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The effect of cooking methods on the mineral content of quinoa (Chenopodium quinoa), amaranth (Amaranthus sp.) and buckwheat (Fagopyrum esculentum)

Publication . Motta, Carla; Nascimento, Ana; Santos, Mariana; Delgado, Inês; Coelho, Inês; Rêgo, A.; Matos, Ana Sofia; Torres, Duarte; Castanheira, Isabel

In this study, we assessed the impact of two cooking methods, steaming and boiling, through the true retention (%TR) of minerals in pseudocereals and rice (varieties Indica and Japonica). Mineral content was determined by ICP-OES. Cooking methods have an impact on mineral composition of pseudocereals with losses up to 20%. Quinoa’s %TR varied from 100% (manganese, phosphorus and iron) in steaming, to 83% (copper) in boiled. In amaranth, it ranged from 98% (copper) in boiling method, to 80% (magnesium) in steaming. Buckwheat presents a %TR of 100% in iron and 87% in zinc. For boiled rice, the losses were higher in the variety Indica, with a decrease of 34% for manganese. Steamed amaranth is a higher density food in particular for manganese, magnesium and phosphorus, which present a recommended nutrient intake (RNI) contribution of 70%, 65% and 44%, respectively. Rice represents the lowest contribution to mineral RNI. This study demonstrates that estimation of mineral intake should be based on data obtained from cooked food.

2016-06Journal article

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Folates in quinoa (Chenopodium quinoa), amaranth (Amaranthus sp.) and buckwheat (Fagopyrum esculentum): Influence of cooking and malting

Publication . Motta, Carla; Delgado, Inês; Matos, Ana Sofia; Gonzales, Gerard Bryan; Torres, Duarte; Santos, Mariana; Chandra-Hioe, Maria V.; Arcot, Jayashree; Castanheira, Isabel

Effects of processing on the contents of five folate vitamers in quinoa, amaranth and buckwheat were analysed using a trienzymatic extraction method followed by LC–MS/MS. Total folate (TF) content, corresponding to the sum of folic acid (FA), 5-methyltetrahydrofolate (5-MTHF) and 10-formyltetrahydrofolate (10-CHOTHF) expressed as folic acid equivalent, in raw quinoa, amaranth and buckwheat were 309 ± 8.07, 228 ± 24.2 and 153 ± 12.4 μg/100 g dw, respectively, being dominantly 5-MTHF. Boiling and steaming reduced the TF in amaranth by 58% and 22%, respectively, whereas up to a 10–15% increase was observed in quinoa. Boiling and steaming did not significantly alter the TF content in buckwheat although significant changes were observed in some individual folate vitamers. Malting, on the other hand significantly increased TF content in amaranth by 21% (276 ± 14.2 μg/100 g dw) and buckwheat by 27% (193 ± 20.0 μg/100 g dw), whereas no significant change in quinoa was observed. Based on the EFSA recommendations, a portion of amaranth and quinoa (either boiled, steamed or malted) may contribute up to more than 25% of the dietary reference value for folates, whereas buckwheat may contribute only 14% when cooked and 19% when malted. Results demonstrate that quinoa, amaranth and buckwheat are good sources of folates, regardless of processing.

2017-12Journal article

Open access

Impact of cooking methods and malting on amino acids content in amaranth, buckwheat and quinoa

Publication . Motta, Carla; Castanheira, Isabel; Bryan Gonzalesb, Gerard; Delgado, Inês; Torres, Duarte; Santos, Mariana; Matos, Ana Sofia

This study reports the effect of boiling, steaming and malting on the amino acid composition of the pseudocereals amaranth, buckwheat and quinoa. For all pseudocereals the foremost amino acid was glutamic acid, presenting 13.2% in both raw and malted (2.2 g/100 g), and 15.6% in steamed (2.5 g/100 g) amaranth; 10.8% in steamed (2.0 g/100 g) and 17.6% in boiled (2.1 mg/100 g) quinoa; 15.4% in malted (2.3 g/100 g) and 21.2% in raw (2.8 g/100 g) buckwheat. Almost all amino acids present in the three pseudocereals evinced a significant increase of the retention values in malted samples, except in amaranth and quinoa for cysteine and glutamic acid, respectively. Histidine and aromatic amino acids presented the highest values of amino acid scores. Cluster analysis allowed to identify the pseudocereals with the highest nutritional protein quality, were boiled and malted quinoa and raw and malted buckwheat were included. Malting process revealed to be the method that produce more effect on the amino acid content for all pseudocereals.

2019-03Journal article

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Amino acid contents and toxically relevant arsenic of rice varieties consumed in Portugal

Publication . Rego, Andreia; Mota, Carla; Gueifão, Sandra; Ventura, Marta; Delgado, Inês; Lopes, Joel; Matos, Ana; Castanheira, Isabel

This study evaluated amino acids, antioxidant capacity, and arsenic species present in Indica and Japonica rice cultivars (Oryza sativa L.) grown in similar regions, as well as brown rice. Essential amino acids in brown rice exhibited a greater abundance when compared to white rice. Lysine was the only essential amino acid with higher concentration in white rice than in brown rice. Results showed antioxidant activity of 0.46 IC50 (mg mL 1) and TPC 0.11 mg eq. GA/g of sample. Total arsenic content in rice samples was about 200 mg/kg. HPLC-ICP-MS determinations revealed iAs as the predominant species in bran samples. Through Spearman’s correlation, negative correlations between six amino acids and total arsenic content in japonica white rice were observed. Sulphur amino acid cysteine presented the highest negative correlation (q = 0.758, p-value = 0.011). Based on our results, a regular benefit-risk assessment for rice products to enhance the consumption choice is recommended.

2018-01Journal article

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