Bestimmung der ernährungsphysiologischen Qualität von Öko-Produkten anhand des antioxidativen Potentials der Lebensmittel

Problemstellung: Die Diskussionen über sichere Lebensmittel (u.a. Rückstände von Pestiziden) im letzten Jahrzehnt hat das Verbraucherverhalten verändert. Viele Verbraucher bevorzugen ökologisch erzeugte Lebensmittel. Allerdings gibt es bis heute noch nicht ausreichende wissenschaftliche Daten dazu, ob ökologisch erzeugte Lebensmittel tatsächlich ernährungsphysiologisch hochwertiger sind als konventionell produzierte. Sekundären Pflanzenstoffen aus Obst und Gemüse (Carotinoiden, Polyphenole) kommt im Allgemeinen eine hohe gesundheitliche Bedeutung zu. Die in der Literatur beschriebenen protektiven Effekte auf entzündliche, atherosklerotische und tumorigene Prozesse werden u.a. auf ihr antioxidatives Potenzial zurückgeführt. Ziel der Studie war es daher zu untersuchen, ob sich der Gehalt an Carotinoiden und Polyphenolen und die antioxidative Kapazität in Lebensmitteln aus konventionellem und ökologischem Anbau unterscheidet. Darüber hinaus wurden drei humane Interventionsstudien durchgeführt, die klären sollten, ob die unterschiedlichen Anbauvarianten (ökologisch/konventionell) Einfluss auf die Bioverfügbarkeit der sekundären Pflanzenstoffe und den antioxidativen Status in vivo haben. Methodik: Im Rahmen des Projektes wurden Äpfel, Karotten und Weizenvollkorn der Erntejahre 2004, 2005 und 2006 aus kontrollierten Anbauversuchen untersucht. Die Gehalte an sekundären Pflanzenstoffen in vitro und in vivo wurden mittels HPLC/DAD/MS quantifiziert. Die antioxidativen Kapazitäten in vivo und in vitro wurden mit drei unterschiedlichen Testsystemen analysiert. Ergebnisse: Die Ergebnisse zeigen, dass die Anbauweise (ökologisch/konventionell) die Bildung von sekundären Pflanzenstoffen und das antioxidatives Potenzial in den untersuchten Lebensmitteln beeinflussen kann. Für die Öko-Produkte kann ein leicht höherer Gehalt und antioxidatives Potenzial bestimmt werden. In den durchgeführten Humanstudien, konnten keine Unterschiede in der Bioverfügbarkeit von Carotinoiden und Polyphenolen zwischen ökologisch und konventionell angebauten Äpfeln bzw. Karotten gezeigt werden. Schlussfolgerung: Die beobachteten Unterschiede im Gehalt an sekundären Pflanzenstoffen sowie im antioxidativen Potenzial zwischen den Anbauweisen sind klein und besitzen geringe ernährungsphysiologische Relevanz

Sind Bio-Äpfel gesünder?

Viele Verbraucher, die sich beim Kauf von Lebensmitteln für Bioprodukte entscheiden, erhoffen sich davon gesundheitsfördernde Effekte. Allerdings liegen bis heute noch nicht genügend wissenschaftliche Daten vor, um ökologisch und konventionell erzeugte Lebensmittel vergleichend ernährungsphysiologisch bewerten zu können. Am Institut für Ernährungsphysiologie der Bundesforschungsanstalt für Ernährung und Lebensmittel (BfEL) wird zurzeit untersucht, ob sich verschiedene pflanzliche Lebensmittel aus ökologischer und konventioneller Anbauweise hinsichtlich ihres Gehaltes an sekundären Pflanzenstoffen und deren ernährungsphysiologischer Wirkung am Menschen unterscheiden

Pomegranate (Punica granatum L.) Extract and Its Anthocyanin and Copigment Fractions—Free Radical Scavenging Activity and Influence on Cellular Oxidative Stress

Secondary plant metabolites, e.g., polyphenols, are widely known as health-improving compounds that occur in natural functional foods such as pomegranates. While extracts generated from these fruits inhibit oxidative stress, the allocation of these effects to the different subgroups of substances, e.g., anthocyanins, “copigments” (polyphenols without anthocyanins), or polymeric compounds, is still unknown. Therefore, in the present study, polyphenols from pomegranate juice were extracted and separated into an anthocyanin and copigment fraction using adsorptive membrane chromatography. Phenolic compounds were determined by high performance liquid chromatography with photodiode array (HPLC–PDA) detection and HPLC-PDA electrospray ionization tandem mass spectrometry (HPLC–PDA–ESI–MS/MS), while the free radical scavenging activity of the pomegranate XAD‑7 extract and its fractions was evaluated by the Trolox equivalent antioxidant capacity (TEAC) assay and electron spin resonance (ESR) spectroscopy. Compared to juice, the total phenolic content and free radical scavenging potential was significantly higher in the pomegranate XAD-7 extract and its fractions. In comparison to the anthocyanin and copigment fraction, pomegranate XAD-7 extract showed the highest radical scavenging activity against galvinoxyl and DPPH radicals. Moreover, the enriched XAD-7 extract and its fractions were able to protect human hepatocellular HepG2 cells against oxidative stress induced by hydrogen peroxide. Overall, these results indicated that anthocyanins and copigments act together in reducing oxidative stress

Enrichment of starch-based extruded cereals with chokeberry (Aronia melanocarpa) pomace: Influence of processing conditions on techno-functional and sensory related properties, dietary fibre and polyphenol content as well as in vitro digestibility

Aiming at providing prototypes for ready-to-eat texturised (RTE) cereal products with reduced glycaemic load, starch blends with chokeberry (Aronia melanocarpa) pomace powder (CPP) rich in dietary fibre (DF) and polyphenols (PP) were extruded using a co-rotating twin-screw extruder. The CPP ratios (25%, 50%) and processing conditions applied (barrel temperature 100 °C, screw speed 200, 400, 600, 800 min−1, water content 13%, 23%) result in specific mechanical energies of 87–336 Whkg−1 and material temperatures of 111–155 °C. Extrudates containing 25% CPP still offer acceptable techno-functional and sensory related physical properties, while higher CPP ratios result in decreased expansion and cell pore size of the slightly darker and softer extrudates. The in vitro glucose release of both extruded blends is reduced by 25% and 50%, respectively. The DF contents are unaffected. As expected, anthocyanins are degraded by about 70% in both blends while phenolic acids and flavonols are fully retained. All PP are already accessible during the stomach phase of an in vitro digestion and are not changed significantly in the intestinal phases. Overall, these data substantiate, that marketable texturised RTE extruded cereals may be developed based on the results presented and on further sensory analysis

Pressurized extraction of unsaturated fatty acids and carotenoids from wet Chlorella vulgaris and Phaeodactylum tricornutum biomass using subcritical liquids

The objective of this study was to investigate the extraction of lipids, for example, mono‐ and polyunsaturated fatty acids (PUFA) as well as carotenoids, from wet microalgae biomass using pressurized subcritical extraction solvents, which meet the requirements of food and feed applications. To demonstrate the effect of the solvent and temperature on the lipid yield, we chose two microalgae species, viz. Chlorella vulgaris and Phaeodactylum tricornutum , differing in their biochemical composition fundamentally. In case of P. tricornutum, ethanol showed the highest fatty acid yield of 85.9% w/w. In addition to eicosapentaenoic acid (EPA), the ethanolic extracts contained exceptional amounts of fucoxanthin (up to 26.1 mg/g d. w.), which can be beneficial to protect unsaturated fatty acids from oxidation processes and in terms of human nutrition. For C. vulgaris , a fatty acid yield of 76.5% w/w was achieved from wet biomass using ethyl acetate at 150°C. In general, an increase in the extraction temperature up to 150°C was found to be important in terms of fatty acid yield when extracting wet microalgae biomass. The results suggest that it is possible to efficiently extract both fatty acids and carotenoids from wet microalgae by selecting suitable solvents and thus circumvent energy‐intensive drying of the biomass

Coproduction of EPA and Fucoxanthin with – A Promising Approach for Up‐ and Downstream Processing

Eicosapentaenoic acid (EPA) and fucoxanthin, a carotenoid, provide a broad variety of health benefits in human nutrition. In this study, an up- and downstream process for the coproduction of EPA and fucoxanthin using the diatom Phaeodactylum tricornutum in flat-panel airlift photobioreactors is proposed. The approach represents a promising alternative to conventional sources for both compounds, viz. marine fish and macroalgae. The productivity as well as the biomass-specific product content were optimized during cultivation. Subsequently, both compounds were extracted, separated and purified using pressurized liquids

Synthesis and in vitro characterization of the genotoxic, mutagenic and cell-transforming potential of nitrosylated heme

Data from epidemiological studies suggest that consumption of red and processed meat is a factor contributing to colorectal carcinogenesis. Red meat contains high amounts of heme, which in turn can be converted to its nitrosylated form, NO-heme, when adding nitrite-containing curing salt to meat. NO-heme might contribute to colorectal cancer formation by causing gene mutations and could thereby be responsible for the association of (processed) red meat consumption with intestinal cancer. Up to now, neither in vitro nor in vivo studies characterizing the mutagenic and cell transforming potential of NO-heme have been published due to the fact that the pure compound is not readily available. Therefore, in the present study, an already existing synthesis protocol was modified to yield, for the first time, purified NO-heme. Thereafter, newly synthesized NO-heme was chemically characterized and used in various in vitro approaches at dietary concentrations to determine whether it can lead to DNA damage and malignant cell transformation. While NO-heme led to a significant dose-dependent increase in the number of DNA strand breaks in the comet assay and was mutagenic in the HPRT assay, this compound tested negative in the Ames test and failed to induce malignant cell transformation in the BALB/c 3T3 cell transformation assay. Interestingly, the non-nitrosylated heme control showed similar effects, but was additionally able to induce malignant transformation in BALB/c 3T3 murine fibroblasts. Taken together, these results suggest that it is the heme molecule rather than the NO moiety which is involved in driving red meat-associated carcinogenesis. © 2020, The Author(s)

An Overview of Adenoid Microbiome Using 16S rRNA Gene Sequencing-Based Metagenomic Analysis

Background and Objectives: the upper respiratory tract harbors the highest bacterial density in the whole respiratory system. Adenoids, which are located in the nasopharynx, are a major site of bacterial colonies in the upper airways. Our goal was to use culture-independent molecular techniques to identify the breadth of bacterial diversity in the adenoid vegetations of children suffering from chronic rhinosinusitis and obstructive sleep apnea. Materials and methods: in total, 21 adenoid samples were investigated using amplification and sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene. Results: among the most common bacterial species found were Veillonella atypica, Fusobactrium nucelatum, Shaalia odontolytica, and Moraxella catarrhalis. Veillonella atypica and Fusbacterium nucelatum dominated the microbiome in all 21 samples, attributing to more than 60% of all detected genetic material. Conclusions: since both Veillonella atypica and Fusobacterium nucleatum are, predominantly, oral cavity and dental microorganisms, our findings may suggest oral microbiome migration deeper into the oropharynx and nasopharynx where these bacteria colonize adenoid vegetations.publishersversionPeer reviewe

Impact of defined thermomechanical treatment on the structure and content of dietary fiber and the stability and bioaccessibility of polyphenols of chokeberry (Aronia melanocarpa) pomace

Dietary fiber is a potential replacement for other ingredients such as starch in reformulated extruded breakfast cereals. Analysis of chokeberry pomace powder revealed a total dietary fiber content of 57.8 ± 2 g/100 g with 76% being insoluble, 20% high molecular soluble and 4% low molecular soluble dietary fiber. The fiber polysaccharide composition was analyzed in detail by using a variety of analytical approaches. Extrusion-like processing conditions were studies in a Closed Cavity Rheometer enabling the application of defined thermal (temperature range 100–160 °C) and mechanical treatments (shear rates between 0.1 s$^{-1}$ and 50 s$^{-1}$) to chokeberry pomace powder. Application of temperatures up to 140 °C irrespective of the mechanical treatment does not remarkably alter dietary fiber structure or content, but reduces the initial content of total polyphenols by about 40% to a final content of 3.3 ± 0.5 g/100 g including 0.63 ± 0.1 g/100 g of anthocyanins, 0.18 ± 0.02 g/100 g of phenolic acids and 0.090 ± 0.007 g/100 g of flavonols, respectively. The retained polyphenols are fully bioaccessible after in vitro digestion, and antioxidant capacity remains unchanged as compared to the untreated pomace powder. Glucose bioaccessibility remains unaffected, whereas glucose content is reduced. It is concluded that chokeberry pomace powder is a good source of dietary fiber with the potential to partially substitute starch in extruded breakfast cereals