. Rice and rice products are a rich source of core macronutrients and act as a chief energy source across the world. The rate of rice consumption ranges from 250 to 650 g per day per person in South East Asian countries. The source of carbohydrates through rice is one of the leading causes of human As exposure. The Gulf population consumes primarily rice and ready-to-eat cereals as a large proportion of their meals. Exposure to arsenic leads to an increased risk of non-communicable diseases such as dysbiosis, obesity, metabolic syndrome, diabetes, chronic kidney disease, chronic heart disease, cancer, and maternal and fetal complications. The impact of arsenic-containing food items and their exposure on health outcomes are different among different age groups. In the Middle East countries, neurological deficit disorder (NDD) and autism spectrum disorder (ASD) cases are alarming issues. Arsenic exposure might be a causative factor that should be assessed by screening the population and regulatory bodies rechecking the limits of As among all age groups. Our goals for this review are to outline the source and distribution of arsenic in various foods and water and summarize the health complications linked with arsenic toxicity along with identified modifiers that add heterogeneity in biological responses and suggest improvements for multi-disciplinary interventions to minimize the global influence of arsenic. The development and validation of diverse analytical techniques to evaluate the toxic levels of different As contaminants in our food products is the need of the hour. Furthermore, standard parameters and guidelines for As-containing foods should be developed and implemented.
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Arsenic is an important environmental pollutant with potential cancer-causing effects. It contributes to acute and chronic toxicity depending on the doses or duration of exposure. In this study, we estimated the concentration of total arsenic in different rice brands sold in Uganda, where rice is a staple food. We conducted an experimental study. Different rice brands were obtained from supermarkets and grocery shops, and assessed for arsenic using atomic absorption spectrometry. The concentrations of arsenic in rice were estimated after boiling, washing, or overnight soaking in plenty of water to see if these methods reduce arsenic levels efficiently in food. The concentrations of arsenic in the different rice brands were compared using an unpaired t-test after setting a p-value of ≤0.05 as significant. The G-rice brand had the lowest arsenic levels of 1.4±0.0002 ppm and the C-rice brand had the highest levels of 2.4±0.004 ppm. The tap water used to boil, soak and wash the rice brands had much higher arsenic levels of 3.5±0.000003 ppm, leading to increased retention of the heavy metal in the rice. Rice brands sold in Kampala city seem to have higher than acceptable arsenic levels. Increased vigilance in terms of routine monitoring for the levels of arsenic in rice and water used during food preparation by the Ugandan food or water safety regulatory authorities is highly recommended.
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This study assessed the effect of soaking on the retention and removal of arsenic (As) along with other toxic elements and nutrients in three types of soaked rice or overnight steeped rice (pantavat), as this food dish was highlighted on the Australian MasterChef program in 2021 as a popular recipe. Results showed that brown rice contained twice as much As as basmati and kalijira rice. Cooking with As-free tap water using the rice cooker method removed up to 30% of As from basmati rice. Around 21-29% removal of total As was observed in soaked basmati, brown, and kalijira rice. However, while 13% of inorganic As was removed from basmati and brown rice, no changes were noted in the kalijira rice. Regarding nutrient elements, both cooking and soaking rice caused significant enrichment of calcium (Ca) whereas potassium (K), molybdenum (Mo) and selenium (Se) were reduced substantially for the tested rice varieties. The nutrients magnesium (Mg), iron (Fe), sulfur (S) and phosphorus (P) did not significantly change. The results indicated that soaking can minimize up to 30% As and soaked rice reduced few nutrients like K, Mo and Se. Data in this study highlights the retention and/or loss of toxic and beneficial nutrients elements in pantavat when As-free water is used to prepare this food.
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This literature review paper highlights the dietary importance, arsenic toxicity, and nutritional value of brown, white, basmati and pigmented rice varieties. Rice is one of the most widely consumed cereals in the world rich in dietary fiber, bioactive compounds such as Melatonin, and Gamma-amino-butyric acid (GABA). However, the edible brown rice is rarely consumed as the most human populations prefer the white polished rice for reasons connected to appearance, taste, palatability, ease of cooking, tradition, safety, and shorter shelf of brown rice which limits the market potential. Rice generally contains more arsenic than any other grains because of its anaerobic growing environment and unique physiology. Brown rice accumulates more arsenic than white rice because arsenic accumulates in the outer hard bran layer of the grain which is removed to make the white rice. Arsenic contamination is also reported in white rice. This also depends on the geographical location of the rice growing area. If the rice is grown in arsenic contaminated water with high arsenic levels, then brown rice accumulates high arsenic which is toxic to human health. Washing rice with water for 4 to 5 times before cooking could reduce arsenic levels in rice. Pigmented varieties of rice are considered valuable for their health benefits due to the presence of Melatonin but consumption is very less. India is the largest producer and exporter of basmati rice in the world. Basmati rice has a medicinal value and consumption is very high. Indian Basmati rice is a premium quality grain loved by people across the world. The chemical compound responsible for aroma in basmati rice is 2-acetyl-1-pyrroline and hence unique among other aromatic long grained rice.
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Rice (Oryza sativa L.) is considered as the staple food for 50% of the world's population. Humans are exposed to arsenic (As) through rice consumption, which is a global health issue that requires attention. The present review reflects the scenario of rice grown in As endemic regions of Asia that has a significant portion of inorganic As (iAs) compared to other rice grown areas around the world. Post-harvesting, pre-cooking, and cooking procedures in South and South-East Asian countries employ As-contaminated groundwater. Polishing of brown rice and parboiling, washing and cooking with As-safe water can reduce As concentration and nutrient level in cooked rice. However, in rural parts of South-east Asia, rice is usually cooked using As-contaminated groundwater and consumption of this As enriched rice and water may cause a significant health exposure in humans. Bioaccessibility and bioavailability of As can be determined using in-vitro and in-vivo techniques that can be utilized as a tool to assess As exposure in humans. Arsenic in cooked rice may be reduced by using newly developed cooking procedures such as Kateh cooking, steam percolating, and the parboiled and absorbed (PBA) method. For individuals living in rural regions, using rainwater or treated surface water for drinking and cooking is also an alternative. Although this study examined the processes involved in the post-harvesting, pre-cooking, and cooking stages, there are still significant research gaps in this area that must be addressed in near future.
Chapter
The high concentration of arsenic (As) in paddy fields and consequently, in rice grains is a critical issue in many rice‐growing areas. Breeding As‐tolerant rice varieties that prevent As uptake and its accumulation in the grains is a major mitigation option. Here, first, we review the literature on soil‐water and rice As relationships, and on mitigation of As‐related thread through varietal improvement, including options for markers‐assisted selection. Second, we present a case study of implementation of genomic selection for As‐tolerance in rice, based on the evaluation of flag leaf and grain As contents of a large diversity panel and a set of advanced inbred lines, grown in a naturally As‐rich paddy field. Third, we discuss the merits of different breeding approaches and argue that genomic selection is the most effective molecular breeding option. Finally, we draw up prospects for the future, in terms of further exploration of genetic diversity for As tolerance and the potential contributions of new plant‐breeding technologies, such as genome editing and the main‐streaming of genomic‐selection approaches.
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Diet is the major route of exposure to arsenic (As), with rice and rice products as food groups with relatively highest As concentrations. This study was aimed at determining the concentrations of total arsenic (total As) and inorganic arsenic (InAs) in rice and rice products. The dietary exposure and health risks for infant and adult population were also estimated. Brown varieties of rice showed higher As levels than white rice (189 vs 132 μg/kg). Toddlers and infants presented the highest dietary exposure to total As (4.08 and 3.99 μg/day, respectively), but unlike the rest of population groups, the main contributor was organic arsenic. Focusing on the contribution of each food item, rice represents the major contributor to InAs exposure by the adult population, while baby cereals and breakfast cereals are the most important contributors for infant exposure. Anyhow, none of the population groups exceeded the lower limit of the BMDL01 range (from 0.3 to 8.0 μg/kg body weight/day) set by EFSA in any of the three exposure scenarios (high, mean, and low) hereby considered. Finally, consumption of white rice varieties or pre-cooked rice, as well as washing rice before cooking, are recommended in order to minimize the exposure to arsenic.
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This study assessed the effect of rinsing and boiling on total content of As (tAs) and of its inorganic and organic forms in different types of rice (polished and brown) from Spain and Ecuador. Rice was subjected to five different treatments. The results showed that the treatment consisting of three grain rinsing cycles followed by boiling in excess water showed a significant decrease in tAs content compared with raw rice. Regarding As species, it is worth noting that the different treatments significantly reduced the content of the most toxic forms of As. The estimated lifetime health risks indicate that pre-rinsing alone can reduce the risk by 50%, while combining it with discarding excess water can reduce the risk by 83%; therefore, the latter would be the preferable method.
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Addition of carbon as methanol or ammonium carbonate to the aqueous analyte solutions in combination with increased plasma power input enhanced the inductively coupled plasma mass spectrometry (ICP-MS) signal intensities of arsenic and selenium. In the presence of the optimum 3% v/v methanol concentration the signal intensities achieved were about 4500-5000 counts s-1 per ng ml-1 of arsenic and about 700-1100 counts s-1 per ng ml-1 of selenium (82Se), corresponding to enhancement factors of 3.5-4.5 compared with aqueous solution for the two elements. Differences in sensitivity (calculated on the basis of analyte atom) were observed between the individual arsenic species and between the selenium species in aqueous as well as in carbon-added solutions. The presence of 3% v/v methanol in the analyte solutions doubled the level of the background signal for arsenic and selenium, but its fluctuation (noise) was not increased. Therefore, the observed increase in analyte sensitivity led to a similar increase in signal-to-noise ratio. The addition of carbon as ammonium carbonate enhanced the arsenic signal by a similar factor but caused severe contamination of the ICP-MS instrument by carbon. In the 3% v/v methanol solutions of arsenic and selenium the signal intensity from antimony (internal standard) was enhanced by a factor of 1.5, which indicates that the enhancement effect of the arsenic and selenium signals by methanol is only to a limited extent caused by improved sample transport/nebulization efficiency. It is proposed that an increased population of carbon ions or carbon-containing ions in the plasma facilitates a more complete ionization of analytes lower in ionization energy than carbon itself. The enhanced detection power for arsenic was applied to arsenic speciation by high-performance liquid chromatography (HPLC)-ICP-MS, and made possible the detection of the arsenocholine ion (AsC) in extracts of shrimp at the 5-10 ng g-1 concentration level. The limit of detection was improved by a factor of 3.4 after addition of methanol and was 4.7 ng g-1 as the AsC ion.
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With rice being the main staple crop in Asian countries such as China, Korea and Japan, the detection of arsenic (As), an element known to be carcinogenic to humans, has been the topic of high public interest. In this study, the total arsenic content in 200 white and 104 brown rice samples collected in Korea was analyzed using a Quadrupole Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). One of the rice grain samples was polished with 3, 5, 7, 9 and 11 degrees of milling and arsenic concentration variance from the surface to the inner core region was investigated. Furthermore, spatial distribution of arsenic over the cross-section of a brown rice grain was obtained using femtosecond Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (fs LA-ICP-MS). For the total arsenic content analysis, 91.7 ± 28.1 and 101 ± 33.6 μg−1 kg−1 of arsenic were measured in the white and the brown rice, respectively. The fs LA-ICP-MS mapping image explains that the higher arsenic concentration in the brown rice is due to high arsenic distribution in the rice husk (protective covering of rice). Consequently, some degree of rice milling may be effective in the reduction of arsenic intake.
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Paddy rice (Oryza sativa L.) is a staple food and one of the major sources of dietary arsenic (As) and cadmium (Cd) in Asia. A field experiment was conducted to investigate the effects of four water management regimes (aerobic, intermittent irrigation, conventional irrigation and flooding) on As and Cd accumulation in seven major rice cultivars grown in Zhejiang province, east China. With increasing irrigation from aerobic to flooded conditions, the soil HCl-extractable As concentrations increased significantly and the HCl-extractable Cd concentrations decreased significantly. These trends were consistent with the As and Cd concentrations in the straw, husk and brown rice. Water management both before and after the full tillering stage affected As and Cd accumulation in the grains. The intermittent and conventional treatments produced higher grain yields than the aerobic and flooded treatments. Cd concentrations in brown rice varied 13.1-40.8 times and As varied 1.75-8.80 times among the four water management regimes. Cd and As accumulation in brown rice varied among the rice cultivars, with Guodao 6 (GD6) was a low Cd but high-As-accumulating cultivar while Indonesia (IR) and Yongyou 9 (YY9) were low As but high-Cd-accumulating cultivars. Brown rice Cd and As concentrations in the 7 cultivars were significantly negatively correlated. The results indicate that As and Cd accumulated in rice grains with opposite trends that were influenced by both water management and rice cultivar. Production of 'safe' rice with respect to As and Cd might be possible by balancing water management and rice cultivar according to the severity of soil pollution.
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Background: In adult populations, emerging evidence indicates that humans are exposed to arsenic by ingestion of contaminated foods such as rice, grains, and juice; yet little is known about arsenic exposure among children. Objectives: Our goal was to determine whether rice consumption contributes to arsenic exposure in U.S. children. Methods: We used data from the nationally representative National Health and Nutrition Examination Survey (NHANES) to examine the relationship between rice consumption (measured in 0.25 cups of cooked rice per day) over a 24-hr period and subsequent urinary arsenic concentration among the 2,323 children (6–17 years of age) who participated in NHANES from 2003 to 2008. We examined total urinary arsenic (excluding arsenobetaine and arsenocholine) and dimethylarsinic acid (DMA) concentrations overall and by age group: 6–11 years and 12–17 years. Results: The median [interquartile range (IQR)] total urinary arsenic concentration among children who reported consuming rice was 8.9 μg/L (IQR: 5.3–15.6) compared with 5.5 μg/L (IQR: 3.1–8.4) among those who did not consume rice. After adjusting for potentially confounding factors, and restricting the study to participants who did not consume seafood in the preceding 24 hr, total urinary arsenic concentration increased 14.2% (95% confidence interval: 11.3, 17.1%) with each 0.25 cup increase in cooked rice consumption. Conclusions: Our study suggests that rice consumption is a potential source of arsenic exposure in U.S. children.
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Dietary exposure from food to toxic inorganic arsenic (iAs) in the general U.S. population has not been well studied. The goal of this research was to quantify dietary As exposure and analyze the major contributors to total As (tAs) and iAs. Another objective was to compare model predictions with observed data. Probabilistic exposure modeling for dietary As was conducted with the Stochastic Human Exposure and Dose Simulation Dietary (SHEDS-Dietary) model, based on data from the National Health and Nutrition Examination Survey. The dose modeling was conducted by combining the SHEDS-Dietary model with the MENTOR-3P (Modeling ENvironment for TOtal Risk with Physiologically Based Pharmacokinetic Modeling for Populations) system. Model evaluation was conducted via comparing exposure and dose-modeling predictions against duplicate diet data and biomarker measurements, respectively, for the same individuals. The mean modeled tAs exposure from food is 0.38 microg/kg/day, which is approximately 14 times higher than the mean As exposures from the drinking water. The mean iAs exposure from food is 0.05 microg/kg/day (1.96 microg/day), which is approximately two times higher than the mean iAs exposures from the drinking water. The modeled exposure and dose estimates matched well with the duplicate diet data and measured As biomarkers. The major food contributors to iAs exposure were the following: vegetables (24%); fruit juices and fruits (18%); rice (17%); beer and wine (12%); and flour, corn, and wheat (11%). Approximately 10% of tAs exposure from foods is the toxic iAs form. The general U.S. population may be exposed to tAs and iAs more from eating some foods than from drinking water. In addition, this model evaluation effort provides more confidence in the exposure assessment tools used.
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Total arsenic and arsenic speciation was performed on different rice types (basmati, long-grain, polished ([white] and wholegrain [brown]) that had undergone various forms of cooking. The effect of rinse washing, low volume (2.5 : 1 water : rice) and high volume (6 : 1 water : rice) cooking, as well as steaming, were investigated. Rinse washing was effective at removing circa. 10% of the total and inorganic arsenic from basmati rice, but was less effective for other rice types. While steaming reduced total and inorganic arsenic rice content, it did not do so consistently across all rice types investigated. Low volume water cooking did not remove arsenic. High volume water : rice cooking did effectively remove both total and inorganic arsenic for the long-grain and basmati rice (parboiled was not investigated in high volume cooking water experiment), by 35% and 45% for total and inorganic arsenic content, respectively, compared to uncooked (raw) rice. To reduce arsenic content of cooked rice, specifically the inorganic component, rinse washing and high volume of cooking water are effective.
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Arsenic contamination of rice by irrigation with contaminated groundwater and secondarily increased soil arsenic compounds the arsenic burden of populations dependent on subsistence rice-diets. The arsenic concentration of cooked rice is known to increase with the arsenic concentration of the cooking water but the effects of cooking methods have not been defined. We tested the three major rice cooking procedures followed globally. Using low-arsenic water (As < 3 microg/L), the traditional method of the Indian subcontinent (wash until clear; cook with rice: water::1:6; discard excess water) removed up to 57% of the arsenic from rice containing arsenic 203-540 microg/kg. Approximately half of the arsenic was lost in the wash water, half in the discard water. A simple inexpensive rice cooker based on this method has been designed and used for this purpose. Despite the use of low-arsenic water, the contemporary method of cooking unwashed rice at rice:water::1:1.5-2.0 until no discard water remains did not modify the arsenic content. Preliminary washing until clear did remove 28% of the rice arsenic. The results were not influenced by water source (tubewell, dug well, pond or rain); cooking vessel (aluminium, steel, glass or earthenware); or the absolute weight of rice or volume of water. The use of low-As water in the traditional preparation of arsenic contaminated rice can reduce the ingested burden of arsenic.
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Arsenic contamination of rice plants by arsenic-polluted irrigation groundwater could result in high arsenic concentrations in cooked rice. The main objective of the study was to estimate the total and inorganic arsenic intakes in a rural population of West Bengal, India, through both drinking water and cooked rice. Simulated cooking of rice with different levels of arsenic species in the cooking water was carried out. The presence of arsenic in the cooking water was provided by four arsenic species (arsenite, arsenate, methylarsonate or dimethylarsinate) and at three total arsenic concentrations (50, 250 or 500 microg l(-1)). The results show that the arsenic concentration in cooked rice is always higher than that in raw rice and range from 227 to 1642 microg kg(-1). The cooking process did not change the arsenic speciation in rice. Cooked rice contributed a mean of 41% to the daily intake of inorganic arsenic. The daily inorganic arsenic intakes for water plus rice were 229, 1024 and 2000 microg day(-1) for initial arsenic concentrations in the cooking water of 50, 250 and 500 microg arsenic l(-1), respectively, compared with the tolerable daily intake which is 150 microg day(-1).
Article
Synchrotron-based X-ray fluorescence (S-XRF) was utilized to locate arsenic (As) in polished (white) and unpolished (brown) rice grains from the United States, China, and Bangladesh. In white rice As was generally dispersed throughout the grain, the bulk of which constitutes the endosperm. In brown rice As was found to be preferentially localized at the surface, in the region corresponding to the pericarp and aleurone layer. Copper, iron, manganese, and zinc localization followed that of arsenic in brown rice, while the location for cadmium and nickel was distinctly different, showing relatively even distribution throughout the endosperm. The localization of As in the outer grain of brown rice was confirmed by laser ablation ICP-MS. Arsenic speciation of all grains using spatially resolved X-ray absorption near edge structure (micro-XANES) and bulk extraction followed by anion exchange HPLC-ICP-MS revealed the presence of mainly inorganic As and dimethylarsinic acid (DMA). However, the two techniques indicated different proportions of inorganic:organic As species. A wider survey of whole grain speciation of white (n=39) and brown (n=45) rice samples from numerous sources (field collected, supermarket survey, and pot trials) showed that brown rice had a higher proportion of inorganic arsenic present than white rice. Furthermore, the percentage of DMA present in the grain increased along with total grain arsenic.
Article
Recent reports of As concentrations in certain food and drinks has garnered public concern and led to a lowering of the US guideline maximum concentration for inorganic As in apple juice and proposed limits for As in rice products. In contrast Se is an essential micro-nutrient that can be limiting when Se-poor soils yield Se-poor food crops. Rare earth element (REE) doubly charged interferences on As and Se can be significant even when initial ICP-MS tuning minimizes doubly charged formation. We analyzed NIST 1547 (peach leaves) and 1515 (apple leaves), which contain high levels of REEs, by quadrupole ICP-MS with (He) collision mode, H2 reaction mode or triple quadrupole ICP-MS (ICP-QQQ) in mass-shift mode (O2 and O2/H2). Analysis by collision cell ICP-MS significantly over-estimated As and Se concentration due to REE doubly charged formation; mathematical correction increased the accuracy of analysis but is prone to error when analyte concentration and sensitivity is low and interferent is high. For Se, H2 reaction mode was effective in suppressing Gd2+ leading to accurate determination of Se in both SRMs without the need for mathematical correction. ICP-QQQ using mass-shift mode for As+ from m/z 75 to AsO+ at m/z 91 and Se+ from m/z 78 to SeO+ at m/z 94 alleviated doubly charged effects and resulted in accurate determination of As and Se in both SRMs without the need for correction equations. Zr and Mo isobars at 91 and 94 were shown to be effectively rejected by the MS/MS capability of the ICP-QQQ.
Article
The effects of polishing, cooking, and storing on total arsenic (As) and As species concentrations in rice were studied adopting typical Japanese conditions. Total and inorganic As levels in three white rice samples polished by removing 10% of bran by weight were reduced to 61–66% and 51–70% of those in brown rice. The As levels in the white rice after three washings with deionized water were reduced to 81–84% and 71–83% of those in raw rice. Rinse-free rice, which requires no washing before cooking because bran remaining on the surface of the rice was removed previously, yielded an effect similar to that of reducing As in rice by washing. Low-volume cooking (water:rice 1.4–2.0:1) rice to dryness did not remove As. The As content of brown rice stored in grain form for one year was stable.
Article
At the present time, the Food and Drug Administration (FDA) accords the highest priority to mercury, lead, cadmium, arsenic, selenium, and zinc in its program on toxic elements in foods. The only regulatory levels for arsenic in foods in the US are the tolerances which have been established for its residues in specified foods, resulting from the application of arsenical pesticides on food and feed crops and from animal feed additives. FDA has monitored for arsenic in its Total Diet Survey since the inception of this program. The data from this program indicate that the average daily intake for arsenic (as AsâOâ) has decreased from about 130 ..mu..g/day in 1968 to about 20 ..mu..g/day in 1974. Most of the arsenic is found in the meat-fish-poultry food class of the total diet. In individual foods, the highest levels were found in fish, with a mean level of about 1.5 ppm (as AsâOâ) in the edible portion of finfish. Much lower levels were found in all the other food types analyzed; of these, the highest levels found were a mean level of 0.08 ppm in chicken and 0.16 ppm in rice. FDA toxicologists do not believe that the aveage daily intake of arsenic, or its levels in the different food commodities, pose a hazard to the consumer.
Article
A method is presented for arsenic speciation analysis in rice using ion chromatography coupled to inductively coupled plasma mass spectrometry. Several procedures for the extraction of arsenic species from rice were investigated and compared. Treatment of the samples with 2 M trifluoroacetic acid for 6 h at 100°C provided good extraction efficiency. Fortification recoveries were 83, 88, 100, and 93% for arsenite (100 ng As g−1), arsenate (100 ng As g−1), methylarsonic acid (MMA, 50 ng As g−1), and dimethylarsinic acid (DMA, 200 ng As g−1), respectively. The arsenate fortification recovery was calculated using the sum of the increase in arsenate and arsenite concentrations because arsenate was partially reduced to arsenite during the extraction process. Thus the sum of their concentrations is reported in this method as total inorganic arsenic. The sum of the arsenic species determined in NIST SRM 1568a rice flour (0.27 µg g−1 As), compared well with the certified total arsenic value (0.29 µg g−1 As). The speciation results obtained for 5 samples of long grain rice and one sample of wild rice are compared with total arsenic concentrations as determined by ICP-MS. The total arsenic concentrations ranged from 0.11 to 0.34 mg kg−1. The sum of the arsenic species extracted and determined by IC-ICP-MS ranged from 84 to 99% of the measured total arsenic concentrations. Inorganic arsenic accounted for 11–91% of the arsenic detected while DMA accounted for most of the remaining arsenic in the samples.
Article
Two Hungarian and one Chinese rice samples were selected in order to establish the extractable arsenic content by washing and cooking in water in a ratio of 6:1, water:rice (cm3:g) by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). Total arsenic concentration of the Zhenshan 97, Risabell and Ko˝röstáj-333 samples were 171.3 ± 7.1 ng g−1, 116.0 ± 3.7 ng g−1 and 139.0 ± 6.1 ng g−1, respectively, which did not exceed the toxic limits established for As in Hungary (0.3 μg g−1) or in China (0.7 μg g−1). The predominant chemical form of As in the raw rice samples determined by on-line high performance liquid chromatography and ICP-MS was arsenite. Moreover, enzymatic hydrolysis with α-amylase + protease and microprobe focused sonication proved that arsenite could be removed in the highest extent by washing and cooking, meanwhile the main As form remaining in the cooked rice was As(V). Thus, it is recommended to prepare rice-containing dishes in abundant water, which should be discarded after washing and cooking. The results were validated with a NIST SRM 1568a.
Article
Tetramethylarsonium has for the first time been identified in a commercially grown food product, rice, constituting up to 5.8% of the total arsenic in the rice.
Article
Arsenic (As) exposure from consumption of rice can be substantial, particularly for the population on a subsistence rice diet in South Asia. Paddy rice has a much enhanced As accumulation compared with other cereal crops, and practical measures are urgently needed to decrease As transfer from soil to grain. We investigated the dynamics of As speciation in the soil solution under both flooded and aerobic conditions and compared As accumulation in rice shoot and grain in a greenhouse experiment. Flooding of soil led to a rapid mobilization of As, mainly as arsenite, in the soil solution. Arsenic concentrations in the soil solution were 7-16 and 4-13 times higher under the flooded than under the aerobic conditions in the control without As addition and in the +As treatments (10 mg As kg(-1) as arsenite or arsenate), respectively. Arsenate was the main As species in the aerobic soil. Arsenic accumulation in rice shoots and grain was markedly increased under flooded conditions; grain As concentrations were 10-15-fold higher in flooded than in aerobically grown rice. With increasing total As concentrations in grain, the proportion of inorganic As decreased, while that of dimethylarsinic acid (DMA) increased. The concentration of inorganic As was 2.6-2.9 fold higher in the grain from the flooded treatment than in that from the aerobic treatment. The results demonstrate that a greatly increased bioavailability of As under the flooded conditions is the main reason for an enhanced As accumulation by flooded rice, and growing rice aerobically can dramatically decrease the As transfer from soil to grain.
Article
At the present time, the Food and Drug Administration (FDA) accords the highest priority to mercury, lead, cadmium, arsenic, selenium, and zinc in its program on toxic elements in foods. The only regulatory levels for arsenic in foods in the U. S. are the tolerances which have been established for its residues in specified foods, resulting from the application of arsenical pesticides on food and feed crops and from animal feed additives. FDA has monitored for arsenic in its Total Diet Survey since the inception of this program. The data from this program indicate that the average daily intake for arsenic (as As(2)O(3)) has decreased from about 130 mug/day in 1968 to about 20 mug/day in 1974. Most of the arsenic is found in the meat-fish-poultry food class of the total diet. In individual foods, the highest levels were found in fish, with a mean level of about 1.5 ppm (as As(2)O(3)) in the edible portion of finfish. Much lower levels were found in all the other food types analyzed; of these, the highest levels found were a mean level of 0.08 ppm in chicken and 0.16 ppm in rice. FDA toxicologists do not believe that the average daily intake of arsenic, or its levels in the different food commodities, pose a hazard to the consumer.
Article
The FDA has conducted the Total Dietary Study (TDS), a yearly market basket programme, since 1961. It is designed to monitor the levels of toxic chemical contaminants (pesticide residues, industrial and elemental contaminants) and essential nutrients in the US food supply. It also provides information on trends in dietary concentrations and exposures for the general population. Foods are collected from retail stores once a year from each of four geographic areas of the US and are analysed either after preparation/cooking or as ready-to-eat. The latest TDS (1991-1997) data show that arsenic (inorganic and organic, > or = 0.03 ppm) was found in 63 (24%) of the 261-264 foods/mixed dishes analysed. The highest concentration was found in seafood, followed by rice/rice cereal, mushrooms, and poultry. Based on the United States Department of Agriculture's 1987-1988 Nationwide Food Consumption Survey, the estimated daily total arsenic average intakes, in microgram/day, are: 2 for infants, 23 for toddlers, 20 for 6-year-old children, 13 for 10-year-old children, 15 for 14-16-year-old boys, 21 for 14-16-year-old girls, 57 for 25-30-year-old men, 28 for 25-30-year-old women, 47 for 40-45-year-old men, 37 for 40-45-year-old women, 92 for 60-65-year-old men, 72 for 60-65-year-old women, 69 for 70-year-old men, and 42 for 70-year-old women. Of the estimated total arsenic intakes for infants, 42% arise from seafood and 31% from rice/rice cereals. Of the estimated total arsenic intakes, seafood contributes 76-90% for children (2-10-year olds), 79-85% for 14-16-year olds, and 89-96% for adults (> or = 25-30-year olds); rice/rice cereals contributes 4-8% for children, 8% for 14-16-year olds, and 1-4% for adults (> or = 25-30-year olds).
Article
A low-level review of the fundamentals of ion-molecule interactions is presented. These interactions are used to predict the efficiencies of collisional fragmentation, energy damping and reaction for a variety of neutral gases as a function of pressure in a rf-driven collision/reaction cell. It is shown that the number of collisions increases dramatically when the ion energies are reduced to near-thermal (< 0.1 eV), because of the ion-induced dipole and ion-dipole interaction. These considerations suggest that chemical reaction can be orders of magnitude more efficient at improving the analyte signal/background ratio than can collisional fragmentation. Considerations that lead to an appropriate selection of type of gas, operating pressure, and ion energies for efficient operation of the cell for the alleviation of spectral interferences are discussed. High efficiency (large differences between reaction efficiencies of the analyte and interference ions, and concomitant suppression of secondary chemistry) might be required to optimize the chemical resolution (determination of an analyte in the presence of an isobaric interference) when using ion-molecule chemistry to suppress the interfering ion. In many instances atom transfer to the analyte, which shifts the analytical m/z by the mass of the atom transferred, provides high chemical resolution, even when the efficiency of reaction is relatively low. Examples are given of oxidation, hydroxylation, and chlorination of analyte ions (V+, Fe+, As+, Se+, Sr+, Y+, and Zr+) to improve the capability of determination of complex samples. Preliminary results are given showing O-atom abstraction by CO from CaO+ to enable the determination of Fe in high-Ca samples.
Article
In Bangladesh, rice is boiled with an excessive amount of water, and the water remaining after cooking will be discarded. We did an on-site experiment to assess the effect of this cooking method on the amount of arsenic retained in cooked rice. The concentration of arsenic in cooked rice was higher than that in raw rice and absorbed water combined, suggesting a chelating effect by rice grains, or concentration of arsenic because of water evaporation during cooking, or both. The method of cooking and water used can affect the amount of arsenic in cooked rice, which will have implications for the assessment of the health risks of arsenic.
Article
Although most edible vegetables do not accumulate As at a high rate, rice, carrots and certain others are exceptions. In addition to nutritional or toxicological considerations, the relatively high level and variety of As species present in rice make it a very suitable matrix for a candidate reference material representative of terrestrial biological samples.An analytical procedure was developed for As speciation in rice based on the use of a 1:1 methanol-water mixture for species extraction, an anion Hamilton PRPX-100 column (at pH 6, and phosphate mobile phase 10 mM), and a cation Hamilton PRP-X200 column (at pH 2.8 in pyridine formiate 4 mM) for species separation and final determination by HPLC-ICP-MS. The detection limits for dry flour rice expressed as As were 2 and 3 ng g(-1) for As(III) and AsB on the cation column and 3, 6 and 5 ng g(-1) for As(V), MMA and DMA, respectively, on the anion column. The methodology developed was applied to check the stability of As species in the water-methanol extract and also under different processing steps and storage time and temperature conditions. It was demonstrated that the As species in the water-methanol extracts stored at +4 degrees C remained stable for at least one month. Once the rice grains are ground, the MMA and As(V) species are not stable under any storage conditions probably due to microbiological activity. When ground rice is gamma-irradiated species remain stable although the AsB does not appear.
Article
Rice is a target food for arsenic speciation based analyses because of its relatively high arsenic concentration and per capita consumption rates. Improved speciation data for rice can be helpful in estimating inorganic arsenic exposures in the U.S. and in endemic populations. The inorganic arsenic exposure for cooked rice should include both the arsenic in raw rice plus the arsenic absorbed from the water used to prepare it. The amount of arsenic absorbed from water by rice during preparation was assessed using five different types of rice cooked in both contaminated drinking water and arsenic-free reagent water. The rice samples were extracted using trifluoroacetic acid (TFA) and speciated using IC-ICP-MS. The TFA procedure was able to extract 84-104% of the arsenic (As) from the five different cooked rice samples. Chromatographic recoveries ranged from 99% to 116%. The dimethylarsinic acid (DMA) and inorganic arsenic concentration ranged from 22 to 270 ng of As/g of rice and from 31 to 108 ng of As/g of rice, respectively, for samples cooked in reagent water. The overall recoveries, which relate the sum of the chromatographic species back to the total digested concentration, ranged from 89% to 117%. The absorption of arsenic by rice from the total volume of water [1:1 to 4:1 (water:rice)] used in cooking was between 89% and 105% for two different contaminated drinking water samples. A comparison of the TFA extraction to an enzymatic extraction was made using the five rice samples and NIST 1568a rice flour. The two extraction procedures produced good agreement for inorganic arsenic, DMA, and the overall recovery. Through the use of IC-ESI-MS/ MS with a parent ion of m/z 153 and fragment ions of m/z 138, 123, and 105, the structure dimethylthioarsinic acid was tentatively identified in two of the rice samples using the enzymatic extraction.
Article
Arsenic is present in rice grain mainly as inorganic arsenic. Little is known about the effect of cooking on inorganic arsenic content in rice and its bioavailability. This study evaluated total arsenic and inorganic arsenic in rice cooked with arsenic-contaminated water, the bioaccessibility of As(III) and As(V) after simulated gastrointestinal digestion, and the extent of arsenic retention and transport by Caco-2 cells used as a model of intestinal epithelia. After cooking, inorganic arsenic contents increase significantly. After simulated gastrointestinal digestion, the bioaccessibility of inorganic arsenic reached 63-99%; As(V) was the main species found. In Caco-2 cells, arsenic retention, transport, and total uptake (retention + transport) varied between 0.6 and 6.4, 3.3 and 11.4, and 3.9 and 17.8%, respectively. These results show that in arsenic endemic areas with subsistence rice diets, the contribution of inorganic arsenic from cooked rice should be considered in assessments of arsenic health risk.
Article
Arsenic concentration in raw rice is not only the determinant in actual dietary exposure. Though there have been many reports on arsenic content in raw rice and different tissues of rice plant, little is known about arsenic content retained in cooked rice after being cooked following the traditional cooking methods employed by the people of arsenic epidemic areas. A field level experiment was conducted in Bangladesh to investigate the influence of cooking methods on arsenic retention in cooked rice. Rice samples were collected directly from a severely arsenic affected area and also from an unaffected area, to compare the results. Rice was cooked according to the traditional methods employed by the population of subjected areas. Arsenic concentrations were 0.40+/-0.03 and 0.58+/-0.12 mg/kg in parboiled rice of arsenic affected area, cooked with excess water and 1.35+/-0.04 and 1.59+/-0.07 mg/kg in gruel for BRRI dhan28 and BRRI hybrid dhan1, respectively. In non-parboiled rice, arsenic concentrations were 0.39+/-0.04 and 0.44+/-0.03 mg/kg in rice cooked with excess water and 1.62+/-0.07 and 1.74+/-0.05 mg/kg in gruel for BRRI dhan28 and BRRI hybrid dhan1, respectively. Total arsenic content in rice, cooked with limited water (therefore gruel was absorbed completely by rice) were 0.89+/-0.07 and 1.08+/-0.06 mg/kg (parboiled) and 0.75+/-0.04 and 1.09+/-0.06 mg/kg (non-parboiled) for BRRI dhan28 and BRRI hybrid dhan1, respectively. Water used for cooking rice contained 0.13 and 0.01 mg of As/l for contaminated and non-contaminated areas, respectively. Arsenic concentrations in cooked parboiled and non-parboiled rice and gruel of non-contaminated area were significantly lower (p<0.01) than that of contaminated area. The results imply that cooking of arsenic contaminated rice with arsenic contaminated water increases its concentration in cooked rice.
Article
Paired grain, shoot, and soil of 173 individual sample sets of commercially farmed temperate rice, wheat, and barley were surveyed to investigate variation in the assimilation and translocation of arsenic (As). Rice samples were obtained from the Carmargue (France), Doñana (Spain), Cadiz (Spain), California, and Arkansas. Wheat and barleywere collected from Cornwall and Devon (England) and the east coast of Scotland. Transfer of As from soil to grain was an order of magnitude greater in rice than for wheat and barley, despite lower rates of shoot-to-grain transfer. Rice grain As levels over 0.60 microg g(-1) d. wt were found in rice grown in paddy soil of around only 10 microg g(-1) As, showing that As in paddy soils is problematic with respect to grain As levels. This is due to the high shoot/soil ratio of approximately 0.8 for rice compared to 0.2 and 0.1 for barley and wheat, respectively. The differences in these transfer ratios are probably due to differences in As speciation and dynamics in anaerobic rice soils compared to aerobic soils for barley and wheat. In rice, the export of As from the shoot to the grain appears to be under tight physiological control as the grain/shoot ratio decreases by more than an order of magnitude (from approximately 0.3 to 0.003 mg/kg) and as As levels in the shoots increase from 1 to 20 mg/kg. A down regulation of shoot-to-grain export may occur in wheat and barley, but it was not detected at the shoot As levels found in this survey. Some agricultural soils in southwestern England had levels in excess of 200 microg g(-1) d. wt, although the grain levels for wheat and barley never breached 0.55 microg g(-1) d. wt. These grain levels were achieved in rice in soils with an order of magnitude lower As. Thus the risk posed by As in the human food-chain needs to be considered in the context of anaerobic verses aerobic ecosystems.
Article
Rice can contain a relatively high amount of arsenic (As). We evaluated total and inorganic As concentrations in 39 samples of different types of rice sold in Spain. The analyses were performed in raw rice and in rice cooked by boiling to dryness in water spiked with As(V) (0.1-1 microg mL(-1)). In raw rice, inorganic As represented 27-93% of total As: total As = 0.188 +/- 0.078 microg g(-1) dry weight (dw); inorganic As = 0.114 +/- 0.046 microg g(-1) dw. After cooking, the rice retained between 45% and 107% of the As(V) added to the cooking water, and the inorganic As concentrations ranged between 0.428 microg g(-1) dw (0.1 microg mL(-1) in the cooking water) and 3.89 microg g(-1) dw (1.0 microg microL(-1) in the cooking water). For raw rice, the inorganic As intake of the Spanish population (16 g raw rice/day) remains below the tolerable daily intake (TDI) proposed by the WHO (2.1 microg inorganic As/day/kg body weight). In rice cooked with water contaminated with As(V), this cereal intake is sufficient to attain the TDI. The results reveal the need to consider the determination of inorganic As and the influence of cooking when evaluating the risks associated with the consumption of rice.
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