Specific Aroma Research Articles

Bridging the Gap: linking Torulaspora delbrueckii Genotypes to Fermentation Phenotypes and Wine Aroma.

Climate change and consumer preferences are driving innovation in winemaking, with a growing interest in non-Saccharomyces species. Among these, Torulaspora delbrueckii (Td) has gained recognition for its ability to reduce volatile acidity and enhance aromatic complexity in wine. However, knowledge regarding its phenotypic and genomic diversity impacting alcoholic fermentation remains limited. Aiming to elucidate the metabolic differences between Td and Saccharomyces cerevisiae (Sc) and the Td intraspecies diversity, we conducted a comprehensive metabolic characterization of fifteen Td strains. This analysis delved beyond standard fermentation parameters (kinetics and major metabolites production) to explore non-conventional aromas and establish genotype-phenotype links. Our findings confirmed that most Td strains produce less acetic acid and more succinate and glycerol than Sc. The overall aromatic profiles of Td strains differed from Sc, exhibiting higher levels of monoterpenes and higher alcohols, while producing less acetate esters, fatty acids, their corresponding ethyl esters, and lactones. Moreover, we identified the absence of genes responsible for specific aroma profiles, such as decreased ethyl esters production, as well as the absence of cell wall genes, which might negatively affect Td performance when compared to Sc. This work highlights the significant diversity within Td and underscores potential links between its genotype and phenotype.

HS–SPME combined with GC–MS and GC–O for characterization of key aroma-active compounds in fruity and grassy peppers (Capsicum chinense Jacq.)

Pepper (Capsicum spp.) is highly popular due to its unique flavor. However, there was limited research on the primary volatiles that influence the different flavors of fresh peppers. In this study, peppers with three aroma compound types denoted as “grassy,” “fruity,” and “no special aroma” (control) were analyzed using sensory evaluation combined with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). Altogether, 393 volatiles were identified by GC–MS, and the main volatiles in peppers (C. chinense Jacq.) were esters and terpenoids. GC–O and relative odor activity value analysis revealed that 2-isobutyl-3-methoxypyrazine had a highly bitter, spicy aroma intensity in all peppers. Hexanal and trans-2-hexenal were the main aroma-active compounds in grassy peppers. In addition, citronellal was determined to be a crucial aroma-active compound in fruity peppers. This study offers a theoretical foundation for guiding the growth of the pepper processing industry and breeding.

Silkworm (Bombyx mori) frass as a novel culinary ‘tea’ application in gastronomy: aroma profile, volatile compounds, and consumer acceptance.

Tea is a popular beverage consumed all around the world. Its origins can be traced back to China, where it has been cultivated for thousands of years. A subcategory of tea is referred to as ‘insect tea’; it is produced using the excrement (frass) of insects that consume plants. This study explored the utilisation of silkworm frass, a by-product of silk production, as a novel beverage in the culinary field. It explored optimal preparation methods, and measured physicochemical properties, volatile aroma compounds, the sensory aroma profile, and consumer acceptance. Silkworm frass was collected and roasted at 160 °C for 0, 30, 40, and 50 minutes. The analysis revealed notable differences in the samples' water activity, moisture content, colour, and pH: Moisture content and water activity decreased, preventing spoilage of the samples, while pH increased, and the colour intensified. The volatile aroma analysis revealed 65 compounds, including alcohols, aldehydes, esters, ethers, ketones, phenols, pyrazines, and hydrocarbons. These compounds exhibited significant variations in concentration depending on the duration of roasting. Sensory evaluation presented distinct attributes associated with each sample, such as earthy and roasted aromas in all samples, and specific aromas of brown herbal aftertaste and tobacco leaves in the 50-min sample, roasted grain aromas in the 40-min sample, and stronger notes of fresh hay for both the 30-min and 50 min sample. The hedonic sensory test revealed that the duration of roasting did not influence consumer preferences in terms of the attributes of taste, aroma, colour, texture, and overall acceptance. The novel ‘tea’ demonstrates potential in the gastronomy industry due to its aroma profile and positive consumer acceptance. It is a promising example of an upcycled culinary product that utilizes by-products from silk farms.

Interaction between a Lactococcus lactis autochthonous starter and a raw goat milk microbial community during long-term backslopping

Traditional cheesemaking processes often involve backslopping practice. However, over successive inoculations, acidification deficiencies may arise. In such cases, adding a starter is recommended to restore the ecosystem stability. This study examines the impact of an autochthonous starter composed of three Lactococcus lactis strains on a raw goat milk microbial community during their evolution. Bacterial composition and technological features (acidification and aroma) were analyzed during communities’ evolution over 800 generations. 16S rRNA gene metabarcoding showed that Lactococcus lactis strains predominated. The raw goat milk community acidification capacities varied early in the evolution and then remained stable. Adding the L. lactis starter to this community stabilized the ecosystem from the beginning of the evolution. The acetoin production was associated with the starter presence, consistent with the establishment of the diacetylatis biovar strain from the starter in the raw goat milk community throughout the evolution. Increased or decreased production of some volatile organic compounds when the starter was added revealed a specific aroma footprint due to interactions between the two communities. This study showed that adding a starter could help to achieve the maximum acidification rate from the early inoculation cycles and could significantly modify the aroma profile during long-term backslopping.

Combined analysis of transcriptome and metabolome reveals the effects of novel aroma-producing Naumovozyma castellii on Feng-flavor Baijiu

Feng-flavor Baijiu has an elegant and pleasant aroma and is one of the four traditional famous liquors in China. A strain of Naumovozyma castellii XF0241 with excellent fermentation performance and rich aroma compounds was isolated and screened from the Feng-flavor fermented grains. Metabolomic analysis showed that the main flavor compounds of XF0241 are esters, terpenes, and heterocyclic compounds, which are important aroma and flavor compounds in Feng-flavor Baijiu. Compared with the model strain N. castellii CBS4309, the yeast's ester, terpenes and heterocyclic compounds were up-regulated by 168.99±45.31 %, 103.54±28.45% and 108.46±36.78% respectively. After adding additional XF0241 to the Feng-flavor fermented grains, the flavor compounds became more abundant, among which the ester showed the highest increase, followed by terpenoids and heterocyclic compounds. Transcriptomic analysis showed that 1134 genes were differentially expressed. The combined analysis of transcriptome and metabolome revealed that 10 enzymes related to ester production and 3 enzymes related to terpenoid biosynthesis, and 1 enzyme related to heterocyclic formation were significantly upregulated. We believe that XF0241 is one of the core yeasts of Feng-flavor Baijiu. Its production of rich aroma compounds plays an important role in the formation of the special aroma of liquor.

Chromosome-scale genome assembly of Docynia delavayi provides new insights into the α-farnesene biosynthesis

Docynia delavayi is an economically significant fruit species with a high market potential due to the special aroma of its fruit. Here, a 653.34 Mb high-quality genome of D. delavayi was first reported, of which 93.8 % of the sequences (612.98 Mb) could be anchored to 17 chromosomes, containing 48,325 protein-coding genes. Ks analysis proved that two whole genome duplication (WGD) events occurred in D. delavayi, resulting in the expansion of genes associated with terpene biosynthesis, which promoted its fruit-specific aroma production. Combined multi-omics analysis, α-farnesene was detected as the most abundant aroma substance emitted by D. delavayi fruit during storage, meanwhile one α-farnesene synthase gene (AFS) and 15 transcription factors (TFs) were identified as the candidate genes potentially involved in α-farnesene biosynthesis. Further studies for the regulation network of α-farnesene biosynthesis revealed that DdebHLH, DdeERF1 and DdeMYB could activate the transcription of DdeAFS. To our knowledge, it is the first report that MYB TF plays a regulatory role in α-farnesene biosynthesis, which will greatly facilitate future breeding programs for D. delavayi.

Characterization of Volatile Organic Compounds and Essential Oil Profile of Pittosporum tobira (Thunb.) W.T. Aiton Cultivated in Tunisia.

The chemical compositions of the essential oils (EOs) of roots, young and old leaves and stems, and flowers of Pittosporum tobira (Thunb.) W.T. Aiton cultivated in Tunisia and of the volatile organic compounds (VOCs) emitted by the powder of each organ were identified. The EOs are extracted from fresh material by hydrodistillation, whereas the VOCs are obtained by head space solid-phase microextraction (HS-SPME) from the powdered dry tissues. Fifty-eight VOCs are identified, while, 105 components are detected for the EOs. The main EOs compounds are α-neoclovene, β-caryophyllene and limonene in roots (22.56, 12.52, and 8.59 %, respectively), viridiflorol in young stems, flowers and young leaves (34.90, 31.60, and 24.60 %, respectively), α-cadinol in young stems and leaves, and flowers (13.80, 10.40, and 9.10 %, respectively), (E)-nerolidol in flowers (13.30 %), and germacrene D in old stems (9.06 %). The major detected VOCs are n-undecane, mainly in young and old leaves (71.40 and 40.90 %, respectively), n-nonane in young leaves and flowers (31.80 and 27.10 %, respectively), α-cubebene in old stems and flowers (22.60 and 15.50 %, respectively), and α-gurjunene and β-gurjunene in roots (14.20 and 12.20 %, respectively). Principal Component Analysis (PCA) carried out on the 26 main volatile compounds (relative content exceeding 6 %) identified both by HS and in the EOs allowed their classification into two groups; compounds specific to roots and those specific to aerial parts. The later are subdivided in to two subgroups; old leaves and stems compounds subgroup, and young leaves and stems, and flowers one. We can notice that the two methods used to extract P. tobira volatile compounds and identify them are complementary. This study defines and differentiates, for the first time, the specific aroma profile of P. tobira from Tunisia. In addition to its ornamental value, all the organs of this species, could be valued as a source of volatile compounds useful in perfume, cosmetics and as food flavoring products.

Physicochemical and Organoleptic Properties of Milkfish Bonggolan (Study Proportion of Fish Meat : Sago Flour and Addition of Sodium tripolyposphate)

Bonggolan is a fish product from the Sidayu, Gresik Regency. Bonggolan is made from a mixture of tapioca flour, fish meat, such as payus fish and spices. Bonggolan has a chewy texture with a savory taste and has a special aroma from fish. Bonggolan has a hard texture when consumed in cold condition. This change causes a decrease in consumer preference. In this study, learned about making bonggolan from milkfish meat, sago flour, and sodium tripolyposphate (STPP). The purpose of the study is to determine the effect of the proportion of fish meat : sago flour and the addition of STPP on the physicochemical and organoleptic properties of milkfish bonggolan. This study used a factorial Completely Randomized Design (CRD) with two factors. The first factor is the proportion of fish meat : sago flour (60 : 40, 50 : 50, 40 : 60). The second factor is the addition of STPP (0.0, 0.1, 0.2%). Data was analyzed using ANOVA level 5%. If there was a difference, the process continues with the DMRT Test 5%. The results of the study is the proportion of fish meat : sago flour (60 : 40) and the addition of 0.2% STPP was the milkfish bonggolan with the optimal treatment. In this treatment obtained a water content of 51.55%, ash content of 2.67%, protein content of 7.66%, fat content of 2.15%, hardness of 199.87 gf, springiness of 11.33 mm, and organoleptic tests showed the value of color 3.96 (neutral), aroma 4.24 (like), taste 4.08 (like), and texture 4.28 (like).

GC-MS Combined with Proteomic Analysis of Volatile Compounds and Formation Mechanisms in Green Teas with Different Aroma Types.

Aroma is one of the key factors for evaluating the quality of green tea. A tender aroma (NX) and floral-like aroma (HX) are two types of high-quality aroma of green tea. In this work, the different aroma types of baked green tea were classified by sensory evaluation. Then, seven tea samples with a typical tender or floral-like aroma were selected for further volatile component analysis by GC-MS. A total of 43 aroma compounds were identified in two different aroma types of baked green tea samples. The PCA showed that linalool, geraniol, 3-hexenyl butyrate, and 3-hexenyl hexanoate were the major volatiles contributing to the HX. On the other hand, most of the alcohol volatiles, such as 1-octanol, 1-octen-3-ol, 1-dodecanol, 1-hexadecanol, phenylethyl alcohol, benzyl alcohol, aldehydes and some hydrocarbons contributed more to the NX. In addition, the chemical composition analysis showed that the content of free amino acids was higher in NX green tea samples, while the content of catechins was relatively higher in HX tea samples. A proteomic analysis revealed that most of the enzymes involved in VPBs pathways, such as phenylalanine ammonialyase, peroxidase, and shikimate-O-hydroxycinnamoyl transferase, were more abundant in NX than in HX tea samples. These results laid a foundation for the aroma formation mechanism of different aroma types of baked green tea and provided some theoretical guidance for the breeding of specific aroma varieties.

Volatile compounds of Croatian cheese in a lamb skin sack prepared from a mixture of goat's and cow's milk

Volatile aroma compounds are one of the main parameters in consumer choice and acceptance of cheese. The traditional way of making cheese, still preserved in Croatia, is the anaerobic ripening of curds in a lamb or goat sack. Cheeses produced in such a way have a specific aroma. The objective of this study was to determine the volatile compounds of Croatian cheese in a lamb skin sack prepared from a mixture of goat's and cow's milk and relate them with the aroma of this traditional cheese. The cheese extracts were obtained by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) and analysed by gas chromatography-mass spectrometry (GCMS). HS-SPME was performed at different temperatures (40, 50 and 60°C) using 2 fibres, divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre and carboxen/ polydimethylsiloxane (CAR/PDMS) fibre. Increasing the extraction temperature resulted in higher sorption of fatty acids on both fibres. A total of 28 volatile compounds were identified in the cheese samples including 13 acids, 10 esters, 2 alcohols, 2 hydrocarbons and 1 ketone. Results revealed that fatty acids were the predominant group of volatile compounds in all samples. In samples obtained by HS-SPME, the most abundant were hexanoic, octanoic, butanoic, acetic and decanoic acid while (Z)-octadec-9-enoic, hexadecanoic, decanoic and tetradecanoic acid were the most abundant in the sample obtained by USE.

Assessment of acid production efficiency and aroma volatile compounds by immobilized fermentation of different carriers on sugarcane original vinegar

Sugarcane original vinegar (SOV) is a healthy beverage worldwide. Almost all the countries or regions in the world have their own kinds of vinegar with special aromas and flavors, which come from the relative raw materials, microorganisms and production processes with vinegar. It is rich in phenolic substances, such as vanillin, coumarin, chlorogenic acid, caffeic acid, ferulic acid, p-coumaric acid, 10 types of luteolin in celery, cinnamic acid, and kaempferol, among which the vanillin, coumarin, chlorogenic and caffeic acids are relatively high (sugarcane original vinegar >5 mg/L, sugarcane vinegar drink >2 mg/L). This study assessed the influence of acetic acid fermentation from sodium alginate, corncobs and rice husk on SOV by immobilized fermentation processes. Volatile organic compounds were determined by solid-phase microextraction (SPME) and gas chromatography (GC-MS). During the first and second fermentation stages, the rice husk carrier enhanced the fermentation process at 24 h as compared to corncobs and sodium alginate. Fermentation with different immobilized carriers revealed 95–115 types of organic volatile compounds, with the relative content of each compound monitored through the area normalization method, representing 98% of the total peak area. The free fermented sugarcane vinegar has found 24 specific compounds. Fifty-seven aroma compounds were identified at different degrees by the ROAV method during fermentation with different immobilized carriers. The key flavor compound was isoamyl acetate and the modified flavor was phenylethyl alcohol. Isoamyl acetate was identified as significant aroma compound in SOV for the first time. Using plant sources as immobilized carriers to ferment fruit vinegar can effectively improve the aroma and acid production efficiency of vinegar. This study enriched the knowledge of the compounds and flavors of SOV and assisted in upgrading the production quality of vinegar.

The effect of pasteurisation and storage on aroma compounds in lager

Why was the work done: To investigate the impact of pasteurisation and storage in bottle on aroma compounds in pale lager beer. How was the work done: Pale lager beer was produced at an industrial scale with 100% pilsner malt and a bottom fermenting yeast. Samples were taken of unpasteurised beer from bright beer tank, after flash pasteurisation and six months after packaging in amber glass bottles. What are the main findings: Post pasteurisation, a marked increase was found in the concentration of 2,3-pentanedione (50%) and diacetyl (33%), presumably reflecting the decomposition by heat of precurser acetohydroxy acids. There was also a marginal increase in dimethyl sulphide (6%) with little or no change in other aroma compounds. Storage for six months in bottle, also resulted in an increase in the level of 2,3-pentanedione, diacetyl and dimethyl sulphide. The linear (Pearson) correlation was > 0.8 for both dimethyl sulphide and diacetyl, and 2,3-pentanedione and diacetyl. Accordingly, it was concluded that the levels in beer of dimethyl sulphide and 2,3-pentanedione are proportionally related to diacetyl. Why is the work important: This work provides an insight into the effects on flavour and aroma of lager of flash pasteurisation and subsequent storage in bottle. The inter-relationship between aroma compounds in beer suggests that such synergies may undermine the sensory perception of threshold levels and identification of specific aromas.

Sensory-directed approach to explore cider typicity: the case of ciders from the Canary Islands (Spain)

PurposeThe main aim of this study is to characterise and identify specific chemo-sensory profiles of ciders from the Canary Islands (Spain).Design/methodology/approachCommercial samples of Canary ciders were compared to ciders from the Basque Country and Asturias. In total, 18 samples were studied, six for each region. The analysis comprised their sensory profiling and chemical characterisation of their polyphenolic profile, volatile composition, conventional chemical parameters and CIELAB colour coordinates. In parallel, the sensory profile of the samples from the Canary Islands was first compared with their Basque and Asturian counterparts by labelled sorting task. Then, their specific aroma profile was characterised by flash profile. Further quantification of sensory-active compounds was performed by GC–MS and GC-FID to identify the volatile compounds involved in their aroma profile.FindingsResults show that Canary ciders present a specific chemical profile characterised by higher levels of ethanol, and hydroxycinnamic acids, mainly t-ferulic, t-coumaric and neochologenic acids, and lower levels of volatile and total acidity than their Asturian and Basque counterparts. They also present a specific aroma profile characterised by fruity aroma, mainly fruit in syrup and confectionary, and sweet flavours related to their highest levels of vinylphenols formed by transformation of hydroxycinnamic acids.Originality/valueAn integrated strategy to explore the typicity of the currently existing Canary ciders in the market was developed. The results are important in that they will help other regions to identify specific typical chemo-sensory profiles and to promote the creation of certifications supporting regional typicity.

Comparison of Different Grades of Innovative Tanyang Congou Black Tea (Minkehong) Based on Metabolomics and Sensory Evaluation

Innovative Tangyang Congou black tea, also known as Minkehong black tea (MKH), is of high quality and hence has gained a reputation on the market. In this study, standard samples of MKH were used as the research material, and the results of sensory evaluation showed that the overall quality of MKH decreased along with the downgrading. The radar chart showed a strong association between higher grades and specific aroma and taste character. Based on the detection of ultra-performance liquid chromatography–mass spectrometry (UPLC–MS) and related analysis, the content of both the ester-type catechins and non-ester catechins decreased along with the downgrading, and the details of their change trends were revealed. The content and dynamic changes in caffeine were also investigated. A total of 19 kinds of amino acids (AAs) were clustered; among them, 4 kinds of AAs, namely, Thr, Leu, Asp, and Ile, significantly contributed to the taste of the tea. Notably, the content of Thr had the highest correlation with the grade of MKH, and the correlation coefficient was 0.991 (p < 0.01). According to gas chromatography–mass spectrometry (GC–MS) detection and analysis, a total of 861 kinds of volatile compounds were detected, the aroma-active compounds in different grades were selected, and an aroma wheel of MKH was constructed. Our results found that non-volatile and volatile compounds not only contribute to defining the level of MKH standard samples but also provide a chemical basis for the measurement of flavour and quality of MKH.

Interaction and Binding Kinetics of Different Substituted Pyrazines with HSA: Based on Multispectral, Physiological Activity, and Molecular Dynamics Simulations

Pyrazine is a kind of compound containing pyrazine ring structure, which has attracted the attention of researchers because of its special aroma and healthcare function. It is currently used in spices, pharmaceuticals, food additives, and other industries. Human serum albumin (HSA) is a transport and storage protein in the human circulatory system. Previous research reported that pyrazine can interact with albumin, but the interaction between pyrazine and HSA has not been reported. Consequently, this study is based on the multispectral method and molecular dynamics (MD) simulation, exploring the interaction between different pyrazines and HSA. The results show that the four pyrazines mainly quench the endogenous fluorescence of HSA through the static quenching mechanism. Molecular docking indicates that hydrophobic forces play a major role in the binding of pyrazines with HSA. At the same time, synchronous fluorescence spectroscopy, circular dichroism (CD), three-dimensional fluorescence spectroscopy, and resonance light scattering (RLS) showed that each pyrazine compound can change the conformation of HSA. MD simulation results show that the combination of four pyrazines and HSA can enhance the stability of HSA. Among them, 2,3,5,6-tetramethylpyrazine (TTMP) and 2,3,5-trimethylpyrazine (TMTP) binding is the most stable and the most unstable combination with HSA, respectively. In addition, the four pyrazines could affect the physiological activity of HSA. This study is of great significance to explore the mechanism of action of pyrazine compounds in vivo and can provide useful information for the application of pyrazine compounds in food.

Enzyme Preparation Characteristics and New Technical Solution Development for Bioconversion of Collagen-Containing Raw Materials

One of the modern challenges facing the food and processing industry is the rational and resource saving technology development for the secondary resources use including collagen containing raw materials. Raw materials bioconversion is a promising solution method for the problem. A man run the research on the enzyme preparation use as hydrolysates of food raw materials including for the meat processing industry; studied the technological solutions appeared in the scientific and technical literature; identified the strengths and weaknesses of hydrolysis methods. Based on the studied data, the authors developed technological approach to the bioconversion of the broiler chicken skin. The developed approach consists in the technological preparation of collagen containing raw materials, its grinding, processing with an enzyme preparation from secondary fish raw materials for 15 minutes at a temperature of (3 ± 2)°C in a refrigerating chamber followed by filtration, regrinding and drying at a temperature of (41 ± 2) °C. According to the results of the conducted studies, the enzyme preparation is capable of collagen compound hydrolyzing, the proteolytic activity is 2.9 U/g. The enzyme preparation is a light-yellow substance with a faint specific aroma, a liquid, slightly viscous consistency. The mass fraction of dry substances in the enzyme preparation is 44%, the mass fraction of protein is 15%. Broiler chicken skin processing with an enzyme preparation resulted in a fine-grained free-running powder of light-yellow color with a mass fraction of 81.1% protein, 14.2% fat, 4.7% moisture, and 64.4% collagen. The ways of using the obtained collagen fermentolysate have been determined. The developed technology of using broiler chicken skin treated with an enzyme preparation is a new modern technical solution in the bioconversion of collagen containing raw materials. A man can exploit it in the food technology of meat pates and minced meat.

Cold-pressed tiger nut (Cyperus esculentus L.) oils: chemical and aromatic profiles, sensory properties, and consumer preferences

In this study, tiger nut oils produced by cold pressing were characterized by means of physicochemical, compositional, and sensory analyses. The major fatty acids were oleic (70.4%), palmitic (13.3%), and linoleic (11.9%) acids. The main sterols were β-sitosterol and stigmasterol (58.3 and 20.5 mg/100 g), and the main tocopherol was α-tocopherol (234.78 μg/g). Syringic acid, apigenin and vanillin were the major phenolic compounds quantified. The cold-pressed oils crystallized at -9.12 °C and melted at -1.87 °C. A sensory panel described the oil with 5 sensory descriptive (almond, nutty, roasted, straw, sweety, soil) terms. A consumer test indicated that appearance, smell/aroma, and taste/flavor scores were above 4.0 on a 5-point hedonic scale. In conclusion, tiger nut oils with retained nutrients and specific aroma could be produced by the cold-pressing technique. Further studies for food and functional food applications of this gourmet oil are anticipated.

Characterization, Stability and Antioxidant Activity of Vanilla Nano-Emulsion and Its Complex Essential Oil.

As a natural flavoring agent, vanilla essential oil has a special aroma and flavor, but its volatility and instability limit its value. Therefore, in this study, vanilla essential oil was compounded with cinnamon essential oil to prepare nano-emulsions (composite nano-emulsions called C/VT and C/VM), and the stability of the composite essential oil emulsions was investigated. Transmission electron microscopy (TEM) images showed that the nano-emulsions were spherical in shape and some flocs were observed in C/VM and C/VT. The results showed that the average droplet sizes of C/VM and C/VT increased only by 14.99% and 15.01% after heating at 100 °C for 20 min, and the average droplet sizes were less than 120 nm after 24 days of storage at 25 °C. Possibly due to the presence of reticulated flocs, which have a hindering effect on the movement of individual droplets, the instability indices of C/VM and C/VT were reduced by 34.9% and 39.08%, respectively, in comparison to the instability indices of C/VM and C/VT. In addition, the results of antioxidant experimental studies showed that the presence of composite essential oil flocs had no significant effect on the antioxidant capacity. These results indicate that the improved stability of the composite essential oil nano-emulsions is conducive to broadening the application of vanilla essential oil emulsions.

Exploring the aromatic typicity of blended red wines from geographically close sub-regions in AOC Corbières: a sensory and chemical approach

Several studies have reported a terroir effect on monovarietal wines originating from geographically close areas, using both aromatic and sensory analyses. However, few studies have evaluated this effect on blended wines, a widespread practice that is recognised as adding great complexity to wines. This study aimed to discriminate blended wines produced in five sub-regions of the Corbières AOC according to their aromatic and sensory profiles and across two vintages: 2018 and 2019. The wines’ aromatic profiles were semi-quantified using HS-SPME-GC-MS, and the sensory descriptors enabling the differentiation of the wines were identified by QDA analysis. Although blending is a frequently used process adapted for the production of homogeneous wines within an appellation, the sensory and chemical profiles enabled us to differentiate wines of the Lagrasse and Lézignan sub-regions from those of the Maritime and Durban sub-regions. The variation in intensity of red fruit jam notes may be linked to terroir factors relating to the micro-climatic conditions. Wines from vineyards in coastal regions or at higher elevations were discriminated by lower intensities of this descriptor. However, other discriminating descriptors, such as amyl, earthy or cooked vegetables, could be related to the winemaking process. Correlations were found between the tendencies observed regarding the sensory markers (such as red fruit jam, butter/lactic, amylic, cooked vegetable) and those regarding the chemical families of aroma or specific aroma compounds (such as ethyl esters, higher alcohols and sulphur compounds), whose production is particularly affected by the winemaking processes. Finally, this study shows that it is possible to discriminate blended wines from different geographically close regions, and that the terroir factor with the greatest influence on this discrimination seems to be linked to winemaking processes, including the type of blending carried out.

The fermentation conditions of low alcoholic three-leaved (Cayratia trifolia (L.) Domin) cider using Saccharomyces cerevisiae HG1.3

Three-leaved Cayratia, a perennial climber, is widely distributed in India, Asia, Africa, and Australia. In Vietnam, it is found in the Mekong Delta with a specific aroma, dark purple berries, and contains an abundant source of bioactive compounds (yellow waxy oil, steroids/terpenoids, flavonoids, and tannins) in whole plants. Taking advantage of the raw source might enhance various fermented juice drinks and increase income for denizens. The initial parameters were pH 3, 4, and 5 with the total soluble solids (TSS) of 18, 20, 22, and 24 °Bx, respectively, to determine the appropriate Cayratia cider making condition. The yeast concentration (0.1, 0.15, 0.2, and 0.25% [w/v], respectively) and fermentation time (24, 48, and 72 h, respectively) at room temperature (28 ± 2°C) were also surveyed. Thereafter, the final product was analyzed for the sensory quality and microbiological and chemical criteria. The fresh Cayratia juice has a pH of 3.2 and 6 °Bx, and the juice recovery efficiency was 74%, equivalent to 0.74 L/kg of the fruit juice amount after squeezing. The low alcoholic juice has 4.62% v/v ethanol content which meets the Vietnam National Standard (TCVN 3215:79, and QCVN 6-2: 2010/BYT) after 72 h of fermentation time. The TSS of 22 °Bx, pH value of 4, and yeast concentration of 0.2% (w/v) are appropriate initial conditions for Cayratia juice with low ethanol content. Cayratia cider with 4.6% (v/v) ethanol content was produced by Saccharomyces cerevisiae HG 1.3 at room temperature 28 ± 2°C with initial TSS of 22 °Bx, pH 4, and inoculation yeast rate of 0.2% w/v. The quality analysis meets Vietnamese standards for food consumption.