رسالة جامعية
Proanthocyanidins in barley and malt analyzed by pressurized liquid extraction, solid-phase extraction and HPLC
| العنوان: | Proanthocyanidins in barley and malt analyzed by pressurized liquid extraction, solid-phase extraction and HPLC |
|---|---|
| المؤلفون: | Zimmermann, Benno F. |
| المساهمون: | Galensa, Rudolf C., König, Gabriele M. |
| بيانات النشر: | Universitäts- und Landesbibliothek Bonn |
| سنة النشر: | 2005 |
| المجموعة: | bonndoc - The Repository of the University of Bonn |
| مصطلحات موضوعية: | Proanthocyanidine, Procyanidine, kondensierte Gerbstoffe, Anthocyanogene, ASE, PLE, SPE, ASPEC, CEAD, acai, Polyamid, Procyanidin, Prodelphinidin, beschleunigte Lösemittelextraktion, Probenvorbereitung, Peakverhältnis, Authentizitätskontrolle, proanthocyanidins, procyanidins, sample preparation, electrochemical detection, barley, malt, beer filtering, polyamide, automatisation, polyphenolic fingerprint, peak ratio, authenticity control, ddc:500 |
| الوصف: | Aim of this work is to develop a convenient method for the determination of proanthocyanidins in barley and malt. In a second step this method is applied to 61 barley and malt samples of different varieties, proveniences and growing years. In the brewing industry proanthocyanidins are of special interest. Main activities of the proanthocyanidins are related to undesired formation of chill haze and to the positively valued augmentation of the antioxidative capacity of beer. The detailed mechanisms are still under discussion. It is clear, that the positive and negative effects of proanthocyanidins depend on their quantity and quality. So determination of the sum of proanthocyanidins does not give sufficient information to discuss their action. Selective analysis of proanthocyanidins is time and labor consuming. Especially sample preparation requires a lot of manual work. Thus, this work presents a fully automated and therefore fast and reliable method for sample preparation of barley and malt followed by HPLC-UV. The here described method bases on extraction using pressurized liquid extraction (PLE). Essentially it is a static solid/liquid extraction with high pressure and eventually high temperature in stainless steel extraction cells. Using the Accelerated Solvent Extractor (ASE) by Dionex, up to 24 samples in a series can be extracted automatically. For the first time, commercially available polyamide cartridges are used for proanthocyanidins. SPE is accomplished automatically by a liquid handling robot, the Automated Sample Preparation with Extraction Cartridges-device (ASPEC) by ABIMED and Gilson. The aspec takes the extracts from the ase and carries out the complete spe procedure. The resulting solution is ready to inject into the HPLC, that separates and quantifies six proanthocyanidins and catechin in one run of 90 min. Sample extraction and extract clean-up are coupled online. This coupling was developed by abimed and Dionex and is tested and established under real laboratory conditions for the first ... |
| نوع الوثيقة: | doctoral or postdoctoral thesis |
| وصف الملف: | application/pdf |
| اللغة: | English |
| العلاقة: | info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:5N-06689; https://hdl.handle.net/20.500.11811/2344Test |
| الإتاحة: | https://doi.org/20.500.11811/2344Test https://hdl.handle.net/20.500.11811/2344Test |
| حقوق: | In Copyright ; http://rightsstatements.org/vocab/InC/1.0Test/ ; openAccess |
| رقم الانضمام: | edsbas.922B2BC2 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |