Improved Bio-Oil Quality from Pyrolysis of Pine Biomass in Pressurized Hydrogen

The pyrolysis of pine sawdust was carried out in a fixed bed reactor heated from 30 °C to a maximum of 700 °C in atmospheric nitrogen and pressurized hydrogen (5 MPa). The yield, elemental composition, thermal stability, and composition of the two pyrolysis bio-oils were analyzed and compared. The result shows that the oxygen content of the bio-oil (17.16%) obtained under the hydrogen atmosphere was lower while the heating value (31.40 MJ/kg) was higher than those of bio-oil produced under nitrogen atmosphere. Compounds with a boiling point of less than 200 °C account for 63.21% in the bio-oil at pressurized hydrogen atmosphere, with a proportion 14.69% higher than that of bio-oil at nitrogen atmosphere. Furthermore, the hydrogenation promoted the formation of ethyl hexadecanoate (peak area percentage 19.1%) and ethyl octadecanoate (peak area percentage 15.42%) in the bio-oil. Overall, high pressure of hydrogen improved the bio-oil quality derived from the pyrolysis of pine biomass.

Development of Korean Indigenous Low-Temperature-Tolerant Yeast for Enhancing the Flavor of Yakju

Yakju, a traditional fermented beverage in Korea, is prepared using various raw materials and methods, and, hence, exhibits various characteristics. Low-temperature-fermented yakju can inhibit the growth of undesirable bacteria and is known for its unique flavor and refreshing taste. To increase the production of volatile aromatic compounds in yakju, strains with strong resistance to low temperatures and excellent production of volatile aromatic compounds were screened from indigenous fruits (grape, persimmon, plum, aronia, wild grape) and nuruk in Korea. One Saccharomyces cerevisiae and three non-Saccharomyces strains were finally screened, and yakju was fermented at 15 °C through mono/co-culture. The analysis of volatile aromatic compounds showed that S. cerevisiae W153 produced 1.5 times more isoamyl alcohol than the control strain and reduced the production of 2,3-butanediol by a third. Similarly, a single culture of Pichia kudriavzevii N373 also produced 237.7 mg/L of ethyl acetate, whereas Hanseniaspora vineae G818 produced ~11 times greater levels of 2-phenethyl acetate than the control. Alternatively, Wickerhamomyces anomalus A159 produced 95.88 mg/L of ethyl hexadecanoate. During principal component analysis, we also observed that the co-culture sample exhibited characteristics of both volatile aroma compounds of the single cultured sample of each strain. Our results suggest that yakju with unique properties can be prepared using various non-Saccharomyces strains.

Sensory and Volatile Profiles of Korean Commercially Distilled Soju Using Descriptive Analysis and HS-SPME-GC-MS

Volatile compositions and sensory characteristics of 11 commercially distilled soju samples were investigated using headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) and sensory descriptive analysis. A total of 59 major volatile compounds, consisting of 32 esters, 10 alcohols, 2 acids, 5 aldehydes, 3 ketones, 1 hydrocarbon, 1 furan, 2 phenols, and 3 miscellaneous compounds, were identified. From the principal component analysis (PCA) of volatile data, MSJ made by atmospheric distillation showed a clear distinction in volatile compositions compared to that of other samples made by vacuum distillation. Based on PCA of the sensory data determined by a panel of ten judges, MSJ was associated with a large amount of longer chain esters that showed high intensities in bitter taste and yeast/nuruk-related flavor attributes. HYJ, LPJ, and HAJ made with rice as a raw material were associated with lower intensities of the alcohol aroma, while JRJ and OKJ aged in oak barrels were associated with fruit flavor, sweet flavor, and brandy aroma. In the partial least squares regression (PLSR) analysis to see any relationship between volatile and sensory data, longer chain esters like ethyl tetradecanoate, and ethyl hexadecanoate were highly associated with bleach aroma. In contrast, positive correlations were seen with barley aroma and yeast flavor with hexanal, nonanal, benzaldehyde, and 2-methoxy-phenol.

Effect of Temperature, Pressure, and Reaction Time on Hydrogenation of Hexadecanoic Acid to 1-Hexadecanol Using a Ru-Sn(3.0)/C Catalyst

Effect of temperature, initial H2 pressure, and reaction time on the selective hydrogenation of hexadecanoate acid to 1-hexadecanol over bimetallic ruthenium-tin supported on carbon (denoted as Ru-Sn(3.0)/C; 3.0 is molar ratio Ru/Sn) has been systematically investigated. Ru-Sn(3.0)/C catalyst was synthesized using a simple hydrothermal method at temperature of 150oC for 24 h followed by reduction with hydrogen at at 400oC and 500°C for 1.5 h. The XRD patterns of reduced Ru-Sn(3.0)/C showed a series diffraction peaks of bimetallic alloy Ru3Sn7 at 2θ = 30.0°; 35.0°; and 41.3° which are recognized as (310), (321), and (411) reflection planes present. The N2-adsorpsion/desorption profiles confirmed that the catalyst structure was microporous and mesoporous sizes with specific surface area (SBET) of 207 m2/g, pore volume (VpBJH) 0.1015 cm3/g, and pore diameter (dpBJH) 1,21 nm. NH3-TPD profile shows that the desorption temperature of 157.1°C was a weak acidity (Bronsted acid site) with amount of acid sites was 0.117 mmol/g. Meanwhile, the desorption temperature of 660.3°C was a strong acidity (Lewis acid site) with amount of acid sites was 0.826 mmol/g. The highest conversion of hexadecanoic acid (86.24%) was achieved at reaction temperature180°C, initial H2 pressure of 5.0 MPa, a reaction time of 6 h in ethanol solvent and afforded yield of hexadecane (0.15%), 1-hexadecanol (4.27%), and ethyl hexadecanoate (81.82%). At reaction temperature of 150°C, H2 of 3.0 MPa, and a reaction time of 18 h, 73.27% of hexadecanoic acid was converted to 1-hexadecanol (0.24%) and ethyl hexadecanoate (73,03%).

Chemical constituents, antimicrobial and antioxidant properties of the aerial parts of Coccinia barteri

Phytochemical analysis of n-hexane, ethyl acetate and methanol extracts of the aerial parts of Coccinia barteri was carried out. These extracts exhibited satisfactory inhibitory activities against bacteria and fungi strains, which include; Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhii, Klebsiella pneumoniae, Candida albicans, Aspergillus niger, Penicillium notatum and Rhizopus stolonifer. Methanol extract of C. barteri possesses antioxidant activity by scavenging DPPH free radical with IC50 of 187.56 μg/mL, using DPPH antioxidant assay. GC-MS analysis of n-hexane, ethyl acetate and methanol extracts of the plant principally revealed the presence of phytol, ethyl hexadecanoate and clionasterol with their corresponding percentage abundance of 57.75%, 18.33% and 9.79%, respectively.

Chemical Compounds from Female and Male Rectal Pheromone Glands of the Guava Fruit Fly, Bactrocera correcta

The guava fruit fly, Bactrocera correcta, is one of the major pests affecting mango (Mangifera indica) and guava (Psidium guajava) production in China. The compound β-caryophyllene was identified from the rectal gland extracts of wild B. correcta males and was demonstrated to be a more specific and potent male lure than methyl eugenol (ME) for B. correcta. In order to find potential additional pheromone attractants for the monitoring and mass-trapping of this fruit fly, a series of chemical and behavioral assays were conducted in this study. Ten compounds were identified from the rectal glands of virgin B. correcta females. These compounds consisted of five major compounds (i.e., ethyl dodecanoate, ethyl tetradecanoate, ethyl (E)-9-hexadecenoate, ethyl hexadecanoate, and ethyl (Z)-9-octadecenoate) in high quantities, and other compounds (i.e., octanal, N-(3-methylbutyl) acetamide, (Z)-9-tricosene, ethyl octadecanoate, and ethyl eicosanoate) in trace amounts, while virtually no compounds were found in male rectal glands. The bioassays indicate that female rectal gland extracts are attractive to virgin females and males. Furthermore, a cyclical production of the five major compounds was found, recurring at roughly 10-d intervals with peaks in 10–13-, 25-, and 35-d-old females. Collectively, these results will contribute to the understanding of pheromone communication in B. correcta and may provide important information for improving existing monitoring and control methods for this pest.

Chemical Composition and Antioxidant Activity of the Fruit Essential Oil of Zizyphus lotus (L.) Desf. (Rhamnaceae)

The essential oil of the fruit of Zizyphus lotus (L.) Desf. belonging to the Rhamnaceae family, was obtained by steam distillation and analyzed by GC-FID and GC-MS. 38 components were identified corresponding to 92% of the total oil. Fatty acids represented the major fraction (78.9%), followed by hydrocarbons (10.8%) while terpenic fraction constituted only 1.1% of the oil (- and β-eudesmol). The fatty acids fraction contained 23 saturated and unsaturated compounds (67.8 and 11%, respectively) from C8 to C18. The major constituents are in decreasing order: ethyl hexadecanoate (12%), decanoic acid (11%), ethyl dodecanoate (9.4%), ethyl hexadec-9-enoate (7.9%), dodecanoic acid (6.5%), ethyl tetradecanoate (6.1%) and tetradecanoic acid (5%). Several studies described the fatty acid composition of different parts of Zizyphus species in the fixed oil. Our study is the first report devoted to the chemical composition of the essential oil of the fruit of this species. The antioxidant property of this oil was evaluated using β-carotene bleaching method.

Minor Volatile Compounds in Traditional Homemade Fruit Brandies from Transylvania-Romania, as Determined by GC-MS Analysis

In order to investigate the minor volatile compounds of traditional homemade fruit brandies from Romania (Transylvania region), as a result of their assortment and provenience, a number of 26 samples (18 plum brandies samples from 3 different counties, 4 samples of apple brandy and 4 samples of pear brandy) were analyzed using liquid-liquid extraction and gas-chromatography coupled with mass-spectrometry (GC-MS) technique. The GC-MS chromatograms of the hexane extracts led to the identification of 34 compounds (9 terpenes, 14 fatty acids esters, 3 free fatty acids, 4 carboxylic acid esters, 1 hydrocarbon, 1 aldehyde and 1 acetal). The most abundant compounds were the fatty acid esters. Chemometric analysis (Principal Component Analysis-PCA) was applied to discriminate the differences between the volatiles’ fingerprint. Considering the plum brandy samples, significant differences have been observed according to their provenience region. Based on relative abundance of determined compounds important differences among samples from different counties can be seen.. Ethyl hexadecanoate was the main factor for this discrimination. When compared the three types of fruit brandies, significant differences were noticed for their content in ethyl esters of hexanoic, benzoic and hexadecanoic acids. For some plum brandies, according to their fingerprint, possible adulteration with apple brandy can be noted, based on their similar volatiles’ pattern. The pear brandy was strongly delimitated by the other two types of brandies. The PCA data showed a good discrimination according to the region of provenience of the plum brandies in parallel with the composition specificity of the three analyzed fruit brandies.

Sesquiterpene Lactones from Elephantopus scaber

The ethanolic and acetone extracts of the whole plant of Elephantopus scaber were found to contain ethyl hexadecanoate, ethyl-9,12-octadecadienoate, ethyl-(Z)-9-octadecenoate, ethyl octadecanoate, lupeol, stigmasterol, stigmasterol glucoside, deoxyelephantopin (1) and two new germacranolide sesquiterpene lactones named 17,19-dihydrodeoxyelephantopin (2) and iso-17,19- dihydrodeoxyelephantopin (3) whose stereostructures were determined by spectroscopic methods, comparison with reported data and single-crystal X-ray analysis.