Effect of parboiling on minerals and heavy metals of selected Sri Lankan traditional rice varieties grown under organic farming

Abstract

The study was conducted to evaluate the effects of parboiling treatment on the minerals and heavy metals of six Sri Lankan traditional rice varieties; Kalu heenati, Pokkali, Gurusinghe wee, Kahawanu, Sudu murunga and Unakola samba. Metals were determined by using ICP-AES and AAS. Parboiling can be considered as a suitable rice processing method for Pokkali and Kahawanu and not for Kalu heenati and Unakola samba in order to furnish the recommended daily intake of the micronutrients. Un-parboiled Kalu heenati and both un-parboiled and parboiled Kahawanu can be considered as the most suitable rice varieties for daily consumption in order to maintain the recommended daily intake of iron. It was identified that Pokkali rice contained the highest iron content of 29.5 mg/100 g. This amount has further increased by 66.7% after parboiling. Therefore both parboiled and unparboiled Pokkali can be considered as the best dietary supplement among these rice varieties for iron deficiency and for pregnant mothers. Selected heavy metals including As, Cd, Pb and Cu were not detected in the selected Sri Lankan traditional rice varieties.

Narrative Review on Nutritional Composition, Antioxidant Activity and Health Benefits of Sri Lankan Traditional Rice Varieties

“…Also, according to the worked done by Kariyawasam and her co-workers [32], this variety consists of 2.1±0.01 mg of Fe, 3.8±0.01 mg of Zn, 0.04±0.0 mg of Mn, 4.52±0.30 mg of K, 1.59±0.20 mg of Mg in 100 g of Sudumurunga rice flour. Hence, all of these nutritious and mineral content may benefit health [32].…”

“…The proximate composition of Sudumurunga variety has shown that it contains 11.9±0.1% of moisture, 9.7±0.3% of crude protein, 1.2±0.0 % of crude ash, 2.7±0.0% of crude fat and 73.6±0.1% total carbohydrates, 1.1±0.0% crude fiber in dry basis [30]. Also, according to the worked done by Kariyawasam and her co-workers [32], this variety consists of 2.1±0.01 mg of Fe, 3.8±0.01 mg of Zn, 0.04±0.0 mg of Mn, 4.52±0.30 mg of K, 1.59±0.20 mg of Mg in 100 g of Sudumurunga rice flour. Hence, all of these nutritious and mineral content may benefit health [32].…”

“…They determined the in-vivo glycemic index (64.0±2.5) and identified Kalu heenati as a medium glycemic index rice cultivar [15]. Also, Kariyawasam and co-workers have shown that Kalu heenati contains the highest free radical scavenging activity in DPPH assay compared to other traditional rice varieties tested in their experiment (Pokkali, Kahawanu, Sudu murunga) [16].…”