Ethyl Heptanoate Research Articles

Characterisation of key volatile compounds in fermented sour meat after fungi growth inhibition

The objective of this study was to explore the effect of fungi on volatiles in sour meat. Here, we investigated the microbial community composition in meat after 80 days of fermentation and concluded that Lactobacillus, Debaryomyces, Pichia, and Wickerhamomyces were the dominant microorganisms in the sour meat. The inhibition of fungi in the sour meat by natamycin reduced the number of volatiles from 74 to 60. Esters, alcohols, aldehydes, ketones, and hydrocarbons were significantly lower in antibiotic-treated group (Group B) than in control group (Group A). The relative odor activity value (ROAV) showed that decanal, 1-octen-3-ol, ethyl heptanoate, and nonanal contributed to the flavor of the sour meat in both groups, and their relative content and contribution were significantly higher in Group A than in Group B, indicating that natamycin attenuated the contribution of these substances to the flavor of the sour meat. Finally, multivariate data analysis was performed to obtain 21 volatiles (variables important in the projection [VIP] > 1) that caused differences in the meat flavor between the two groups. The study provides a theoretical basis for future research on mechanisms of flavor formation in fermented products from a microbial perspective.

Effects of secondary fermentation of four in-bottle Saccharomyces cerevisiae strains on sparkling cider sensory quality

In this study, the first fermentation of Fuji apple juice was carried out using Saccharomyces cerevisiae WLS21 and continued a second fermentation using S. cerevisiae HYJ1, HYJ2, PE2, and Y41 in sealed bottles after adjusting the sugar level. The physicochemical indexes, aromas, and sensory characteristics of four sparkling ciders were analyzed. The results revealed that HYJ2 produced the highest amount of ethanol and Y41 had the highest pressure in the bottle at the end of fermentation. Y41 produced the highest citric and succinic acids and HYJ1 produced higher fumaric acid and total volatiles. HYJ1 cider had an obvious herbaceous odor, and Y41 cider had a fruity character. Sixty-seven volatiles were detected from four sparkling ciders (55 fermentative and 12 non-fermentative aromas). Esters (EEFAs and HAAs) were the main volatile aroma family produced during secondary fermentation, and terpenes contributed the most to fruity odor. Based on univariate (ANOVA) and multivariate analysis of variance (PLS-DA) screening of four cider significant variables, 13 volatiles with variable predictive importance (VIP)≥1 were identified. PLSR analysis revealed that 2-methylbutyl acetate, ethyl heptanoate, 2-methyl-1-butanol, nonanal, 2-nonanone, β-damascenone, and linalool were potential volatile markers for OAV>1.

Enzymatic Characterization of Purified β-Glucosidase from Non-Saccharomyces Yeasts and Application on Chardonnay Aging

The application of β-glucosidase from non-Saccharomyces yeasts to improve wine aroma has been widely explored. However, few enzymes are active under the severe conditions of wine aging (high ethanol concentration, low temperature, and low pH). Therefore, the application of β-glucosidase in wine aging needs further research. In this study, the β-glucosidases Mg-βgl and Hu-βgl extracted from Meyerozyma guilliermondii NM218 and Hanseniaspora uvarum BF345 were purified and used in young Chardonnay wines aged for 50 days. The enzyme activity of the two enzymes was measured. The effects of the two enzymes and a commercial β-glucosidase (An-βgl) on the volatile composition and sensory quality of the wine were also determined. The results showed that Mg-βgl and Hu-βgl had high specific activity of 1.95 U/mg and 2.11 U/mg, respectively, maintaining the activity of 70–80% at 20 °C, pH of 3.0–4.0, and 15% ethanol, corresponding to wine aging conditions. Analysis of volatiles with GC-MS showed a 65–70% increase in total terpenoids and new detection of C13-norisoprenoids when the wines were treated with the three β-glucosidases. In addition, wines treated with Mg-βgl and Hu-βgl had more hexanol, phenylethanol, ethyl octanoate, ethyl heptanoate, and ethyl caprate than wines treated without and with An-βgl. In sensory analysis, the judges showed a greater preference for Hu-βgl-treated wines, to which they attributed pleasant sweet, floral, honey, pomelo, and banana aromas. The results of this study not only offer a way to improve flavor complexity in wine but also provide a reference for the use of other edible sources of β-glucosidase in wine aging.

Effect of sequential fermentation with four non-Saccharomyces and Saccharomyces cerevisiae on nutritional characteristics and flavor profiles of kiwi wines

To improve the functional properties and flavor complexity of kiwi wine using different non-Saccharomyces cerevisiae, Wickeramomyces anomala (Wa), Zygosaccharomyces rouxii (Zr), ZygoSaccharomyces bailii (Zb) and Schizosaccharomyces pombe (Sp) were inoculated sequentially with S. cerevisiae (Sc). The physicochemical and sensorial profiles of the wines were evaluated. The evolution of cells showed that non-Saccharomyces exhibited varying degrees of fermentation vigor and only acted during the first vinification stage. Ethanol content, pH, ΔE and organic acids in the wines varied according to the yeasts used. Compared with the pure Sc fermentation, the sequential fermentations of Wa-Sc and Sp-Sc significantly increased the production of polyphenols. Fifteen volatile compounds with relative odor activity values (rOAV) ≥ 1.0 were identified. Furthermore, principal component analysis (PCA) revealed that Zr-Sc and Sp-Sc were correlated with higher levels of ethyl esters (ethyl hexanoate, ethyl heptanoate, ethyl decanoate), isoamyl acetate and 2-phenyl-1-ethanol in the wines, improving the flower and sweet notes. Zr-Sc also enhanced the tropical fruity aroma. Sequential inoculation with Zb was related to the contents of acetate esters, ethyl butyrate, methyl butyrate and cineole, triggering the tropical fruity odor. In addition, the partial least-squares regression (PLSR) revealed that acetate esters contributed greatly to the tropical fruity note.

Characterization of Flavor Active Volatile and Non-Volatile Compounds in the Chinese Dry-Cured Red Drum (Sciaenops ocellatus)

ABSTRACT The volatile compounds and sensory characteristics of dry-cured red drum (Sciaenops ocellatus, DCRD), a traditional and popular dried Chinese dry-cured fish product, were evaluated by sensory-directed flavor analysis. The results showed umaminess, saltiness and kokumi were the main taste properties of DCRD. The high content of umami and sweet amino acids and the proportion of small molecular taste-active peptides were the main contributors for the taste. Aldehydes were the main aroma-acitve compounds, in addition to alcohols, ketones, and easters, and a longer dry-curing time was beneficial to the formation of flavor compounds. The key aroma compounds, whose odor activity values is greater than 1 (in parentheses), contained 3-methyl-butanal, heptanal, hexanal, nonanal, octanal, 3-methyl-butanol, 1-octen-3-ol, 1-heptanol, 1-hexanol, 1-pentanol, 3-octanone , 6-methyl-5-hepten-2-one, ethyl heptanoate, cis-4-decenal, and ethyl caproate. This is the first time to evaluate the flavor of DCRD, which can provide a theoretical basis for regulating the production of flavor substances.

Analyzing the minor volatilome of\xa0Torulaspora delbrueckii\xa0in an alcoholic fermentation

Torulaspora delbrueckii is an emerging yeast species in the beverage and food industry that is suitable for alcoholic fermentation and to improve the organoleptic quality of wine, beer, mead, and other beverages. Modern consumer preference toward new flavors and products drives the application of T. delbrueckii to ferment less traditional fruits and vegetables. Thus, it has become increasingly relevant to define those metabolites produced in minute quantities by T. delbrueckii, because they may have an impact when producing these new alcoholic beverages. In this study, we have identified metabolites of T. delbrueckii and have compared them with those of Saccharomyces cerevisiae in a controlled setting with a synthetic, high glucose medium using gas chromatography coupled to flame ionization detector (GC–FID) and stir bar sorptive extraction (SBSE) with GC coupled to mass spectrometry (MS). Results showed that T. delbrueckii produced metabolites with higher changes in odor activity complexes than S. cerevisiae: ethyl propanoate, 1,1-diethoxyethane, ethyl isobutyrate, ethyl butyrate, isoamyl acetate, ethyl heptanoate, nonanal, and decanal. We also report seven metabolites detected for the first time in T. delbrueckii. This datum serves to expand the knowledge of T. delbrueckii performance and shows that application of this yeast species is more suitable to a wide array of beverage producers.

RIFM fragrance ingredient safety assessment, ethyl heptanoate, CAS Registry Number 106-30-9

• Ethyl heptanoate; a safety assessment based on RIFM's criteria. • A safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC.

Discrimination of Fruit Beer Based on Fingerprints by Static Headspace-Gas Chromatography-Ion Mobility Spectrometry

Fruit beer, a recognized special beer, is produced with fruit addition during fermentation, maturation, or the refermentation process. Volatile organic compounds of seven fruit beers were investigated using a gas chromatography-ion mobility spectrometry (GC-IMS) technique. A total of 38 compounds were identified, and volatiles in the seven beers differed greatly. The concentration of nonanal, methyl octanoate, ethyl 2-methylbutanoate, propyl hexanoate, and methyl 2-methylbutanoate was high, and the first two compounds were the characteristic volatiles in the pineapple beer. Apple beer had a higher concentration of butyl acetate, isobutyl acetate, methyl heptanoate, and butanal. Butyl acetate was the specific apple beer volatile. Peach beer showed a higher concentration of 3-methylbutanal, methional, phenylacetaldehyde, α-pinene as well as 2,3-diethyl 5-methylpyrazine, and the last was detected only in the peach beer. Ethyl heptanoate and maltol were abundant in the cranberry beer, whereas linalool, furaneol, and benzaldehyde were rich in the cherry beer, and benzaldehyde was the characteristic cherry beer volatile. Raspberry beer had abundant 3-pentanone, ethyl propanoate, and E-2-hexenol, whereas blueberry beer had abundant ethyl 2-hydroxypropanoate. Discrimination and classification of the seven fruit beers were effectively performed by the principal component analysis (PCA) method with good dispersion, and all groups had corresponding attribution areas in the PCA map. The cumulative contribution rate of the first two PCs was 60%. This study offers an approach for the analysis of the volatiles of fruit beers and could help in the verification of adulteration in fruit beers.

Determination and comparison of flavor (retronasal) threshold values of 19 flavor compounds in Baijiu.

Nineteen compounds, including ten esters, six acids, and three alcohols, were characterized and considered as significant tastants and aromas in Baijiu (Chinese Liquor). The flavor (retronasal) threshold values (FTVs) of these 19 compounds were determined by the 10 samples test method in hydroalcoholic solutions (46%v/v in ethanol). The FTVs of the compounds were calculated based on the best estimate threshold method. All the FTVs determined by the professional Chinese Baijiu tasters were lower than those by the nonprofessional tasters. For instance, the detection (2.31mg/kg)andrecognition(11.74mg/kg)valuesofethyl hexanoate determined by the nonprofessional group were higher than the respectively corresponding values 0.44 and 3.80mg/kg determined by the professional group. All of the odor activity values (OAVs) of ethyl valerate (OAV: 1176.00 to 2321.17), ethyl octanoate (OAV: 6841.20 to 7851.60), and 1-butanol (OAV: 26.78 to 39.72) in Gujinggong Baijiu were more than 10-fold larger than their dose-over-threshold values (DoTs), for which the DoTs of ethyl valerate, ethyl octanoate, and 1-butanol were 92.84 to 183.25, 180.03 to 206.62, 1.18 to 1.75, respectively. On the contrary, the OAVs of ethyl heptanoate (OAV: 3.60 to 5.70) and isoamyl alcohol (OAV: 1.18 to 1.57) were lower than their corresponding DoTs at 152.62 to 241.63 and 12.26 to 16.41. The results demonstrated that it is necessary to consider and compare their DoTs and OAVs simultaneously on evaluating the contribution of flavor compounds in Baijiu. PRACTICAL APPLICATION: Sensory evaluation of threshold values of various flavor compounds could be significantly affected by their existing matrix. Most of the published results of the flavor threshold value of compounds were determined from the matrix such as beer, whiskey, red wine, rather than Chinese Baijiu. The results of this work not only could provide valuable information for flavor studies of Chinese Baijiu but also give useful information for the Baijiu industry to quality control.

Development of volatiles and odor-active compounds in Chinese dry sausage at different stages of process and storage

The effect of process and storage on the volatiles and odorant profile of Chinese dry sausage was evaluated, as well as its physicochemical parameters. Microbial esterification and wine (27.54%–43.35%), and lipid oxidation (11.30%–34.92%) played a key role in flavor profile during process and storage. A significant increase of each volatile was detected during process except gradual decrease of volatiles from spices, while a gradual decrease of each volatile was detected during storage except significant increase of volatiles from lipid oxidation and esterification. 15 and 6 odor-active compounds were respectively correlated (P<0.05) with the process and storage time. Level of heptanal, 1-octen-3-ol, the ethyl of 2-methylbutanoic, 3-methylbutanoic, butanoic, benzoic, hexanoic, heptanoic, octanoic and decanoic acid were best discriminators of process stage, while (E)-2-nonenal, ethyl hexanoate, ethyl heptanoate, and methyl decanoate, were marker compounds of storage time. An objective method was established to evaluate the stages of process and storage for samples.

Functional Analysis of Odorant-Binding Proteins 12 and 17 from Wheat Blossom Midge Sitodiplosis mosellana Géhin (Diptera: Cecidomyiidae)

Simple SummarySitodiplosis mosellana is one of the most destructive pests of wheat. Adults rely highly on wheat spike volatiles to search and locate oviposition sites. Insect odorant-binding proteins (OBPs) are important in binding and transporting host plant volatiles to the olfactory receptors. Therefore, OBP-based behavioral interference is believed to be a novel and effective pest management strategy. The objectives of this study were to clone two S. mosellana female antenna-enriched OBP genes (SmosOBP12 and SmosOBP17), determine the functions of the encoded SmosOBP proteins in binding wheat volatiles, and investigate behavioral responses of female S. mosellana to odorant molecules. Results indicated that SmosOBP12 had a broader ligand-binding spectrum than SmosOBP17 to wheat volatiles. Female S. mosellana showed intensive response to 3-hexanol, 1-octen-3-ol, D-panthenol, 3-carene, (Z)-3-hexenylacetate, hexyl acetate, methyl salicylate, heptyl acetate, ethyl heptanoate, α-farnesene, and ocimene. Notably, all these compounds except α-farnesene exhibited strong affinity to SmosOBP12. In conclusion, SmosOBP12 may play more crucial roles than SmosOBP17 in perception and transportation of biologically active host volatiles. This information has enhanced our molecular understanding of the S. mosellana olfaction, which could also serve as an important reference for developing attractants or repellents to control this pest.The wheat blossom midge Sitodiplosis mosellana, one of the most disastrous wheat pests, depends highly on olfactory cues to track suitable plants. To better understand the olfactory recognition mechanisms involved in host selection, in the present study we cloned two S. mosellana adult antenna-specific odorant binding protein (OBP) genes, SmosOBP12 and SmosOBP17, and evaluated bacterially expressed recombinant proteins for their selectivity and sensitivity for host wheat volatiles using the fluorescence-based ligand binding assay. The results showed that both SmosOBPs effectively bound alcohol, ester, ketone, and terpenoid compounds. Particularly, SmosOBP12 had significantly higher affinities (Ki < 10.5 μM) than SmosOBP17 (Ki2 > 0.1 μM) to 3-hexanol, 1-octen-3-ol, D-panthenol, 3-carene, (Z)-3-hexenylacetate, hexyl acetate, methyl salicylate, heptyl acetate, and ethyl heptanoate. Consistently, S. mosellana females were attracted to all these chemicals in a behavioral assay using Y-tube olfactometer. SmosOBP12 also bound aldehyde, but neither bound alkanes. Notably, SmosOBP12 exhibited strong affinity to ocimene (Ki = 8.2 μM) that repelled S. mosellana. SmosOBP17, however, was insensitive to this compound. Taken together, our results indicate that SmosOBP12 may play a greater role than SmosOBP17 in perceiving these biologically active plant volatiles.

Fate of Hop and Fermentation Odorants in Commercial Belgian Dry-Hopped Beers over 2 Years of Bottle Storage: Key-Role of Oxidation and Hop Esterases

The aim of the present work was to compare levels of short chain fatty acids, esters, terpenoids and polyfunctional thiols in (mostly bottle-refermented) commercial Belgian dry-hopped beers before and after 2 years of storage at 20 °C (the usual best-before date in Belgium). Among the hop-derived volatiles, the terpenoids linalool and geraniol, the polyfunctional thiols 3SHol, 3SHA and 3S4MPol, and the esters ethyl isobutyrate, ethyl isovalerate and ethyl heptanoate (up to 499, 53, 0.2, 2, 3, 84, 63, and 19 µg/L, respectively) were found above their sensory thresholds in most fresh dry-hopped beers. The fermentation-derived esters reached concentrations similar to those previously reported for non-dry-hopped beers, with ethyl hexanoate and isoamyl acetate (up to 0.4 and 3.9 mg/L, respectively) often above their sensory thresholds. Except ethyl isovalerate (more than 85% still present), most hop odorants and fermentation esters showed degradation over the 2-year storage period: only 45%–70% of linalool, geraniol, and ethyl hexanoate and even less than 40% for polyfunctional thiols, ethyl isobutyrate, and ethyl heptanoate initial concentrations were detected after storage. How the dry-hopping process affects this degradation was further investigated in model media. Fermentation esters proved to be more strongly impacted in dry-hopped than in non-dry-hopped beers because of hop esterase activity. In addition to being aware of the need to avoid hop esterases, craft brewers are here advised to use bottle refermentation for its ability to regenerate some flavors and consume packaged oxygen. No deleterious effect of yeast, such as short chain fatty acid excretion, was evidenced.

Experimental investigation and molecular dynamic simulation of thermophysical properties of biodiesel surrogates: The binary mixtures of n-hexadecane with ethyl hexanoate and ethyl heptanoate

The thermophysical properties of biodiesel surrogates are of great importance for the development of the new and clean fuel substitutes or additives. Experimental investigation and molecular dynamic simulation of the related thermophysical properties such as the liquid density, kinematic viscosity and surface tension over a sufficient wide temperature range will facilitate the corresponding researches of selecting the proper fuel surrogates and designing the spray system of the internal combustion engine. Therefore, the present study investigated liquid surface tension and kinematic viscosity of the proposed physical biodiesel surrogates of n-hexadecane with ethyl hexanoate and ethyl heptanoate by the surface light scattering method at three mole fractions (0.25, 0.50 and 0.75) over the temperature range from (353.15 to 433.15) K. Additionally, the liquid density was also determined by a U-tube densimeter in the temperature range between (293.15 and 433.15) K. Meanwhile, three force fields including OPLS-AA, GROMOS and AMBER were selected and validated with n-hexadecane and ethyl heptanoate in a wide temperature range and the GROMOS force field was demonstrated to be the best one for the description of the three thermophysical properties of the two fluids. A further molecular dynamic simulation with GROMOS force field was applied to the proposed binary surrogates of n-hexadecane with ethyl hexanoate and ethyl heptanoate, and the results for the three properties agreed well with their experimental values over the entire temperature range.

Effects of the Mixed Fermentation of Torulaspora delbrueckii and Saccharomyces cerevisiae on the Non-Volatile and Volatile Compounds and the Antioxidant Activity in Golden Dried Longan Wine

The aim of this study was to investigate the effects of Torulaspora delbrueckii and Saccharomyces cerevisiae, as pure fermenters and mixed fermenters (simultaneous and sequential culture), on the production of nonvolatiles and volatiles, and on the antioxidant activity in Golden Dried Longan juice and Golden Dried Longan wines. Alanine, arginine, glutamic acid, leucine, proline, and gamma-aminobutyric acid (GABA) were the most prominent amino acids that were found in these wines. The Golden Dried Longan Wine fermented with monocultures of S. cerevisiae and T. delbrueckii produced a total volatile aroma content of 393.21 mg/l and 383.20 mg/l, respectively. Simultaneous culture of the two organisms produced the highest total volatile aroma content, that affected most volatile compounds including isobutanol, ethyl acetate, ethyl decanoate, ethyl heptanoate, ethyl hexanoate, ethyl pentanoate, isoamyl acetate, and isobutyl acetate. Of the four treatments, the sequential culture possessed the highest total phenolic content (5.80 mg gallic acid equivalents (GAE)/ml). In addition, the total phenolic content significantly correlated with the antioxidant activity of the Golden Dried Juice and Golden Dried Longan Wine. These results suggest that co-cultures of the two organisms used in the production of the Golden Dried Longan Wine may improve the intensity and complexity of its aroma.

A group contribution method to predict the thermal conductivity of fatty acid methyl esters and fatty acid ethyl esters components of biodiesel

Recently, biodiesel is considered as a potential alternative fuel in internal combustion engines, because of their beneficial effects on pollution emission and engine performance. In this work, a group contribution method (GCM) to predict the thermal conductivity of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) components of biodiesel as a function of the temperature (290 K to 350 K) is presented. Nearly 120 experimental thermal conductivity data points at different temperatures compiled for nine esters (methyl hexanoate, methyl octanoate, methyl pelargonate, methyl decanoate, ethyl valerate, ethyl valerate, ethyl heptanoate, ethyl octanoate, ethyl decanoate) were used for presenting and optimizing the formula. Additionaly, 51 experimental data points compiled for four esters (methyl myristate, methyl laurate, ethyl myristate and ethyl laurate) were employed to validate the model parameters, and the maximum and average absolute deviation are 0.61% and 1.97%. It is evident that the new proposed GCM models to predict the thermal conductivity of FAMEs and FAEEs are with high accuracy.

Determination of the aroma changes of Zhengrong vinegar during different processing steps by SPME–GC–MS and GC-O

Zhengrong vinegar is one of the renowned popular condiments in China, which has been consumed around Hebei province for about 136 years. Its different processing steps are considered as important and critical steps that are responsible for the generation of representative flavors besides the acetic acid. An HS-SPME coupled with GC–MS method was used to evaluate the changes of the volatiles of the vinegar that were generated during the different processing steps including before adding salt (BAS), after adding salt (AAS), after filtration (AF) and final product (FP). In addition, aroma-active volatiles of the final vinegar product were characterized by GC-O coupled with detection frequency technique (modified frequency, MF%) that is a combination of aroma intensity and aroma frequency values that can be used to improve the description of a reliable data from GC-O. Among the 42 detected volatiles, 38 of them were positively identified by their corresponding authentic compounds. Besides, 24 volatiles were recognized as aroma-active volatiles. On the other hand, the content of individual volatile groups was decreased along with the continuation of the fermentation process from the BAS step to FP step, except the aldehydes group that displayed a slight increase. Of which, 2-pentylfuran and ethyl heptanoate disappeared in the AF and FP samples. The main contributors to the Zhengrong aroma profile that had MF (%) > 80 included isovaleric acid, 2-acetoxy-3-butanone, hexanoic acid, ethyl hexanoate, 3-(methylthio)propyl acetate, decanal and 2-phenyl-2-butenal, while the volatile compounds that had a middle MF in a range between 70 and 80 were 2-methylbutanoic acid, tetramethylpyrazine, nonanal, 1,2-dimethoxybenzene, 4-ethylphenol, ethyl benzoate, ethyl benzeneacetate, 2-phenylethyl acetate and 4-ethylguaiacol.

The general odorant receptor GmolOR9 from Grapholita molesta (Lepidoptera: Tortricidae) is mainly tuned to eight host-plant volatiles.

Grapholita molesta is one of the most destructive fruit pests distributed worldwide. Odorant receptors (ORs) located on the dendritic membrane of chemosensory neurons are deemed to be key molecules for sensing exogenous chemical signals. In this study, GmolOR9, a general OR from G. molesta, was functionally characterized. Quantitative real-time polymerase chain reaction revealed that GmolOR9 was more highly expressed in adults than in other stages, including eggs, larvae, and pupae. GmolOR9 expression was highly significantly more in the antennae of females than in those of males, and the highest level occurred in the antennae of 3-day-old female adults. GmolOR9 was broadly tuned to eight of 47 odorant components tested, including (Z)-3-hexenyl acetate, butyl propionate, ethyl hexanoate, ethyl heptanoate, 1-hexanol, (Z)-3-hexenol, 2-ethyl-1-hexanol, and linalool, by in vitro heterologous expression. Furthermore, electroantennogram responses indicated that the effects of dsOR9-injected females to (Z)-3-hexenyl acetate dramatically decreased. These results suggested that GmolOR9 might be involved in detecting host-plant volatiles. Moreover, (Z)-3-hexenyl acetate might serve as a potential attractant for the biological control of G. molesta.

Alcohol acyltransferase gene and ester precursors differentiate composition of volatile esters in three interspecific hybrids of Vitis labrusca × V. Vinifera during berry development period

This study investigated the accumulation of esters in three hybrid grape cultivars during berry development under two vintages to elucidate the differentiation on their esters biosynthesis. Results showed ‘Moldova’ showed lower esters content than ‘Campbell Early’ and ‘Catawba’ resulting from its limited AAT gene expression and 20 different encoded amino acids. The volatile esters compositions of ‘Campbell Early’ and ‘Catawba’ in both vintages were different. Correlation analysis revealed that concentrations of hexyl acetate, 2-phenethyl acetate, ethyl (E,E)-2,4-hexadienoate and ethyl phenylacetate were related to their corresponding alcohols level, whereas threonine and alanine affected ethyl heptanoate formation. Transcriptome analysis indicated that 1847, 1781 and 1870 DEGs, at E-L 35, 36 and 38, respectively, were characterized between ‘Campbell Early’ and ‘Catawba’. The expression level of genes related to the volatile ester precursors biosynthesis, including PRX-VIT_211s0016g05320, PAO-VIT_217s0000g09100, ACOX-VIT_212s0028g02660, ACOX-VIT_216s0022g01120, echA-VIT_205s0077g00860 and ACOX-VIT_200s0662g00010, exhibited a positive correlation to the concentrations of their corresponding volatile esters.

Favoring Alkane Primary Carbon–Hydrogen Bond Functionalization in Supercritical Carbon Dioxide as Reaction Medium

The selectivity of a catalytic alkane functionalization process can be modified just changing the reaction medium from neat alkane to supercritical carbon dioxide (scCO2). A silica supported copper complex bearing an N-heterocyclic carbene ligand promotes the functionalization of carbon–hydrogen bonds of alkanes by transferring the CHCO2Et group from N2═CHCO2Et (ethyl diazoacetate, EDA). In neat hexane, only 3% of the primary C–H bonds (ethyl heptanoate being the product) are functionalized in that manner, whereas the same reaction carried out in scCO2 provides a 30% yield in this linear ester. Such an effect seems to be induced by an electronic density flux from the NHC ligand to the surrounding carbon dioxide molecules.

An in-situ forming implant formulation of naltrexone with minimum initial burst release using mixture of PLGA copolymers and ethyl heptanoate as an additive: In-vitro, ex-vivo, and in-vivo release evaluation

An in-situ forming implant formulation of naltrexone (NTX) was achieved based on a minimum initial burst release of NTX in the in-vitro release medium using a Box-Behnken design. Variables such as percent of copolymer by weight, copolymer composition (PLGA 756s: PLGA 504H), and percent ethyl heptanoate by weight as an additive in formulation were investigated. The in-vitro, ex-vivo, and in-vivo release of the optimized formulation was investigated. The rabbit-blood concentrations of the optimized formulation and Vivitrol® were compared to ensure their equivalency. The initial burst release of the optimized formulation in the in-vitro release over the first 24 h, 6.18 ± 0.91%, was significantly (p < 0.05) lower than that of the formulation containing 100% of PLGA 504H (17.45 ± 1.07%) and 100% of PLGA 756s (11.82 ± 1.03%). The Cmax of NTX (21.06 ± 2.9 ng/mL) from the optimized formulation was close to that of Vivitrol® (21.11 ± 2.89 ng/mL). Also, the absolute bioavailability (F) and the range of serum concentration of NTX (C) of the ISFI formulation (F = 18.29, C = 6.18–22.84) were similar to Vivitrol® (F = 16.83, C = 6.83–23.09). These results indicate that the optimized formulation can reach an effective therapeutic concentration for treating opioid and alcohol dependence.