Structural analogues of homoeriodictyol as flavor modifiers. Part III: short chain gingerdione derivatives.

In order to find new flavor modifiers, various short chain gingerdione derivatives were synthesized as structural analogues of the known bitter masker homoeriodictyol and evaluated by a sensory panel for masking and sweetness enhancing activities. 1-(4-Hydroxy-3-methoxyphenyl)hexa-3,5-dione ([2]-gingerdione) and the homologue 1-(4-hydroxy-3-methoxyphenyl)hepta-3,5-dione ([3]-gingerdione) at concentration ranges 50-500 mg kg (-1) showed the most promising masking activity of 20-30% against bitterness of a 500 mg kg (-1) aqueous caffeine solution. Additionally, both compounds were able to reduce the bitterness of a 5 mg kg (-1) quinine solution by about 20%; however, the bitter tastes of salicine, the model peptide H-Leu-Trp-OH, and KCl solutions were not reduced. Whereas for bitter masking activity a vanillyl moiety seems to be important, some of the tested isovanillyl isomers showed an interesting sweet enhancing effect without exhibiting a significant intrinsic sweetness. The isomer 1-(3-hydroxy-4-methoxyphenyl)hexa-3,5-dione ([2]-isogingerdione) at 100 mg kg (-1) caused a significant and synergistic increase of 27% of sweet taste of a 5% sucrose solution.

Identification of allyl esters in garlic cheese.

This study describes the identification of six allyl esters in a garlic cheese preparation and in a commercial cream cheese. The extracts were prepared by liquid/liquid extraction and concentrated by the SAFE process. The identification of the allyl esters of acetic, butyric, hexanoic, heptanoic, octanoic, and decanoic acids is based on the correlation of their mass spectrometric data and chromatographic retention time data obtained from the extracts with those of authentic standards. In addition to the gas chromatography (GC)/mass spectrometry analysis, the flavor ingredients were characterized by GC sniffing by a trained flavorist. Some of the esters were isolated by preparative GC.

New bitter-masking compounds: hydroxylated benzoic acid amides of aromatic amines as structural analogues of homoeriodictyol.

Starting from the known bitter-masking flavanones eriodictyol and homoeriodictyol from herba santa some structurally related hydroxybenzoic acid amides of benzylamines were synthesized and evaluated as masking agents toward bitterness of caffeine by sensory methods. The closest structural relatives of homoeriodictyol, the hydroxybenzoic acid vanillylamides 5-9, were the most active and were able to reduce the bitterness of a 500 mg L(-1) caffeine solution by about 30% at a concentration of 100 mg L(-1). 2,4-Dihydroxybenzoic acid vanillylamide 7 showed a clear dose-dependent activity as inhibitor of the bitter taste of caffein between 5 and 500 mg L(-1). Additionally, it was possible to reduce the bitterness of quinine and salicine but not of the bitter peptide N-l-leucyl-l-tryptophan. Combinations of homoeriodictyol and amide 7 showed no synergistic or antagonistic changes in activity. The results for model compound 7 suggested that the hitherto unknown masking mechanism is probably the same for flavanones and the new amides. In the future, the new amides may be alternatives for the expensive flavanones to create flavor solutions to mask bitterness of pharmaceuticals or foodstuffs.

Product-oriented flavor research: learnings from the past, visions for the future.

In the past flavor research and the development of new flavorings were constantly driven by the interaction of flavor analysis, structure elucidation, and chemical synthesis accompanied by sensory. Highly potent flavor compounds were identified in numerous food products and helped to establish a powerful toolbox for flavorists. Nowadays we experience the merging of various scientific disciplines, for example medicine, biology, chemistry, and various technologies in the field of flavor research, which shows direct impact on our understanding of flavors. At the same time modern life has profoundly changed our eating habits. This situation generates new challenges for product development teams, which represent all facets of technologies. This paper will illustrate different examples for the evolution of product-oriented flavor research and future trends.

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance as complementary analytical techniques for unambiguous identification of polymethoxylated flavones in residues from molecular distillation of orange peel oils (Citrus sinensis).

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance techniques with ultraviolet/diode array detection were used as complementary analytical tools for the reliable identification of polymethoxylated flavones in residues from molecular distillation of cold-pressed peel oils of Citrus sinensis. After development of a liquid chromatographic separation procedure, the presence of several polymethoxy flavones such as sinensetin, nobiletin, tangeretin, quercetogetin, heptamethoxyflavone, and other derivatives was unambiguously confirmed. In addition, proceranone, an acetylated tetranortriterpenoid with limonoid structure, was identified for the first time in citrus.

Evaluation of bitter masking flavanones from Herba Santa (Eriodictyon californicum (H. and A.) Torr., Hydrophyllaceae).

Products made from Herba Santa (Eriodictyon californicum (H. & A.) Torr.) have been used as bitter remedies for some pharmaceutical applications for many years, but they are actually too aromatic to be useful for many food or pharmaceutical applications. In sensory studies flavanones homoeriodictyol (1), its sodium salt (1-Na), sterubin (2), and eriodictyol (4) could significantly decrease the bitter taste of caffeine without exhibiting intrinsic strong flavors or taste characteristics. Further investigations on 1-Na elicited a broad masking activity between 10 and 40% toward different chemical classes of bitter molecules (e.g. salicin, amarogentin, paracetamol, quinine) but not toward bitter linoleic acid emulsions. For caffeine and amarogentin, dose-response studies were performed; the masking activity toward bitter taste for both compounds reached a plateau at higher concentrations of 1-Na. Due to these facts, homoeriodictyol sodium salt (1-Na) seems to be a very interesting new taste modifier for food applications and pharmaceuticals.

New woody and ambery notes from cedarwood and turpentine oil.

The development of a new product in the chemical industry is still driven by needs like technical properties, price/performance ratio, biodegradability, or product safety. However, in terms of improving more and more on ecological criteria, summarized under such catchphrases as sustainable development or green chemistry, another important aspect is to use renewable resources as starting materials. This is not significantly new in fragrance chemistry, and there are a lot of raw materials in the perfume oils that are derived from molecules of renewable resources. Two commonly used materials are: longifolene (from turpentine oil) and cedrene (from cedarwood oil). These compounds are very suitable for the synthesis of woody and ambery notes, and even though it seemed that all possibilities were exhausted, it is actually still feasible to discover new molecules with excellent olfactory properties such as Ambrocenide (50a), which is available in three steps from alpha-cedrene. Some of these molecules will be treated in this review, both with respect to synthesis as well as structural and sensory aspects.

Synthesis of lipophilic clovamide derivatives and their antioxidative potential against lipid peroxidation.

Some N-(hydroxycinnamoyl)-L-tyrosine and L-DOPA alkyl esters were synthesized and evaluated as a variation of the clovamide (N-caffeoyl-L-3,4-dihydroxyphenylalanine) structure, a known antioxidant found in red clover. The amides were prepared in good yields starting from methyl and dodecylesters of L-tyrosine and L-DOPA by reacting with the N-hydroxysuccinimidyl esters of ferulic, sinapic, and acetyl-protected caffeic acid, respectively. In the DPPH* (2,2-diphenyl-1-picrylhydrazyl) and superoxide radical quencher assays they showed radical scavenging activity equal to or higher than those of the standard antioxidants ascorbic acid and tocopherol. The antioxidative potentials of the clovamide derivatives against bulk lipid oxidation, as determined by the accelerated autoxidation of oils, were equal to or higher than those of the standard antioxidants; some of the compounds were able to protect an emulsion of linoleic acid/beta-carotene against oxidation. N-Caffeoyl L-tyrosine methyl ester and the N-cinnamoyl L-DOPA alkyl esters especially were potent antioxidants in bulk lipids and moderate protectants in emulsions.

3,4-Dihydroxymandelic acid, a noradrenalin metabolite with powerful antioxidative potential.

The decarboxylated noradrenaline metabolite 3,4-dihydroxymandelic acid [DHMA, 2-(3,4-dihydroxyphenyl)-2-hydroxyacetic acid] occurs in different mammalian tissues, especially in the heart. To elucidate the physiological function of DHMA, the antioxidative and radical scavenging activity was determined by physicochemical and cell-based test systems. In the 2,2-diphenyl-1-picrylhydrazyl assay it shows a 4-fold higher radical scavenging activity compared to the standard antioxidants ascorbic acid, tocopherol, and butylated hydroxytoluene. DHMA is also a very potent superoxide radical scavenger and shows a 5-fold smaller IC(50) value compared to standard ascorbic acid. Again, in most cases the antioxidative power of DHMA against bulk lipid oxidation determined by accelerated autoxidation of oils is much higher than for the standard antioxidants. In soybean oil and squalene a DHMA/alpha-tocopherol mixture (1:1 w/w) shows a synergistic effect. Last but not least, 0.001 and 0.0005% levels of DHMA protect human primary fibroblasts against H(2)O(2)-induced oxidative stress as determined by the 2',7'-dichlorofluorescein assay.