Dorothea Ehlers

HPLC analysis of tonka bean extracts

Based on the results of GC-MS analysis, an HPLC procedure was developed for the determination of coumarin, dihydrocoumarin, melilotic acid (o-dihyd-rocoumaric acid), methyl melilotate, ethyl melilotate, 5-hydroxymethylfurfural ando-coumaric acid which are characteristic compounds of tonka beans. The presence of melilotic acid and ethyl melilotate in tonka beans has not been reported previously. Following HPLC analysis of tonka bean extracts produced in the laboratory and one sample of commercially available tonka bean absolute, evidence was provided that solvents used for production are decisive for the kind and amount of the compounds detected.

Analysis of Tahiti vanilla by high-performance liquid chromatography

ZusammenfassungIn der Literatur finden sich widersprüchliche Angaben über die Zusammensetzung von Tahiti-Vanille, insbesondere im Hinblick auf einen Piperonalgehalt. Mittels HPLC wurden Untersuchungen an Tahiti-Vanille-Schoten und Tahiti-Vanille-Resinoid durchgeführt. Im Vergleich mitVanilla planifolia enthielten die Schoten relativ niedrige Gehalte an Vanillin und Vanillinsäure, relativ hohe Gehalte anp-Hydroxybenzoesäure sowie erhebliche Mengen an Anissäure und Anisalkohol. Weiterhin war Anisaldehyd, nicht jedoch 3-Ethoxy-4-hydroxy-benzaldehyd (”Ethylvanillin⇌49d), Cumarin oder Piperonal nachweisbar. Im Resinoid lagen die gleichen Inhaltsstoffe vor wie in den Schoten und entsprachen hinsichtlich Menge und Mengenverhältnis den erwarteten Werten. Es wird vermutet, daß die positiven Piperonalbefunde aus der Literatur auf einer Untersuchung verfälschter Vanilleschoten basieren.AbstractIn the literature there is contradictory information on the compounds of Tahiti vanilla, particularly concerning the piperonal content. Because of this, Tahitian beans and Tahiti vanilla resinoid were analysed by HPLC. Compared with results obtained onVanilla planifolia, the Tahitian beans contained relatively low amounts of vanillin and vanillic acid, relatively high amounts ofp-hydroxybenzoic acid and considerable amounts of anisic acid and anisyl alcohol. Furthermore, although anisaldehyde was detectable, 3-ethoxy-4-hydroxy-benzaldehyde (“ethylvanillin”), coumarin and piperonal were not. The resinoid contained the same compounds as the beans in the expected amounts and ratios. It has to be supposed that reports of positive piperonal results refer to research on adulterated vanilla beans.

Compounds of Vanillons (Vanilla pompona Schiede)

Abstract The typical heliotropin-like odor that has been previously associated with vanillons (Vanilla pompona Schiede, Guadeloupe vanilla) was thought to be due to piperonal (heliotiopin). This could not be confirmed by our HPLC analysis of vanillons, although the examined vanillons pods were found to possess a strong heliotropin-like odor, yet no piperonal was detected. Furthermore, it was ascertained that the vanillons contained p-hydroxybenzoic acid, vanillic acid, p-hydroxybenzaldehyde, p-anisyl alcohol, p-anisic acid and p-anisaldehyde in addition to vanillin, and that their composition evidently resembled more strongly Tahiti than Bourbon vanilla.

Hochdruckflüssigchromatographische Untersuchung von Vanille-CO2-Hochdruckextrakten

HPLC has been used for the determination of vanillin,p-hydroxybenzaldehyde, vanillic acid,p-hydroxybenzoic acid, ethyl vanillin, piperonal and coumarin in CO2 extracts and alcoholic extracts of vanilla beans. Ethyl vanillin, piperonal and coumarin were found in none of the samples. By measuring vanillin,p-hydroxybenzaldehyde, vanillic acid andp-hydroxybenzoic acid a great difference between the amount and the ratio of these main components of the usual alcoholic vanilla extracts and the CO2 vanilla extracts was shown. The present requirements for vanilla extracts and products containing vanilla extracts refer only to the composition of alcoholic extracts for which, in contrast to CO2 vanilla extracts, many studies have been published. The critical examination of products containing CO2 vanilla extracts by using the ratios of vanilla compounds found in the present literature could lead to erroneous complaints. For the purpose of estimating the influence of the extraction solvent on the yield of vanillin, one sample of vanilla beans of each provenance was extracted besides the CO2 extraction also with the solvents ethanol-water according to the method for a single-fold extract and with the solvents dichloromethane and hexane. In all three cases dichloromethane was found to be the best solvent. Furthermore, the ethanol-water extraction tended to give 6–22% more vanillin than the CO2 extraction. To achieve unequivocal results, the examination of more samples is necessary.ZusammenfassungMittels Hochdruckflüssigchromatographie wurden handelsübliche CO2-Extrakte von Vanilleschoten aus Madagaskar, Java und Bali sowie handelsübliche alkoholische Vanilleextrakte auf Vanillin,p-Hydroxybenzaldehyd, Vanillinsäure undp-Hydroxybenzoesäure sowie auf Ethylvanillin, Piperonal und Cumarin untersucht. In keiner der Proben waren die drei letztgenannten Stoffe nachweisbar; hinsichtlich Vanillin,p-Hydroxybenzaldehyd, Vanillinsäure undp-Hydroxybenzoesäure führten die Meßwerte zu dem Ergebnis, daß sich CO2-Vanilleextrakte in ihrer Zusammensetzung deutlich von handelsüblichen alkoholischen Vanilleextrakten unterscheiden: die untersuchten Inhaltsstoffe liegen hier sowohl in anderen Mengen als auch in anderen Verhältnissen zueinander vor. Die derzeit gestellten Anforderungen an Vanilleextrakte und daraus hergestellte Erzeugnisse beziehen sich ausschließlich auf die Zusammensetzung alkoholischer Extrakte, über die im Gegensatz zu CO2-Vanilleextrakten bereits zahlreiche Publikationen vorliegen. Bei Produkten, die mit CO2-Vanilleextrakten hergestellt worden sind, könnte es bei einer Zugrundelegung der aus den bisherigen Veröffentlichungen abgeleiteten Verhältniszahlen zu unberechtigten Beanstandungen kommen. Um den Einfluß des Extraktionsmittels auf die Ausbeute an Vanillin abschätzen zu können, wurde jeweils bei einer Charge Vanilleschoten pro Anbaugebiet außer der CO2-Extraktion zusätzlich eine Extraktion mit Ethanol-Wasser entsprechend der Rezeptur zur Herstellung eines „Single-Fold“-Extraktes, sowie eine Extraktion mit Dichlormethan bzw. Hexan durchgeführt. Das beste der hier getesteten Extraktionsmittel war Dichlormethan. Es zeigte sich weiterhin die Tendenz, daß bei einer Ethanol/Wasser-Extraktion 6–22% mehr Vanillin gewonnen wird als bei einer CO2-Extraktion. Für eine eindeutige Aussage hierzu müßten jedoch noch mehr Proben untersucht werden.

Hochdruckflüssigchromatographische Untersuchung von Zimt-CO2-Hochdruckextrakten im Vergleich mit Zimtölen

Nowadays supercritical CO2 extracts of cinnamon and cassia are coming more and more in trade. Contrary to cinnamon and cassia oils there are very few references in literature about these. Commercially available supercritical CO2 extracts of cinnamon and cassia barks (cinnamon type Ceylon and type Madagascar, cassia type China and type Indonesia) were analysed by HPLC and compared with cinnamon and cassia oils. The results of the analysis showed that the main compounds evidently differed depending on the species of cinnamon (Cinnamomum zeylanicum, C. cassia andC. burmanii) and on the kind of sample, whereby there was a great difference not only between oils and CO2 extracts, but also between so-called „selective extracts“ (40°C/90 bar) and „total extracts“ (40°/280–300 bar).ZusammenfassungÜber Zimthochdruckextrakte, die neuerdings zunehmend im Handel anzutreffen sind, liegen im Gegensatz zu Zimtölen bisher fast keine Literaturangaben vor. Mittels HPLC wurden daher handelsübliche Zimtrinden-CO2-Hochdruckextrakte vonCinnamomum zeylanicum (Ceylon- und Madagaskar-Zimt),C. cassia (Chinesischer Zimt) undC. burmanii (Padang-Zimt) im Vergleich mit Zimtölen untersucht. Dabei zeigte sich, daß die relevanten Inhaltsstoffe abhängig von der Zimtart einerseits und der Probenart andererseits in unterschiedlichen, charakteristischen Konzentrationen vorlagen, wobei sich nicht nur Öle und Hochdruckextrakte, sondern auch sog. „Selektivextrakte“ (40°C/90 bar) und „Totalextrakte“ (40°C/ 280–300 bar) deutlich voneinander unterschieden.

Electron spin resonance spectroscopy investigations of fresh fruit. Evidence of treatment with ionizing radiation

This paper describes the development of a method for the identification of irradiated fresh fruits by measurement of the e.p.r. spectra of pips, kernels or stones. Measurement parameters were optimized and the irradiation specific spectrum was assigned to a cellulose radical by comparison with the e.p.r. spectrum of pure cellulose. Several fruits especially different varieties of strawberries were examined giving the following results: Detectable minimum doses were between 0.4 kGy and 0.9 kGy and the intensity of the irradiation specific signals was found to be linear up to doses of 11 kGy. The lifetime of the specific radicals (at room temperature and at deep freezing temperatures) was long enough compared to the storage time of fresh fruits. Additional information about the nature of the unspecific central signal was gained measuring the samples which were stored at different temperatures. The main conclusion of this study is that the e.p.r. method seemes to be well suited for the use in routine control and should be tested in an intercomparison to establish a routine method for the identification of irradiated fresh fruits.This paper describes the development of a method for the identification of irradiated fresh fruits by measurement of the e.p.r. spectra of pips, kernels or stones. Measurement parameters were optimized and the irradiation specific spectrum was assigned to a cellulose radical by comparison with the e.p.r. spectrum of pure cellulose. Several fruits especially different varieties of strawberries were examined giving the following results: Detectable minimum doses were between 0.4 kGy and 0.9 kGy and the intensity of the irradiation specific signals was found to be linear up to doses of 11 kGy. The lifetime of the specific radicals (at room temperature and at deep freezing temperatures) was long enough compared to the storage time of fresh fruits. Additional information about the nature of the unspecific central signal was gained measuring the samples which were stored at different temperatures. The main conclusion of this study is that the e.p.r. method seemes to be well suited for the use in routine control and should be tested in an intercomparison to establish a routine method for the identification of irradiated fresh fruits.