Fruity Aroma Research Articles

Elucidation of the sweetening mechanism of sweet orange fruit aroma compounds on sucrose solution using sensory evaluation, electronic tongue, molecular docking, and molecular dynamics simulation

Sweetness enhancement through aroma has been suggested as a strategy to mitigate sugar addition in foods, but such enhancement depends on the type of aroma. Ethyl propanoate, ethyl 2-methylbutanoate, octyl acetate, ethyl butanoate, ethyl hexanoate, butyl hexanoate, γ-terpinene, nootkatone, and acetophenone with fruity aroma from sweet orange were selected as the objects to investigate the sweetening effect of aroma compounds in a 5% sucrose solution using an artificial sensory tongue and an electronic tongue. The results showed that nine aroma compounds exerted a significant effect on the sweetness, among which ethyl butanoate, ethyl propanoate, and ethyl 2-methylbutanoate imparted a more comfortable effect. Subsequently, the mechanism of their sweetening action was studied by molecular simulation. Molecular docking results indicated that the binding free energy decreased below −5.9 kcal/mol in the presence of aroma compounds, indicating that sucrose was more tightly docked to the sweet taste receptor. Molecular dynamics (MD) further implied that under the influence of ethyl butanoate, the stable time of binding was advanced by 15 ns, and the amino acids forming hydrogen bonds changed from LYS65, ASP278, GLU302, SER165, and SER303 to SER165, ASP142, LYS65, and GLU302. The interaction depends on hydrogen bonds, water bridges, and hydrophobic forces.

Effects of natural and synthetic antioxidants addition on the characteristic flavor and metabolites of walnut oil during oxidation

Antioxidants are commonly used to enhance the oxidative stability of oils, while its effects on flavor are rarely investigated. In this paper, the antioxidant capacity of two synthetic and two natural antioxidants in walnut oil (WO) were evaluated firstly. Tert-butyl hydroquinone (0.2 g/kg, TBHQ 0.2) and rosemary extract (0.5 g/kg, RE 0.5) exhibited better antioxidant activity. The volatile organic compounds (VOCs) profile changes of WO with TBHQ and RE addition were explored. It is suggested that TBHQ 0.2 and RE 0.5 can effectively delay the increase of VOCs, especially aldehydes. The concentrations of differential metabolites of WO during oxidation including 1-octen-3-ol, hexenal, and (E)-2-heptenal in RE 0.5 were lower than TBHQ 0.2 group, which were original from linolenic acid and linoleic acid. Sensory evaluation indicated TBHQ and RE can maintain the original aroma of WO during oxidation, while RE can enhance the green and fruity aroma.

Effects of storage time on flavor characteristics of bran-free fermented Baijiu by using electronic sensory, descriptive sensory analysis, GC × GC–MS, and ICP-MS

By examining and analyzing bran-free fermented Baijiu (BFB) with varying storage periods (0–20 years), it was observed that the overall concentration of volatile compounds initially increases and subsequently decreases over time. Furthermore, BFB exhibited more kinds of long chain esters, higher concentration of acetals, and reduced furfural content. The process of cellaring can enhance the aged, sweet, and fruity aroma of BFB. 16 flavor compounds, including 1,1-diethoxyethane, ethyl dodecanoate, and ethyl hexadecanoate, can be used as markers for vintage BFB, and electronic sensory technology was capable of discerning BFB in different years. The results of redundancy analysis (RDA) showed a positive correlation between metals and aldehydes, esters, and ketones, while indicating a negative correlation with acids and alcohols. Al, Fe, and Ca underwent the most significant changes during storage period, and they were positively correlated with differential substances, such as benzaldehyde, vanillin, ethyl isovalerate, and ethyl palmitate (P < 0.01).

Widely targeted metabolomic analysis reveals metabolite changes induced by incorporating black tea fermentation techniques in oolong tea processing for quality improvement

Oolong tea, a semi-fermented tea, has a prominent fruity and floral aroma, resembling green tea's astringency and pungency but lacking black tea's mellowness. Oolong tea incorporating black tea fermentation techniques (OT-IBTFT) not only retained its excellent floral and fruity aroma but also reduced astringency and enriched taste. However, metabolite changes remain unknown. In this study, widely targeted metabolomic analysis showed OT-IBTFT reduced prunin, gallocatechin, methyl gallate, and increased loliolide by changing the flavonoid biosynthesis and biosynthesis of secondary metabolites pathways, thereby reducing the astringency and increasing the mellow taste and richness to improve oolong tea quality. In addition, Wrap-rolling 5 times increased fermentation, improving the color and aroma of oolong tea by increasing theaflavic acid and 2-furoic acid, is more significant than wrap-rolling once. In conclusion, these findings provide a theoretical basis for the improvement of oolong tea processing techniques and flavor and quality control.

САХАРНОЕ ПЕЧЕНЬЕ И КЕКСЫ, ОБОГАЩЕННЫЕ ПЛОДАМИ ШИПОВНИКА МАЙСКОГО

The purpose of research is to study the effect of different amounts of rosehip powder on the quality of sugar cookies and cakes made from premium wheat flour. Tasks: preparing powder from the pulp of rose hips; setting up a laboratory experiment with different dosages of rosehip powder (RP); a comparative study of its effect on quality and nutritional value using the example of sugar cookies and muffins. RP was added to products in amounts of 3, 6, 9, 12 and 15 % instead of wheat flour in dry matter. The control for the studied variants were products without RP. The object of study is a fine powder of light orange color, with a fruity aroma, sweet and sour, slightly astringent taste. The humidity of the RP was (9.3 ± 0.23) %; titratable acidity – (14.1 ± 0.17) mmol H+/100 g; vitamin C content – 3.66 %; content of polyuronides (pectin substances) – 13.8 %. A tasting assessment of sugar cookies showed the optimal option with the addition of 6 and 9 % RP; For the cake, the optimal option was to add 12 % powder. A further increase in the amount of added RP showed a deterioration in the organoleptic properties due to the appearance, taste and aroma of the products. The moisture content of the products did not depend on the amount of RP and was in the range of 8.8–9.2 % for cookies and 12.5–13.0 % for cake. In the control sample and variants with a dosage of 3 and 6 %, the porosity of the cookies was assessed as good; for options with dosages of 9 and 12 % – average; 15 % is bad. The wetness of cookies decreased with an increase in the amount of added PS. In sugar cookies with 6 % RP, the vitamin C content increases by 121 mg/100 g compared to the control; in the Stolichny cake, when adding 12 % PS, it increases by 241 mg/100 g.

Evolution of Aroma Profiles in Vitis vinifera L. Marselan and Merlot from Grapes to Wines and Difference between Varieties.

The fermentation process has a significant impact on the aromatic profile of wines, particularly in relation to the difference in fermentation matrix caused by grape varieties. This study investigates the leaching and evolution patterns of aroma compounds in Vitis vinifera L. Marselan and Merlot during an industrial-scale vinification process, including the stages of cold soak, alcohol fermentation, malolactic fermentation, and one-year bottle storage. The emphasis is on the differences between the two varieties. The results indicated that most alcohols were rapidly leached during the cold soak stage. Certain C6 alcohols, terpenes, and norisoprenoids showed faster leaching rates in 'Marselan', compared to 'Merlot'. Some branched chain fatty-acid esters, such as ethyl 3-methylbutyrate, ethyl 2-methylbutyrate, and ethyl lactate, consistently increased during the fermentation and bottling stages, with faster accumulation observed in 'Marselan'. The study combines the Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) model based on odor activity values to elucidate the accumulation of these ethyl esters during bottle storage, compensating for the reduction in fruity aroma resulting from decreased levels of (E)-β-damascenone. The 'Marselan' wine exhibited a more pronounced floral aroma due to its higher level of linalool, compared to the 'Merlot' wine. The study unveils the distinctive variation patterns of aroma compounds from grapes to wine across grape varieties. This provides a theoretical framework for the precise regulation of wine aroma and flavor, and holds significant production value.

Uncovering the Shuixian tea grades hierarchy in Chinese national standard: From sensory evaluation to microstructure and volatile compounds analysis

Basic standard samples are integral for ensuring consistency and quality control of tea. Understanding the real reasons behind the hierarchical system of Shuixian tea grades in the Chinese national standard is crucial to the scientific development of tea standardization. In this investigation, different grade samples of Shuixian tea strictly conformed to the Chinese national standard, serving as the research objects. Sensory evaluation, SEM and HS-SPME-GC–MS were employed to comprehensively analyze the aroma characteristics. The odor profiles of special grade samples predominantly featured floral and fruity aromas, which attributed to compounds such as geraniol, indole, phenylethyl alcohol. Additionally, hexanal, (E)-3-hexen-1-ol and other compounds contributed to fruity and sweet aroma in first grade. Notably, the predominant roasted and sweet aromas of second grade were attributed to compounds including pyridine, 2,5-dimethyl-pyrazine. This study lays a solid foundation for the scientific development of Chinese national standards and international standard system.

Integrated Transcriptomic and Metabolomic Analysis Revealed Abscisic Acid-Induced Regulation of Monoterpene Biosynthesis in Grape Berries.

Monoterpenes are a class of volatile organic compounds that play crucial roles in imparting floral and fruity aromas to Muscat-type grapes. However, our understanding of the regulatory mechanisms underpinning monoterpene biosynthesis in grapes, particularly following abscisic acid (ABA) treatment, remains elusive. This study aimed to explore the impact of exogenous ABA on monoterpene biosynthesis in Ruiduhongyu grape berries by employing Headspace Solid-Phase Micro-Extraction Gas Chromatography-Mass Spectrometry (HS-SPME/GC-MS) analysis and transcriptome sequencing. The results suggested significant differences in total soluble solids (TSS), pH, and total acid content. ABA treatment resulted in a remarkable increase in endogenous ABA levels, with concentrations declining from veraison to ripening stages. ABA treatment notably enhanced monoterpene concentrations, particularly at the E_L37 and E_L38 stages, elevating the overall floral aroma of grape berries. According to the variable gene expression patterns across four developmental stages in response to ABA treatment, the E_L37 stage had the largest number of differential expressed genes (DEGs), which was correlated with a considerable change in free monoterpenes. Furthermore, functional annotation indicated that the DEGs were significantly enriched in primary and secondary metabolic pathways, underlining the relationship between ABA, sugar accumulation, and monoterpene biosynthesis. ABA treatment upregulated key genes involved in the methylerythritol phosphate (MEP) pathway, enhancing carbon allocation and subsequently impacting terpene synthesis. This study also identified transcription factors, including MYB and AP2/ERF families, potentially modulating monoterpene and aroma-related genes. Weighted gene co-expression network analysis (WGCNA) linked ABA-induced gene expression to monoterpene accumulation, highlighting specific modules enriched with genes associated with monoterpene biosynthesis; one of these modules (darkgreen) contained genes highly correlated with most monoterpenes, emphasizing the role of ABA in enhancing grape quality during berry maturation. Together, these findings provide valuable insights into the multifaceted effects of exogenous ABA on monoterpene compounds and grape berry flavor development, offering potential applications in viticulture and enology.

Study of the fruity aroma of red wines made from grape varieties potentially adapted to climate change using a semi-preparative HPLC method

Under climate change, the fruity aroma of Bordeaux red wines is changing, tending toward undesirable aromas like dried and cooked fruits. To adapt to these changes in aroma, a strategy could be to introduce to Bordeaux vineyards late-ripening grape varieties more suited to drier, sunnier and warmer conditions. A comparative analysis involved traditional Bordeaux red wines (Merlot, Cabernet-Sauvignon, and Cabernet franc) and those from late-ripening grape varieties originating from high-temperature climates (Yiannoudin, Syrah, Agiorgitiko, Xinomavro, Touriga Nacional, Grenache, and Tempranillo). Using a semi-preparative HPLC method, aroma extracts from these ten red wines were fractioned, isolating fruity notes for HPLC–Fruity Aromatic Reconstitutions (FAR). Through a free sorting task, three clusters emerged. Targeted GC-MS analysis highlighted nine compounds characterizing sensory clusters, including ethyl 2-methylpropanoate, ethyl hexanoate, ethyl 6-hydroxyhexanoate, linalool, α-terpineol, α- and β-ionones, hexanol and (Z)-3-hexenol. Through the realization of sensory profiles, it has been demonstrated that by incorporating these compounds into a fruity model solution, fresh red- and black-berry fruit notes are intensified.

Unveiling the synthesis of aromatic compounds in sauce-flavor Daqu from the functional microorganisms to enzymes

Aromatic compounds serve as the primary source of floral and fruity aromas in sauce-flavor (Maotai flavor) baijiu, constituting the skeleton components of its flavor profile. Nevertheless, the formation mechanism of these compounds and key aroma-producing enzymes in sauce-flavor Daqu (fermentation agent, SFD) remain elusive. Here, we combined metagenomics, metaproteomics, metabolomics, and key enzyme activity to verify the biosynthesis pathway of aromatic compounds and to identify key enzymes, genes, and characteristic microorganisms in SFD. The results showed that the later period of fermentation was critical for the generation of aromatic compounds in SFD. In-situ verification was conducted on the potential key enzymes and profiles in various metabolites, providing comprehensive evidence for the main synthetic pathways of aromatic compounds in SFD. Notably, our results showed that primary amine oxidase (PrAO) and aldehyde dehydrogenase (ALDH) emerged as two key enzymes promoting aromatic compound synthesis. Additionally, two potential key functional genes regulating aromatics generation were identified during SFD fermentation through correlation analysis between proteins and relevant metabolites, coupled with in vitro amplification test. Furthermore, original functional strains (Aspergillus flavus-C10 and Aspergillus niger-IN2) exhibiting high PrAO and ALDH production were successfully isolated from SFD, thus validating the results of metagenomics and metaproteomics analyses. This study comprehensively elucidates the pathway of aromatic compound formation in SFD at the genetic, proteomic, enzymatic, and metabolomic levels, providing new ideas for the investigation of key flavor substances in baijiu. Additionally, these findings offer valuable insights into the regulatory mechanisms of aromatic compounds generation.

Chemical Profile and Aroma Effects of Major Volatile Compounds in New Mulberry Leaf Fu Brick Tea and Traditional Fu Brick Tea.

This study aimed to investigate the aroma effects of key volatile compounds in a new type of mulberry leaf Fu brick teas (MTs) and traditional Fu brick teas (FTs). Headspace solid-phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS), sensory evaluation, and chemometrics were used to determine the differences in key flavour qualities between the two. The results showed that a total of 139 volatile components were identified, with aldehydes, ketones, and alcohols dominating. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) combined with the odour activity value (OAV) showed that seven aroma compounds had an OAV > 10, including 2-(4-methylcyclohex-3-en-1-yl) propan-2-ol with floral and fruity aroma and green attributes, 6-methylhept-5-en-2-one, (E)-6,10-dimethyl-5,9-Undecadien-2-one, (3E,5E)-octa-3,5-dien-2-one, Benzaldehyde, and (E)-3,7,11,15-tetramethylhexadec-2-en-1-ol, which were more abundant in MTs than FTs; Cedrol with sweet aroma attributes was more consistent in MTs than FTs, and we suggest that these odour compounds are important aroma contributors to MTs. Taken together, these findings will provide new insights into the mechanism of formation of the characteristic attributes of aroma in MTs.

Microbial cell factory for butyl butyrate production: Knowledges and perspectives.

Butyl butyrate is a short-chain fatty acid ester (C8) with a fruity aroma. It has broad prospects in the fields of foods, cosmetics and biofuels. At present, butyl butyrate is produced by chemical synthesis in the industry, but it is highly dependent on petroleum-based products. The growing concerns regarding the future scarcity of fossil fuels have been strongly promoted the transition from traditional fossil fuels and products to renewable bioenergy and biochemicals. Therefore, it is necessary to develop a green biochemical technology to replace traditional petroleum-based materials. In recent years, microorganisms such as Escherichia coli and Clostridium have been engineered to serve as cell factories for the sustainable one-pot production of short-chain fatty acid esters, including butyl butyrate. This opinion highlights the recent development in the use of lipases and alcohol acyltransferases (AATs) for butyl butyrate production in microbial fermentation, as well as future perspectives.

Volatile Profile Characterization of Jujube Fruit via HS-SPME-GC/MS and Sensory Evaluation.

Current research does not fully elucidate the key compounds and their mechanisms that define the aroma profile of fresh jujube fruits. Therefore, this study conducted a comprehensive analysis of both free and glycosidically bound aroma compounds in fresh jujube fruits of ten cultivars. Utilizing gas chromatography-mass spectrometry (GC-MS), we identified 76 volatile free aroma compounds and 19 glycosidically bound volatile compounds, with esters, aldehydes, and ketones emerging as the predominant volatile compounds in the jujube fruits. Odor activity value (OAV) analysis revealed that the primary aroma profile of the jujubes is characterized by fruity and fatty odors, with β-damascenone being a key contributor to the fruity aroma, and (E)-2-oct-en-1-al and nonanal significantly influencing the fatty aroma. Moreover, the integration of sensory evaluation and partial least squares regression (PLSR) analysis pinpointed octanal, (E)-2-oct-en-1-al, nonanal, β-damascenone, and pentanal as significant contributors to the jujube's characteristic aroma, while isoamyl acetate was identified as significantly influencing the fatty acid taste. This study not only underscores the complexity of the jujube aroma composition but also highlights the impact of environmental factors on aroma profiles, offering valuable insights into the sensory characteristics of jujube fruits.

Comparison of Flavor Profiles of Honey Peach Cultivars by Gas Chromatography–Mass Spectrometry (GC–MS) with Odor Activity Values (OAVs), E-Tongue, and Sensory Evaluation Combined with Chemometrics

The honey peach is popular due to its unique flavor. However, the flavor characteristics of honey peaches cultivated in Yangzhou and Wuxi remain unclear. In this study, the flavor profiles in five famous honey peaches, Yangzhou Baifeng (YBF), Yangzhou Zhonghujing (YZHJ), Yangzhou Wanhujing (YWHJ), Wuxi Baifeng (WBF), and Wuxi Wanhujing (WWHJ), were investigated using gas chromatography-mass spectrometry (GC–MS) combined with odor activity values (OAVs), electronic tongue (E-tongue) and sensory evaluation. A total of 84 flavor substances were identified by GC–MS and 17 odor-active compounds were detected with OAVs more than 1. WBF samples had the highest concentration of total volatile compounds, and relatively higher OAVs of γ-decalactone and γ-dodecalactone contributed to peach-like aroma. Principal component analysis (PCA) and heatmap analysis indicated that the honey peach cultivars from different origins and varieties had distinct aroma and taste profiles. Sensory evaluation demonstrated that WBF samples had the highest scores of peach-like, fruity aroma, sweetness, juiciness and overall acceptability. Partial least squares regression (PLSR) was performed to investigate the correlation between physicochemical properties, odor-active compounds, E-tongue measurements and sensory attributes. Results indicated that linalool and umami had significant contribution to honey peach sensory attributes, and further confirmed that YBF was characterized by floral aroma and WBF was similar with peach-like and green attributes. The results of this study provide a comprehensive understanding of flavor characteristics and differences of the honey peaches, which could contribute to the further development and production of these products.

Instrumental and sensory tools to evaluate the production potential of a new type of sparkling wine from umbu (Spondias tuberosa)

Umbu is a native fruit from the Brazilian Caatinga Biome, which is a source of income for families involved in extractivism. This fruit is highly perishable and production losses have been experienced. The production of sparkling wine can be a strategy for better use and to add value to this fruit. Furthermore, consumers have been attracted to innovative beverages, produced with alternative raw materials and with an exotic and pleasant aroma. The potential for producing sparkling wine from umbu was evaluated through physical-chemical, instrumental (gas chromatography with detection by mass spectrometry and olfactometry) and sensory analyses (acceptance test, Just-about-right (JAR) scale, and penalty analysis). Both the base wine and the sparkling wine meet all regulatory physicochemical parameters. The volatile profile of umbu pulp contains mainly terpenes (55%), while esters predominated in the base and sparkling wines (32 and 33%, respectively). In sparkling wines, hexanoic acid (3114 mg L−1) and linalool (1266 mg L−1) were the major compounds. Among the 26 odor-active compounds of sparkling wines are mainly ethyl esters with fruity aroma (acetate, decanoate, and 2-phenylacetate; OSME area: 4.8, 4.8, and 5.0%, respectively), and terpenes with floral notes (p-cymene, geranic oxide and linalool; OSME area: 8.5, 7.4, and 6.9%, respectively). The acceptance and purchase intention tests endorsed the commercialization expectation, although JAR scale and penalty analysis showed that the umbu aroma and sweetness may be improved. The potential of umbu for the production of sparkling wines has been proven, which satisfies the current market demand for innovative beverages.

Development of sensory tools for green rooibos (Aspalathus linearis (Burm.f.) R.Dahlgren) and changes in quality attributes during shelf-life storage.

Green rooibos (Aspalathus linearis (Burm.f.) R.Dahlgren) herbal tea is popular due to its health-promoting properties. Information on its characteristic sensory profile is scarce and sensory tools to define product variation are needed. The storage conditions and time during its shelf-life are hypothesized to affect the product quality. Production batches from two producers spanning 5 years (n = 57) were analyzed using descriptive sensory analysis. Primary attributes (>30 median intensity; 100% occurrence frequency) included 'hay/dried grass', 'cooked oats', 'tobacco', 'honey' and 'caramel' aromas, and astringent mouthfeel. 'Cooked vegetables', 'green grass', 'stewed fruit', 'rooibos-woody', 'marmalade' and 'cardboard' aromas, sweet taste and bitter taste were secondary attributes (10-20 median intensity; 100% occurrence frequency). The same flavor attributes were present, except for sweet-associated and fruity notes. A sensory lexicon and sensory wheels for aroma and palate attributes were constructed from the data. The shelf-life stability of green rooibos was evaluated in moisture-impermeable (pouches) and moisture-permeable (sachets) packaging at 25 and 40 °C at 60% relative humidity over 24 weeks. Green rooibos samples stored in pouches at 4 °C were also evaluated. Storage in sachets led to moisture uptake (~10 g (100 g)-1 dry basis) and an increase in water activity (>0.6), causing degradation of chlorophyll and dihydrochalcones. Changes in color and sensory profile (decreased vegetal, cereal and cardboard aromas and increased sweet-associated and fruity aromas) were evident and more pronounced at the higher storage temperature. Storage at ≤25 °C in moisture-impermeable packaging material is recommended for green rooibos herbal tea. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of tea green leafhopper (Empoasca onukii Matsuda) sucking on the quality of Oriental Beauty

AbstractThis study aimed to investigate the effects of tea green leafhopper damage on the sensory quality and metabolite composition of Oriental Beauty by using tea leaves from different varieties of tea plants and processing factories. The results indicated that tea green leafhopper damage could reduce bitterness and increase the level of fruity aroma, which was related to the content changes of catechin components and alcohol substances. Furthermore, the tea green leafhopper salivary treatment experiment revealed that the decrease of catechin content and increase of theaflavin content were mainly influenced by the action of saliva and mechanical injury, and changes in volatile components such as linalool oxidation were responsible for the alteration in aroma. These findings provide a theoretical reference for the aroma formation and quality improvement of Oriental Beauty.

Esters and higher alcohols regulation to enhance wine fruity aroma based on oxidation-reduction potential

Fruity aroma is a crucial element in reflecting the flavor of wine, believed to be closely linked to esters and higher alcohols associated with the oxidation-reduction potential (ORP) of wine. In this work, the impact of ORP on the production of esters and higher alcohols, and consequently the fruity aroma in Cabernet Sauvignon (CS) and Ecolly wines were investigated. Results revealed that the maximum concentration of medium-chain fatty acid ethyl esters (MCFAEEs) was achieved at −80 mV, which was 48.78% and 25.10% higher than those of the CK groups (ORP without artificial control) in CS and Ecolly wines, respectively. However, the concentrations of acetates and higher alcohols in CS were not significantly different from that in CK, while those in Ecolly were elevated. Additionally, the temperate fruity aroma in CS and citrus aroma in Ecolly wines were enhanced at −80 mV. Partial least-squares regression further indicated that, higher alcohols contributed positively to these enhanced aromas of CS and Ecolly. MCFAEEs have also been suggested to have a positive impact on the fruity and floral aromas for CS and tropical fruity aroma for Ecolly wines. Our work provides an alternative for improving the aroma quality of wine through fermentation process.

Uncovering the flavor differences between black rice wine and glutinous rice wine by GC-MS, GC-IMS, HPLC, and electronic sensory analysis

The black rice bran component (BRBC) is the main difference between black rice and glutinous rice, but its influence on the flavor of rice wines brewed from them is ambiguous. To address this, the flavor profiles and compounds of four rice wines — brewed from glutinous rice (B), glutinous rice with BRBC (added), polished black rice (without BRBC), and whole black rice (HH) — were analyzed using e-nose, GC-MS and GC-IMS. The e-nose revealed significant aroma profile differences between B and HH, with 47 and 49 volatile compounds detected by GC-MS and GC-IMS, respectively. Orthogonal partial least-squares discrimination and fold change analysis highlighted the significant impact of BRBC on the aroma differences between HH and B. Chemometrics and odor activity values identified isoamyl acetate, ethyl caprylate, (E)-2-octenal, phenylethyl acetate, ethyl caproate, 2,4-heptadienal, and 1-octen-3-ol as key contributors to the fresh and fruity aroma in B, while ethyl butanoate, ethyl isoiautyrate, benzene acetaldehyde, (E)-2-octen-1-ol, guaiacol, and heptanal were predominant in HH, contributing to its rich and complex aroma. The e-tongue indicated significant taste distinctions between HH and B, potentially due to the influence of the black rice bran component on the regulation of organic acid and free amino acid content. This study provides new insights into the regulation of rice wine flavor through raw materials.

Influence of dielectric barrier discharge plasma processing in the volatile compounds and aroma of cashew apple juice

Cashew apple juice is a popular beverage in several parts of the world due to its unique fruity aroma. However, the high styrene concentration contributes to an undesirable balsamic note. To address this issue, cold plasma technology was proposed to alter the juice's volatile compounds, thereby improving its flavor. This study has evaluated the effects of cold plasma on the volatile compounds and aroma of cashew apple juice. The research was conducted by applying dielectric barrier discharge plasma to the juice, varying the frequency (50–1000 Hz) and processing times (5–20 min) while keeping a constant voltage (18 kV). The plasma treatment induced noteworthy changes in the volatile compounds of the juice. Specifically, there was a significant decrease in volatile organic acids (73%) and an increase in aldehydes (52%), alcohols (67%), and short-chain esters (11%). Plasma induced the internal scission of fatty acids and esters, which resulted in the formation of short-chain esters and aldehydes. Further processing has oxidized the aldehydes, generating alcohols and isomerized short-chain esters, which generate branched esters. Cold plasma, however, did not significantly reduce the styrene concentration and could not mitigate the off-flavor caused by this compound.