Odor, taste, and flavor perception of some flavoring agents

Psychophysical functions for the odor, taste, and flavor offive common flavorings were obtained by the method of magnitudeestimation. The stimuli included three simple compounds (vanillin,piperonal, and benzaldehyde) and two complex ones (natural vanillaextract and artificial almond essence). The odor intensity ofall the flavorings grew much less rapidly with concentrationthan did taste intensity. The growth of flavor for the complexsubstances and piperonal behaved very much like taste. For vanillinand benzaldehyde, the flavor functions resembled taste functionsat high concentrations but showed a tendency to flatten at lowerconcentrations. These findings implied that, at least for someflavorings, the growth of flavor reflects the most salient featureon the particular concentration range studied. At low concentrationsodor seems to be the most important feature and so flavor functionsare generally flat, but at high concentrations taste becomesthe salient feature and so flavor functions steepen.     

Key Odorants in Cured Madagascar Vanilla Beans (Vanilla planiforia) of Differing Bean Quality

The effects of pressure on the enzyme activities of Lacto-bacillus helveticus LHE-511 were examined. Treatment at 400 MPa at 30°C for 10 min completely inhibited acid-producing activity, but the activities of aminopeptidase (AP) and X-prolyl dipeptidyl aminopeptidase (X-PDAP), which are important for acceleration of cheese ripening, increased. These results showed that pressure treatment of L. helveticus LHE-511 selectively inactivates its acid-producing activity.     

Localization of beta-D-glucosidase activity and glucovanillin in vanilla bean (Vanilla planifolia Andrews)

The morphology, anatomy and histology of mature green vanilla beans were examined by light and transmission electron microscopy. Beans have a triangular cross-section with a central cavity containing seeds. Each angle is lined with tubular cells, or papillae, while the cavity sides consist of placental laminae. The epicarp and endocarp are formed by one or two layers of very small cells, while the mesocarp contains large, highly vacuolarized cells, the cytoplasm being restricted to a thin layer along the cell walls. The radial distributions of glucovanillin and beta-glucosidase activity, measured on p-nitrophenyl-beta-glucopyranoside and glucovanillin, are superimposable and show how beta-glucosidase activity increases from the epicarp towards the placental zone, whereas glucovanillin is exclusively located in the placentae and papillae. Subcellular localization of beta-glucosidase activity was achieved by incubating sections of vanilla beans in a buffer containing 5-bromo-4-chloro-3-indolyl-beta-d-glucopyranoside as a substrate. Activity was observed in the cytoplasm (and/or the periplasm) of mesocarp and endocarp cells, with a more diffuse pattern observed in the papillae. A possible mechanism for the hydrolysis of glucovanillin and release of the aromatic aglycon vanillin involves the decompartmentation of cytoplasmic (and/or periplasmic) beta-glucosidase and vacuolar glucovanillin.     

Inhibition of bacterial quorum sensing by vanilla extract

AIMS: The purpose of this study was to search for a novel quorum sensing inhibitor and analyse its inhibitory activity. METHODS AND RESULTS: Quorum sensing inhibition was monitored using the Tn-5 mutant, Chromobacterium violaceum CV026. Vanilla beans (Vanilla planifolia Andrews) were extracted using 75% (v/v) aqueous methanol and added to C. violaceum CV026 cultures. Inhibitory activity was measured by quantifying violacein production using a spectrophotometer. The results have revealed that vanilla extract significantly reduced violacein production in a concentration-dependent manner, indicating inhibition of quorum sensing. CONCLUSIONS: Vanilla, a widely used spice and flavour, can inhibit bacterial quorum sensing. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that the intake of vanilla-containing food materials might promote human health by inhibiting quorum sensing and preventing bacterial pathogenesis. Further studies are required to isolate specific substances from vanilla extract acting as quorum sensing inhibitors.     

Coat Protein Gene of Cymbidium mosaic virus from Vanilla fragrans in Reunion Island

Nucleotide and amino acid sequences of the coat protein (CP) of 12 isolates of Cymbidium mosaic virus from Vanilla fragrans in Reunion Island (CyMV‐R) were compared with each other and with those of previously described Asian strains. Alignment revealed that CyMV‐R isolates were highly homologous, suggesting that one strain is prevalent in Reunion. This strain also showed high homology with the Korean CyMV‐K2 and Singapore CyMV‐S2 strains, but nucleotide additions resulted in the carboxy‐terminal ends of the CP sequences differing from those of the Korean CyMV‐K1 and Singapore CyMV‐K1 strains.     

Circular Dichroism of Borate Complexes of Aldonic Acid γ-Lactones and Its Application to the Stereochemistry of Vicinal cis-Hydroxyl Groups in Lactone Rings

A method is reported, by chelate formation between borate ion and vic.-cis diols, to determine the configuration at Cβ in aldonic acid γ-lactones. Chelate formation is detected by red shift and decrease in the molar ellipticity of the CD maximum in borate buffer. It was also detected by the decrease in the rate of hydrolysis of the lactone ring at pH 9, as measured by the decrease in the CD maximum.     

Molecular diversity of Fusarium oxysporum causing rot diseases of vanilla in south India

Incidence of root, stem and beans rot of vanilla (Vanilla planifolia Andrews) caused by Fusarium oxysporum Schlecht was surveyed in vanilla growing areas of south India during December 2008. The incidence of the disease varied from 1 to 100% in different locations. A total of 60 isolates of F. oxysporum were obtained from diseased samples, and nine morphologically different isolates were taken for molecular characterization using Randomly Amplified Polymorphic DNA (RAPD) markers to study the genetic variability if any, among them. PCR amplification of total genomic DNA with random oligonucleotide primers generated unique banding patterns depending upon primers and isolates. Nine oligonucleotide primers were selected for the RAPD assays, which resulted in 384 bands for nine isolates of F. oxysporum. The number of bands obtained was entered into a NTSYS and the results showed that the variability among the pathogen isolates was moderate. The nine isolates studied were grouped into single major cluster at 0.66 similarity index. Hence, it is inferred that F. oxysporum infecting vanilla in south India consists of a single clonal lineage with a moderate level of genetic diversification.     

不同植物生长调节物质对驱蚊香草细胞脱分化的效应

以驱蚊香草的幼嫩叶片为外植体,在MS培养基上添加各种不同浓度植物生长调节物质进行单因子试验。研究结果表明,不同植物生长调节物质对驱蚊香草的诱导效应不同。2,4-D对驱蚊香草愈伤组织的诱导效果最好;6-BA对芽的诱导显著;NAA对根的分化作用明显。而单独使用NAA,可以从外植体、愈伤组织、根、芽、苗一步完成。