Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
This original research article investigated new rice cooking methods to maximize the removal of inorganic arsenic (Asi), a known carcinogen, from rice grains. The study compared traditional static cooking methods, which use fixed water-to-rice ratios, with novel percolating water techniques. In these percolating methods, either arsenic-free or low-arsenic near-boiling water was continuously passed through rice to physically remove leached arsenic. Two main percolating technologies were tested: a laboratory Soxhlet apparatus recycling distilled water, and a domestic coffee percolator using tap water. The research systematically examined how different cooking water volumes and continuous water flow affected the efficiency of arsenic removal, and measured the effects on both inorganic arsenic and other rice nutrients. The findings were evaluated for both polished (white) and wholegrain rice, with implications for both industrial and domestic rice preparation and heavy metal risk mitigation.
Who was studied?
The study focused on 41 rice samples widely available to UK consumers, representing both polished (white) and wholegrain (brown) rice types. These rice samples originated from diverse global sources, including Spain, Italy, Thailand, France, Egypt, Japan, Australia, Lebanon, Pakistan, Turkey, the USA, and the EU. Of these, 13 samples were wholegrain and the remainder polished. The rice was sourced from major UK retailers to ensure that findings would be relevant to commonly consumed products. The arsenic content and cooking loss were analyzed on these samples under various cooking methods, with both laboratory-controlled and domestic-scale experiments conducted to reflect potential real-world and industrial applications.
Most important findings
| Critical Point | Details |
|---|---|
| Water-to-rice ratio and arsenic removal | Increasing the water-to-rice ratio in conventional cooking significantly enhances inorganic arsenic removal. At a 12:1 ratio, an average of 57±5% Asi was removed, with up to 70% in some cases, and more removal from wholegrain rice. |
| Percolating water technologies | Both Soxhlet (laboratory) and coffee percolator (domestic) methods achieved high Asi removal. Soxhlet percolation removed 59±8% (polished) and 69±10% (wholegrain), with up to 85% in some samples. Coffee percolator removed 49±7%. |
| Rice type and arsenic removal | Wholegrain rice had higher initial Asi but also saw more efficient removal with percolation methods, likely due to distribution of Asi in grain layers. However, in percolator trials, removal did not significantly differ by type. |
| Other elements and nutrients | Percolating methods significantly reduced potassium (by 53%) and phosphorus (by 7%), but did not significantly affect calcium, copper, iron, manganese, sulphur, or zinc. Dimethylarsinic acid (DMA) was minimally removed. |
| Practical implications for industry and households | Continual flow (percolation) cooking is feasible domestically and in industrial settings, offering a scalable solution to reduce Asi in rice products, including baby rice and rice milk. |
Key implications
The study demonstrates that percolating water technologies, both at laboratory and domestic scale, are highly effective in reducing inorganic arsenic content in rice, far surpassing traditional methods. This approach can be readily adapted to industrial food processing and home cooking, offering a critical, immediate strategy for reducing heavy metal exposure through rice consumption. Adoption in manufacturing of rice-based products, especially those for infants, could significantly mitigate health risks associated with arsenic.
Citation
Carey M, Jiujin X, Gomes Farias J, Meharg AA. Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water. PLoS ONE. 2015;10(7):e0131608. doi:10.1371/journal.pone.0131608
Arsenic is a naturally occurring metalloid that ranks first on the ATSDR toxic substances list. Inorganic arsenic contaminates water, rice and consumer products, and exposure is linked to cardiovascular disease, cognitive deficits, low birth weight and cancer. HMTC’s stringent certification applies ALARA principles to protect vulnerable populations.
