Effect of maize processing methods on the retention of minerals, phytic acid and amino acids when using high kernel-zinc maize

Abstract

High kernel-zinc maize varieties are available to consumers in several countries in Latin America to contribute to increase the zinc intake of their populations. Minerals, phytic acid and amino acids retention were measured after processing six maize varieties including three high kernel-zinc, one quality protein maize and two conventional maize. Grain for each variety was processed into tortillas , arepas and mazamorra , common maize dishes in the region. To evaluate the effect of processing kernel-zinc maize varieties on zinc retention, varieties were grouped in zinc biofortified maize (ZBM) and non-ZBM. Iron, zinc, phytic acid, tryptophan and lysine concentrations in non-processed maize were 17.1–19.1 ​μg/g DW, 23.9–33.0 ​μg/g DW, 9.9–10.0 ​mg/g DW, 0.06–0.08% and 0.27–0.37%, respectively. In tortillas , the iron, zinc, phytic acid and lysine content did not change (p ​< ​0.05) compared to raw grain, while tryptophan decreased by 32%. True retention of iron in arepas and mazamorra was 43.9 and 60.0%, for zinc 36.8 and 41.3%, and for phytic acid 19.3 and 25.1%. Tortillas had higher zinc retention than arepas and mazamorra due to use of whole grain in the nixtamalization process. Therefore, to contribute to higher zinc intake, nixtamalized tortilla prepared with biofortified zinc maize is recommended. Additionally, promotion of whole grain flour to prepare arepas should be explored to enhance the intake of minerals that are usually confined to aleurone layers and germ.

Physico-Functional and Nutritional Properties of Pigmented and Non-pigmented Maize Available In Bangladesh

“…Calcium content of different colored maize ranged from 140.16 ± 10.8 mg/100 g to 317.39 ± 16.3 mg/100 g. Purple maize contained the highest Ca (317.39 ± 16.3 mg/100 g) which is similar to mixed and deep red maize while white maize contained the lowest Ca (140.16 ± 10.8 mg/100 g). Ca content in maize found much higher than the value (5.96 mg/100 g) reported by Gallego-Castillo et al (2021). Mg content of different colored maize ranged from 214.81 ± 6.8 to 245.06 ± 18.3 mg/100g.…”

Improvement in nutritional quality of traditional unleavened flat bread using Quality Protein Maize

“…However, the lysine and tryptophan contents in chapatti were lower as compared to flours which could be due to the effect of baking conditions ( 40 ). A study by Gallego-Castillo et al ( 41 ) in non-QPM and QPM-based processed products, namely tortillas, arepas, and mazamorra, showed a true retention value of tryptophan content that is 62.27, 16.67, 15.91%, and 66.29, 23.44, and 19.69%, respectively. During processing, the reduction in lysine content might be due to the occurrence of the Maillard reaction, which modifies the starch and protein structures and leads to more availability of reducing sugars and reactive sites of protein, respectively ( 42 ).…”

Nutrient composition, starch microstructure and thermal properties, and in vitro availability of selected minerals of nixtamalized Philippine quality protein maize variety IPB Var 6 and the production of healthy loaf bread using nixtamalized corn–wheat flour blends

“…According to Gibson et al (2006), the availability of micronutrients such as calcium, iron, and zinc in plant foods is low due to the interactions between organic components forming insoluble or soluble complexes in the acidic pH of the stomach and the relatively neutral pH of the intestinal tract. Also, phytic acid is a strong chelator of divalent cations such as Ca 2+ , Fe 2+ , and Zn 2+ and as a result, the availability of these minerals may be limited due to the insoluble compounds formed between the phytic acid and the minerals (Gallego‐Castillo et al, 2021). The studies of Bressani et al (2002, 2004) revealed that nixtamalization could significantly decrease the phytic acid content of nixtamalized corn which they directly related to the increased availability of the minerals.…”

“…chelator of divalent cations such as Ca 2+ , Fe 2+ , and Zn 2+ and as a result, the availability of these minerals may be limited due to the insoluble compounds formed between the phytic acid and the minerals (Gallego-Castillo et al, 2021). The studies of Bressani et al (2002Bressani et al ( , 2004 availability of calcium and iron was 19.18% and 2.05%, respectively, while in vitro zinc availability was below the detection limit.…”