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Background: Pseudocereals are nutrient-rich grains with high mineral content but also phytate content. Phytate is a mineral absorption inhibitor. The study's aim was to evaluate phytate degradation during spontaneous fermentation and during Lactobacillus plantarum 299v® fermentation of quinoa, canihua, and amaranth grains and flours. It also aimed to evaluate the accessibility of iron, zinc, and calcium and to estimate their bioavailability before and after the fermentation of flours with starter culture. Lactic acid, pH, phytate, and mineral content were analyzed during fermentation., Results: Higher phytate degradation was found during the fermentation of flours (64-93%) than during that of grains (12-51%). Results suggest that phytate degradation was mainly due to endogenous phytase activity in different pseudocereals rather than the phytase produced by added microorganisms. The addition of Lactobacillus plantarum 299v® resulted in a higher level of lactic acid (76.8-82.4 g kg -1 DM) during fermentation, and a relatively quicker reduction in pH to 4 than in spontaneous fermentation. Mineral accessibility was increased (1.7-4.6-fold) and phytate : mineral molar ratios were reduced (1.5-4.2-fold) in agreement with phytate degradation (1.8-4.2-fold) in fermented flours. The reduced molar ratios were still above the threshold value for the improved estimated mineral bioavailability of mainly iron., Conclusion: Fermentation proved to be effective for degrading phytate in pseudocereal flours, but less so in grains. Fermentation with Lactobacillus plantarum 299v® improved mineral accessibility and estimated bioavailability in flours. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

A sensitive and simple method for the simultaneous determination of nutritionally important minerals in food samples is in great demand. Ion chromatography coupled with UV-vis detection is shown to be an appropriate technique for this objective. The method is based on the formation of mineral complexes by pyridine-2,6-dicarboxylic acid in the mobile phase. The complexes are then postcolumn derivatized with 4-(2-pyridylazo)resorcinol (PAR), resulting in mineral-PAR complexes that are detected by UV-vis absorption at 500 nm. This facilitates the simultaneous separation and quantification of minerals in one chromatographic run. Within 16 min, Cu, Ni, Zn, Co, Mn, and Fe are analyzed. When a 50 microL injection volume is used, the average detection limit is 5 ppb in the injection liquid. The detection limit makes it a superior alternative to AAS and, in several applications, also an alternative to ICP-MS techniques. Different sample treatments were evaluated. The concentration of acid in the treated sample varied with the sample treatment, which may cause a limitation for the injection volume. A crucial prerequisite to achieve the reported detection limits and to obtain reliable results is to completely exclude all contamination from instruments and materials.

Background: Quinoa is a pseudocereal with relatively high content of proteins and minerals that also contains mineral inhibitors such as phytate. The aim of the present study was to evaluate lactic acid fermentation and dry roasting on the nutritional quality and sensory attributes of quinoa. Various processes were evaluated, and quinoa grains were dry‐roasted, milled, and fermented, either with or without the addition of wheat phytase or activated quinoa phytase (added as back‐slop starter), for 10 hr. In other processes, raw quinoa flour was fermented for 10 hr or 4 hr and dry‐roasted. Hedonic sensory evaluation was then performed to evaluate the acceptability of the fermented flours prepared as porridges. Results: The combined dry roasting and fermentation processes significantly (p <.05) degraded phytate between 30% and 73% from initial content. The most effective process was fermentation of raw quinoa flour followed by dry roasting, which improved the estimated zinc and iron bioavailability. Particularly, estimated zinc bioavailability improved from low (Phy:Zn 25.4, Phy·Zn:Ca 295) to moderate (Phy:Zn 7.14, Phy·Zn:Ca 81.5). Phytate degradation was mainly attributed to the activation of endogenous phytase during fermentation. Dry roasting was effective in improving the sensory attributes of the fermented quinoa flour. Porridge made with raw quinoa flour fermented for 4 hr and dry‐roasted was more favorable to overall acceptability than that which was fermented for 10 hr and dry‐roasted. Conclusion: Fermentation of quinoa flour for 4 hr followed by dry roasting was successful in improving both nutritional and sensory attributes of the final product. [ABSTRACT FROM AUTHOR]

The content of zinc, iron, calcium and phytate in the 16 most consumed foods from 5 villages in a tropical rural area of Bolivia was analyzed. The food items were selected according to a completed food frequency questionnaire. Minerals were analyzed by atomic absorption and phytates by HPIC chromatography. The molar ratios of phytate:mineral are presented as indication of the mineral bioavailability. Within the analyzed food, quinoa is a potential source of minerals: zinc 3.65, iron 5.40 and calcium 176 mg/100 g; however, it also has the highest content of phytate 2060 mg/100 g. Cereals and legumes showed high concentration of phytates (from 142 to 2070 mg/100 g), roots and tubers have lower concentrations (from 77 to 427 mg/100 g). In general, both phytate contents and molar ratios Phy:Zn (phytate:zinc), Phy:Fe (phytate:iron) and Phy:Ca (phytate:calcium) in most of the analyzed foods were at levels likely to inhibit the absorption of these minerals. Significant positive associations ( p < 0.01) were found between the level of phytate and minerals in food, for zinc ( r = 0.714), iron ( r = 0.650) and calcium ( r = 0.415). The results compared to data from USA or from Bolivia showed some discrepancies, confirming the need for more reliable data for dietary evaluations and interventions. [ABSTRACT FROM AUTHOR]