Yellow peas (YP), chickpeas (CP), and fava beans (FB) are staple legumes rich in iron, offering a potential dietary source of this essential mineral (1) . However, due to anti-nutritional factors such as phytates, the bioavailability of iron in these legumes is limited (2) . Cooking processes, such as boiling, may improve iron bioaccessibility by breaking down these inhibitors, making iron more readily absorbable (3) . This study aims to assess iron bioaccessibility from YP, CP, and FB after boiling, exploring whether cooking can enhance their nutritional contribution. By investigating the effects of boiling on these legumes, this research seeks to provide insights on a food preparation method that can naturally improve dietary iron absorption. Commercially bought samples of each legume (100 g) were boiled in 1 L of water for 30 minutes using a pressure cooker (80kPa). Samples were freeze-dried then ground into powder. The mineral content of all samples was analysed using inductively coupled plasma optical emission spectrometry (ICP-OES). Phytic acid levels in the samples were quantified using the Megazyme kit. Iron bioaccessibility was assessed via ICP-OES following a simulated in vitro digestion. Data are the mean ± SEM from 3 independent experiments, analysed using One-way ANOVA and Dunnett’s test. The iron content was reduced significantly (P<0.0001) in all three legumes after boiling. After in vitro digestion, the iron bioaccessibility decreased in all three legumes compared with the raw foods: YP, raw 56.6 ± 1.1%, boiled 6.3 ± 0.3%; CP, raw 33.2 ± 1.5%, boiled 18.3 ± 0.9%; FB, 83.3 ± 0.8% to 23.4 ± 2.3%.However, , phytic acid content was significantly reduced (P<0.0001) after the boiling in all three legumes. Boiling significantly reduces both the iron content and bioaccessibility in the legumes. This suggests that conventional boiling may lead to leaching of iron into the cooking water potentially diminishing its nutritional value. However, boiling was also found to induce thermal degradation of phytic acid in the legumes, thereby significantly reducing its content. These results highlight a potential trade-off between a vital cooking method and the preservation of essential minerals in legumes. By optimizing cooking techniques to minimize nutrient loss, it may be possible to enhance iron retention and bioaccessibility in these dietary staples. Therefore, further investigation into alternative cooking methods is warranted to maximize the nutritional benefits of legumes in human diets.
Wang et al. (Fri,) studied this question.