Fruit Volatile Fingerprints Characterized among Four Commercial Cultivars of Thai Durian (Durio zibethinus)

Ripe durian fruits produce unique volatiles of pungent odor comprising esters, alcohols, ketones, and sulfur-containing compounds. Recently, “Chanthaburi 1” hybrid bred from 2 famous commercial cultivars of “Chanee” and “Monthong” claimed to be less fragrant during ripening, but there was no report. The present study compared the volatile profiles from 3 Thai commercial cultivars of “Kanyao,” “Chanee,” and “Monthong” compared to “Chanthaburi 1”, and the relationships of the cultivars were organized using the volatile fingerprints. Out of 41 volatile compounds detected by SPME/GC-MS in ripe durian flesh, 33 compounds were esters, but only 14 esters were found in “Chanthaburi 1.” Ripe flesh of most durian cultivars contains ethyl-2-methyl butanoate and ethyl hexanoate as the active volatiles. “Chanthaburi 1” contained fewer components with low odor activity value (OAV) of the volatiles. “Chanee” ripe flesh exhibited the strongest durian smell among the four varieties, whereas “Monthong” exhibited a strong apple-like fruity odor and “Kanyao” was more green fruity. Diethyl disulfide and 3, 5 dimethyl-1, 2, 4-trithiolane contributing pungent smells of garlic or onion were found only in “Chanthaburi 1” and “Monthong.” In terms of detected volatiles, “Kanyao” and “Chanee” were highly close when “Monthong” was apart. PCA analysis revealed that “Chanthaburi 1” contained ester compounds ancestrally related to the parents, “Chanee” in the component I and “Monthong” in the component II. These data could be beneficial for managing the status of Thai durians in global markets.

Impact of malolactic fermentation with Lactobacillus plantarum on volatile compounds of sea buckthorn juice

Malolactic fermentation using sea buckthorn (Hippophaë rhamnoides) juice as raw material was performed with six different strains of Lactobacillus plantarum. Increasing juice pH from 2.7 to 3.5 or adapting cells to low pH (i.e., acclimation) prior to inoculation allowed malolactic fermentation with all tested strains. Moreover, reducing pH of the growth medium from 6 to 4.5 with l-malate had little or no impact on biomass production. Volatile profile of sea buckthorn juice was analyzed with HS-SPME–GC–MS before and after fermentation. A total of 92 volatiles were tentatively identified and semi-quantified from sea buckthorn juice, majority of which were esters with fruity odor descriptors. Esters and terpenes were decreased in both inoculated and control juices during incubation. Microbial activity increased the levels of acetic acid (vinegar like), free fatty acids (cheese like), ketones (buttery like), and alcohols with fruity descriptors. Conversely, aldehydes associated with “green” aroma were decreased as a result of fermentation. Juices fermented with DSM 1055 had the highest acid and alcohol content, while fermentation with DSM 13273 resulted in the highest content of ketones. Compared to inoculation with other strains, fermentation with strains DSM 16365 and DSM 100813 resulted in rapid malolactic fermentation, less production of volatile acids, and lower loss of esters and terpenes important for natural sea buckthorn flavor.

Early Detection of Diabetic Ketoacidosis by Breathalyzer in a Sailor Reporting for Duty

Diabetic ketoacidosis (DKA) is a severe medical condition involving the uncontrolled hyperglycemia and ketoacidosis that results from impaired insulin utilization. The biochemical response to insulin resistance or deficiency is a ketotic state in which fatty acids are converted to ketone bodies for an alternative energy source. Patients in DKA acutely develop severe symptoms, typically over the course of 24–48 hours. Classic symptoms include nausea, vomiting, lethargy, altered mental status, and abdominal pain. As the time course of ketoacidosis is relatively rapid, it is rare to identify a developing case of DKA prior to symptom onset. In this atypical case, the author presents an asymptomatic 37-year-old active duty male without a history of diabetes, whose DKA detection was inspired by an elevated breathalyzer reading. The Sailor underwent routine breath alcohol analysis per command instruction upon reporting for duty. In the absence of recent alcohol intake, the elevated breathalyzer reading is associated with the Sailor’s metabolic ketoacidosis. Acetone, one of three primary ketone bodies generated in DKA is notable as the cause of the hallmark fruity odor breath of DKA patients. In this case, it is converted to isopropanol, an agent that is detectable by breathalyzers.

Intensification of enzyme catalysed synthesis of hexyl acetate using sonication

This present study focuses on ultrasound assisted process intensification of hexyl acetate synthesis via lipozyme RMIM catalysed transesterification of hexanol with triacetin by using hexane as a solvent. Hexyl acetate, an ester with fruity odor and significant green note is mostly used as flavor and fragrance material in various areas. Effect of various parameters on conversion of hexyl acetate such as molar ratio, enzyme loading, temperature, power, agitation speed and duty cycle was studied systematically. With the molar ratio of 1:1 of hexanol to triacetin with 4% enzyme loading (w/v), at agitation speed of 100 rpm with application of sonication at 60 W power and 70% duty cycle resulted in to 83% conversion at 50°C temperature in 4 h when compared with conventional method which requires 9 h for 68% conversion.

Aroma Profile of Galangal Composed of Cinnamic Acid Derivatives and Their Structure-Odor Relationships

Cinnamic acid derivatives are important odorants due to their characteristic scent. Some fragrance materials, such as cinnamon bark, matsutake mushrooms, and Kaempferia galanga L. rhizome (galangal), contain several cinnamic acid derivatives as important odor constituents. The main odor constituent of galangal is ( E)-ethyl 4-methoxycinnamate, but the odor of this compound is different from that of galangal. We investigated the aroma profile of galangal using our previously described method that considers the intermolecular interactions of the odorant compounds with their receptors. Odorant compounds in galangal were extracted by hexane extraction, steam distillation, and headspace sampling. The odor of the hexane extract was different from that of the steam distillate and similar to that of galangal; therefore, we searched for the key compounds contributing to the aroma profile of galangal by separating the constituents of the hexane extract. A fraction with a galangal-like odor was obtained by bulb-to-bulb distillation of the hexane extract. The main component of this fraction was not ( E)-ethyl 4-methoxycinnamate, but rather ethyl cinnamate. These results indicate that ethyl cinnamate is more important in the aroma profile of galangal than ( E)-ethyl 4-methoxycinnamate. GC-MS analysis revealed that this fraction contained aromatic compounds, cyclic terpenes, and linear chain compounds in addition to ethyl cinnamate. We synthesized cinnamic acid derivatives and examined the importance of the odor expression of these cinnamic acid derivatives. Cinnamic acid derivatives lacking a p-methoxy group had a strong fruity odor. Replacement of the hydrogen atom at the para position with a methoxy group altered and weakened the odor. We found that a p-methoxy group in cinnamic acid derivatives plays an important role in the aroma profile of galangal.

Biological characterization of fungal endophytes isolated from agarwood tree Aquilaria crassna Pierre ex Lecomte

In recent years, a considerable number of studies on the role of microbes in agarwood production have been carried out in plants of the species Aquilaria. Based on the fact that there is a relationship between the microorganisms residing inside the plant and the agarwood formation, we isolated and characterized endophytic fungi associated with A. crassna samples collected from Southern Vietnam. Morphological identification and DNA barcoding analysis of the fungal endophytic isolates indicated that they were classified at least into three groups of diverse genera: Geotrichum, Fusarium and Colletotrichum belonging to families Dipodascaceae, Nectriaceae and Glomerellaceae, respectively. Noteworthy, Geotrichum candium strain SHTr1 isolated from a dark colored woody sample of agarwood was able to produce a fruity odor and exhibited a slight antimicrobial activity against the test bacterium Staphylococcus aureus. Another fungal isolate, Fusarium verticillioides SHTr3’s, showed a moderate antimicrobial activity against a test Gram positive bacteria Bacillus subtillis and S. aureus with MIC values at 50 μg.mL-1. At 200 μg.mL-1, the ethyl acetate extracts of fungal isolates F. verticillioides SHTr3 and Colletotrichum truncatum SHTrHc7 were found to have comparable scavenging abilities on DPPH-free radicals with 53.87 and 71.82%, respectively. The present results contribute to a depiction of a diverse fungal endophytic community in Vietnamese agarwood plant A. crassna and provide important information for further understanding of the role of endophytic fungi in agarwood formation and therapeutic applications of host plants in general.

Volatile Composition of Six Horsetails: Prospects and Perspectives

Six horsetails were investigated for volatile organic compounds (VOC) by GC-MS using organic solvent extraction. Seventy-five VOC biosynthesized from the shikimic, lipidic and terpenic pathways including isoprenoid derivatives were detected from these putative natural resources. E. palustre var. americana contained mainly lipidic derivatives, i.e., 1-octen-3-ol (mushroom-like odor), ( E)-2-hexenoic acid (fruity odor) and ( E)-2-hexenal (green odor). Many isoprenoid flavour precursors, i.e., 3-oxo-α-ionol (spicy odor) and ( E, E)-pseudoionone (balsamic odor), as well as odorous benzenic derivatives, i.e, phenylethanal (hyacinth, lilac note) and 2-phenylethanol (rose odor) contributed to the odor of E. arvense. The volatile pattern of E. telmateia is dominated by high amounts of isoprenoids and benzenic derivatives. The complex volatile profiles of E. hyemale and E. ramosissimum are based on ferulic acid isomers, along with either ( E)-2-heptenal (green vegetable-like odor) or 4-vinylguaiacol (spicy clove smoky odor) for E. hyemale and E ramosissimum, respectively. The broad spectrum of E. scirpioides shows the lowest VOC content with high amount of isoprenoids (46.9%), mainly ionone derivatives. Equisetum resources are of great interest as bioactive litter and new potential functional feed ingredients.