Concentrations Of Volatile Compounds Research Articles

Quality and quantitative traits of non-alcoholic beer with flavour-improved taste

The non-alcoholic and low-alcohol beer market has grown significantly in recent years and is predicted to continue growing. However, non-alcoholic and low-alcohol beers have organoleptic problems and are not recognized by many consumers. The increasing popularity of alcohol-free beers (AFBs) fosters the industry's interest in delivering the best possible product. Yet, a remaining sensory issue of AFBs is the over-perception of wort flavor, caused by elevated concentrations of small volatile flavor compounds (i.e.aldehydes)still remains. Previously, molecular sieves (hydrophobic ZSM-5 type zeolites) were found as most suitable to remove these flavors by adsorption with high selectivity from the AFBs. In this work, a flavor-improved beer is produced at a pilot-scale using this novel technology, and its chemical composition, sensory profile, and stability are evaluated against a reference. Aldehyde concentrations in the flavor-improved product were found 79–93% lower than in the reference. The distinct difference was confirmed with a trained sensory panel and could be conserved even after three months of ageing at 30ºC. Future work will focus on the process design to scale up this technology. It is established that the release of a new kind of beer is economically profitable, since the expansion of the range contributes to a more complete use of production capacity, and consequently, reduced costs per unit of production, which ultimately leads to an increase in the profit of the enterprise.

Dynamic changes in metabolomics and flavoromics during industrial scale fermentation of Chinese traditional soy sauce

Flavor substances are crucial to the quality of soy sauce and closely related to the intermediate metabolites. This study systematically explored the dynamic changes in physicochemical characteristics, metabolomics and flavoromics during traditional Chinese soy sauce fermentation. The results indicated that the amino acid nitrogen gradually increased to 0.95 g/100 mL on the 13th day and then stabilized, and the changes of reducing sugars increased to 66.40 mg/mL on the 7th day and then slowly decreased. A total of 90 volatile compounds and 1172 non-volatile metabolites were detected. In the early fermentation period (1–7 day), alcohols, aldehydes and ketones were the main volatile compounds, but as fermentation proceeded, phenols and esters gradually accumulated. The total content of volatile compounds, mainly alcohols and phenols, reached the highest value on the 23rd day. Non-volatile metabolites were mainly amino acids, organic acids, lipids and carbohydrates, and the content and types of varied with fermentation time. KEGG analysis indicates there were significant changes in the proline and arginine metabolism in the middle and late periods (7–28 day) compared to the early fermentation period. Correlation analysis indicating a delicate balance between the transformation of metabolites and the formation of volatile compounds in traditional Chinese soy sauce.

Impact of Pure, Co-, and Sequential Fermentations with Hanseniaspora sp. and Saccharomyces cerevisiae on the Volatile Compounds of Ciders

Pure, co-, and sequential fermentations of Hanseniaspora uvarum, H. guilliermondii, and Saccharomyces cerevisiae strains were evaluated to improve the aromatic quality of ciders. In sequential fermentations, Hanseniaspora strains were used as starter, followed by S. cerevisiae inoculation succeeding one, two, and three days of fermentation. Kinetics, physicochemical parameters, and volatile compounds were assessed during 10 days of fermentation. The headspace technique was used to capture the volatile compounds from the ciders obtained in each experiment and analyzed by gas chromatography. Fermentations with pure strains of Hansenisaspora sp. showed a high population (>1010 CFU/mL) but had a low fermentation rate (2.3–3.8 CO2 g/L/d), low consumption of amino acids (20–40 mg/L) with a high residual content, high sugar consumption (80–90 g/L), and low alcohol content (<2.0% v/v). The H. uvarum strain produced a notably high ester content (245 mg/L). In the co-fermentations, H. guilliermondii with S. cerevisiae highlighted a significant production of higher alcohols, similar to that produced by S. cerevisiae alone (152–165 mg/L). In general, the maximum fermentation rate of the sequential inoculations was lower than co-fermentations but showed low residual nitrogen content (<69 mg/L) and good conversion of sugars into ethanol (4.3–5.7% v/v). The highest concentrations of volatile compounds were observed in treatments involving the two non-conventional strains: H. uvarum with S. cerevisiae inoculation after three days (564 mg/L) and H. guilliermondii after just one day (531 mg/L) of fermentation. These differences stemmed from the metabolic activity of the strains. H. uvarum was influenced by the presence of Saccharomyces, whereas H. guilliermondii did not exhibit this effect. Thus, a pure H. uvarum inoculum has the potential to produce a demi-sec cider with low alcohol content and high content of esters, contributing to a fruity aroma. In addition, ciders with sequential inoculation were the most promising for dry cider processing concerning fermentation parameters and bioaroma enrichment.

Changes in volatile compounds in withering tea leaves after infestation with tea green leafhopper (Empoasca onukii Matsuda)

The effects of withering, cultivar yellowing, and Empoasca onukii infestation on tea leaf aroma have each been characterized, but variations in volatile compound (VC) contents as a result of co-occurrence of these factors remain unclear. In the present study, we analyzed VC contents in E. onukii-damaged leaves of Camellia sinensis (L.) cv. ‘Yinghong No. 9’ and the yellow bud variant ‘Yellowish Yinghong No. 9’ during the withering process. We found that glycoside-derived volatiles (GDVs) were the most abundant type of VCs, accounting for more than 83% of the total VC content. Linalool formed the main body of the tea aroma, contributing a floral, fruity scent. Differential accumulation of octanal and geranyl acetone in fresh leaves corresponded to differences in the aroma profiles between Yellowish Yinghong No. 9 and Yinghong No. 9. A higher degree of withering did not alter the pleasant aroma odors of Yellowish Yinghong No. 9, but rather maintained the floral, fruity flavors and reduced greenish odors and levels of defense-related compounds (e.g., benzeneacetaldehyde, benzyl nitrile) induced by E. onukii infestation. This study clearly establishes the effects of withering on the aroma profiles of E. onukii-infested leaves in both a standard and a yellow bud mutant tea variety, suggesting a method of maintaining the economic value of even insect-damaged tea leaves.

Monitoring of changes in the concentration of volatile organic compound in beef irradiated with accelerated electrons

The need to develop safe methods for radiation processing of food products to improve their quality and extend their shelf life stimulates new scientific research aimed at increasing their effectiveness. Oxidation of lipids and proteins occurred under the impact of ionizing radiation in products with a high fat and water content, such as chilled meat and fish products, leads to the formation of volatile organic compounds in the product thus giving it a specific smell and taste. During storage, biochemical processes associated with microbial enzymatic activity and auto-oxidation develop in processed refrigerated products. These processes also modify the volatile organic compounds, which affect the organoleptic properties of the product. The method of gas chromatography-mass spectrometry was used to study the behavior of volatile compounds identified in irradiated beef samples both immediately after irradiation and four days later to determine the effective dose range for the radiation processing of beef. Monitoring of the content of volatile compounds in beef samples irradiated by 1-MeV electrons within a dose range from 0.25 to 5 kGy showed that the content of certain alcohols, aldehydes, and alkanes exhibited pronounced dose- and time-dependent character. The developed mathematical model describes the dependence of the concentration of volatile compounds identified immediately after irradiation in beef samples on the irradiation dose. The model is based on the simultaneous occurrence of two competing processes: the decomposition of compounds due to their oxidation and accumulation due to oxidation of other compounds after exposure to ionizing radiation. The results obtained revealed that the effective dosage range of radiation treatment lies between 250 and 1000 Gy.

Aviation Mutagenesis Alters the Content of Volatile Compounds in Dahongpao (Camellia sinensis) Leaves and Improves Tea Quality.

Aviation mutagenesis is a fast and efficient breeding method. In this study, we analyzed the effect of aviation mutagenesis on volatile compounds and odor characteristics in Dahongpao fresh leaves and gross tea for the first time. The results showed that aviation mutagenesis significantly increased the total volatile compounds of Dahongpao fresh leaves and gross tea. Aviation mutagenesis most critically significantly increased the content of beta-myrcene in Dahongpao fresh leaves, prompting its conversion to beta-pinene, cubebol, beta-phellandrene, zingiberene, (Z,Z)-3,6-nonadienal, and 6-pentyloxan-2-one after processing, which in turn enhanced the fruity, green, spicy, and woody odor characteristics of the gross tea. This study provided a reference for further exploration of aviation mutagenic breeding of Camellia sinensis.

Effects of Bacillus amyloliquefaciens on volatile components and nutrient element contents of Mentha piperita L. grown under salt stress

Bacillus amyloliquefaciens (Ba) was applied to Mentha piperita L. (peppermint) seedlings grown at various salt levels (0, 50, 75, and 100 mM) for 42 days (six weeks). The study was conducted in a total of eight groups, with 24 seedlings per group. At the end of the study, the seedlings were analyzed for plant nutrient elements and volatile compound contents. The negative effect of salt was observed in almost all parameters. When all groups were evaluated for plant nutrient elements, Ba had a positive effect on Zn, Mn, Cu, and Na values compared to the control, but it did not show any effect on B, Fe, K, P, Mg, and Ca. In volatile compounds, limonene was detected as the major component in all groups. As a result of the evaluation based on limonene, the highest rate was found in the control, and the lowest rate was found in 100 mM NaCl. The salt-dependent inhibition between the groups with the highest and lowest limonene was 73%. While the negative effects of salt were observed in almost all parameters, the promoter effects of Ba were not as pronounced.

Volatile Compounds Content and Sensory Profile of Katuk (Sauropus androgynus) Leaves After Household Scale Heating

Katuk (Sauropus androgynus) is an indigenous Indonesian plant, and the leaves are often consumed as fresh or processed vegetables. Despite its potential, there are no reports on the volatile compounds content and sensory profile of Katuk leaves after being processed using household scale heating. Therefore, this study aimed to determine the volatile compounds content and sensory profiles of Katuk leaves after household scale heating (steaming and boiling). The extraction of constituents was carried out using the headspace-solid phase microextraction method, followed by identification with gas chromatography-mass spectroscopy. The sensory profile analysis was performed using the free choice profiling method with untrained panelists. The analysis results showed the presence of 16 volatile compounds derived from 7 groups, including aldehydes (5 compounds), alcohol (3 compounds), other components (3 compounds), ketones (2 compounds), as well as benzene, terpenoids, and esters (1 compound). The dominant compounds found in fresh Katuk leaves were alcohol [(Z)-3-hexene-1-ol]. Meanwhile, aldehydes (benzaldehyde, nonanal, benzeneacetaldehyde, and (E)-2-pentenal) and alcohol (1-Heptanol and Nerolidol) were dominant in the steamed samples, with benzene (naphthalene) being predominantly found in the boiled samples. The sensory profile analysis results showed that fresh Katuk leaves had a grassy and earthy aroma with a grassy flavor, while the boiled samples had a smooth and juicy texture. The dominant attributes found in steamed Katuk leaves included moist, tender, and tasteless. Based on these findings, household scale heating could modify the composition of volatile compounds, thereby affecting the sensory profile. The results obtained were expected to serve as a foundation for the processing of Katuk leaves at both industry and household levels.

Comprehensive analysis of the effect of etiolated tea cultivars and harvest seasons on volatile compounds and in vitro antioxidant capacity in steamed green teas

To explore the effects of harvest seasons and etiolated cultivars on the volatile compounds of steamed green teas, this study analyzed comprehensively the volatile compounds of steamed green teas using simultaneous distillation extraction-gas chromatography–mass spectrometry (SDE-GC–MS) and chemometrics analytical techniques in combination with odor activity value (OAV). Additionally, the in vitro antioxidant capacity of the steamed green teas was evaluated. The results showed that 95 volatile compounds were identified, among which aldehydes, ketones, alcohols, and acids were the main types in steamed green teas made from etiolated tea cultivars. Furthermore, the relative content of volatile compounds in steamed green tea was significantly negatively correlated with season (P < 0.05). In steamed green teas harvested in different seasons, spring tea contained a higher abundance of volatile compounds such as (+)-δ-cadinene, farnesyl acetone, carvenone, trans-β-ionone, and nerolidol. The differences of total volatile compounds among the three etiolated tea cultivars were not remarkable (P > 0.05). Combined with the OAV, 20 and 19 key aroma compounds in steamed green teas from different harvest seasons and cultivars were identified, respectively, which could bring unique aromas to different steamed green tea samples. By comparison, summer tea had the strongest antioxidant capacity, while there was no obvious difference in the antioxidant capacity among cultivars. This study provided a scientific basis for the aroma quality of steamed green teas made from etiolated tea cultivars in different harvest seasons.

Characterization of the effect of non-Saccharomyces cerevisiaes on the non-volatile constituents and volatile profiles of low-alcoholic pomegranate beverages

To create the low-alcoholic beverages with excellent nutritional properties and flavor qualities, pomegranate juice was fermented with 16 strains of non-Saccharomyces yeasts from 9 species without added sugar. The effects of different yeasts on the non-volatile constituents (vitamins, organic acids, polyphenols), volatile compounds and sensory characteristics of the fermented beverages were comprehensively evaluated. The study revealed that non-Saccharomyces fermentations resulted in a higher abundance of polyphenols compared to the pomegranate juice and S. cerevisiae WLS21 (Sc21). The monomer phenols in Meyerozyma guilliermondii 12 (Mg12) were approximately twice the total of CK and 1.3 times of Sc21. Moreover, they led to a higher concentration of volatile compounds than the pomegranate juice. A total of 94 volatile compounds were identified in the pomegranate fermented beverages. In contrast to S. cerevisiae, Wickerhamomyces anomalus 1-1 and 10 (Wa1-1, Wa10), Pichia kudriavzevii 8 (Pk8) and Mg12 resulted in more acetate esters, and Zygosaccharomyces rouxii IFO 1130 and 53 (Zr1130, Zr53) yield higher levels of ethyl esters. A total of 40 volatiles with a relative odour activity value (rOAV) of ≥ 0.1 were identified, of which 14 were selected for principal component analysis (PCA). The sensory analysis confirmed that Zr1130, Zr53, Wa1-1, Wa10 and Pk8 strains exhibited superior aroma generation compared to Sc21. Furthermore, the partial least-squares regression (PLSR) analysis revealed that cherry, red fruits, black currant, citrus fruits, raspberry, black berry, pineapple, floral, sour and alcoholic odours had a significantly positive impact on the overall acceptability of the fermented beverages.

The different responses of Batocera horsfieldi adults to Juglans regia bark and leaf volatile compounds

AbstractBatocera horsfieldi (Hope) (Coleoptera: Cerambycidae) is an important pole borer pest. It causes serious harm to various hosts, particularly Juglans regia L. (Juglandaceae). In this study, headspace solid‐phase microextraction (HS‐SPME), gas chromatography–mass spectrometry (GC–MS), and electroantennogram (EAG) responses were combined to examine the mechanism by which B. horsfieldi adults locate their host, J. regia. The results showed that J. regia contained 65 volatile compounds in all, with 36 and 42 volatile substances in bark and leaves, respectively. Moreover, terpenes accounted for the largest relative content among the volatile compounds of bark and leaves, 43.4 and 78.9%, respectively. Ten of 19 selected volatile components elicited significant EAG responses in adult B. horsfieldi, which indicated that the pest may prefer certain volatile compounds when selecting a host. Sex and volatile concentration affected the responses of B. horsfieldi. Male adults had the strongest EAG responses to 1‐octen‐3‐ol, whereas female adults had the strongest EAG responses to linalool. Host selection in B. horsfieldi was somewhat positively associated with the concentrations of the effective volatile compounds in the host. Furthermore, B. horsfieldi showed varying preferences for isomers. This work provided data support for the development of insect attractants, and laid a theoretical foundation for the ecological protection of local forestry.

Effect of different pretreatments on the hydrolysis efficiency and flavor of squid viscera (Dosidicus gigas)

In order to better utilize the proteins in squid viscera (Dosidicus gigas), the effects of different pretreatments on the degree of hydrolysis (DH) and volatile compounds of hydrolysates were studied. The DH was used as an indicator to select alkaline protease as the optimal protease from 8 types of proteases. The hydrolysis conditions of alkaline protease and the flavor of the hydrolysates were investigated through single-factor, response surface methodology, and pretreatment-assisted hydrolysis experiments. The results showed that alkaline protease had the highest DH (42.08 ± 0.58%), with enzyme dosage of 1.5%, hydrolysis temperature of 45 °C, hydrolysis time of 5 h, and liquid-solid ratio of 4:1. The DH of the ultrasound group was significantly higher than other groups, with the highest DH (45.67 ± 0.34%) after ultrasound for 40 min (U40). The proportion of molecular weight < 1 kDa and the content of free amino acids (1613.64 mg/100 g) were the highest at U40. The electronic nose results indicated that the composition of organic sulfur and aliphatic compounds in U40 showed significant differences compared to other products. The U40 sample had the highest type and content of volatile compounds (especially benzaldehyde), which was more conducive to the volatilization of flavor substances. In conclusion, U40 pretreatment can effectively improve the DH and flavor of hydrolysates.

Application effects of NaCl substitute on the fermentation profile of Pixian douban (broad bean paste).

The effects of a reduced-salt substitute (composed of NaCl, sodium gluconate, KCl, L-histidine, and L-lysine) applied in the fermentation of traditional Pixian douban (PXDB) were explored in this study according to sensory quality, physicochemical characteristics, color, colony count, and the contents of free amino acids (FAAs), organic acids, and volatile flavor compounds. The results showed that the PXDB with a 15% salt substitution had the most attractive reddish-brown color, a mellow fragrance, and the lowest total colony count of the three pastes. The fermentation quality of the 15% salt substitute PXDB was superior to that of the control groups, its sensory quality was more readily accepted, and the contents of its amino acid nitrogen, FAAs and organic acids had increased by 0.1050, 0.3290, and 3.9068mg/g, respectively. Moreover, the concentrations of the main aroma compounds in the PXDB containing the salt substitute were higher than those of the control. These included phenylethanol, 3-methylthiopropanol, isoamyl alcohol, furfural, benzaldehyde, phenylacetaldehyde, nonanal, isoamyl aldehyde, 4-ethylphenol, and, particularly, 2,6-dimethylpyrazine, which had increased as much as 100 times. Correlation analysis showed that Glu, Phe, Tyr, Gly, Leu, Val, Asp, Ile, citric acids, and succinic acids were all positively correlated with the main aroma and contributed to the generation of PXDB's characteristic flavor, and main aroma substances in turn positively influence PXDB flavor sensory attributes. Overall, these results showed the application of the 15% salt substitute during PXDB fermentation improved the quality of the paste and, thus, would benefit the development of reduced-salt PXDB.

The effect of different non-Saccharomyces strains on the flavour characteristics of mead

AbstractAs research advances, it is generally acknowledged that non-Saccharomyces yeast contribute to the addition of aromatic compounds during mead fermentation. In this experiment, eight different non-Saccharomyces strains and Saccharomyces cerevisiae co-fermentation, their aroma composition, and basic physicochemical parameters were investigated. More than 30 compounds with favourable impact were discovered using solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS). Co-fermentation of non-Saccharomyces spp. and S. cerevisiae can affect the concentration of volatile compounds, so that the mead presents different aroma characteristics. Co-fermented meads of Wickerhamomyces anomalus strains and S. cerevisiae (Wa 27-Sc and Wa 5-Sc) had higher alcohol, acids, aldehyde, and ester concentrations than those fermented with S. cerevisiae alone. In terms of taste, Wa 27-Sc was superior to Wa 5-Sc. Overall, the Wa 27-Sc received the highest score for its strong secondary aroma and good mouthfeel. The results show that the W. anomalus Wa 27 strain has a good potential to produce high quality mead.

Qualitative traits and peel essential oil profiles of 24 Italian and international lemon varieties

Lemon (Citrus limon L. Burm. f.) is used for fresh consumption because it is rich in several nutraceutical products especially vitamin C. The physicochemical properties and the bioactive compounds of the peel, such as the essential oil, are strictly depended on the genotype. In this context, peel and juice qualitative traits of 24 lemon cultivars were described: 20 varieties of the Italian germplasm, mostly belonging to Femminello (F.) lines, and 4 international varieties were studied. This study which may be considered one of the few examples carried out on a large number of varieties of a single Citrus species, was conducted over two years and the oils collected by hydro-distillation of the flavedo were analyzed by GC-FID and GC-MS. Differences were observed in the oil yields. For an easier comparison the essential oils’ component were subdivided in five classes: monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes and others (not terpenoidic compounds). Among the monoterpene hydrocarbons, in all the cultivars the most abundant compounds were limonene, followed by β-pinene and γ-terpinene. In particular, Monachello showed the highest content of monoterpene hydrocarbons, while the lowest value was observed in F. Carrubaro, Fino and Akragas. Femminello lines are interesting cultivars for qualitative traits of the juice (organic acids and vitamin C) and for the highest content of volatile compounds in the peel, such as limonene, myrcene, β-pinene, α-pinene, γ-terpinene and sabinene. Significant differences in morphological and physicochemical traits were observed: fruits of Lemox, F. Adamo and F. Scandurra showed to be seedless, while high acidity content was observed in F. 2Kr, which also showed the highest vitamin C content.

Volatilome and flavor analyses based on e-nose combined with HS-GC-MS provide new insights into ploidy germplasm diversity in Platostoma palustre

Platostoma palustre (Mesona chinensis Benth or Hsian-tsao, also known as “Xiancao” in China), is an edible and medicinal plant native to India, Myanmar, and Indo-China. It is the main ingredient in the popular desserts Hsian-tsao tea, herbal jelly, and sweet herbal jelly soup. P. palustre is found abundantly in nutrient-rich substances and possesses unique aroma compounds. Variations in the contents of volatile compounds among different germplasms significantly affect the quality and flavor of P. palustre, causing contradiction in demand. This study investigates the variation in the volatile compound profiles of distinct ploidy germplasms of P. palustre by utilising headspace gas chromatography-mass spectrometry (HS-GC–MS) and an electronic nose (e-nose). The results showed significant differences in the aroma characteristics of stem and leaf samples in diverse P. palustre germplasms. A total of sixty-seven volatile compounds have been identified and divided into ten classes. Six volatile compounds (caryophyllene, α-bisabolol, benzaldehyde, β-selinene, β-elemene and acetic acid) were screened as potential marker volatile compounds to discriminate stems and leaves of P. palustre. In this study, leaves of P. palustre showed one odor pattern and stems showed two odor patterns under the influence of α-bisabolol, acetic acid, and butyrolactone. In addition, a correlation analysis was conducted on the main volatile compounds identified by HS-GC–MS and e-nose. This analysis provided additional insight into the variations among samples resulting from diverse germplasms. The present study provides a valuable volatilome, and flavor, and quality evaluation for P. palustre, as well as new insights and scientific basis for the development and use of P. palustre germplasm resources.

Characterization and comparison of flavors in fresh and aged fermented peppers: Impact of different varieties

The flavor profiles of fresh and aged fermented peppers obtained from four varieties were thoroughly compared in this study. A total of 385 volatile compounds in fermented pepper samples were detected by flavoromics (two-dimensional gas chromatography–time-of-flight mass spectrometry). As fermentation progressed, both the number and the total concentration of volatile compounds changed, with esters, alcohols, acids, terpenoids, sulfur compounds, and funans increasing, whereas hydrocarbons and benzenes decreased. In contrast to the fresh fermented peppers, the aged fermented samples exhibited lower values of pH, total sugars, and capsaicinoids but higher contents of organic acids and free amino acids. Furthermore, the specific differences and characteristic aroma substances among aged fermented peppers were unveiled by multivariate statistical analysis. Overall, 64 volatiles were screened as differential compounds. In addition, Huanggongjiao samples possessed the most abundant differential volatiles and compounds with odor activity values > 1, which were flavored with fruity, floral, and slightly phenolic odors. Correlation analysis demonstrated that the levels of 23 key aroma compounds (e.g., ethyl 2-methylbutyrate, 1-butanol, and ethyl valerate) showed a significantly positive correlation with Asp, Glu and 5 organic acids. By contrast, there is a negative association between the pH value and total sugar. Overall, aging contributed significantly to the flavor attributes of fermented peppers.

Effects of Non-Saccharomyces Yeasts and Their Pairwise Combinations in Co-Fermentation with Saccharomyces cerevisiae on the Quality of Chunjian Citrus Wine.

Non-Saccharomyces (NSc) yeasts have great potential in improving wine qualities. In this study, two NSc and two Saccharomyces cerevisiae (Sc) samples were tested on their performance of mono-inoculated and composite culture in the fermentation of Chunjian citrus wine. The cell count, Brix degree, total sugar, total acidity, alcohol level, pH value, color intensity (CI), and tonality were determined to evaluate the contribution of NSc to the quality of citrus wine in the mixed fermentation. Volatile compounds were analyzed by HS-SPME-GC-MS, and sensory evaluation was carried out. During the 9-day fermentation, the mixed-culture wine exhibited a higher cell concentration than the pure culture. After the fermentation, mixed-culture wine specifically decreased the concentrations of unfavorable volatile compounds, such as isobutanol and octanoic acid, and increased favorable volatile compounds, including ethyl octanoate, ethyl decanoate, and phenylethyl acetate. The quality category of the citrus wine was improved compared with the Sc mono-inoculated wines, mainly in regard to aroma, retention, and sweetness. The study shows that the mixed fermentation of NSc and Sc has positive impacts on reducing alcohol level and total acidity and increasing CI. The present work demonstrates that the mixed fermentation of NSc and Sc has enormous beneficial impacts on improving the quality of citrus wine.

A Multisensor Device Intended as an IoT Element for Indoor Environment Monitoring.

This work presents a multisensor device which is intended as an element of IoT for indoor environment (IE) monitoring. It is a portable, small-size, lightweight, energy-efficient direct-reading instrument. The device has an innovative design and construction. It offers real-time measurements of a wide spectrum of physical and chemical quantities (light intensity, temperature, relative humidity, pressure, CO2 concentration, content of volatile organic compounds including formaldehyde, NO2, and particulate matter), data storage (microSD; server as an option), transmission (WiFi; GSM and Ethernet as options), and visualization (smartphone application; PC as an option). Commercial low-cost sensors were utilized, which have been arranged in the individual sensing modules. In the case of gas sensors, dynamic exposure was chosen to ensure a minimum response time. The MQTT protocol was applied for data transmission and communication with other devices, as well as with the user. The multisensor device can collect huge amounts of data about the indoor environment to provide the respective information to the IoT. The device can be configured to control actuators of various auxiliary devices and equipment including external systems used for ventilation, heating, and air conditioning. The prototype is fully operational. The exemplary results of IE monitoring were shown.

Deciphering the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during soy juice fermentation using phenotypic and transcriptional analysis.

To reduce the environmental and health concerns related to food, an alternative diet is recommended, containing 50% of plant-based proteins. Soy juice, which is protein rich, is a relevant alternative to animal milk, for the production of yogurt-like products. However, soy "beany" and "green" off-flavors limit the consumption of such products. The lactic acid bacteria (LAB) used for fermentation can help to improve the organoleptic properties of soy products. But metabolic data concerning LAB adapted to soy juice are lacking. The aim of this study was, thus, to decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during fermentation of a soy juice, based on a multidisciplinary approach. This result will contribute to give tracks for a relevant selection of starter. Indeed, the improvement of the organoleptic properties of these types of products could help to promote plant-based proteins in our diet.