Thermolabile essential oils, aromas and flavours: Degradation pathways, effect of thermal processing and alteration of sensory quality

Study on dynamic changes in characteristic volatile compounds uncovers aroma development of Hainan Dayezhong (Camellia sinensis var. assamica) black tea

To elucidate the characteristic aroma of Hainan Dayezhong black tea, GC-MS, GC-olfactometry, and electronic nose analyses were used to examine the changes in volatile compounds. A total of 527 volatiles were identified and quantified, of which 80 compounds with relative odor activity values exceeding 1 in dried tea samples were selected as biomarkers. Floral and sweet-associated volatiles, including damascenone, benzaldehyde, and linalool, were proposed to be responsible for the characteristic aroma. Our results indicated that multiple stresses occurring during withering, rolling, and fermentation contributed to the distinctive floral aroma, while the thermal effects of drying enhanced sweet odors by volatilizing certain fragrant compounds, thereby improving the final quality of the dried tea. These findings provide a foundation for quality control in practical manufacturing and will contribute to the development of standard operating procedures for producing Hainan Dayezhong black tea with desirable aromas.

Enhancing beef tallow flavor through enzymatic hydrolysis: Unveiling key aroma precursors and volatile compounds using machine learning

Lipids are critical precursors of aroma compounds in beef tallow. This study investigated how enzymatic hydrolysis treatment affected the aroma precursors and flavor of beef tallow during the manufacturing process. Using gas chromatography-mass spectrometry and high-resolution gas chromatography-ion mobility spectrometry, 100, 111, and 122 aroma compounds were identified in beef tallow at three processing stages namely, raw beef fat, enzymatic hydrolysates, and enzymatic beef tallow. Employing machine learning methods, including fold change analysis, partial least squares-discriminant analysis, and random forest algorithms, we identified 26 potential aroma biomarkers strongly associated with the manufacturing process. Furthermore, debiased sparse partial correlation analysis revealed the significant contribution of C22:2, C22:6 n3, C20:3 n3, C20:1, C18:1 n9t, C18:1 n6t, and C18:2 n6t to aroma compound formation, thereby enhancing our fundamental understanding of flavor precursors and their enzymatic transformation.

Active food packages for cake conservation: Antifungal potential of bean starch biodegradable films with orange peel essential oil

This study aimed to apply antifungal films as biodegradable active packages for cake conservation. Native or octenyl succinic anhydride (OSA)-modified carioca bean starches (4 %, w/v) were used to produce films incorporated with orange peel essential oil (5 % and 10 %, v/w). d-limonene was determined as the major compound (94.25 %) in orange peel essential oil. Filmogenic solutions exhibited greater stability due to OSA modification. The films presented a continuous morphology, high luminosity (97.0 %), and low opacity (8.6 %), moisture content of 24.2 %, solubility in water of 38.0 %, and a water vapor permeability of 4.97 g.mm/m2.day.KPa. They remained intact after 24 h of immersion in water. The mechanical properties included a tensile strength (5.44 MPa) and an elongation at break (52.0 %). The antifungal activity of the essential oil and the films against Penicillium crustosum and Aspergillus flavus was high, with higher inhibition of A. flavus. Films produced from OSA-modified starch exhibited improved morphological properties, showing increased homogeneity over native starch films. The bean starch films with 10 % orange peel essential oil exhibited an enhanced antifungal effect. They were used for the application in cake conservation, displaying high inhibition of fungi with the potential for the formation of biodegradable active food packaging.

Integration of volatilomics and microbiome diversity reveals key flavor-related metabolic pathways in semi-dried large yellow croaker (Pseudosciaena crocea)

A complex microbial community is critical for developing unique flavors in semi-dried large yellow croaker (Pseudosciaena crocea). Volatilomics analysis identified hexanal, heptanal, nonanal, phenylacetaldehyde, 1-octen-3-ol, and butanoic acid were identified as the key flavor compounds in the fish. Clostridium sensu stricto was the dominant genus, with a relative abundance of 79.78 % after 4 days of air-drying. Validation results showed a positive association between the accumulation of nonanal, phenylacetaldehyde, and butanoic acid and the presence of Clostridium sensu stricto. Significant correlations were also observed between the genera of Lactobacillus and Microbacterium and the key flavor compounds of hexanal and heptanal. Microorganisms contribute to the metabolism of these compounds, primarily through the metabolism of phenylalanine, linoleic acid, linolenic acid, arachidonic acid, and pyruvate. This flavor-regulating role of microorganisms presents them as potential targets for flavor enhancement in traditional aquatic products.

Investigating the Olfactory Impact of Monoterpenic Compounds on Fruity Aroma Perception in Model Red Wine Solutions

This study investigated the impact of monoterpenic compounds on red wine fruity aroma perception in different matrices and at different concentrations typically found in red wines. Fruity aromatic reconstitutions (FAR) containing sixteen esters that represent the fruity pool of red wine and eight monoterpenic compounds at low, medium, and high concentrations were prepared in dilute alcohol solution (FAR-DAS) and in dearomatized red wine (FAR-DRW). Sensory analysis applied to the olfactory detection threshold of the fruity pool revealed that α-terpineol, at the subthreshold level, and 1,8-cineole, at the suprathreshold level, significantly boosted the olfactory detection threshold of the fruity pool. The results of sensory profiles showed that the presence of a mixture of monoterpenic compounds at a medium concentration in FAR-DAS and in FAR-DRW induced changes in fruity perception. Their addition increased the intensity of black-berry fruit descriptors, such as fresh and jammy blueberry and blackcurrant fruit notes. Moreover, the presence of α-terpineol (130 μg/L), 1,8-cineole (4 μg/L), and linalool (38 μg/L), respectively, increased the fresh raspberry, fresh and jammy blueberry, and jammy blackcurrant notes in FAR-DAS. Across all matrices, the presence of monoterpenic compounds at medium levels consistently amplified black-berry fruit notes. This research provides insights into the impact of monoterpenic compounds on red wine fruity aroma, shedding light on specific enhancing effects of certain monoterpenic compounds via perceptual interactions at various concentrations and in different matrices.

The Role of Essential Oils on Sleep Quality and Other Sleep-related Issues: Evidence from Clinical Trials

Essential oils (EOs) are a volatile mixture of bioactive compounds extracted from aromatic plants. The composition of EOs varies, which majorly depends on the extraction methods and plant parts. Aromatherapy using EOs has been reported for its several beneficial effects in humans. Aromatherapy is considered a complementary and/ or adjuvant therapeutic approach for treating several illnesses, especially to improve mental health and well-being. The incidence of sleep disorders, specifically insomnia, is nowadays increased, possibly due to urbanization and lifestyle. The studies showed that EOs-based treatments using lavender EO, bergamot EO, cinnamon EO, and rosemary EO (alone or in combinations) could improve sleep quality, duration, and deprivation in healthy subjects and patients, those who suffer from sleep-related issues. The current manuscript details the outcomes of EO-based treatments on the sleep quality of humans and the possible mechanisms associated with the health-promoting properties of EOs. Also, the toxicity and adverse effects of EOs have been discussed. The study indicated that EOs are potent adjuvant therapeutic candidates to manage mood-associated complications in humans. Moreover, the aromatherapeutic field requires detailed studies on toxicity and dose determination, which could provide safe and effective therapeutic results.

Deep Eutectic Solvents for Essential-Oil Delivery and Bacterial-Infected Wound Healing

Essential oils (EOs) are volatile secondary metabolites of natural plants with multitudinous pharmacological activities. However, limited by their properties, such as low solubility, high volatility, photothermal instability, irritation, release, etc., EOs encounter significant challenges in pharmaceutical applications. Deep eutectic solvents (DESs) have been developed for the transdermal delivery of biomolecules and lipid-soluble drugs. Herein, a series of DES carriers were synthesized to improve the undesirable properties of EOs. We first optimized the DESs according to solubilization and aqueous dispersity using Chimonanthus nitens Oliv. EO (COEO) as a model EO. Then, the EO-DES formulations were diluted to prepare optimal aqueous EO-DES nanoformulations (AqEDs). Mechanically, hydrogen bonding allowed the DES to dissolve the complex components in EOs; meanwhile, the interaction forces, such as π-π stacking and hydrogen bonding, drove the EO-DES to assemble into nanostructures in aqueous conditions, forming AqEDs. Lastly, a case study demonstrated that clove EO-AqEDscould effectively promote methicillin-resistant Staphylococcus aureus-infected wound healing in vivo, along with biocompatibility. This AqED strategy provides a generalized platform for solubilizing EOs and improving their transdermal/topical delivery.

Modified Cinnabaris-stabilized Pickering emulsions loaded with the essential oil of Acorus tatarinowii Schott: preparation, characterization and in vitro evaluation

Essential oil of Acorus tatarinowii Schott (ATEO) have significant biological activity, but their physical and chemical properties are unstable and susceptible to interference by external factors, resulting in oxidation, decomposition, and isomerization of essential oils (EOs), ultimately diminishing the quality of EOs and escalating clinical risks. In this research, based on the concept of " combination of medicine and adjuvant, " the unsuitable stabilizer Cinnabaris in Lingzhu powder prescription was modified with a SiO2 surface to become a stabilizer suitable for Pickering emulsion. The modified Cinnabaris was synthesized, with a focus on exploring the surface modification of Cinnabaris to facilitate its role as a stabilizer in Pickering emulsion. Thermal stability studies showed that modified Cinnabaris-stabilized emulsion had higher EOs retention and lower peroxide value and hydrogen peroxide content. GC-MS analysis showed that the volatile components in the emulsion were more stable than the EOs. In vitro dissolution experiments showed that in the dissolution medium of artificial gastric juice and artificial intestinal juice, compared with the ATEO, the release in Pickering emulsion was faster within 48 h, indicating that the ATEO had been encapsulated in Pickering emulsion, which could improve the in vitro dissolution rate of EOs. This study convincingly demonstrates the potential of modified Cinnabaris-stabilized Pickering emulsion to improve the thermal stability and in vitro dissolution rate of EOs.

Preparation and insecticidal performance of 1,8-cineole/cellulose acetate electrospun fibrous membranes

Plant essential oils and their components have broad application prospects as substitutes for chemical pesticides. However, the burst release and persistence time need to be optimized. In this study, 1,8-cineole (1,8-CIN) was embedded in degradable cellulose acetate (CA) by electrospinning to achieve sustained release. The results showed that the sustained-release membrane had good morphology and thermal stability. The release test showed that the deficiency of the explosive release of 1,8-CIN improved after encapsulation, and 21.74 % of the drug remained after 42 days. In the application test, the fiber membrane could kill the test insects in a short period of time and affect the behavior choices of the test insects. It affected the growth and oviposition of the test insects and reduced adult longevity by 13.64 % and oviposition by 23.35 %. This study can improve the utilization rate of pesticides, alleviate environmental pressure, and provide new ideas for pest control.

Alternative protein sources from selected legumes and mushrooms in the development of high-protein instant soup for the elderly

Elderly people are susceptible to malnutrition due to many factors. An essential public health priority is ensuring that seniors have appropriate nutrition to prevent and treat malnutrition and dehydration as well as fulfilling the nutrition necessity. This study was conducted to utilize selected legumes and mushrooms to develop a high-protein instant soup (HPIS) product that is nutritious and suitable for the consumption of the elderly. Black bean, along with oyster mushroom and split-gill mushrooms, exhibited considerable amounts of protein (19.13 ± 1.13, 2.77 ± 0.09, and 4.65 ± 0.61 g/100 g, respectively), calcium (2308.65 ± 113.07, 640.19 ± 0.80, and 743.89 ± 0.66, respectively), iron (40.84 ± 2.42, 7.31 ± 0.05, and 40.10 ± 2.15, respectively), and zinc (18.06 ± 1.07, 3.87 ± 0.03, and 26.23 ± 0.78, respectively) content, and were incorporated into the HPIS formula. Drum dryer rotation speed significantly affected the HPIS properties. The study on the effect of different rotation speeds (3, 5, 7, and 9 RPM) used during the drying process revealed the use of 7 RPM resulting in the soup product with considerable quality. The optimized HPIS formula, which was supplemented with minerals, was moderately liked (7.1-7.5) by the elderly consumer. The majority of the consumers accepted the product (97 %) and were interested in purchasing the product (91 %) if it was available on the market. Incorporating selected legumes and mushrooms resulted in a soup product containing nutrition conforming to the Thai recommended daily intake (RDI), possessing adequate physicochemical and sensory properties for the consumption of the elderly.

GC-MS Combined with Fast GC E-Nose for the Analysis of Volatile Components of Chamomile (Matricaria chamomilla L.)

Chamomile has become one of the world's most popular herbal teas due to its unique properties. Chamomile is widely used in dietary supplements, cosmetics, and herbal products. This study aimed to investigate the volatile aromatic components in chamomile. Two analytical techniques, gas chromatography-mass spectrometry (GC-MS) and an ultra-fast gas chromatography electronic nose, were employed to examine samples from Xinjiang (XJ), Shandong (SD), and Hebei (HB) in China, and imported samples from Germany (GER). The results revealed that all chamomile samples contained specific sesquiterpene compounds, including α-bisabolol, bisabolol oxide, bisabolone oxide, and chamazulene. Additionally, forty potential aroma components were identified by the electronic nose. The primary odor components of chamomile were characterized by fruity and spicy notes. The primary differences in the components of chamomile oil were identified as (E)-β-farnesene, chamazulene, α-bisabolol oxide B, spathulenol and α-bisabolone oxide A. Significant differences in aroma compounds included geosmin, butanoic acid, 2-butene, norfuraneol, γ-terpinene. This study demonstrates that GC-MS and the ultra-fast gas chromatography electronic nose can preliminarily distinguish chamomile from different areas, providing a method and guidance for the selection of origin and sensory evaluation of chamomile. The current study is limited by the sample size and it provides preliminary conclusions. Future studies with a larger sample size are warranted to further improve these findings.

Modulating peppermint oil flavor release properties of emulsion-filled protein gels: Impact of cross-linking method and matrix composition

For some food applications, it is desirable to control the flavor release profiles of volatile flavor compounds. In this study, the effects of crosslinking method and protein composition on the flavor release properties of emulsion-filled protein hydrogels were explored, using peppermint essential oil as a model volatile compound. Emulsion-filled protein gels with different properties were prepared using different crosslinking methods and gelatin concentrations. Flavor release from the emulsion gels was then monitored using an electronic nose, gas chromatography-mass spectrometry (GC-MS), and sensory evaluation. Enzyme-crosslinked gels had greater hardness and storage modulus than heat-crosslinked ones. The hardness and storage modulus of the gels increased with increasing gelatin concentration. For similar gel compositions, flavor release and sensory perception were faster from the heat-crosslinked gels than the enzyme-crosslinked ones. For the same crosslinking method, flavor release and perception decreased with increasing gelatin concentration, which was attributed to retardation of flavor diffusion through the hydrogel matrix. Overall, this study shows that the release of hydrophobic aromatic substances can be modulated by controlling the composition and crosslinking of protein hydrogels, which may be useful for certain food applications.

Preparation and Characterization of Prickly Ash Peel Oleoresin Microcapsules and Flavor Retention Analysis

Prickly ash peel oleoresin (PPO) is a highly concentrated oil of Prickly ash essential oil and has a stronger aroma. However, its low water solubility, high volatility, difficulty in transport and storage, and decomposition by light, heat, and oxygen limit its wider application. To solve this problem, this study used freeze-drying or spray-drying, with soybean protein isolate (SPI) or gum Arabic (GA), combined with aqueous maltodextrin (MD) as the encapsulating agents to prepare four types of PPO microcapsules (POMs). Spray-dried microcapsules with GA as the encapsulating agent achieved a high encapsulation efficiency (EE) of 92.31 ± 0.31%, improved the thermal stability of the PPO, and had spherical morphology. (Headspace solid-phase microextraction/gas chromatography-mass spectrometry) HS-SPME/GC-MS detected 41 volatile compounds in PPO; of these, linalool, β-myrcene, sabinene, and D-limonene were identified as key flavor components. Principal component analysis (PCA) effectively distinguished the significant differences in flavor between PPO, spray-dried SPI/MD microcapsules (SS), and spray-dried GA/MD microcapsules (SG). During 15 days of air-exposure, the loss of flavor from SG (54.62 ± 0.54%) was significantly lower than PPO (79.45 ± 1.45%) and SS (57.55 ± 0.36%). During the air-exposure period, SG consistently had the highest antioxidant capacity, making it desirable for PPO packaging, and expanding its potential applications within the food industry.

Utilization of Peptidoglycans from Lactic Acid Bacterial Cell Walls for the Mitigation of Acrylamide and 5-Hydroxymethylfurfural

Acrylamide (AA) and 5-hydroxymethylfurfural (HMF), which are potentially carcinogenic to humans, are often produced during the hot processing of foods. This study first used a molecular docking model to simulate the binding behavior of four lactic acid bacteria peptidoglycans (PGNs) to AA/HMF, and the binding rate of LAB-based PGNs to AA/HMF was evaluated in vitro. In silico results show that interaction energy is the driving force responsible for the adsorption of LAB-derived PGNs to AA/HMF. In vitro results showed that the PGN of B. lactis B1-04 bound the most AA (28.7%) and HMF (48.0%), followed by L. acidophilus NCFM, B. breve CICC 6079, and L. plantarum CICC 22135. Moreover, an AA/HMF-bound layer on the cell surface of B. lactis B1-04 was observed via AFM and SEM due to adsorption. XPS analysis indicated the removal rate of AA/HMF by selected strains was positively correlated with the proportion of C-O, C=O, and N-H groups of PGNs. The atoms O1, O2, O3, O4, N1, N2, N3, H1, and H2 are involved in the adsorption of LAB-based PGNs to AA/HMF. Thus, the PGNs derived from these four Lactobacillus strains can be regarded as natural adsorbents for the binding of AA/HMF.

Thermal reaction products and formation pathways of two monoterpenes under in situ thermal desorption conditions that mimic vaping coil temperatures

Vaping has become more popular and different brands and types of vaping devices have rapidly emerged. However, little is known about the potential health risks of human inhalation exposures to the volatile chemicals in the vapour, which includes both directly vaporised components of vaping liquid and their reaction products formed during vaping processes. This study investigated reaction products of two monoterpenes (α-pinene and terpinolene) that are used as flavouring agents in vaping liquids with a focus on the identification of reaction products and their formation pathways. The thermal desorption was conducted under an in situ condition that is in the range of heating coil temperature in vaping by thermally desorbing the chemicals at a temperature range of 100-300 °C. Additional clean air was introduced during the thermal desorption. 36 and 29 reaction products were identified from α-pinene and terpinolene, respectively, at a relative concentration of 0.01% and greater in the desorbed mixture. 3-Carene was the dominant reaction product of α-pinene, while reaction products of terpinolene was dominated by p-isopropenyltoluene. Several reaction pathways including ring opening, allylic oxidation, cyclo-etherification, Wagner-Meerwein rearrangement, epoxidation, cleavage and removal of partial structure, and dehydration were involved in the formation of various reaction products. These pathways and resulting relative concentrations of residual parent compound and reaction products were influenced by both temperature and amount of air present during thermal desorption. The study results demonstrate possible existence of reaction products from thermally labile chemicals like monoterpenes in vaping aerosols and can help inform policies regulating vaping devices and products to protect public health.

Rgl-exomiR-7972, a novel plant exosomal microRNA derived from fresh Rehmanniae Radix, ameliorated lipopolysaccharide-induced acute lung injury and gut dysbiosis

Plant-derived exosome-like nanoparticles (ELNs) have been proposed as a novel therapeutic tool for preventing human diseases. However, the number of well-verified plant ELNs remains limited. In this study, the microRNAs in ELNs derived from fresh Rehmanniae Radix, a well-known traditional Chinese herb for treating inflammatory and metabolic diseases, were determined by using microRNA sequencing to investigate the active components in the ELNs and the protection against lipopolysaccharide (LPS)-induced acute lung inflammation in vivo and in vitro. The results showed that rgl-miR-7972 (miR-7972) was the main ingredient in ELNs. It exerted stronger protective activities against LPS-induced acute lung inflammation than catalpol and acteoside, which are two well-known chemical markers in this herb. Moreover, miR-7972 decreased the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), reactive oxygen species (ROS) and nitric oxide (NO) in LPS-exposed RAW264.7 cells, thereby facilitating M2 macrophage polarization. Mechanically, miR-7972 downregulated the expression of G protein-coupled receptor 161 (GPR161), activating the Hedgehog pathway, and inhibited the biofilm form of Escherichia coli via targeting virulence gene sxt2. Therefore, miR-7972 derived from fresh R. Radix alleviated LPS-induced lung inflammation by targeting the GPR161-mediated Hedgehog pathway, recovering gut microbiota dysbiosis. It also provided a new direction for gaining novel bioactivity nucleic acid drugs and broadening the knowledge on cross-kingdom physiological regulation through miRNAs.

A new green approach for Lavandula stoechas aroma recovery and stabilization coupling supercritical CO2 and natural deep eutectic solvents

This work investigated a green approach to obtain and stabilize Lavandula stoechas L. volatile organic compounds with sensory aroma characteristics by using alternative solvents, namely supercritical carbon dioxide (scCO₂) and deep eutectic solvents (DES). The CO₂ extracts were dispersed in different DES mixtures (betaine:ethylene glycol (1:3), betaine:glycerol (1:2), and glycerol:glucose (4:1)) and their stability was monitored during 6 months of storage at room temperature by monitoring the headspace (HS) profile. The CO₂ extract was used as the control. It was initially determined that there was a dominant presence of oxygenated monoterpenes (67.33-77.50%) in the extracts. During storage, significant changes occurred in the samples' HS, such as the decrease in terpene hydrocarbons which also affected the presence of oxygenated terpenes, which increased in certain cases. Moreover, the highest formation of new components was recorded in the control which could be an indicator of decreased stability. The DESs-CO₂ were more stable than the CO₂ control and among them, betaine:ethylene glycol stood out as the most adequate systems for maintaining the stability of L. stoechas HS components. For the visual estimation of similarities and dissimilarities among the samples, chemometric pattern recognition approaches were applied including the hierarchical cluster analysis, principal component analysis, and sum of ranking differences.

Impact of cooking methods on the quality, sensory and flavor compounds of Sichuan pepper oleoresin

Sichuan pepper oleoresin (SPO) is highly appreciated by the food industry as well as consumers for flavor. To understand the overall flavor of SPO and how the quality changes during practical application, this study investigated the effects of five cooking methods on the quality, sensory, and flavor compounds of SPO. The differences in physicochemical properties and sensory evaluation responded to potential changes in SPO after cooking. The SPO after different cooking could be clearly distinguished by E-nose and PCA. Based on the qualitative analysis of volatile compounds, 13 compounds were screened by OPLS-DA that had the ability to explain above differences. Further analysis of taste substances revealed that pungent substances (hydroxy-α-sanshool) were significantly reduced in SPO after cooking. And the conclusion that the degree of bitterness significantly increased was predicted by E-tongue. The PLS-R model was developed to achieve correlation analysis between aroma molecules and sensory quality.

Effect of Different Vegetable Oils on the Flavor of Fried Green Onion (Allium fistulosum L.) Oil

The flavor of fried green onion oil (Allium fistulosum L.) is widely applied and popular in Chinese cuisine. This work aimed to explore the effects of different varieties of vegetable oils on the flavor profile generation of fried green onion oil. The volatile flavor components of seven different kinds of fried green onion oils, i.e., soybean oil, palm oil, olive oil, corn oil, sunflower oil, camellia oil, and colza oil, were identified and analyzed by sensory analysis, gas chromatography–mass spectrometry (GC-MS) and electronic nose. The results showed that sensory analysis and electronic nose were accepted to detect the odor diversities of different kinds of fried green onion oil sensitively. A total of 103 volatile flavor components were identified positively, and the key aromas included aldehydes and sulfur-containing compounds that correlated highly with green grass, oily, pungent and shallot scent attributes. Meanwhile, fatty acid compositions showed that there were no significant changes in the types of fatty acids before and after frying, but the relative content was not different. Accordingly, the unsaturated fatty acids (UFA, C18:1, C18:2, C18:3, and C20:1) had a significant influence on the flavor of frying oil, which was peculiarly prone to oxidation and heat degradation reactions. These results provided a theoretical basis for further application of fried onion flavor in the food industry.

Basic sensory properties of essential oils from aromatic plants and their applications: a critical review

With higher standards in terms of diet and leisure enjoyment, spices and essential oils of aromatic plants (APEOs) are no longer confined to the food industry. The essential oils (EOs) produced from them are the active ingredients that contribute to different flavors. The multiple odor sensory properties and their taste characteristics of APEOs are responsible for their widespread use. The research on the flavor of APEOs is an evolving process attracting the attention among scientists in the past decades. For APEOs, which are used for a long time in the catering and leisure industries, it is necessary to analyze the components associated with the aromas and the tastes. It is important to identify the volatile components and assure quality of APEOs in order to expand their application. It is worth celebrating the different means by which the loss of flavor of APEOs can be retarded in practice. Unfortunately, relatively little research has been done on the structure and flavor mechanisms of APEOs. This also points the way to future research on APEOs.Therefore, this paper reviews the principles of flavor, identification of components and sensory pathways in humans for APEOs. Moreover, the article outlines the means of increasing the efficiency of using of APEOs. Finally, with respect to the sensory applications of APEOs, the review focuses on the practical application of APEOs in food sector and in aromatherapy.

Antioxidant Activity and GC-MS Profile of Cardamom (Elettaria cardamomum) Essential Oil Obtained by a Combined Extraction Method-Instant Controlled Pressure Drop Technology Coupled with Sonication

Cardamom Essential oils are highly demanded because of their antimicrobial, anti-inflammatory, and antioxidant activities. Nonetheless, retrieving quality extracts quickly with efficient energy savings has been challenging. Therefore, green technologies are emerging as possible alternatives. Thus, this study evaluates the yield and quality of the instant controlled pressure drop (DIC) process coupled with ultrasound-assisted extraction (UAE) of cardamom essential oil (CEO). Likewise, the antioxidant activity, chemical profile of CEO, and microstructure of seeds were analyzed. This study analyzed 13 different treatments with varying saturated steam processing temperatures (SSPT), thermal processing times (TPT), and 1 control. The results showed that CEO yield increased significantly by DIC (140 °C and 30 s) and UAE compared to the control (22.53% vs. 15.6%). DIC 2 (165 °C, 30 s) showed the highest DPPH inhibition (79.48%) and the best Trolox equivalent antioxidant capacity (TEAC) by the control with 0.60 uMTE/g. The GC/MS analysis showed 28 volatile constituents, withα-Terpinyl acetate, geranyl oleate, and oleic acid being the most abundant. DIC (140 °C and 30 s) and UAE showed the best yield and chemical profile. The SEM microscopy of untreated seeds revealed collapsed structures before the oil cell layer, which reduced the extraction yield, contrary to DIC-treated seeds, with more porous structures. Therefore, combining innovative extraction methods could solve the drawbacks of traditional extraction methods.

Metabolomics insights into the potential of encapsulated essential oils as multifunctional food additives

Growing consumer concern about foodborne disease outbreaks and health risks associated with chemical additives has propelled the usage of essential oils (EOs) as novel food additives, but are limited by instability. In this regard, a series of EOs nano/micro-capsules have been widely used to enhance their stability and improve food quality. However, classical food quality assessment methods are insufficient to fully characterize the effects of encapsulated EOs on food properties, including physical, biochemical, organoleptic, and microbial changes. Recently, the rapid development of high-throughput sequencing is accelerating the application of metabolomics in food safety and quality analysis. This review seeks to present the most recent achievements in the application of non-targeted metabolomics to identify and quantify the overall metabolite profile associated with food quality, which can guide the development of emerging food preservation technologies. The scientific findings confirm that metabolomics opens up exciting prospects for biomarker screening in food preservation and contributes to an in-depth understanding of the mechanisms of action (MoA) of EOs. Future research should focus on constructing food quality assessment criteria based on multi-omics technologies, which will drive the standardization and commercialization of EOs for food industry applications.

Nano-Encapsulation of Citrus Essential Oils: Methods and Applications of Interest for the Food Sector

Citrus essential oils possess many health-promoting benefits and properties of high interest in the food and agri-food sector. However, their large-scale application is limited by their sensitivity to environmental factors. Nanostructures containing citrus essential oils have been developed to overcome the high volatility and instability of essential oils with respect to temperature, pH, UV light, etc. Nanostructures could provide protection for essential oils and enhancement of their bioavailability and biocompatibility, as well as their biological properties. Nano-encapsulation is a promising method. The present review is mainly focused on methods developed so far for the nano-encapsulation of citrus essential oils, with emphasis on lipid-based (including liposomes, solid lipid nanoparticles, nanostructured lipid particles, and nano- and micro-emulsions) and polymer-based nanostructures. The physico-chemical characteristics of the obtained structures, as well as promising properties reported, with relevance for the food sector are also discussed.

Citrus juice off-flavor during different processing and storage: Review of odorants, formation pathways, and analytical techniques

As the most widespread juice produced and consumed globally, citrus juice (mandarin juice, orange juice, and grapefruit juice) is appreciated for its attractive and distinct aroma. While the decrease of characteristic aroma-active compounds and the formation of off-flavor compounds are easy to occur in processing and storage conditions. This review provides a comprehensive literature of recent research and discovery on citrus juice off-flavor, primarily focusing on off-flavor compounds induced during processing and storage (i.e., thermal, storage, light, oxygen, package, fruit maturity, diseases, centrifugal pretreatment, and debittering process), formation pathways (i.e., terpene acid-catalyzed hydration, caramelization reaction, Maillard reaction, Strecker degradation, and other oxidative degradation) of the off-flavor compounds, effective inhibitor pathway to off-flavor (i.e., electrical treatments, high pressure processing, microwave processing, ultrasound processing, and chemical treatment), as well as odor assessment techniques based on molecular sensory science. The possible precursors (terpenes, sulfur-containing amino acids, carbohydrates, carotenoids, vitamins, and phenolic acids) of citrus juice off-flavor are listed and are also proposed. This review intends to unravel the regularities of aroma variations and even off-flavor formation of citrus juice during processing and storage. Future aroma analysis techniques will evolve toward a colorimetric sensor array for odor visualization to obtain a "marker" of off-flavor in citrus juice.

Comparison of the Antioxidant Activities and Polysaccharide Characterization of Fresh and Dry Dendrobium officinale Kimura et Migo

It is generally believed that fresh Dendrobium officinale (FDO) has more significant pharmacological activity than dried Dendrobium officinale (DDO); however, the difference has not been clearly shown. Our study compared their antioxidant properties both in vitro and in vivo, and the molecular weight arrangement and monosaccharide composition of the fresh Dendrobium officinale polysaccharides (FDOPs) and the dried Dendrobium officinale polysaccharides (DDOPs) were analyzed by HPLC-GPC and GC-MS. The results showed that the FDO and its polysaccharides had more significant effects on scavenging DPPH, ABTS, and hydroxyl radicals than the DDO. In addition, both the FDO and DDO significantly reduced lipid peroxidation levels and increased the SOD, T-AOC, CAT, and GSH levels in mice with acute liver damage caused by CCl₄, while the FDO and its polysaccharides were more effective. Histopathological analysis further verified the protective effect of the Dendrobium polysaccharides on CCl₄-induced liver injury. The determination of the polysaccharides revealed that the polysaccharide and mannose contents of the FDO were significantly higher than their dried counterparts, and the homogeneous arrangement of the polysaccharides in the FDO was degraded into three polysaccharide fragments of different molecular weights in the DDO. Overall, our data identified differences in the antioxidant activities of the FDO and DDO, as well as the reasons for these differences.

Unpruning improvement the quality of tea through increasing the levels of amino acids and reducing contents of flavonoids and caffeine

Tea tree [Camellia sinensis var. sinensis or assamica (L.) O. Kuntze], an important crop worldwide, is usually pruned to heights of 70 to 80 cm, forming pruned tea tree (PTT) plantations. Currently, PTTs are transformed into unpruned tea tree (UPTT) plantations in Yunnan, China. This has improved the quality of tea products, but the underlying reasons have not been evaluated scientifically. Here, 12 samples of sun-dried green teas were manufactured using fresh leaves from an UPTT and the corresponding PTT. Using sensory evaluation, it was found that the change reduced the bitterness and astringency, while increasing sweetness and umami. Using high performance liquid chromatography detection showed that the contents of free amino acids (theanine, histidine, isoleucine and phenylalanine) and catechin gallate increased significantly (P < 0.05), whereas the content of alanine decreased significantly (P < 0.05). A liquid chromatography–mass spectrometry-based metabolomics analysis showed that the transformation to UPTT significantly decreased the relative levels of the majority of flavonols and tannins (P < 0.05), as well as γ-aminobutyric acid, caffeine and catechin (epigallocatechin, catechin, epigallocatechin gallate, gallocatechin gallate), while it significantly increased the relative contents of catechins (gallocatechin, epicatechin, epicatechin gallate and catechin gallate), phenolic acids and some amino acids (serine, oxidized glutathione, histidine, aspartic acid, glutamine, lysine, tryptophan, tyramine, pipecolic acid, and theanine) (P < 0.05). In summary, after transforming to UPTT, levels of amino acids, such as theanine increased significantly (P < 0.05), which enhanced the umami and sweetness of tea infusions, while the flavonoids (such as kaempferol, myricetin and glycosylated quercetin), and caffeine contents decreased significantly (P < 0.05), resulting in a reduction in the bitterness and astringency of tea infusions and an increase in tea quality.

Combination Strategies of Different Antimicrobials: An Efficient and Alternative Tool for Pathogen Inactivation

Despite the discovery and development of an array of antimicrobial agents, multidrug resistance poses a major threat to public health and progressively increases mortality. Recently, several studies have focused on developing promising solutions to overcome these problems. This has led to the development of effective alternative methods of controlling antibiotic-resistant pathogens. The use of antimicrobial agents in combination can produce synergistic effects if each drug invades a different target or signaling pathway with a different mechanism of action. Therefore, drug combinations can achieve a higher probability and selectivity of therapeutic responses than single drugs. In this systematic review, we discuss the combined effects of different antimicrobial agents, such as plant extracts, essential oils, and nanomaterials. Furthermore, we review their synergistic interactions and antimicrobial activities with the mechanism of action, toxicity, and future directions of different antimicrobial agents in combination. Upon combination at an optimum synergistic ratio, two or more drugs can have a significantly enhanced therapeutic effect at lower concentrations. Hence, using drug combinations could be a new, simple, and effective alternative to solve the problem of antibiotic resistance and reduce susceptibility.

Coacervation as a Novel Method of Microencapsulation of Essential Oils-A Review

These days, consumers are increasingly "nutritionally aware". The trend of "clean label" is gaining momentum. Synthetic additives and preservatives, as well as natural ones, bearing the E symbol are more often perceived negatively. For this reason, substances of natural origin are sought tfor replacing them. Essential oils can be such substances. However, the wider use of essential oils in the food industry is severely limited. This is because these substances are highly sensitive to light, oxygen, and temperature. This creates problems with their processing and storage. In addition, they have a strong smell and taste, which makes them unacceptable when added to the product. The solution to this situation seems to be microencapsulation through complex coacervation. To reduce the loss of essential oils and the undesirable chemical changes that may occur during their spray drying-the most commonly used method-complex coacervation seems to be an interesting alternative. This article collects information on the limitations of the use of essential oils in food and proposes a solution through complex coacervation with plant proteins and chia mucilage.

In-situ TD-GCMS measurements of oxidative products of monoterpenes at typical vaping temperatures: implications for inhalation exposure to vaping products

Vaping is gaining in popularity. However, there is still much that remains unknown about the potential risk and harms of vaping. Formation of oxidative products is one of such areas that are not well understood. In this study, we used an in-situ thermal desorption GC/MS method to investigate the formation of oxidative products of several monoterpenes at or below typical vaping temperatures. Among the five tested monoterpenes, the unchanged portion of the parent compound in the vapour varied from 97 to 98% for myrcene to 11–28% for terpinolene. The majority of formed oxidative products in the vapour have a molecular weight of 134 (loss of two hydrogens), 150 (insertion of one oxygen and loss of two hydrogen atoms) or 152 (insertion of one oxygen atom). Three products, likely to be p-(1-propenyl)-toluene, β-pinone and fenchol were also observed. This is the first in-situ thermal desorption GC/MS study to investigate the possible formation of oxidative products of monoterpenes, one of the major components in vaping liquids, at temperatures that are relevant to the vaping process. Although the toxicity of inhaling these oxidative products is not clear yet, allergic and irritation reactions associated with oxidized monoterpene oils are well documented. Therefore, potential adverse effects of inhaling these oxidative products during vaping could be investigated to help support human risk assessment.

Effects of High-Pressure, Hydrothermal, and Enzyme-Assisted Treatment on the Taste and Flavor Profile of Water-Soluble Ginger (Zingiber officinale) Extract

Ginger, a plant widely consumed worldwide, is used as a spice or to enhance the flavor of foods. In this study, the taste characteristics (gingerol, shogaol, and amino acid) of extracts treated with various solubilizing methods were objectively compared. In addition, an E-nose confirmed the flavor pattern combined with principal component analysis (PCA) between each extract gas chromatogram-tandem mass spectrometry was performed to compare and analyze volatile compounds between extraction methods. As a result, high-pressure enzyme-assisted extraction (HPE) and hydrothermal enzyme-assisted extraction (HWE) treatment effectively improved the extraction yield of ginger and the contents of gingerol and shogaol and removed the bitter taste. In addition, radar charts of both E-nose and PCA provided the distribution of flavor substances in HPE and HWE products of ginger. After enzyme-assisted treatment, a strong fruity and piquant flavor was noted. In conclusion, it is suggested that ginger extract of enzyme-assisted treatment has increased flavor compounds and can be an excellent food material.

Essential Oil Variability of Azorean Cryptomeriajaponica Leaves under Different Distillation Methods, Part 1: Color, Yield and Chemical Composition Analysis

This study mainly deals with the effect of hydrodistillation (HD) and water-steam distillation (WSD) methods on the color, yield, and chemical profile of the essential oil (EO) from Cryptomeria japonica fresh leaves from São Miguel Island (Azores Archipelago, Portugal). The yields of EO–HD (pale-yellowish) and EO–WSD (colorless) samples were 1.21% and 0.45% (v/w), respectively. The GC–FID, GC–MS, and 13C-NMR analyses of EO–HD vs. EO–WSD revealed (i) a high-content of monoterpenes (72.8% vs. 86.7%), mainly α-pinene (34.5% vs. 46.4%) and sabinene (20.2% vs. 11.6%), and oxygenated mono- and sesquiterpenes (20.2% vs. 9.6%); (ii) similar sesquiterpene (1.6% vs. 1.6%), β-myrcene (5.9% vs. 5.8%), and camphene (3.5% vs. 3.8%) contents; and (iii) significant differences in other classes/components: EO–HD is richer in oxygenated sesquiterpenes (17.1%, mainly elemol (10.4%) and α-eudesmol (3.4%)) and diterpenes (3%; mostly phyllocladene), while EO–WSD is richer in oxygenated monoterpenes (7.2%, mainly terpinen-4-ol (5.4%)), p-cymene (4.4%), and limonene (3.2%). Overall, the color, yield, and quantitative composition of the EO samples studied are strongly influenced by the distillation method. Nonetheless, this C. japonica leaf EO displayed a consistent α-pinene- and sabinene-rich composition. The same chemotype was found in a commercial Azorean C. japonica leaf EO sample, obtained by industrial steam distillation (SD), as well as in Corsica C. japonica leaf EO–HD. Furthermore, the bioactive composition of our EO samples revealed the potential to be used in green plant protection and in the medical, food, cosmetic, and household industries.