Browsing by Subject "Minerals"

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Comparative analysis of minerals, carotenoids, and tocochromanols in ripe seeds, immature seeds and tepals of bitter and non-bitter quinoa genotypes
(2026) Lauer, Luise Amelie; Kollmar, Marius; Schmöckel, Sandra M.; Frank, Jan
Quinoa (Chenopodium quinoa Willd.) contains high amounts of minerals, carotenoids and vitamin E (tocochromanols), but also antinutrients, such as saponins. Based on their saponin content, quinoa can be classified into “bitter” and “non-bitter” genotypes. Carotenoids (lutein, zeaxanthin, β-carotene, β-cryptoxanthin), vitamin E and saponins share a precursor in their respective biosynthesis pathways. Thus, we investigated whether the downregulation of saponin biosynthesis in non-bitter quinoa affects the contents of minerals and lipid-soluble compounds compared to bitter quinoa. The analytes were quantified in ripe seeds of fifty (23 bitter and 27 non-bitter) quinoa genotypes. A subset of twelve genotypes (6 bitter and 6 non-bitter) was analyzed for carotenoids and tocochromanols in immature seeds and their tepals. Total mineral (8206 mg/kg vs. 8646 mg/kg) and carotenoid contents (314 µg/100 g vs. 242 µg/100 g) did not differ between bitter and non-bitter ripe seeds. However, non-bitter quinoa seeds contained higher lutein and total tocochromanol (driven by tocotrienols) contents than bitter genotypes. Carotenoid and tocochromanol contents in immature seeds and tepals did not differ between phenotypes; tepals had up to 74-fold higher contents than the seeds. In conclusion, the downregulation of saponin biosynthesis in non-bitter quinoa genotypes does not affect the biosynthesis of carotenoids and tocochromanols.
Mineral and phytic acid content as well as phytase activity in flours and breads made from different wheat species
(2023) Longin, C. Friedrich H.; Afzal, Muhammad; Pfannstiel, Jens; Bertsche, Ute; Melzer, Tanja; Ruf, Andrea; Heger, Christoph; Pfaff, Tobias; Schollenberger, Margit; Rodehutscord, Markus
Wheat is of high importance for a healthy and sustainable diet for the growing world population, partly due to its high mineral content. However, several minerals are bound in a phytate complex in the grain and unavailable to humans. We performed a series of trials to compare the contents of minerals and phytic acid as well as phytase activity in several varieties from alternative wheat species spelt, emmer and einkorn with common wheat. Additionally, we investigated the potential of recent popular bread making recipes in German bakeries to reduce phytic acid content, and thus increase mineral bioavailability in bread. For all studied ingredients, we found considerable variance both between varieties within a species and across wheat species. For example, whole grain flours, particularly from emmer and einkorn, appear to have higher mineral content than common wheat, but also a higher phytic acid content with similar phytase activity. Bread making recipes had a greater effect on phytic acid content in the final bread than the choice of species for whole grain flour production. Recipes with long yeast proofing or sourdough and the use of whole grain rye flour in a mixed wheat bread minimized the phytic acid content in the bread. Consequently, optimizing food to better nourish a growing world requires close collaboration between research organizations and practical stakeholders ensuring a streamlined sustainable process from farm to fork.
The mineralosphere—interactive zone of microbial colonization and carbon use in grassland soils
(2021) Boeddinghaus, Runa S.; Marhan, Sven; Gebala, Aurelia; Haslwimmer, Heike; Vieira, Selma; Sikorski, Johannes; Overmann, Jörg; Soares, Margarida; Rousk, Johannes; Rennert, Thilo; Kandeler, Ellen
To improve our understanding of early microbial colonization of pristine minerals and their group-specific C utilization, we exposed minerals (illite/goethite/quartz) amended with artificial root exudates (ARE, glucose, and citric acid) in grassland soils for a period of 24 weeks. FTIR spectra indicated that mineral-associated ARE were used within the first 2 weeks of exposure and were replaced by other carbohydrates derived from living or dead cells as well as soil-borne C sources transported into the mineralosphere after heavy rain events. Fungi and Gram-positive bacteria incorporated ARE-derived C more rapidly than Gram-negative bacteria. Gram-negative bacteria presumably profited indirectly from the ARE by cross-feeding on mineral-associated necromass of fungi and Gram-positive bacteria. The Gram-negative bacterial phyla Verrucomicrobia, Planctomycetes, Gemmatimonadetes, Armatimonadetes, and Chloroflexi showed a positive correlation with Gram-negative PLFA abundances. After 24 weeks of exposure in the grassland soils, abundances of soil microorganisms in the mineralosphere reached only 3.1% of the population density in soil. In conclusion, both bacteria and fungi slowly colonize new surfaces such as pristine minerals, but quickly assimilate artificial root exudates, creating an active microbial community in the mineralosphere.