Aromatic Complexes Research Articles

Indigenous yeast can increase the phenolic acid and volatile ester compounds in Petit Manseng wine.

Indigenous yeasts are generally found in grapes, vineyards, and natural environments. Sequential inoculation and fermentation with non-Saccharomyces cerevisiae yeast (H30) and Saccharomyces cerevisiae (YT13) also improve the flavor of wine. This study sequentially inoculated fermented Petit Manseng and natural grape juice with native H30 and YT13 selected from vineyards in Yantai, China. The sensory characteristics of Petit Manseng wine were evaluated by detecting the primary organic acids, phenolic acid compounds, and volatile ester compounds. The results showed that the lactic acid content of the natural wine fermented sequentially with H30 and YT13 increased by 490 μg/L compared with the control group, while the ferulic acid content was 1.4 times that of the single-yeast fermentation group. Furthermore, butyrolactone and anthocyanidin propionate were present in the mixed fermentation group, increasing the aroma complexity of Petit Manseng wine and providing high-quality yeast resources that increase the regional characteristics when producing dry white wine.

TRATEGI PENGEMBANGAN VISUALISASI DESAIN KEMASAN KOPI ARABIKA GAYO UNTUK MENINGKATKAN PREFERENSI MINAT KONSUMEN

Gayo Arabica coffee is a high-quality specialty coffee with a distinctive, complex aroma and a fairly strong viscosity. By developing a visualization of the Gayo Arabica coffee packaging design, the coffee product is expected to be more accepted in the market according to consumer preferences. This study aimed to formulate a strategy for developing visualization of the Gayo Arabica coffee packaging design. Factors that cover the problem of packaging design visualization included colour, shape, brand, illustration/image, information/labeling, and local and cultural wisdom. The formulation strategy for packaging design visualization development could be completed using the soft systems methodology (SSM). The use of the SSM method providds two recommended activities, namely technical activities and policy activities. The results of this study can be used as a reference or reference for the industry or interested parties in considering the visualization of designs related to the packaging of Gayo Arabica coffee products. Keywords: Aceh, conceptual model, Gayo arabica, rich picture, soft systems methodology

Effect of Inter-Row Peanut Growing in the Vineyard on the Quality of 'Cabernet Sauvignon' Grape Fruits and Wines in Northwest China.

In order to solve the problem of premature grape ripening due to global warming, inter-row peanut growing in viticulture was applied. In this two-year (2018-2019) study, the peanut (Arachis hypogaea L.) was used to cover the ground between rows in the vineyards located in the semi-arid Northwest China, Xinjiang. The results showed that reflected solar radiation and temperature around the fruit zone with the peanuts growing were decreased. Compared with clean tillage, the grapes with covering peanuts had lower total soluble solids (TSS) and higher titratable acidity (TA) in the berries. Lower alcohol content and higher total acid (TA) was also found in their corresponding wines. Inter-row peanut growing treatment significantly decreased the contents of flavonols in the grapes and their wines in the two consecutive years, but no significant effect on flavanols was observed in the resulting wines. Norisoprenoids and esters in the grapes and the wines were increased with the peanut growing treatment, respectively. Additionally, compared to clean tillage, the peanut covering significantly improved the sensory value of the wines, especially the aroma complexity of the wines. This study helps us to better understand the feasibility of applying inter-row peanut growing in the viticulture of ground management in the semi-arid climate of Northwest China.

Improving Aroma Complexity with Hanseniaspora spp.: Terpenes, Acetate Esters, and Safranal

Hanseniaspora vineae and Hanseniaspora opuntiae are apiculate yeasts normally found on the skins of ripe grapes and at the beginning of alcoholic fermentation. Several studies have reported that these species can provide interesting sensory characteristics to wine by contributing high levels of acetate esters and can increase the mouthfeel and body of wines. The present work aims to evaluate the use of these two species sequentially with Saccharomyces cerevisiae to improve the sensory profile of Albillo Mayor white wines. The fermentations were carried out in triplicate in 150 L stainless steel barrels. At the end of the alcoholic fermentation polysaccharides, colour, and an extensive study of the aromatic profiles were measured. Results showed up to 1.55 times higher content of 2-phenylethanol in H. opuntiae wines and up to three times higher concentration of fermentative esters in H. vineae wines than in the controls. Interestingly, it should be noted that the compound safranal was identified only in the H. vineae wines. These results indicated that the species studied are an interesting bio-tool to improve the aromatic profile of Albillo Mayor white wines. A novel non-targeted NMR-based metabolomics approach is proposed as a tool for optimising wine productions with standard and sequential fermentation schemes using apiculate yeast strains due to its discriminant capacity to differentiate fine features between wine samples from the identical geographical origin and grape variety but diverse fermentations or vintages.

Immobilization of lager yeast by hydrocolloids as supporting matrix for improving fermentation performance of high gravity brewing

The objective of this study was to investigate the effects of six kinds of hydrocolloids supplementations, namely κ-carrageenan, gellan gum, pectin, gum ghatti, karaya, and guar gum as the supporting matrix, on the fermentation kinetics of lager yeast during high gravity beer fermentation. Results showed that hydrocolloids supplementations significantly accelerated fermentation and resulted in higher consumption of reducing sugar and free amino nitrogen, and higher production of ethanol and flavor volatiles. Compared to the control, wort fermentability and ethanol production were increased by 19.3% and 25.0%, respectively, by κ-carrageenan supplementation. Furthermore, volatile compounds formation and aroma complexity (25 new volatile compounds) of green beers were improved by hydrocolloids supplementation, and the reduction in acetic acid and acetaldehyde contents was observed, which suggested favorable flavor characteristics. Results of SEM images revealed that hydrocolloids supplementation induced the immobilization of yeast cells through flocculation, providing a protective effect on the physiological characterization of lager yeast during high gravity brewing.

Influence of Sodium Salicylate on Self-Aggregation and Caffeine Solubility in Water-A New Hypothesis from Experimental and Computational Data.

The present study analyzed experimental data from volumetric and viscosimetric measurements and computational simulations to understand caffeine hydration and aggregation properties in 0.1 mol∙kg-1 of sodium salicylate aqueous solution. Sodium salicylate reduces the bitter taste and increases the solubility of caffeine in water, which is the main reason for their combination in food products. The results noted in volumetric and viscosimetric measurements indicate that sodium salicylate promotes the self-aggregation of caffeine in water. After self-aggregation, the hydration number of caffeine significantly increases. Molecular simulations have allowed us to hypothesize how salicylate increases caffeine solubility. At the molecular level, relocating salicylate moiety from the parallel stacking (π-π) aromatic complex with caffeine and its hydration could be the main reason for increasing the solubility of caffeine in water. The presented study provides clear guidelines on the choice of additives to increase caffeine's solubility in aqueous media. The choice of salicylate as an additive to increase the solubility of caffeine is very important because caffeine and salicylate are found in combination in a large number of formulations.

Using wild yeasts to modulate the aroma profile of low-alcoholic meads.

In recent years, ample research has focused on applying wild (especially non-Saccharomyces) yeasts in producing alcoholic beverages. Common characteristics of wild yeast strains include simultaneous high production of fruity and floral aroma compounds and low ethanol production. In this study, mead starter cultures were selected based on preliminary screening of wild yeast strains from a Brazilian culture collection (n = 63) for their ability to produce aroma-active compounds. The selected strains included one strain of Saccharomyces cerevisiae and three non-Saccharomyces strains (Pichia jadinii, Torulaspora delbrueckii, and Kluyveromyces lactis). These strains were used to ferment honey must prepared with Aroeira honey, adjusted to 24°Brix, which took 36days to complete. Single culture fermentations and co-fermentations with S. cerevisiae and non-Saccharomyces strains were carried out. The quality of the produced beverages was evaluated by sugar consumption and production of alcohols and organic acids, analyzed with high-performance liquid chromatography. The volatile organic compound composition was analyzed with gas chromatography-mass spectrometry. Meads with various ethanol amounts (4.7-11.0% v/v) and residual sugar contents (70.81-160.25gl-1) were produced. In addition, in both single-strain fermentation and co-fermentation with S. cerevisiae, meads produced with either Torulaspora delbrueckii or Kluyveromyces lactis had a roughly three-fold higher content of honey-aroma compound phenethyl acetate and a higher hedonic impression score than meads produced with only S. cerevisiae. These results demonstrated non-Saccharomyces yeasts' ability to increase aroma complexity and improve the sensory quality of low-alcoholic meads.

Application of a Single-Type eNose to Discriminate the Brewed Aroma of One Caffeinated and Decaffeinated Encapsulated Espresso Coffee Type

This paper assesses a custom single-type electronic nose (eNose) applied to differentiate the complex aromas generated by the caffeinated and decaffeinated versions of one encapsulated espresso coffee mixture type. The eNose used is composed of 16 single-type (identical) metal–oxide semiconductor (MOX) gas sensors based on microelectromechanical system (MEMS). This eNose proposal takes advantage of the small but inherent sensing variability of MOX gas sensors in order to provide a multisensorial description of volatiles or aromas. Results have shown that the information provided with this eNose processed using LDA is able to successfully discriminate the complex aromas of one caffeinated and decaffeinated encapsulated espresso coffee type.

Characterisation of aldo-keto reductases from Lactobacillus reuteri DSM20016

Lactobacillus reuteri DSM20016 has several aldo-keto reductases (AKRs), and they were heterologously expressed in E. coli BL21 (DE3) in this study. Subsequently, these AKRs were purified, and their enzymatic properties were investigated. It was found that these enzymes used NADPH as coenzyme and did not depend on metal ions. The optimum pH of these AKRs was a slightly acidic (AKR-1 and AKR-6: 5.5; AKR-3 and AKR-8: 6; AKR-2 and AKR-4: 6.5). These enzymes had a broad substrate spectrum and could convert a variety of aldehydes to alcohols; however, they did not catalyze the reverse reactions. All results showed that Lactobacillus reuteri had the ability to produce various volatile compounds, which allowed Lactobacillus reuteri to impart complex aroma to something.

Reconstruction of Simplified Microbial Consortia to Modulate Sensory Quality of Kombucha Tea.

Kombucha is a fermented tea with a long history of production and consumption. It has been gaining popularity thanks to its refreshing taste and assumed beneficial properties. The microbial community responsible for tea fermentation—acetic acid bacteria (AAB), yeasts, and lactic acid bacteria (LAB)—is mainly found embedded in an extracellular cellulosic matrix located at the liquid–air interphase. To optimize the production process and investigate the contribution of individual strains, a collection of 26 unique strains was established from an artisanal-scale kombucha production; it included 13 AAB, 12 yeasts, and one LAB. Among these, distinctive strains, namely Novacetimonas hansenii T7SS-4G1, Brettanomyces bruxellensis T7SB-5W6, and Zygosaccharomyces parabailii T7SS-4W1, were used in mono- and co-culture fermentations. The monocultures highlighted important species-specific differences in the metabolism of sugars and organic acids, while binary co-cultures demonstrated the roles played by bacteria and yeasts in the production of cellulose and typical volatile acidity. Aroma complexity and sensory perception were comparable between reconstructed (with the three strains) and native microbial consortia. This study provided a broad picture of the strains’ metabolic signatures, facilitating the standardization of kombucha production in order to obtain a product with desired characteristics by modulating strains presence or abundance.

Highly efficient mesoporous ZSM-5 for trace olefin removal from aromatic stream

Steam cracking and reforming processes always produce aromatic streams containing trace amounts of olefins, which are harmful to certain processes and applications in the petrochemical industry. In the aromatics complex, clay is used to remove trace olefins. Unfortunately, it has a limited lifespan and must be replaced frequently. In this study, mesoporous ZSM-5 is investigated for its application in the removal of trace olefins. It is prepared using two templates: Tetrapropylammonium bromide and Dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, resulting in a mesoporous structure with a high pore volume and external surface area. There is an optimum amount of DMOD necessary to achieve the desired degree of mesoporosity within a zeolite. Even though mesoporous ZSM-5 has a similar surface area to microporous ZSM-5, its external surface area is 1.3 to 2.0 times greater than conventional ZSM-5. Consequently, mesoporous ZSM-5 has a higher activity when it comes to removing trace olefins from an aromatic stream than microporous ZSM-5.

Crystal structure, thermodynamic behavior, and luminescence properties of a new series of lanthanide halogenated aromatic carboxylic acid complexes

Five lanthanide complexes with polydentate coordination were successfully synthesized by volatilization of 2,4-difluorobenzoate and o-phenanthroline ligands. The structure general formula is [Ln(2,4-DFBA) 3 (phen)] 2 , (Ln = La( 1 ), Gd( 2 ), Tb( 3 ), Dy( 4 ), Ho( 5 ); 2,4-DFBA = 2,4-difluorobenzoate, phen = o-phenanthroline). The crystal structures of five complexes were determined, and supramolecular structures were probed. Characterization was performed by elemental analysis, IR, Raman spectroscopy and XRD, followed by an examination of the fluorescence and heat capacity properties. The molar heat capacities of complexes 4 and 5 were determined in detail by the DSC apparatus, and the thermodynamic functions were calculated. Finally, the fluorescence properties of complexes 3 and 4 were investigated. Using DFT, the HOMO, LUMO energy levels of the ligands and their single and triplet state energy levels were calculated at the level of the valence layer cleavage 6-311G(d,p) basis group, and the fluorescence enhancement mechanism was explained from the energy transfer perspective.

Inheritance of esters and other volatile compounds responsible for the fruity aroma in strawberry.

Cultivated strawberry, Fragaria × ananassa, has a complex aroma due to the presence of more than 350 volatile organic compounds (VOCs). However, a mixture of only 19 compounds, called Key Volatile Compounds (KVC), can impart the main strawberry aroma. The octoploid nature of the cultivated strawberry species (2n = 8x = 56) adds complexity to the heritance of the accumulation of the volatiles responsible for aroma. An F1 population cross between two breeding parental lines, FC50 and FD54, was phenotyped for aroma by SPME GCMS during six harvests. A total of 58 compounds were identified: 33 esters, nine terpenes, seven aldehydes, four lactones, two furans, one acid, one alkane and one alcohol, of which 16 were KVCs. A total of 179 QTLs were found, and 85 of these were detected in at least three harvests, of which 50 QTLs were considered major (LOD > 4.0) and detected in five or six analyzed harvests. Several clusters of ester QTLs associated with fruity aroma were discovered, such as QTLs for esters that share hexanoate group that were mapped in LG4A (Hexanoate_4A), those that share acetate and octyl groups in LG6A (Acetate_6A and Octyl_6A) or those with the same methyl group in LG7B (Methyl_7B). Different terpene QTLs associated with floral aroma appear grouped in a cluster in LG3C (Terpene_3C). Some of these clusters of QTLs were validated in a second F2 population, a cross of “Camarosa” and “Dover,” that was also phenotyped for three years. Selected SNPs from floral and fruity aroma QTLs were tested in a third population, which will most likely be useful for marker-assisted breeding (MAB).

Evolution of Triangular All-Metal Aromatic Complexes from Bonding Quandaries to Powerful Catalytic Platforms.

This manuscript describes an overview on the literature detailing the observation of trinuclear complexes that present delocalized metal-metal bonds similar to those of regular aromatics, which are formed combining main group elements. A particular emphasis is given to the structural and electronic features of aromatic clusters that are sufficiently stable to allow their isolation. In parallel to the description of their key bonding properties, the work presents reported catalytic applications of these complexes, which already span from elaborated C-C-forming cascades to highly efficient cross-coupling methods. These examples present peculiar aspects of the unique reactivity exerted by all-metal aromatic complexes, which can often be superior to their established, popular mononuclear peers in terms of chemoselectivity and chemical robustness.

PSP with trained assessors as alternative for descriptive analysis of a product with a complex sensory profile

Rapid sensory profiling of a product over time presents a challenge in quality control, particularly when the product has a complex aroma and flavour profile. Polarized sensory positioning (PSP), based on the comparison of samples to fixed references, allows for rapid sensory profiling and data collection across multiple sessions. The efficacy of partial and global PSP for broad-based sensory profiling of honeybush infusions, prepared from five Cyclopia species (C. genistoides, C. subternata, C. maculata, C. intermedia and C. longifolia), was investigated. Trained assessors conducted partial PSP on aroma (P-PSPa) and palate (P-PSPp), as well as global PSP. A continuous scale and five poles, representing the respective Cyclopia species, were used to evaluate the honeybush infusions. Data, aggregated over three sessions per PSP variant, were subjected to multiple factor analysis (MFA). Similar product configurations were obtained when comparing the principal component analysis (PCA) bi-plot of the descriptive sensory analysis data and the MFA plots of partial and global PSP (RV coefficients ≥ 0.87). P-PSPa was as effective as global PSP in discriminating between honeybush tea samples. Application of PSPa by trained assessors is recommended for quality control in the honeybush tea industry: in this variant of PSP assessors focus on one modality, thereby potentially reducing sensory fatigue. Cyclopia genistoides, C. longifolia and C. maculata herbal teas formed one group, indicating that these herbal teas could be blended without losing sensory character. Cyclopia subternata and C. intermedia formed separate groups, indicating their suitability for species-specific marketing.

Genome sequencing and oenologically relevant traits of the Uruguayan native yeast <i>Issatchenkia terricola</i>

Issatchenkia terricola 0621 is a non-Saccharomyces yeast strain isolated from Tannat grapes from Uruguayan vineyards; it stands out for its ability to produce high levels of β-glucosidase activity, which contributes to the aromatic complexity of wines. To delve into the potential oenological applications of this strain, its high-quality genome was obtained and explored, allowing the main central carbon and nitrogen metabolic pathways to be reconstructed. I. terricola is able to utilise glycerol as the sole carbon source in a way that has not previously been described for yeasts. The genes of the fermentome and those involved in stress resistance during winemaking were also identified, and differences were found when compared to S. cerevisiae, which may explain why I. terricola is unable to complete fermentation. The pathways responsible for natural aroma synthesis were also reconstructed, and the production of aromatic acids, alcohols, esters, acetates and lactones was verified experimentally. Finally, sequences encoding for β-glucosidases, in addition to the previously characterised one, were identified in the genome. The work presented here lays the groundwork for experimental research focused on the dissection of the metabolism of a native non-Saccharomyces strain and its application for oenological and biotechnological purposes.

Role of Yeasts on the Sensory Component of Wines.

The aromatic complexity of a wine is mainly influenced by the interaction between grapes and fermentation agents. This interaction is very complex and affected by numerous factors, such as cultivars, degree of grape ripeness, climate, mashing techniques, must chemical–physical characteristics, yeasts used in the fermentation process and their interactions with the grape endogenous microbiota, process parameters (including new non-thermal technologies), malolactic fermentation (when desired), and phenomena occurring during aging. However, the role of yeasts in the formation of aroma compounds has been universally recognized. In fact, yeasts (as starters or naturally occurring microbiota) can contribute both with the formation of compounds deriving from the primary metabolism, with the synthesis of specific metabolites, and with the modification of molecules present in the must. Among secondary metabolites, key roles are recognized for esters, higher alcohols, volatile phenols, sulfur molecules, and carbonyl compounds. Moreover, some specific enzymatic activities of yeasts, linked above all to non-Saccharomyces species, can contribute to increasing the sensory profile of the wine thanks to the release of volatile terpenes or other molecules. Therefore, this review will highlight the main aroma compounds produced by Saccharomyces cerevisiae and other yeasts of oenological interest in relation to process conditions, new non-thermal technologies, and microbial interactions.

Allelic diversity of the <i>FaOMT</i> gene (mesifurane biosynthesis) in promising strawberry cultivars and selected forms developed at the I.V. Michurin Federal Science Center

Background. Fruit aroma is an important consumer trait of strawberry varieties. Identification of genotypes carrying the genes of the aromatic complex in fruits is an important stage in the development of new cultivars with aromatic fruits. The purpose of this study was to analyze the allelic state of the FaOMT fruit aroma gene in strawberry cultivars and selected forms developed at the I.V. Michurin Federal Science Center to identify promising genotypes for use in breeding for fruit aroma.Materials and methods. The research materials were strawberry cultivars and promising selected forms developed at the I.V. Michurin FSC using the methods of introgressive and intervarietal hybridization. Allelic state of the FaOMT gene was identified with the codominant marker FaOMT-SI/NO.Results and conclusion. The FaOMT fruit aroma gene is represented in the studied strawberry varieties and forms by three combinations of alleles: the homozygous state of the functional allele, the heterozygous combination of the alleles, and the homozygous state of the nonfunctional allele. Cvs. ‘Rubinovy kaskad’, ‘Privlekatelnaya’ and ‘Feyerverk’ are characterized by a heterozygous combination of alleles of the FaOMT gene. Cvs. ‘Lastochka’, ‘Pamyati Zubova’, ‘Flora’, ‘Yarkaya’ and ‘Urozhaynaya CGL’ are characterized by the homozygous state of the FaOMT+ allele. Selected strawberry forms 928-12, 26-5, 72-71 and 62-41 have the heterozygous genotype; hybrids 298-19-9-43 and 932-29 are characterized by the homozygous state of the FaOMT+ allele; selected forms 61-12 and 65-26 are characterized by the homozygous state of the nonfunctional FaOMT– allele. Strawberry forms promising for breeding, with the homozygous state of the functional FaOMT+ allele, were identified: cvs. ‘Lastochka’, ‘Pamyati Zubova’, ‘Flora’, ‘Yarkaya’ and ‘Urozhaynaya CGL’, and selected forms 298-19-9-43 and 932-29.

Impact of Torulaspora delbrueckii During Fermentation on Aromatic Profile of Vidal Blanc Icewine.

Non-Saccharomyces yeasts usually have a positive effect on improving the diversity of wine aroma and increasing the differentiation of wine products. Among these non-Saccharomyces yeast species, Torulaspora delbrueckii is often studied and used in winemaking in recent years, but its application in icewine has not been reported yet. In this study, indigenous T. delbrueckii strains (TD1 and TD2) and Saccharomyces cerevisiae strains (commercial yeast SC1 and indigenous icewine yeast SC2) were sequentially inoculated for icewine fermentations; meanwhile, pure S. cerevisiae (SC1 and SC2) fermentations were used as the control; TD1, TD2, and SC2 strains used were screened from spontaneous fermentations of Vidal blanc icewine. The aim was to investigate the effect of T. delbrueckii on the aroma complexity of icewine, which is of great significance to the application of T. delbrueckii in icewine production. The results showed that T. delbrueckii was completely replaced by S. cerevisiae at the middle and later fermentative stages in mixed culture fermentations. Compared with the icewine fermented with pure S. cerevisiae, mixed culture fermented icewines contained lower acetic acid and ethanol, and higher glycerol. The inoculation of T. delbrueckii greatly impacted the levels of several important volatile compounds, and more 2-phenylethyl alcohol, isoamyl acetate, linalool, D-limonene, p-cymene and cineole were produced, and the fruity, flowery, and sweet characteristic was intensified. Moreover, the relevance of strain-specificity within T. delbrueckii to aroma compound differences was shown. To our knowledge, this study is the first to investigate the application of T. delbrueckii in Vidal blanc icewine fermentation, and volatile aroma compounds in the icewine fermented by T. delbrueckii and S. cerevisiae.

Quality improvement of jujube wine through mixed fermentation with Saccharomyces cerevisiae and Bacillus licheniformis

Routine analysis, electronic sensory methods, and HS-SPME-GC-MS were used to evaluate the effect of S. cerevisiae and S. cerevisiae + Bacillus licheniformis on the quality of jujube wine. The results show that all wine samples showed significant differences in color, taste, amino acids, organic acids, and aroma (p < 0.05), while the color quality of co-fermented jujube wine was better. On the sensory scale, co-fermentation improved the taste complexity of jujube wine with a unique flavor and typical aroma. HS-SPME-GC-MS analysis revealed 37 characteristic volatile compounds in co-fermented jujube wine. Therefore, using B. licheniformis in the wine fermentation process can significantly improve microbial biotransformation efficiency and flavor. Our results show that the mixed culture of B. licheniformis and S. cerevisiae could be a valuable tool to adjust volatile components and improve the aroma complexity of jujube wine.