High-throughput screening for aroma production in food fermentations.

A microtiter plate (MTP) method was developed to screen 1064 unique microorganisms-substrate fermentations for production of 68 target aroma compounds. Based on the number of hits identified by GC-MS, 50 fermentations were repeated at 50-mL scale in flasks. Comparison of GC-MS data showed that scaling up from MTP to flask did not generally result in large differences between the volatile profiles, even with a wide variety of substrates (juice, food slurry and food side-streams) and microorganisms (yeast, bacteria and fungi) used. From the screening results, Lactobacillus plantarum fermentation of chilli pepper was further studied as a high amount of phenols, especially guaiacol and 4-ethylphenol, was produced after fermentation. From HPLC-MS and sensory analysis, capsaicin was shown to be a probable precursor for these phenols and a potential mechanism was proposed. The protocol described herein to screen aroma compounds from fermentation of agri-food products and side streams can support development of clean label flavourful food ingredients.

ß-Orcinol-type depsides from the lichen Thamnolia vermicularis.

A phytochemical investigation of a herb tea made from Thamnolia vermicularis led to the isolation of three new ß-orcinol-type depsides (1, 2 and 3), along with seven known compounds hypothamnolic acid (4), 3'-methylevenic acid (5), baeomycesic acid (6), squamatic acid (7), methyl 3'-methyllecanorate (8), barbatinic acid (9) and atranorin (10). The structures of the new compounds were determined on the basis of spectroscopic evidence, including 1-D and 2-D NMR and ESI-MS techniques.

New dammarane-type glycosides from the roots of Gynostemma pentaphyllum.

Twelve new dammarane-type glycosides ( 1- 12) were isolated from the ethanol extract from the roots of a wild-type of Gynostemma pentaphyllum. The structures of the compounds were elucidated by 1D and 2D NMR spectroscopic analysis as well as by chemical degradation. The compounds contained six structurally diverse aglycons similar to those of the reported ginseng saponins with differences in the oligosaccharide moieties.

Diterpenoids from Euphorbia neriifolia.

Nine diterpenoids were isolated from the stems of Euphorbia neriifolia Linn. with their structures established by 1D and 2D NMR techniques. Relative stereochemistries were determined by ROESY, and single-crystal X-ray experiments.

Neolignans and flavonoids from the root bark of Illicium henryi.

Two new neolignans (1 and 2) were isolated from the root bark of Illicium henryi, along with four known neolignans and seven known flavonoids (3-13). Their structures were elucidated on the basis of spectroscopic and chemical methods. The absolute configurations of compounds 1 and 2 were determined by the CD spectrum.

Dammarane-type glycosides and long chain sesquiterpene glycosides from Gynostemma yixingense.

A new dammarane-type glycoside and a new long chain sesquiterpene glycoside, along with nine known compounds 20(S)-ginsenoside Rh1 (3), 20(R)-ginsenoside Rh1 (4), ginsenoside F1 (4), amarantholidoside IV (6), ginsenoside Rc (7), 20(S)-ginsenoside Rg2 (8), 20(R)-ginsenoside Rg2 (9), ginsenoside Rd (10) and gypenoside XLVI (11) were isolated from Gynostemma yixingense. The structures of the new compounds were determined on the basis of spectroscopic analysis, including 1D-, 2D-NMR and ESI-MS techniques as well as by comparison of the spectral data with those of related compounds as 2 alpha,3beta,20(S)-trihydroxydammar-24-ene-3-O-[beta-D-glucopyranosyl((1-->2)-beta-D-glucopyranosyl]-20-O-[beta-D-xylopyranosyl((1-->6)-beta-D-glucopyranoside] (1) (2E,6E)-10-beta-D-glucopyranosyl-1,10,11-trihydroxy-3,7,11-trimethyldodeca-2,6-diene (2).

WITHDRAWN: Eight new C21 steroidal glycosides from Cynanchum wilfordii.

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