Phytate, iron, zinc, and calcium content of common Bolivian foods and their estimated mineral bioavailability.

There is a scarcity of information on mineral and phytate content in plant-based foods in Bolivia. This study aimed to analyze iron, zinc, calcium, and phytate content and estimate the mineral bioavailability of foods consumed in Chapare, Bolivia. Minerals and phytate were analyzed, and bioavailability was estimated in 17 food samples. Leafy vegetables and green legumes had the highest mineral content, followed by pseudocereals. Estimated mineral bioavailability was low for cereals, dry legumes, pseudocereals, and flaxseeds foods mainly due to phytate content. But estimated zinc bioavailability for black cornmeal, yellow corn, and dry peas was moderate. Strong correlations (p < 0.01) were found between the three minerals, while phytate correlated negatively to iron, zinc, and calcium. To get an overview of the estimated mineral bioavailability of plant-based diets, we have included foods, from the same area, analyzed in a previous study where the evaluated diet covers 80% of RNI for iron and zinc, but <40% of calcium. In conclusion, leafy vegetables and green legumes had the highest contents of minerals and the lowest phytate content of the foods analyzed in the study. The usage of processing strategies and dietary diversification to reduce phytate content would significantly improve estimated mineral bioavailability in plant-based diets.

Effect of fermentation and dry roasting on the nutritional quality and sensory attributes of quinoa.

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.