Effects of the Pre-Cooking Process Using Acetic Acid and Citric Acid on Lead Concentration in Rice

Abstract

Rice is one of the most highly consumed foodstuffs in the world. In keeping with this, produced rice of many regions of the world contains high lead content. The present research was done to study the effects of the pre-cooking process of rice with acetic acid and citric acid on the concentration of lead. Rice samples were divided into 5 different pre-cooking treatment groups of soaking in acetic acid 1% and soaking in citric acid 1% (2 hrs), boiling with acetic acid 1% and boiling with citric acid 1% (20 min) and finally 6 times rinsing with deionized water. Then, measurement of lead remains was done using an atomic absorption optical spectrometer equipped with a detector of graphite furnace with deuterium lamp. The mean concentration of lead in primary rice samples without any processing operation was 87±4.8 ppb. The mean concentration of lead in rice samples processed with soaking in acetic acid, soaking in citric acid, boiling with citric acid, boiling in acetic acid and finally 6 times rinsing with deionized water were 55±3.8, 14±1.6, 32±2.4, 14±1.1 and 30±0.5 ppb, respectively. The highest reeducation percent of lead in rice samples was obtained in both soaking with citric acid and boiling with citric acid (84%). In keeping with the high concentrations of lead in studied rice samples, obtained concentrations were lower than the allowed limit of lead announced with the international standard organization of Iran (150 ppb). Boiling and soaking of rice samples with citric acid 1% can be a convenient and fast way to reduce the concentration of lead in rice samples.

Reducing the cadmium, inorganic arsenic and dimethylarsinic acid content of rice through food-safe chemical cooking pre-treatment

“…Zou et al (2019) found that citric acid could remove cadmium from bran, while Wu et al (2016) established that citric acid could be used to reduce this element from brown rice flour. Citric acid treatment also was found to reduce lead (Behrouzi et al, 2020a) and total arsenic (Behrouzi et al, 2020b) from rice grain. Here we optimise procedures to remove cadmium from intact rice using citric acid, and then developed processes to neutralize the subsequent acidification of pH.…”

Assessment of Rice Marketed in Iran with Emphasis on Toxic and Essential Elements; Effect of Different Cooking Methods

“…Therefore, regarding the importance of rice for nutritional value, the quality control and safety of this nutrient in terms of its contaminants, especially toxic and essential elements, are very important. Previous study reported that rice can be contaminated with various pollutants, including toxic metals such as aluminum (Al), chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) through water, soil, and climatic conditions; thus, considering the high consumption of rice by most different people of society, the assessment of toxic and essential elements impacts on the health of consumers is necessary [5][6][7][8].…”

Removal of Toxic and Essential Nutrient Elements from Commercial Rice Brands Using Different Washing and Cooking Practices: Human Health Risk Assessment

“…Sharafi, et al [ 51 ] reported Pb content in raw rice varied from 47.5 to 1208.4 µg/kg, which was much higher than our findings. Behrouzi, et al [ 54 ] reported mean Pb content in Iranian raw rice was 87 ± 4.8 µg/kg. Another study from Iran reported the raw rice concentration of Pb was 1750 µg/kg [ 52 ].…”

“…Al-Saleh and Abduljabbar [ 56 ] reported a 65% reduction in Cd in raw rice when grains were rinsed three times with deionized water. Behrouzi, et al [ 54 ] reported a 37% reduction in Pb from Iranian raw rice when washed six times with deionized water. Many studies have demonstrated that washing of rice prior to cooking can efficiently reduce the levels of trace elements such as As, Cd, and Pb in cooked rice samples, which is in agreement with the results of this study [ 49 , 57 , 58 , 59 , 60 ]; although, the higher percentage of reduction in TEs from washing in other studies may be due to the soaking of rice with water for longer period of time and using a higher volume of water in washing, which could influence a higher reduction in TEs.…”