Browsing by Subject "Carotenoids"

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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.
Plant-based burger patties are a source of bioaccessible iron and zinc
(2025) Pospiech, Jonas; Kruger, Johanita; Frank, Jan
Background: The consumption of plant-based meat alternatives has increased substantially in recent years. However, due to the presence of absorption inhibitors, such as phytate, oxalate, and condensed tannins, the uptake of zinc and iron from plant foods may be low. We therefore quantified minerals (Fe, Zn), inhibitors (phytate, oxalate, condensed tannins), and enhancers (ascorbic acid, carotenoids) of mineral absorption in pea protein-, soy protein-, soy flour-, and sunflower protein-based burger patties and the resulting bioaccessibility of the contained iron and zinc conducting in vitro digestion experiments. Results: The soy flour-based burger had nearly complete bioaccessibility for zinc (105 ± 6 %) and iron (101 ± 11 %), while the three other plant burgers had significantly lower bioaccessibilities (zinc, 9–12 %; iron, 43–57 %). The phytate but not the oxalate and condensed tannin contents of the patties were negatively correlated with the bioaccessibility of iron and zinc (p < 0.05). Conclusion: Plant-based meat alternatives may be an important source of bioaccessible iron and zinc, if they contain low amounts of phytate, and may contribute to an adequate supply of these minerals. Conclusion: Plant-based meat alternatives may be an important source of bioaccessible iron and zinc, if they contain low amounts of phytate, and may contribute to an adequate supply of these minerals.