Ethyl Tetradecanoate Research Articles

Molecular Sensomics Combined with Random Forest Model Can Reveal the Evolution of Flavor Type of Baijiu Based on Differential Markers.

Baijiu is popular with a long history and balanced flavor. Flavor type is the most widely used classification mode for Baijiu. However, the evolutionary relationships of Baijiu flavor types and the differential markers between flavor types are still unclear, significantly impacting the development of the Baijiu industry. In this study, a total of 319 trace components were identified using gas chromatography-olfactometry-mass spectrometry and gas chromatography-mass spectrometry. Among them, 91 trace components with high odor active values or taste active values were recognized as flavor components. Then random forests were conducted to screen differential markers between the derived and basic flavor types, while a principal component analysis assessed their effectiveness in distinguishing the flavor types of Baijiu. Finally, 19 differential markers (including 3-methylbutyric acid, pentanoic acid, 2-butanol, 2,3-butanediol, ethyl pro-panoate, isobutyl acetate, ethyl butanoate, ethyl hexanoate, ethyl heptanoate, ethyl lactate, ethyl 2-hydroxy butanoate, isopentyl hexanoate, ethyl nonanoate, isopropyl myristate, ethyl tetradecanoate, ethyl benzoate, 2,4-di-t-butylphenol, 2-methylbutanal and 3-octanone) were screened and proven to effectively reveal the evolution of Baijiu flavor types; these were further verified as key differential markers using addition tests and a correlation analysis.

Unveiling the dynamic microbial succession and metabolic characteristics during traditional fermentation of hainan shanlan rice wine

The objective of this study was to reveal the microbial succession and metabolic characteristics during traditional fermentation of Hainan Shanlan rice wine (HSRW). Correlations between core microorganisms and key metabolites were explored. Four bacterial genera (Pediococcus, Levilactobacillus, Pantoea and Limosilactobacillus) and 3 fungal genera (Saccharomyces, Rhizopus, and Saccharomycopsis) were the dominant in HSRW. Alcohols, esters and organic acids were the main metabolites in the HSRW. 2-Ethyl-1-hexanol, dimethylsilanediol, pentaethylene glycol, ethyl hexadecanoate, ethyl tetradecanoate and (E)-9-octadecenoic acid ethyl ester were identified as the characteristic volatile flavor compounds. Malic acid and lactic acid were the primary organic acids. Spearman correlation analysis revealed that Levilactobacillus and Pediococcus were the core functional microorganisms and exhibited significant associations with key metabolites. This study provides a scientific and practical foundation for elucidating the potential value of core functional microorganisms and for the development of Directed Vat Set in the industrial prodution of HSRW.

Potential Correlation between Microbial Diversity and Volatile Flavor Substances in a Novel Chinese-Style Sausage during Storage.

A novel Chinese-style sausage with Chinese traditional fermented condiments used as additional ingredients is produced in this study. The aim of this study was to investigate the microbial community's structure, the volatile flavor substances and their potential correlation in the novel Chinese sausage. High-throughput sequencing (HTS) and solid-phase microextraction-gas chromatography-mass spectrometry (GC-MS) were, respectively, used to analyze the microbial diversity and volatile flavor substances of the novel Chinese-style sausage during storage. The results showed that Firmicutes, Proteobacteria and Actinobacteria were the predominant bacterial genera, and Hyphopichia and Candida were the predominant fungal genera. A total of 88 volatile flavor substances were identified through GC-MS, among which 18 differential flavor compounds were screened (VIP > 1), which could be used as potential biomarkers to distinguish the novel sausages stored for different periods. Lactobacillus exhibited a significant negative correlation with 2,3-epoxy-4,4-dimethylpentane and acetoin and a significant positive correlation with 2-phenyl-2-butenal. Hyphopichia significantly positively correlated with ester. Leuconostoc significantly positively correlated with ethyl caprate, ethyl palmate, ethyl tetradecanoate and ethyl oleate while it negatively correlated with hexanal. This study provides a theoretical basis for revealing the flavor formation mechanisms and the screening of functional strains for improving the flavor quality of the novel Chinese-style sausage.

ISOLATION AND STRUCTURE ELUCIDATION OF SECONDARY METABOLITE COMPOUNDS FROM Curcuma aeruginosa

Black turmeric (Curcuma aeruginosa) is Indonesian medicinal plant belonging to the Zingeberaceae family, mostly found on Java. This study aimed to determine the new molecular structures of the compounds isolated from black turmeric originating from Indonesia. Isolation of the secondary metabolite compounds was initiated by solid-liquid extraction using the maceration method with ethanol solvent, followed by liquid-liquid extraction using the partition method with n-hexane and dichloromethane as solvents. Separation and purification were carried out using vacuum liquid chromatography (VLC) and gravity column chromatography (GCC). The isolated compounds were characterized using spectroscopic methods, including UV-Vis, IR, and NMR spectroscopy. The isolation resulted in three sesquiterpenoid compounds, (E)-7-isopropyl-4,10-dimethylcyclodec-10-ene-5,8-dione (curdione), (1R,10R)-Epoxy-(-)-1,10-dihydrocurdione, and zedoalactone B, together with two common terpenes, ethyl tetradecanoate and 1-hexadecene.

Viscosity of methyl and ethyl esters: Experiments and modeling

Viscosity and density have been measured for a number of ethyl esters (ethyl ethanoate, ethyl butanoate, ethyl dodecanoate and ethyl tetradecanoate) at four temperatures between 288.15 and 323.15 K at 101.3 kPa. The measurements are also reported for four of their binary mixtures, over the whole range of compositions, as well as for a single, equimolar ternary and one equimolar, quaternary mixture. The viscosity was measured with a Stabinger viscometer, whilst the density was measured by means of a vibrating U-tube densimeter. The combined expanded uncertainty (k ≈ 2) for the density is 1.7 kg⋅m−3, and relative one for the viscosity is 0.014.The measured viscosity of pure ethyl esters, together with the published literature values, were correlated by means of the extended hard-sphere (EHS) model that has its basis in kinetic theory and the molecular description of the fluid. A separate correlation was developed for methyl esters, based only on the published viscosity values. The correlations, for both families of esters, are valid in the temperature range 283 to 373 K and pressures up to 200 MPa, for all the esters up to and including methyl tetracosanotae and ethyl eicosanoate. The EHS model was used to predict the viscosity of mixture of esters. The measured viscosity data were represented with the average absolute deviation of 2.5% and a maximum deviation of 6.4%.

Evaluation of the essential oils and teas produced from the Bahia and Pará cocoa almond husks

Brazil is one of the largest producers of cocoa in the world and, consequently, of the husks of cocoa almonds. This material is an industrial food waste from which it is possible to produce an aromatic tea. The aim of this work was to evaluate the chemical composition of the essential oils of the husks of cocoa almond samples from Bahia and Pará states. Total phenolic (Folin-Ciocalteu) and flavonoid (AlCl3) contents, antioxidant capacity (DPPH assay) and toxicity (Artemia salina bioassay) of its infusions were also evaluated. Essential oils were isolated by hydrodistillation and analyzed by GC techniques. Only tetradecanoic acid, n-hexadecanoic acid, ethyl tetradecanoate and methyl oleate were detected in all samples. Pyrazines are probably produced during the roasting of the seeds. The infusions presented moderate antioxidant potentials that were highly correlated with their total phenolic and flavonoid contents, and were classified as non-toxic.

Comparative Analysis with GC–MS of Fatty Acids and Volatile Compounds of Taraxacum kok-saghyz Rodin and Taraxacum officinale as Edible Resource Plants

Taraxacum kok-saghyz Rodin (TKS) is a potential edible resource plant that is rich in inulin, lipid, protein and other active ingredients. In this study, HS-SPME/GC–MS was used to analyze volatile compounds (VCs) and profile the fatty acids in TKS roots and leaves, and the results were compared with those from Taraxacum officinale (TO). A total of 105 and 107 VCs were detected in the leaves and roots of seven dandelion samples (three TKS and four TO), amongst which the main VCs were ethyl tetradecanoate, ethyl linolenate, ethyl linoleate, dihydroactinidiolide, ethyl palmitate, β-ionone, 3,5-octadien-2-one, β-ionone 5,6-epoxide, geranyl acetone, benzaldehyde, safranal, 2-Pentylfuran, farnesene and β-elemene. Linoleic acid and linolenic acid were the dominant fatty acids in seven dandelion samples, and the ratio of unsaturated to saturated fatty acids was larger than 4. Principal component analysis showed that the differences in VCs and fatty acid levels between different dandelion samples mainly came from different places of origin, while the differences between different varieties in the same place of origin was minor; i.e., the VCs and fatty acid levels of TKS and TO collected from the same place were basically similar.

Isolation and Cytotoxicity Evaluation of Long Chain Bioactive Compounds from Commiphora swynnertonii (Burtt)

Commiphora swynnertonii (Burtt) is a medicinal plant with diverse traditional uses in Tanzania. However, there is limited information on isolation and cytotoxicity properties of bioactive compounds responsible for its pharmacological activities. Hence, this study attempted to isolate and assess toxicity properties of bioactive compounds from its leaves, stem barks and whole root. Isolation of bioactive compounds was done by column chromatography method. There structures were deduced with the aid of NMR and GC-MS data and comparison with spectral data available in the literatures. Cytotoxicity evaluation was done by brine shrimp lethality test (BSLT) method. Chromatographic separation led to isolation of Hexacosane (1), Ethyl octadecanoate (2) and Octacosanol (3) from the leaves; Ethyl pentadecanoate (4) and Hexacosanoic acid (5) from the stem barks and Ethyl tetradecanoate (6), Methyl pentadecanoate (7) and Ethyl hexadecanoate (8) from the whole root. BSLT evaluation revealed that all compounds were non-toxic to brine shrimp larvae (LC50 >100 µg/ml). This study reports the isolation of these compounds for the first time from this plant, moreover, their presence demonstrates the usefulness of C. swynnertonii as a good source of pharmacological active reported compounds which authenticate its diverse uses in traditional medicine. Furthermore, the revealed non-toxic effect of these compoundsshows safety and possibly its traditional use has no cytotoxicity effect. Yet, further studies on toxicity of these compounds are recommended.

Microbial Diversity and Volatile Flavor Changes during Gayangju Fermentation, a Traditional Korean House Rice Wine.

Physicochemical changes in fermented alcoholic beverages are significantly related to microbial community development during fermentation. Due to its unusually long fermentation, Gayangju, a traditional Korean house rice wine fermented with nuruk as the traditional starter, gives rise to a strong yeast community and, therefore, a high ethanol concentration and different flavors. However, no detailed analysis has been examined. Changes in microbial community structure during Gayangju fermentation were examined using both culture-dependent and culture-independent methods. During fermentation, Saccharomyces cerevisiae and Saccharomycopsis fibuligera were dominant during all stages of the fermentation. In contrast, Candida parapsilosis, Hanseniaspora guilliermondii, Pichia anomala, Malassezia cuniculi and P. fermentans were identified as minor. P. anomala appeared after the second brewing and then remained constant. Among the 19 compounds identified in this study as order-active compounds, 2-methyl-1-butanol (isoamyl alcohol) was the major compound that increased during the long fermentation stage. Most of the odor-active compounds such as 2,3-butanediol, 3-methyl-1-butanol, ethyl tetradecanoate, ethyl decanoate, ethyl dodecanoate, butanoic acid, 3-methylbutanoic acid (isovaleric acid), 2-methylbutanoic acid, 2-methyl-1-propanol, ethyl acetate, ethyl caprylate, 2-phenylethanol, and 3-methylbutyl acetate increased as the fermentation progressed during 68 days of fermentation, which showed significant differences in the concentrations of odor-active compounds of commercially fermented makgeolli.

Characterization of Korean Distilled Liquor, Soju, Using Chemical, HS-SPME-GC-MS, and Sensory Descriptive Analysis.

The volatile compounds and sensory profiles of 18 different types of distilled soju, chosen with regard to various raw materials and distillation methods (atmospheric vs. vacuum), were explored using headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) and descriptive analysis. General chemical properties such as pH, total acidity (TA), total soluble solids (°Brix), and lactic acid concentration were also determined. A total of 56 volatile compounds, comprising 31 esters, 11 alcohols, 1 acid, 4 aldehydes, 3 ketones, and 6 miscellaneous compounds, were identified. From the principal component analysis (PCA) of the volatile data, samples made using atmospheric distillation such as MSO and PJU showed a clear difference from decompressed distillation samples. Based on the PCA of the sensory data, there was also a clear distinction between samples by their distillation method. To explore relationships among chemical, volatile, and sensory data sets, multiple factor analysis (MFA) was applied. Yeasty and earthy flavors showed a close relationship with 1-nonanol, octatonic acid, and longer-chain esters such as ethyl phenylacetate and ethyl tetradecanoate, and with chemical parameters such as TA, °Brix, and lactic acid.

Electrophysiological Responses of Bactrocera kraussi (Hardy) (Tephritidae) to Rectal Gland Secretions and Headspace Volatiles Emitted by Conspecific Males and Females.

Pheromones are biologically important in fruit fly mating systems, and also have potential applications as attractants or mating disrupters for pest management. Bactrocera kraussi (Hardy) (Diptera: Tephritidae) is a polyphagous pest fruit fly for which the chemical profile of rectal glands is available for males but not for females. There have been no studies of the volatile emissions of either sex or of electrophysiological responses to these compounds. The present study (i) establishes the chemical profiles of rectal gland contents and volatiles emitted by both sexes of B. kraussi by gas chromatography–mass spectrometry (GC–MS) and (ii) evaluates the detection of the identified compounds by gas chromatography–electroantennogram detection (GC–EAD) and –electropalpogram detection (GC–EPD). Sixteen compounds are identified in the rectal glands of male B. kraussi and 29 compounds are identified in the rectal glands of females. Of these compounds, 5 were detected in the headspace of males and 13 were detected in the headspace of females. GC–EPD assays recorded strong signals in both sexes against (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, 2-ethyl-7-mehtyl-1,6-dioxaspiro[4.5]decane isomer 2, (E,Z)/(Z,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, and (Z,Z)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane. Male antennae responded to (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, 2-methyl-6-pentyl-3,4-dihydro-2H-pyran, 6-hexyl-2-methyl-3,4-dihydro-2H-pyran, 6-oxononan-1-ol, ethyl dodecanoate, ethyl tetradecanoate and ethyl (Z)-hexadec-9-enoate, whereas female antennae responded to (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane and 2-methyl-6-pentyl-3,4-dihydro-2H-pyran only. These compounds are candidates as pheromones mediating sexual interactions in B. kraussi.

Fecal Metabolomes in Response to Feed Supplemented with Fermented <i>Parkia biglobosa</i> and <i>Sphenostylis stenocarpa</i> in Obese Rats

The ubiquitous consumption of junk foods has drastically contributed to the exponential rise in the incidence of obesity. Hence, the present study explores the therapeutic effect of selected indigenous wild bean Sphenostylis stenocarpa (Otili) and condiment fermented Parkia biglobosa (Iru) on obese rats. The rats were fed with a high fat diet for four weeks and the gut microbiota was monitored every other day throughout the period of the experiment. Then, the fecal metabolome was analysed by Gas Chromatography Mass Spectroscopy (GC-MS). Although there was a decrease in the mean weight of rats treated with fermented iru compared with those given Otili, it was not statistically significantly (p ≤ 0.05). The organisms identified from the fecal samples of the fermented Iru groups are Proteus vulgaris, Bacillus cereus and Esherichia coli while those identified from the Otili group include Escherichia coli, and Citrobacter Freundii. However, further study revealed that Otili and Iru had a similar faecal metabolome. Medium chain fatty acids, such as Decanoic acid, Octanoic acid, ethyl tetradecanoate, Hexadecanoic acid, Methyl tetradecanoate, 9-Hexadecanoic acid, Hexadecnoic acid, cis-10-Hepadecanoic acid, are the most common compounds found in this study. This suggests the fact that the associated gut microbiota from breakdown of respective food samples must have actively mediated in their roles of ameliorating the effect of obesity.

Effects of a Small Increase in Carbon Dioxide Pressure during Fermentation on Wine Aroma.

The present study tested the effect of a slight increase in pressure (from 0 to 1 bar) during the fermentation on the wine aroma profile. Fermentations were carried out with a commercial dry yeast on Sangiovese juice in the absence of berry skins. The wine samples fermented under slight overpressure conditions were found to be significantly different from the control samples produced at atmospheric pressure in relation to several chemical compounds. Concentrations of many esters (i.e., isoamyl acetate, ethyl acetate, ethyl hexanoate, hexyl acetate, ethyl dodecanoate, and ethyl tetradecanoate), and acids (i.e., hexanoic acid, octanoic acid, and decanoic acid) increased, while concentrations of two acids (i.e., isobutyric and isovaleric acid) decreased. These differences, notably the higher concentration of esters, are usually associated with a more intense fruity attribute. Triangular sensory tests revealed that the significant chemical differences were also perceivable; hence, introducing a slight pressure increase during the alcoholic fermentation could be a useful tool in managing the aroma profile of wine.

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.

Identification of volatile compounds, quantification of glycerol and trace elements in distilled spirits produced in Mozambique.

Distilled spirits, in addition to satisfying the legal requirements with respect to its composition, must possess a sensorial quality capable of satisfying its consumers. The present work describes the analysis of volatile compounds, trace elements and glycerol in thirteen samples of Mozambican spirits collected in different regions of the country. Extraction of volatile components was a accomplished using the headspace SPME technique, the quantification of glycerol was achieved by UV/Vis spectroscopy and the determination of trace elements by atomic absorption spectrometry. Of the 35 volatile compounds identified, 19 were esters, of which ethyl hexanoate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, ethyl laurate, ethyl hexadecanoate, ethyl tetradecanoate, ethyl benzenepropanoate, 3-methylbutyl acetate and isoamyl alcohol were the predominant compounds found in the different samples, contributing to the characteristics and aroma of the beverages. As for glycerol, concentrations below 5mgL-1 were observed in all the samples studied. The samples were found to be contaminated by metals such as copper, lead and zinc. In addition, the results provided information on the quality of Mozambican spirits regarding some aspects related to the determination of metals and glycerol. This information might stimulate producers to be more attentive to the conditions of production and the risks involved in achieving good quality spirits.

Chemical Composition of the Rectal Gland and Volatiles Released by Female Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae)

The composition of the rectal gland secretion and volatiles emitted by female Queensland fruit fly, Bactrocera tryoni was investigated. Esters were found to be the main compounds in the gland extracts and headspace, while amides were the minor compounds in the gland extracts and headspace. Ethyl dodecanoate, ethyl tetradecanoate, ethyl (Z9)-hexadecenoate and ethyl palmitate were the main esters in the gland extracts, while ethyl dodecanoate and ethyl tetradecanoate were the main esters in the headspace. Four amides (N-(3-methylbutyl)acetamide), N-(2-methylbutyl)propanamide, N-(3-methylbutyl)propanamide, and N-(3-methylbutyl)-2-methylpropanamide were found in the gland extracts and the headspace. Among the amides, N-(3-methylbutyl)acetamide and N-(3-methylbutyl)propanamide were the main amides in the gland extracts and the headspace. Traces of three spiroacetals were found both in the gland extracts and in the headspace. (E,E)-2,8-Dimethyl-1,7-dioxaspiro[5.5]undecane, (E,E)-2-ethyl-8-methyl-1,7-dioxaspiro[5.5]undecane, (E,E)-2-propyl-8-methyl-1,7-dioxaspiro[5.5]undecane. All compounds found in the headspace were present in the extract of the rectal gland suggesting that the rectal gland is the main source of the headspace volatiles, whose function remains to be elucidated. This is the first comprehensive chemical analysis of the rectal gland secretions and volatiles of female B. tryoni, and further laboratory and field bioassays are required to determine the function of compounds identified in this study. Discovery of the same amides previously identified in the male rectal gland in the female rectal gland raises questions about the pheromonal role previously suggested for these compounds.

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.

Olfactory impact of esters on rose essential oil floral alcohol aroma expression in model solution

This study focused on the impact of esters on the perception of floral aroma in rose essential oil. Various aromatic reconstitutions were prepared, consisting of 10 alcohols and 9 esters, all the concentrations found in rose essential oil. Sensory analysis by the triangular tests revealed the interesting behavior of certain compounds among the 9 esters following their addition or omission. The results tend to highlight the important role of ethyl octanoate, ethyl tetradecanoate, citronellyl acetate, geranyl acetate, and 2-phenethyl acetate of esters in rose essential oil. The “olfactory threshold” (OT) of the 5 esters, the floral reconstitution and the mixtures of ester and floral reconstitution were evaluated in alkanes solution. Through the Feller's additive model analysis, it was found that the presence of ethyl octanoate, ethyl tetradecanoate, and citronellyl acetate led to a significant in decrease the OT of the mixtures, whereas geranyl acetate raised the OT. The floral reconstitution in alkanes solution was supplemented with the 5 esters at high, medium, and low concentration, then analyzed by quantitative descriptive analysis. It was revealed that ethyl octanoate, ethyl tetradecanoate, and citronellyl acetate adding overall aroma, and geranyl acetate masking the overall aroma perception in a model floral mixture. Sensory profiles highlighted changes in the perception of aroma nuances in the presence of the 5 esters, with specific perceptive interactions, and reported on the graph based on two parameters [σ = f(τ)]. This paper provided a reference for the flavourists.

Comparison of oenological property, volatile profile, and sensory characteristic of Chinese rice wine fermented by different starters during brewing

ABSTRACTOenological properties, volatile profiles, and sensory characteristics between Chinese Hong Qu rice wine (HQW) and Chinese Wheat Qu rice wine (WQW) were investigated. Forty and thirty-five volatile compounds in HQW and WQW were, respectively, identified. According to the door activity values (OAVs > 1), isoamyl acetate, ethyl octanoate, ethyl tetradecanoate, nonanal, and 2-methoxy-phenol were the major flavour contributors for HQW and WQW. Principal component analysis (PCA) showed that middle-chain fatty-acid (C6-C12) ethyl esters were the dominant representative flavour in HQW and WQW. Sensory evaluation indicated that the aroma of esters and alcohols differed largely between HQW and WQW. By partial least squares regression (PLSR), middle-chain fatty-acid-ethyl-esters (FAEEs) had a strong impact on the sensory attributes of fruit aroma, continuation, and full body in HQW and WQW.

Concurrent measurement of high-pressure binary phase equilibrium, density and dynamic viscosity

New equipment offering a novel combination of concurrent binary phase equilibria, saturated fluid density and dynamic viscosity determination, was developed. The setup (Pmax 30MPa; Tmax 393K) includes a variable volume view cell to determine bubble/dew points and density, with a quartz-crystal resonator to measure dynamic viscosity. Phase equilibrium is determined visually, using a synthetically known composition (SynVisVar). Uncertainties in measurements are 0.06MPa in pressure, <0.0005 in mass fraction, and 0.2 K in temperature. Density is calculated to within <0.003 of the value. The dynamic viscosity is determined by measuring the frequency shift over the quartz crystal, to within <0.01 of the value. Equipment verification was done using n-dodecane and benzene at 0.1–30MPa and 313–353K while contributing to available benzene literature. Binary equilibrium measurements were verified using CO2+ethyl tetradecanoate while presenting new data on the dynamic viscosity and density of the saturated binary phase.