Browsing by Person "Schmid-Staiger, Ulrike"

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Flavor-boosting of Phaeodactylum tricornutum by fermentation with edible mushrooms
(2024) Rigling, Marina; Liang, Jiaqi; Entenmann, Isa; Frick, Konstantin; Schmid-Staiger, Ulrike; Xiang, Can; Kopp, Lena; Bischoff, Stephan C.; Zhang, Yanyan
Microalgae are a promising and sustainable source of nutritious food, especially for use in alternatives to fish and seafood. Among them, Phaeodactylum tricornutum (PT) stands out for its potential to revolutionize future diets with its rich nutrient profile and eco-friendly cultivation methods. However, its typically fishy and “brackish water” off-odor has been a significant deterrent. Using 13 basidiomycetes as starter cultures, the dynamic changes in the aroma were studied. To better understand the aroma development during fermentation, odor-active compounds were identified using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry–olfactometry. By submerged fermentation lasting 39 and 51 hours with Pleurotus citrinopileatus (PCI) and Pleurotus eryngii (PER), respectively, the unpalatable odor of PT was transformed into savory and seafood-like aromas, while retaining most of the valuable carotenoids (fucoxanthin and β-carotene were retained at 75 % and 90 %) and fatty acids (eicosapentaenoic acid and docosahexaenoic acid were preserved at 80 % of their initial concentrations). Throughout the fermentation process, key odorants responsible for the algae's initial green, grassy, and unpleasant odor were reduced, while compounds responsible for savory and seafood-like fragrances increased. A series of sulfur compounds, such as dimethyl disulfide, were found to be major contributors to the post-fermentation aroma.
Potentially beneficial effects on healthy aging by supplementation of the EPA-rich microalgae phaeodactylum tricornutum or its supernatant - a randomized controlled pilot trial in elderly individuals
(2022) Stiefvatter, Lena; Frick, Konstantin; Lehnert, Katja; Vetter, Walter; Montoya-Arroyo, Alexander; Frank, Jan; Schmid-Staiger, Ulrike; Bischoff, Stephan C.
Dietary supplements that promote healthy aging are mostly warranted in an aging society. Because of age-related risks, anti-inflammatory and anti-oxidative agents such as microalgae are potential candidates for intervention. In a randomized controlled trial, we tested Phaeodactylum tricornutum (PT), a microalgae rich in eicosapentaenoic acid (EPA), carotenoids, vitamins, and β-glucans, cultured in bioreactors. In this pilot trial, 19 healthy elderly received supplements for two weeks based on either the whole PT (A), the β-1,3-glucan-rich PT supernatant (SupB), the combination thereof (A+SupB), or a Comparator product (Comp). The primary outcome variable plasma interleukin-6 was reduced after treatment with A+SupB compared to the Comp group (p = 0.04). The mobility parameters 5 s sit-to-stand test (p = 0.04 in the A group) and by trend gait speed (p = 0.08 in the A+SupB diet) were improved compared to Comp. No treatment effects were observed for fatty acids, compared to Comp but omega-6 to -3 fatty acid ratio (p = 0.006) and arachidonic acid/EPA ratio (p = 0.006) were reduced within group A+SupB. Further, the SupB study product reduced faecal zonulin (p = 0.03) compared to the Comp. The data revealed an anti-inflammatory and potentially anti-oxidative effect of particular PT preparations, suggesting that they might be suitable for effects in healthy elderly.
Tocochromanol profiles in Chlorella sorokiniana, Nannochloropsis limnetica and Tetraselmis suecica confirm the presence of 11′-α-tocomonoenol in cultured microalgae independently of species and origin
(2022) Montoya-Arroyo, Alexander; Lehnert, Katja; Muñoz-González, Alejandra; Schmid-Staiger, Ulrike; Vetter, Walter; Frank, Jan
11′-α-Tocomonoenol (11′-αT1) is structurally related to vitamin E and has been quantified in the microalgae Tetraselmis sp. and Nannochloropsis oceanica. However, it is not known whether 11′-αT1 is present in other microalgae independent of species and origin. The aim of this study was to analyze the tocochromanol profiles of Chlorella sorokiniana, Nannochloropsis limnetica, and Tetraselmis suecica and to determine if 11′-αT1 is present in these microalgae. Cultured microalgae were freeze-dried and the presence and identity of α-tocomonoenols were confirmed by LC-MSn (liquid chromatography coupled to mass spectroscopy) and GC-MS (gas chromatography coupled to mass spectroscopy). Tocochromanol profiles were determined by HPLC-FLD (liquid chromatography with fluorescence detection) and fatty acid profiles (as fatty acid methyl esters; FAME) by GC-MS. As confirmed by LC-MSn and GC-MS, 11′-αT1 was the dominant αT1 isomer in cultured microalgae instead of 12′-αT1, the isomer also known as marine-derived tocopherol. αT1 represented less than 1% of total tocochromanols in all analyzed samples and tended to be more abundant in microalgae with higher proportions of polyunsaturated fatty acids. In conclusion, our findings confirm that αT1 is not restricted to terrestrial photosynthetic organisms, but can also accumulate in microalgae of different species, with 11′-αT1—and not the marine-derived tocopherol (12′-αT1)—as the predominant αT1 isomer.