Assessment Wine Aroma Persistence by Using an in Vivo PTR-ToF-MS Approach and Its Relationship with Salivary Parameters.

To better understand wine aroma persistence, the nasal cavity of nine volunteers was monitored by Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) after they rinsed their mouths with three rosé wines (one control and the same wine supplemented with two tannin extracts) during four minutes. Wines were aromatised with a mixture of five target aroma compounds. Results showed that wine aroma persistence was highly compound-dependent: while esters disappeared very fast, other compounds such as linalool remained in the oral cavity for longer times after wine expectoration. A low effect of tannins (at 50 mg/L) on nasal cavity parameters was observed, with the exception for the compound ethyl decanoate that was significantly higher released in the presence of tannins. Strong interindividual differences on aroma persistence were also found. Significant positive correlations with the salivary total protein content and negative with the salivary flow were observed for specific compounds. This work has studied for the first time in vivo wine aroma persistence in real time from an analytical perspective.

Volatiles Mediating Parasitism of Euschistus conspersus and Halyomorpha halys Eggs by Telenomus podisi and Trissolcus erugatus.

This study identified chemicals found on the eggs of two stink bug species, one native to western North America, Euschistus conspersus, and an invasive species from Asia, Halyomorpha halys. The responses of two scelionid egg parasitoids, Trissolcus erugatus and Telenomus podisi, toward natural stink bug egg volatiles, and synthetic reconstructions of egg volatiles, were tested in bioassays. A compound, methyl (2E,4Z)-2,4-decadienoate, previously identified as the major component of the male-produced aggregation pheromone of E. conspersus, was the major volatile identified from extracts of E. conspersus eggs. In contrast, for H. halys, the sesquiterpenoids that compose the male-produced aggregation pheromone of this species were not detected on eggs, whereas the presence of hexadecanal, octadecanal, and eicosanal was detected. In laboratory olfactometer tests, both Tr. erugatus and Te. podisi females were attracted to extracts of E. conspersus eggs, and to synthetic methyl (2E,4Z)-2,4-decadienoate. However, female Tr. erugatus and Te. podisi wasps were repelled, both by extracts of H. halys eggs and by a blend of the aldehydes identified from H. halys eggs. A follow-up field study, using hexane-washed and intact E. conspersus as sentinel eggs, showed that the parasitoids Trissolcus erugatus and Gryon obesum emerged from these eggs. Sentinel hexane-washed eggs treated with 3 ng of methyl (2E,4Z)-2,4-decadienoate were parasitized more by these two species than were hexane-washed or unwashed eggs, whereas hexane-washed eggs treated with a comparable dose of the C16,18,20 aldehyde mixture were avoided by these parasitoids. In a further field experiment, Trissolcus basalis was the primary parasitoid found in sticky traps baited with methyl (2E,4Z)-2,4-decadienoate, indicating that this species was attracted to, but either did not oviposit or develop in the E. conspersus sentinel eggs in the previous experiment.

Natural variability in acyl moieties of sugar esters produced by certain tobacco and other Solanaceae species.

A unique feature of glandular trichomes of plants in the botanical family Solanaceae is that they produce sugar esters (SE), chemicals that have been shown to possess insecticidal, antifungal, and antibacterial properties. Sugar esters of tobacco (Nicotiana tabacum) provide pest resistance, and are important flavor precursors in oriental tobacco cultivars. Acyl moieties of SEs in Nicotiana spp., petunia, and tomato are shown to vary with respect to carbon length and isomer structure (2-12 carbon chain length; anteiso-, iso-, and straight-chain). Sugar esters and their acyl groups could serve as a model to explore the basis of phenotypic diversity and adaptation to natural and agricultural environments. However, information on the diversity of acyl composition among species, cultivars, and accessions is lacking. Herein, described is the analysis of SE acyl groups found in 21 accessions of Nicotiana obtusifolia (desert tobacco), six of Nicotiana occidentalis subsp. hesperis, three of Nicotiana alata, two of N. occidentalis, four modern tobacco cultivars, five petunia hybrids, and one accession each of a primitive potato (Solanum berthaultii) and tomato (Solanum pennellii). A total of 20 different acyl groups was observed that were represented differently among cultivars, species, and accessions. In Nicotiana species, acetate and iso- and anteiso-branched acids prevailed. Straight-chain groups (2-8 carbons) were prominent in petunias, while octanoic acid was prominent in N. alata and N. × sanderae. Two unexpected acyl groups, 8-methyl nonanoate and decanoate were found in N. occidentalis subsp. hesperis. Longer chain groups were found in the petunia, tomato, and potato species studied.

Consumption of medium- and long-chain triacylglycerols decreases body fat and blood triglyceride in Chinese hypertriglyceridemic subjects.

OBJECTIVES: To investigate the effects of medium- and long-chain triacylglycerol (MLCT) on blood triglyceride (TG) in Chinese hypertriglyceridemic subjects. METHODS: A double-blind controlled clinical trial was carried out, in which 112 subjects with hypertriglyceridemia were randomly divided into two dietary oil groups: (1) long-chain triacylglycerol (LCT) and (2) MLCT. All subjects were requested to ingest fixed energy and to continue their normal activity levels, and to consume LCT or MLCT oil at 25-30 g daily during the study period. Anthropometric measurements of body weight, body mass index (BMI), body fat, body fat percentage, waist and hip circumference (WC and HC), areas of subcutaneous and visceral fat by computed tomography scanning and blood biochemical markers were measured at the beginning and end of the study. RESULTS: There were 50 and 51 subjects left in LCT and MLCT groups, respectively. There were no significant differences in daily intake of energy, protein, fat and carbohydrate, as well as the daily physical activity between the two groups during the study. After 8 weeks, MLCT group showed a significant decrease in body weight, BMI, WC, HC, ratio of WC and HC, body fat, body fat percentage and subcutaneous fat when compared with the initial values. The decrease in body weight, BMI, WC, body fat and subcutaneous and visceral fat was significantly greater in MLCT group than that in the LCT group. Furthermore, the serum concentrations of TG in MLCT group were significantly lower than those in the LCT group. CONCLUSIONS: Consumption of MLCT may reduce body weight, body fat and blood TG in hypertriglyceridemic subjects under an appropriate dietary regime.

Influence of fatty acids on wine foaming.

The influence of fatty acids (free and bound as ethyl esters) on wine foaming was studied in different white wines and the corresponding sparkling wines. Moreover, from three of these wines the foam formed by CO(2) injection was separated, and two fractions were then obtained: foam wine (FW) and remainder wine (RW). In these fractions and the sparkling wines produced from them, foam properties and fatty acids were also determined. The free fatty acids C8, C10, and C12 were negatively correlated with foamability (HM), whereas the ethyl esters of hexanoic, octanoic, and decanoic acids were positively related to HM. The value of HM was directly proportional to the ratio of esterified to unesterified fatty acids. This was confirmed by the changes that occur in the esterification ratio during the second fermentation and aging. No influence was observed on either the Bikerman coefficient or the stability time of foam.

Polyphosphate kinase is essential for biofilm development, quorum sensing, and virulence of Pseudomonas aeruginosa.

The human opportunistic pathogen Pseudomonas aeruginosa causes a variety of infections in immunocompromised hosts and in individuals with cystic fibrosis. A knockout mutation in the polyphosphate kinase (ppk) gene, encoding PPK responsible for the synthesis of inorganic polyphosphate from ATP, renders P. aeruginosa cells unable to form a thick and differentiated biofilm. The mutant is aberrant in quorum sensing and responses in that production of the quorum-sensing controlled virulence factors elastase and rhamnolipid are severely reduced. In a burned-mouse pathogenesis model, the virulence of the mutant is greatly reduced with severe defects in the colonization of mouse tissues. The conservation of PPK among many bacterial pathogens and its absence in eukaryotes suggest that PPK might be an attractive target for antimicrobial drugs.

Role of Yersinia intermedia and Pseudomonas putida in the development of a fruity off-flavour in pasteurized milk.

Analysis by gas chromatography-mass spectrometry of pasteurized milk with a fruity (pineapple like) off odour and a sour, rancid and soapy taste indicated the presence of concentrations at microg/ml levels of ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, octanoic acid, decanoic acid and dodecanoic acid. The off-odour and taste were attributed to the presence of these compounds in the milk. Microbiological examination confirmed that the milk was also contaminated with a series of psychrotrophic bacteria including Yersinia intermedia, Pseudomonas putida and Rahnella aquatilis. Growth of isolates of these bacteria in UHT milk at 23 degrees C for 7 d showed that Yer. intermedia produced significant quantities of the C4-C12 alkanoic acids; Ps. putida produced only small quantities of these acids and Rah. aquatilis produced none. In addition, Yer. intermedia and Ps. putida also produced small but significant quantities of the corresponding ethyl esters. In milk inoculated with both Yer. intermedia and Ps. patida, the quantity of ethyl esters produced was greater than that found in cultures containing only one of the isolates. These studies indicated that Yer. intermedia was the principal source of the alkanoic acids in the tainted milk and that the major producer of the corresponding ethyl esters was Ps. patida. This is the first report that Yer. intermedia and Ps. putida can cause an off-odour or taste in dairy products.

Cellular fatty acid composition of Francisella tularensis.

Several unusual fatty acids characterized strains of Francisella tularensis. Long-chain (C20-C26) acids and the hydroxy acids 2-hydroxy-decanoate, 3-hydroxy-hexadecanoate, and 3-hydroxy-octadecanoate appeared to be of special diagnostic value.

The total structure of cerexin A (studies on antibiotics from the genus Bacillus. XVI.

The constituent fatty acid of cerexin A was elucidated to be beta-hydroxy isoundecanoic acid by gas chromatography, mass spectrometry and nuclear magnetic resonance. The asparaginyl asparagine linkage in the amino acid sequence of the antibiotic, which has been previously described, was proved to be a normal alpha-carboxylpeptide bond by dehydration-reduction procedure. The three asparagine residues in the sequence were isolated separately and their chiralities were determined. The structure of cerexin A was concluded from the above results.