Phenethyl Research Articles

Influence of Terroir on the Grain Composition, and Volatile Profile of Irish Grain (Wheat) New Make Spirit

Terroir refers to the combination of environmental factors, such as climate, soil, and agricultural practices, that shape the characteristics of a crop, contributing to the unique qualities of the final product. The concept has been traditionally linked to wine, but some recent findings suggest that it also holds importance for distilled spirits. The expanding Irish distilling sector is shifting towards local raw materials such as wheat and rye, driven by regulatory changes, economic benefits, and consumer demand for sustainable local products. This research examines the effects of wheat variety, geographical location, and harvest year on grain composition and volatile composition of the new make spirit. For this study, twenty lab-scale wheat whiskey samples were produced from five different wheat varieties grown at two different locations in Ireland over two consecutive years. The wheat samples were analysed for grain composition and the volatile profiling of new make spirit samples by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography–mass spectrometry (GC-MS). A total of fifty-one volatile compounds were detected, with ethanol, ethyl acetate, phenyl ethyl alcohol, and 3-methyl-1-butanol being predominant. Principal component analysis revealed that both the harvest year and geographical location moderately influenced the volatile compound distribution of the new make spirit, which is explained by a 43.25% variance. ANOVA analysis revealed that grain composition was significantly influenced by harvest year, location, and wheat variety. The 2020 samples showed higher protein and β-glucan content, whereas samples from the location Tipperary had higher starch content. This study indicates that terroir—specifically seasons (year) and geography (location)—affects the characteristics of wheat-based Irish whiskey, highlighting opportunities for distillers to differentiate their products by leveraging local environmental factors.

Olfactory Dysfunction and Limbic Hypoactivation in Temporal Lobe Epilepsy.

The epileptogenic network in temporal lobe epilepsy (TLE) contains structures of the primary and secondary olfactory cortex such as the piriform and entorhinal cortex, the amygdala, and the hippocampus. Olfactory auras and olfactory dysfunction are relevant symptoms of TLE. This study aims to characterize olfactory function in TLE using olfactory testing and olfactory functional magnetic resonance imaging (fMRI). We prospectively enrolled 20 individuals with unilateral TLE (age 45 ± 20 years [mean ± SD], 65% female, 90% right-handed) and 20 healthy individuals (age 33 ± 15 years [mean ± SD], 35% female, 90% right-handed). In the TLE group, the presumed seizure onset zone was left-sided in 75%; in 45% of the individuals with TLE limbic encephalitis was the presumed etiology; and 15% of the individuals with TLE reported olfactory auras. Olfactory function was assessed with a Screening Sniffin' Sticks Test (Burkhart, Wedel, Germany) during a pre-assessment. During a pre-testing, all individuals were asked to rate the intensity, valence, familiarity, and associated memory of five different odors (eugenol, vanillin, phenethyl alcohol, decanoic acid, valeric acid) and a control solution. During the fMRI experiment, all individuals repeatedly smelled eugenol (positively valenced odor), valeric acid (negatively valenced odor), and the control solution and were asked to rate odor intensity on a five-point Likert scale. We acquired functional EPI sequences and structural images (T1, T2, FLAIR). Compared to healthy individuals, individuals with TLE rated the presented odors as more neutral (two-sided Mann-Whitney U tests, FDR-p < 0.05) and less familiar (two-sided Mann-Whitney U tests, FDR-p < 0.05). fMRI data analysis revealed a reduced response contrast in secondary olfactory areas (e.g., hippocampus) connected to the limbic system when comparing eugenol and valeric acid in individuals with TLE when compared with healthy individuals. However, no lateralization effect was obtained when calculating a lateralization index by the number of activated voxels in the olfactory system (two-sided Mann-Whitney U test; U = 176.0; p = 0.525). TLE is characterized by olfactory dysfunction and associated with hypoactivation of secondary olfactory structures connected to the limbic system. These findings contribute to our understanding of the pathophysiology of TLE. This study was preregistered on OSF Registries (www.osf.io).

Effect of Mixed Strains on Microbial Community and Flavor Metabolites in Fermentation Process of Chi-Flavor Baijiu

The distinct flavor of chi-flavor baijiu (CFB) has garnered significant attention in China. After the optimization of fermentation conditions, Pichia anomala and Lactobacillus plantarum were introduced into the fermentation process to enhance the flavor. Samples inoculated with these mixed strains (SY) exhibited higher levels of alcohol (from 33.04 to 178.55 mg/L) and esters (from 49.51 to 130.20 mg/L) compared to the control group (KB). In SY, P. anomala and L. plantarum were the predominant microorganisms, while Pediococcus and Saccharomyces were more prevalent in KB. Moreover, 68 volatile flavor compounds were detected in SY, as opposed to 64 in KB. Notably, Pichia showed a positive correlation with key flavor compounds. The synergistic fermentation with exogenous strains led to a 52.38% increase in phenethyl alcohol and a 4.91% increase in ethyl lactate. Additionally, the levels of other flavor compounds, like ethyl acetate, γ-nonanolactone, and (E)-2-octenal, also increased. The results demonstrated that the addition of P. anomala and L. plantarum to the fermentation process of CFB significantly increased the contents of flavor compounds. This research reveals valuable insights into flavor enhancement and the microbial community dynamics in CFB production.

The Effect of Platelet-Rich Plasma and Hyaluronic Acid Nasal Injections in the Treatment of Traumatic Olfactory Dysfunction.

Objective: Platelet-rich plasma (PRP) has been injected into the olfactory cleft to treat olfactory dysfunction related to coronavirus disease 2019. In this study, we aimed to evaluate the effect of PRP combined with hyaluronic acid (HA) nasal injection in the treatment of traumatic olfactory dysfunction. Methods: Patients who had lost olfactory function after experiencing head trauma and were willing to receive PRP and HA nasal injections for treatment were enrolled. Before nasal injection, 10 cc of blood was drawn from the patients. The drawn blood was injected into a centrifuge tube for processing, and finally, 5 cc of the PRP mixed with HA was drawn out using an empty syringe. The PRP mixed with HA was injected into the upper part of the middle nasal septum and the medial side of the middle turbinate of the patient's nasal cavity under a nasal endoscope. The olfactory function of each patient was evaluated by the phenyl ethyl alcohol (PEA) odor detection threshold test before and at both 1 and 3 months after nasal injection and the traditional Chinese version of the University of Pennsylvania Smell Identification Test at 3 months after nasal injection. Results: A total of 28 patients received PRP and HA nasal injections between August and December of 2023 and came back for evaluation of the effect. In all, 20 (71.4%) patients felt their olfactory function improved 1 month after injection, and 24 of 28 (85.7%) patients reported their olfactory function improved at 3 months after injection. The bilateral or unilateral PEA threshold decreased in 22 (78.6%) patients 1 month after injection, and decreased in 15 (53.6%) patients 3 months after injection. Conclusions: Our results show that PRP and HA nasal injections were associated with favored patient-reported outcomes and improved the olfactory threshold in the treatment of traumatic olfactory dysfunction.

Navigational Signals for Insect and Slug Parasitic Nematodes: The Role of Ascorbate-Glutathione System and Volatiles Released by Insect-Damaged Sweet Pepper Roots.

This study of underground multitrophic communication, involving plant roots, insects, and parasitic nematodes, is an emerging field with significant implications for understanding plant-insect-nematode interactions. Our research investigated the impact of wireworm (Agriotes lineatus L. [Coleoptera: Elateridae]) infestations on the ascorbate-glutathione system in sweet pepper (Capsicum annuum L.) plants in order to study the potential role in root-exudate-mediated nematode chemotaxis. We observed that an A. lineatus infestation led to a decrease in leaf ascorbate levels and an increase in root ascorbate, with corresponding increases in the glutathione content in both roots and leaves. Additionally, a pigment analysis revealed increased carotenoid and chlorophyll levels and a shift towards a de-epoxidized state in the xanthophyll cycle. These changes suggest an individual and integrated regulatory function of photosynthetic pigments accompanied with redox modifications of the ascorbate-glutathione system that enhance plant defense. We also noted changes in the root volatile organic compound (VOC). Limonene, methyl salicylate, and benzyl salicylate decreased, whereas hexanal, neoisopulegol, nonanal, phenylethyl alcohol, m-di-tert-butylbenzene, and trans-β-ionone increased in the roots of attacked plants compared to the control group. Most notably, the VOC hexanal and amino acid exudate cysteine were tested for the chemotaxis assay. Nematode responses to chemoattractants were found to be species-specific, influenced by environmental conditions such as temperature. This study highlights the complexity of nematode chemotaxis and suggests that VOC-based biological control strategies must consider nematode foraging strategies and environmental factors. Future research should further explore these dynamics to optimize nematode management in agricultural systems.

Monorhinal and Birhinal Odor Processing in Humans: an fMRI investigation.

The olfactory nerve, also known as cranial nerve I, is known to have exclusive ipsilateral projections to primary olfactory cortical structures. However, the lateralization of olfactory processes is known to depend on the task and nature of stimuli. It still remains unclear whether olfactory system projections in humans also correspond to functional pathways during olfactory tasks without any trigeminal, perceptual or cognitive-motor components. Twenty young healthy subjects with a normal sense of smell took part in an olfactory functional magnetic resonance imaging (fMRI) study. We used two types of nostril specific stimulation, passive (no sniffing) and active (with sniffing), with phenyl ethyl alcohol, a pure olfactory stimulant, to investigate fMRI activity patterns in primary and secondary olfactory-related brain structures. Irrespective of the stimulated nostril and the type of stimulation, we detected symmetrical activity in primary and secondary olfactory-related brain structures such as the primary olfactory cortex, entorhinal cortex, and orbitofrontal cortex. In the absence of perceptual or cognitive-motor task demands, the perception of monorhinally presented pure odors is processed bilaterally in the brain.

Synergistic action of bacteriophage and metabolites of Pseudomonas fluorescens JB3B and Streptomyces thermocarboxydus 18PM against Enterotoxigenic Escherichia coli and Bacillus cereus and their biofilm

BackgroundFoodborne disease and food spoilage are the prime public health issue and food security round the globe. Significant disease outbreaks mostly linked to the existence of pathogenic bacteria that extremely challenging due to the persistence of biofilm-forming. Proteins and bacterial metabolites have been shown to have good antibacterial activity and effectively removal bacterial biofilm. Recently, bacteriophage and their encoded lytic proteins such as lysin have attracted attention as potential alternative agent to control undesirable pathogens in human body infection, increasing food safety as advance preservations and medical treatment such as phage therapy. For these reasons, the efficacy of bacteriophage and their potential in combination with bacterial metabolites from Phyllosphere and Actinomycetes bacteria (Pseudomonas fluorescens JB3B and Streptomyces thermocarboxydus 18PM crude extracts) was the aim of this present study.ResultsIn this study, bacteriophage BC-VP (1.28 ± 0.29 × 1011 PFU/ml) and ETEC-phage-TG (8.9 ± 2.19 × 108 PFU/ml) isolated from artificial lake water from previous study showed potential activity to control Bacillus cereus (BC) and Enterotoxigenic Escherichia coli (ETEC) population. The combination of BC-VP with metabolite (P. fluorescens JB3B and S. thermocarboxydus 18PM) which were known from previous study had antibiofilm activities were able to inhibit (86.1%; 83.3%) and destruct (41%; 45.5%) biofilm formation of B. cereus respectively. Likewise, the synergy of bacteriophage ETEC-phage-TG with the same crude extract also showed promising activity against biofilm of ETEC with percentage of inhibition (81.9%; 76.4%) and percentage of destruction (54.1%; 44.4%). Application in various food, combination of BC-VP and bacterial metabolite extract (P. fluorescens JB3B; S. thermocarboxydus 18PM) were able to reduce Bacillus cereus population in mashed potato (99.6%; 99.4%) at cold temperature (4 °C) and (68.9%; 56.6%) at room temperature (28 °C), boiled pasta (99.5%; 99.4%) and (84.7%; 75.7%), also soymilk (96.9%; 96.7%) and (42.4%; 39.4%) respectively. Likewise, combination of ETEC-phage-TG and bacterial metabolite (P. fluorescens JB3B; S. thermocarboxydus 18PM) potentially reduced ETEC population after two different temperatures (4 °C and 28 °C) incubation in bean sprouts (TFTC; TFTC) and (47.5%; 49.1%), chicken meat (TFTC; TFTC) and (58.1%; 54%), also minced beef (99.5%; 99.4%) and (41.1%; 28%). GC-MS determination performed, oxalic acid, phenol, phenylethyl alcohol, N-hexadecanoic acid, and pyrolol[1,2-a]pyrazine-1,4-dione, hexadro-3-92-methylpropyl was the most active compound in P. fluorescens JB3B. 2,4-Di-tert-butylphenol, phenyl acetic acid, N-Hexadecanoic acid, pyrolol[1,2-a]pyrazine-1,4-dione, hexadro-3-92-methylpropyl, and Bis(2-ethylhexyl) phthalate was most active compound in the S. thermocarboxydus 18PM isolates.ConclusionsThe combination of isolated bacteriophages and bacterial metabolite showed promising results to be used as biocontrol candidate to overcome biofilm formed by foodborne and food spoilage bacteria using their ability to produce antibiofilm compounds and lytic activity. In addition, this combination also potentially reduces the use or replace the drawbacks of common application such as antibiotic treatment.

Comparative Analysis of Microbial Diversity and Metabolic Profiles during the Spontaneous Fermentation of Jerusalem Artichoke (Helianthus tuberosus L.) Juice.

Jerusalem artichoke juice is valued for its nutritional content and health benefits. Spontaneous fermentation enhances its flavor, quality, and functional components through microbial metabolic activities. This study used high-throughput sequencing to analyze microbial community changes, and LC-MS and GC-MS to detect secondary metabolites and flavor compounds during fermentation. During natural fermentation, beneficial bacteria like Lactobacillus and Pediococcus increased, promoting lactic acid production and inhibiting harmful bacteria, while environmental bacteria decreased. Similarly, fungi shifted from environmental types like Geosmithia and Alternaria to fermentation-associated Pichia and Penicillium. A total of 1666 secondary metabolites were identified, with 595 upregulated and 497 downregulated. Key metabolic pathways included phenylpropanoid biosynthesis, with significant increases in phenylalanine, tryptophan, and related metabolites. Lipid and nucleotide metabolism also showed significant changes. Flavor compounds, including 134 identified alcohols, esters, acids, and ketones, mostly increased in content after fermentation. Notable increases were seen in Phenylethyl Alcohol, Ethyl Benzenepropanoate, 3-Methylbutyl Butanoate, Ethyl 4-Methylpentanoate, 5-Ethyl-3-Hydroxy-4-Methyl-2(5H)-Furanone, Ethyl Decanoate, Hexanoic Acid, and 1-Octanol. γ-aminobutyric acid (GABA) and other functional components enhanced the health value of the juice. This study provides insights into microbial and metabolic changes during fermentation, aiding in optimizing processes and improving the quality of fermented Jerusalem artichoke juice for functional food development.

Biofunctionality of a new vinegar rich in anthocyanin from red-fleshed Niedzwetzky's apple: An ornamental plant.

In recent years, red-fleshed apple has attracted a lot of attention due to its pleasant appearance, taste, and being a valuable source of anthocyanins. Generally, different types of this apple are known as ornamental apple plants that are rarely found in various regions around the world like New Zealand, Kazakhstan, Kyrgyzstan, Australia,China, and Turkey. This study focused on the accumulation and changes of the bioactive and aroma-related volatile components at different production stages of a red-fleshed apple vinegar. The aim of this study is to produce an anthocyanin- and vitamin C-rich vinegar (NAV) from red-fleshed Niedzwetzky's apple for the first time. According to the results, in this vinegar, it wasdetermined high concentrations of total phenolic content (904.8mg-GAE/mL), total flavonoid content (0.25mg-EGCE/mL), vitamin C content (3024.3mg-AAE/mL), and 1,1-diphenyl-2-picrylhydrazyl (8.33mmol-TE/mL), as well as FRAP (13.57mmol-ISE/mL), respectively. Moreover, total anthocyanin content value was found to be 6.46mg/g. One of the components that provide the specified functional effect in this vinegar is chlorogenic acid, which constitutes the main phenolic compound, and the other one is cyanidin-3-glucoside, which is the major anthocyanin in this vinegar. The main volatile components associated with the aroma of vinegar are -acetic acid, -phenylacetic acid (5067.7µg/100mL), -phenethyl alcohol (3096.1µg/100mL), and -nonanoic acid (2939.0µg/100mL) compounds. Consequently, it is recommended to expand the range of Niedzwetzky's apples in the production and consumption of food products such as functional vinegar. Thus, a new vinegar with high functional properties will be introduced to the worldwide food industry. PRACTICAL APPLICATION: In this study, vinegar was produced from the small and dark-red-flesh-colored fruits of Niedzwetzky's apple tree, which is known in a small part of the world and is generally used as an ornamental plant due to its red-pink flowers. It has been determined that the produced vinegar has high bioavailability due to the apples with red inner flesh and high anthocyanin content and has a desirable aromatic content. Thus, a food product with high functional quality and desirable aroma, accessible to consumers all over the world, has been produced from a little-known fruit.

Research Progress of Pharmacological Mechanism of Cistanche in the Treatment of Vascular Dementia

Vascular dementia is one of clinical common type of dementia, its pathogenesis is complex, the incidence of rising trend year by year, the serious influence the patient's life and health. In the category of traditional Chinese medicine, vascular dementia belongs to the category of "dementia", and its etiology and pathogenesis are mostly related to "deficiency of kidney essence". Studies have found that Cistanche deserticola is a traditional Chinese medicine with a high frequency in the treatment of vascular dementia. It has the effects of toning kidney Yang, nourishing essence blood, moistening intestine and purging, and has definite advantages in preventing vascular dementia. C. deserticola chemical composition including echinacea glycosides, mullein indican, c. deserticola total glycosides, phenylethyl alcohol glycosides, flavonoids and polysaccharides, removal of oxygen free radicals and improve antioxidant compounds with resistance to oxidative stress; It plays an anti-vascular dementia role by clearing β-amyloid protein, reducing neuronal apoptosis, protecting hippocampal neurons, and regulating neurotransmitters to protect cholinergic nerves. This article reviews the pharmacological effects of cistanche deserticola on vascular dementia. As to provide theoretical basis for the use of c. deserticola and evidence-based support.

Parallel Plate Capacitor Model at the Nanoscale for Stable and Gigantic SERS Activity of the 4-MBA@R-AuNP-4-MBA@R-AuNP System.

Selective use of ingredients out of a specific natural product (e.g., fruit, leaf, flower, or honey extract) or their mixture (e.g., bacteria, viruses, fungi, plants, etc.) by smart manipulation of precursors and reaction conditions to synthesize nanoparticles can provide us a low-cost, environmentally friendly route for their industrial-scale production. The presence of more than one active ligand (sourced natural product extract) on the surface not only makes them the most stable (electrostatically) and monodispersed (controlled kinetics) but also devoid of any external ligand-assisted aggregation. This empowered us to modify the surface of the nanoparticles in a monolayered fashion or to couple between nanoparticles through a ligand-assisted chemical coupling pathway to avoid their aggregation and hence to keep their nanoscale property intact. A metal-to-ligand charge transfer (MLCT) trajectory combined with electromagnetic field-induced coherent capacitive coupling between two nanoparticles was introduced to explain the gigantic Raman enhancement observed from these nanoparticles. As a model system, we have synthesized the nanoparticles from rose extract as the active ligand ingredient source for 2-phenyl ethanol, linalool, citronellol, nerol, geraniol, pyrogallol (C6H3(OH)3), and quercetin (3,3',4',5,7-pentahydroxyflavone) and the surface of the synthesized nanoparticles has been modified by 4-mercaptobenzoic acid (4-MBA) acting as a Raman tag. The obtained structural and spectroscopic data correlate well between our numerical and density functional theory (DFT)-based calculations to justify their gigantic SERS activity, which may lead us to propose an unexplored coherent capacitive coupling-based Raman enhancement mechanism.

The molecular effects of ozone on human hemoglobin oligomerisation pre- and post-COVID-19 infection accompanied by favoured antioxidant roles of cinnamaldehyde and phenyl ethyl alcohol

Many studies have shown that oxidative stress plays a pivotal role in pathogenesis of coronavirus disease 2019 (COVID-19). In the present work, a case-study was conducted by comparing human hemoglobin (Hb) oligomerization upon autohemotherapy before and after COVID-19 infection. Structural changes of Hb exposed to different concentrations of ozone (40, 60, and 80 μg/ml) in whole blood, before COVID-19 infection, was compared to Hb exposed to the highest concentration of ozone (80 μg/ml) in whole blood, in the presence of two antioxidants, cinnamaldehyde (Cin) and phenyl ethyl alcohol (PEA), after COVID-19 infection. The structural analyses in this study was performed using various techniques, including DPPH radical scavenging assay, intrinsic fluorescence spectroscopy, circular dichroism (CD) spectroscopy, UV–VIS absorption spectroscopy, SDS-PAGE, dynamic light scattering (DLS), and molecular docking studies. The results showed that Hb oligomerization by ozone increased significantly after COVID-19 infection. In addition, at an ozone concentration of 80 μg/ml, the affinity of heme groups for globin chains and to oxygen molecules were shown to increase, whereas the stability of Hb decreased. In contrary, the addition of Cin and PEA prevented the adverse effects of ozone with PEA showing more efficacy in maintaining the native structure of Hb. Taken together, these results provided insights into the adverse effects of COVID-19 infection on Hb oligomerization and highlighted the importance of an individual's antioxidant capacity in protecting Hb from ozone, especially high ozone concentrations in autohemotherapy, and further emphasised the importance of personalising the concentration of ozone for patient administration, in order to provide a safe and effective autohemotherapy treatment.

Comprehensive investigation on the flavor difference in five types of tea from JMD (Camellia sinensis 'Jinmudan').

Jinmudan (JMD) is a high-aroma variety widely cultivated in China. The current study primarily focuses on the key volatile metabolites in JMD black and oolong teas,and investigates the impact of processing technologies on the aroma quality of JMD tea. However, few studies have explored the suitabilityof JMD for producing a certain type of tea or the characteristic quality differences among various JMD teas using multivariate statistical analysis methods. The principal volatile metabolites contributing to the floral quality of JMD tea are linalool, geraniol, indole and phenethyl alcohol. In JMD black tea (BT), the key volatile metabolites include methyl salicylate, geraniol, (E)-β-ocimene and phenethyl alcohol. In JMD oolong tea (OT), the key volatile metabolites include indole, linalyl valerate and phenethyl alcohol. In JMD yellow tea (YT), the key volatile metabolites include methyl salicylate, geraniol and terpinolene. In JMD white tea (WT), the key volatile metabolites include methyl salicylate, geraniol and terpinolene. In JMD green tea (GT), the key volatile metabolites include (E)-β-ocimene, indole and geraniol. Comparative analysis and KEGG pathway enrichment analysis revealed that flavonoid biosynthesis is the primary metabolic pathway responsible for the taste differences among various tea types. GT exhibited higher levels of phloretin, dihydromyricetin and galangin. The contents of vitexin, tricetin in YT were relatively higher. The contents of aromadendrin and naringenin in BT were higher, while OT contained higher levels of kaempferol. Additionally, WT showed higher contents of 3-O-acetylpinobanksin and 3,5,7-pinobanksin. This study explained the reasons for the quality differences of different JMD tea and provided a reliable theoretical basis for the adaptability of JMD tea. © 2024 Society of Chemical Industry.

Comparative Metabolomic Responses of Three Rhododendron Cultivars to the Azalea Lace Bug (Stephanitis pyrioides).

Rhododendron, with its high ornamental value and ecological benefits, is severely impacted by the azalea lace bug (Stephanitis pyrioides), one of its primary pests. This study utilized three Rhododendron cultivars, 'Zihe', 'Yanzhimi', and 'Taile', to conduct a non-targeted metabolomic analysis of leaf samples before and after azalea lace bug stress using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GCMS) and liquid chromatography-mass spectrometry (LCMS). A total of 81 volatile metabolites across 11 categories and 448 nonvolatile metabolites across 55 categories were detected. Significant differences in metabolic profiles were observed among the different cultivars after pest stress. A total of 47 volatile compounds and 49 nonvolatile metabolites were upregulated in the most susceptible cultivar 'Zihe', including terpenes, alcohols, nucleotides, amino acids, and carbohydrates, which are involved in energy production and secondary metabolism. Conversely, 'Yanzhimi' showed a downtrend in both the differential volatiles and metabolites related to purine metabolism and zeatin biosynthesis under pest stress. The resistant cultivar 'Taile' exhibited moderate changes, with 17 volatile compounds and 17 nonvolatile compounds being upregulated and enriched in the biosynthesis of amino acids, pentose, glucuronate interconversions, carbon metabolism, etc. The phenylalanine metabolic pathway played an important role in the pest resistance of different susceptible cultivars, and relevant metabolites such as phenylethyl alcohol, methyl salicylate, and apigenin may be involved in the plant's resistance response. The results of this study provide a new perspective on the metabolomics of Rhododendron-insect interactions and offer references for the development of pest control strategies.

Enhancing cider quality through co-fermentation with acid protease and esterase-producing Metschnikowia species and Saccharomyces cerevisiae.

To date, cider production has primarily relied on Saccharomyces cerevisiae. Introducing novel non-Saccharomyces yeasts can enhance the diversity of cider properties. Among these, the Metschnikowia genus stands out for its ability to produce hydrolytic enzymes that may impact the sensorial and technological properties of cider. This study focused on evaluating the impact of three Metschnikowia species - Metschnikowia koreensis (Mk), M. reukaufii (Mr), and M. pulcherrima (Mp) - which exhibit acid protease and esterase activity, on the quality enhancement of cider. The research findings indicate that the overall quality of cider produced through co-fermentation with these species surpassed that of cider fermented with mono-fermentation of S. cerevisiae (Sc). The cider fermented with the Sc + Mk combination exhibited the lowest levels of harsh-tasting malic acid and higher levels of softer lactic acid. Sensory array analysis also demonstrated that the Sc + Mk fermented cider exhibited high sensor response values for compounds contributing to a complex overall olfactory composition and richness. Furthermore, the Sc + Mk fermented cider exhibited the highest total quantity and variety of volatile organic compounds (VOCs). Specifically, the concentrations of phenethyl alcohol, 3-methyl-1-butanol, ethyl octanoate, and decanoic acid were notably elevated in comparison with other groups. This study illustrates that Metschnikowia species, particularly M. koreensis, show significant potential as starters for cider due to their various technological properties, including acidity modulation, aroma enhancement, and color improvement. The findings of this study provide a foundation for improving cider quality by co-fermenting S. cerevisiae with innovative starter cultures. © 2024 Society of Chemical Industry.

Enhancing phenylethyl alcohol production in Pichia fermentans via adaptive laboratory evolution under NaCl stress

Our previous research demonstrated phenylethyl alcohol was the key aroma in fermented chili peppers, identifying Pichia fermentans as the primary strain responsible for its production. However, the regulatory mechanisms underlying its production remained unclear. To address this, adaptive laboratory evolution against NaCl was utilized in this study to enhance the production of phenethyl and reveal the mechanism of metabolic regulatory of phenethyl alcohol in Pichia fermentans. Under high NaCl stress, the evolved strains increased phenylethyl alcohol production capacity by up to 64.01%. The improved NaCl tolerance of the strains contributes to the higher phenylethyl alcohol yield, primarily because phenylethyl alcohol, like NaCl, causes high osmotic pressure on the strain. The strain responds to NaCl stress by altering cell membrane components and related transport proteins through relevant gene mutations. Additionally, it enhances phenylethyl alcohol production efficiency by upregulating key enzyme-encoding genes (ARO8 and ADHs) in the Ehrlich pathway.

Comparison of methods for calculating the enthalpy of vaporization of binary azeotropic mixtures

Objectives. To calculate the molar enthalpy of vaporization of binary homogeneous mixtures based on isothermal and isobaric vapor–liquid equilibrium data, and to compare the results of calculation of molar enthalpy of vaporization by different methods with experimental data.Methods. Simulation of the vapor–liquid equilibrium of binary systems according to the Non-Random Two Liquid “local compositions” equation and thermodynamic calculations of molar vaporization enthalpies of binary mixtures at different conditions of vapor–liquid equilibrium were used.Results. Arrays of calculated data were obtained with regard to molar enthalpies of vaporization for 25 compositions of binary azeotropes (isothermal, isobaric conditions of phase equilibrium), and the full range of compositions of the benzene–ethanol system at atmospheric pressure.Conclusions. The accuracy of thermodynamic methods for calculating the vaporization enthalpy of binary azeotropic mixtures according to vapor–liquid equilibrium data is higher in 85% of cases for isothermal, and in 75% of cases for isobaric conditions. By taking into account the influence of temperature on the activity coefficients of components in the liquid phase, the values of excess molar enthalpy both for azeotrope compositions and for the full concentration range of the benzene–ethanol system under isobaric conditions of liquid–vapor phase equilibrium can be accurately reproduced.

A thorough evaluation of flavor characteristics among various retail peanut oil products using multivariate statistical methods

AbstractFlavor is a crucial characteristic of peanut oils, exerting a significant impact on their quality and acceptability. However, given the uncertainty in the correlations between flavor attributes and volatile compounds, assessing the flavor quality of commercial peanut oil retail products (PORPs) based on updated analysis techniques remains challenging. In this study, 21 commercial samples were collected for investigating this correlation. From the sensory evaluations, the 16 fragrant PORPs show differences esp. for the roasted (4.25–10), the sweet (0–4.25), and the steamed (0–4.25) attributes while the roasted attribute is dominant for all the products. For volatile profile analysis with updated analytical technology, the fragrant PORPs also show significant difference in terms of volatile profiles and intensities. The total intensity can differ from 16.37 to 66.59 mg/kg. Multivariate statistical methods (MSMs) revealed the significant correlations between volatile compounds and specific sensory attributes. Notably, 1‐hexanol and phenylethyl alcohol demonstrate a strong correlation with the raw peanut flavor attribute. Benzeneacetaldehyde (BA) exhibited a positive correlation with sweet flavor. dl‐Pantolactone has a positive effect on roasted flavor. Hexanal and 3‐octen‐2‐one are highly related to off‐flavor notes. In addition, based on machine learning (ML), three groups of volatile compounds were found to be highly correlated with specific flavor attributes. Notably, a cluster comprising seven compounds, namely 2‐ethenyl‐6‐methylpyrazine, 2‐methyl‐6‐[(E)‐1‐propenyl]pyrazine, benzaldehyde, BA, nonanal, dl‐pantolactone, and 2‐acetopyridine exhibiting a positive correlation with roasted, steamed, and sweet flavor attributes. Furthermore, recombination experiments were conducted to verify the synergistic effect of these seven compounds on flavor performance and agreements were reached.

Enhancing physicochemical properties, organic acids, antioxidant capacity, amino acids and volatile compounds for ‘Summer Black’ grape juice by lactic acid bacteria fermentation

To investigate the effect of lactic acid bacteria fermentation on the quality of ‘Summer Black’ grape juice, this study characterized the differences in physicochemical properties, organic acids, antioxidant capacity, amino acids and volatile compounds among different treatments. The results showed that the pH and total sugar of all fermentation groups were lower than those of the CK (control group) sample. ZR (Lactobacillus plantarum) sample had the highest DPPH and OH− scavenging ability, and the total phenol and total flavonoid content of SR (Streptococcus thermophilus) sample were increased by 5.2% and 4.1%, respectively. The contents of tartaric acid, malic acid, and citric acid were improved significantly by LAB fermentation. The content of Asp, Thr, Ser, Glu, and Gly in the SR sample was significantly higher than in the CK sample. Phenylethyl alcohol, lactic ethyl ester, L-menthol, citronellol, and nerol were produced by LAB fermentation, giving fruit and floral aroma, and streptococcus thermophilus has a higher potential to enhance the aromatic flavor of ‘Summer Black’ grape juice. 20 chemical indicators were determined to explain the differences between groups by OPLS-DA.

Revealing the differences in aroma of black tea under different drying methods based on GC–MS, GC-O

Drying greatly affects the aroma of black tea. In this study, the differences in aroma of black tea under hot-air drying (HD), sun drying (SD), and pan-fired drying (PD) were investigated through quantitative descriptive analysis. Headspace solid-phase microextraction and solvent assisted flavor evaporation combined with gas chromatography–mass spectrometry and gas chromatography-olfactory were used to analyze the overall aroma profile of black tea. Aroma extract dilution analysis and odor activity values revealed that 15 aroma-active compounds led to differences in aroma, namely linalool, geraniol, phenylethyl alcohol, phenylacetaldehyde, (Z) -linalool oxide (furanoid), β-damascenone, dimethyl sulfide, methional, 2-methylbutanal, 3-methylbutanal, methyl salicylate, β-myrcene, hexanal, 1-octen-3-ol, and heptanal. Among them, geraniol, linalool, and methional significantly enhanced the floral and roasty aroma of HD, while hexanal enhanced the green aroma of SD. Finally, our results were validated through aroma recombination and addition experiments. This study provides a theoretical basis for improving the aroma of black tea.