Alcohol Concentration Research Articles

Utilization of hyperspectral imaging for the analysis of aroma components of Soy Sauce-Aroma Type Baijiu

This study sought to develop a hyperspectral imaging (HSI)- and machine learning (mL)-based method to quantitatively analyze the composition of alcohols and esters of Soy Sauce-Aroma Type Baijiu (SSAB). First, preprocessed the spectral data in the 900–1700 nm NIR range using various algorithms. Then, particle swarm optimization-support vector regression (PSO-SVR) and random forest (RF) models were established based on the full wavelength and the feature wavelength spectral data. In the preprocessing method, the external parameter orthogonalization (EPO) method demonstrated superior modeling performance in most cases. Spearman correlation analysis revealed a significant positive correlation between the concentrations of ethanol and alcohols in the SSAB samples, with an r-value of 0.93. Ethyl acetate and ethyl lactate also showed a significant positive correlation with esters, with r-values of 0.87 and 0.88, respectively. Combining the relevant compounds with feature wavelengths as input yields a model with high accuracy, with an Rp2 of 0.997 and RMSEP of 0.118 mg/L for alcohols and an Rp2 of 0.996 and RMSEP of 0.017 mg/L for esters. The results indicate that HSI can achieve non-destructive and accurate detection of alcohols and esters in the aroma of SSAB, providing a new method for aroma analysis in Baijiu.

Solar collector inspired by the polar bear: Fluorescent‐reinforcing photothermal conversion efficiency

AbstractThe crucial point of solar thermal utilization makes solar heat collector gathering much attention. In this study, imitating polar bears' fur structure, fluorescent materials are modified into a solar heat collector, and the photothermal conversion is evaluated to examine the influence of polyvinyl alcohol concentration, fluorescent luminescence type and fluorescence concentration. The test results indicate that fluorescent materials that has a greater Stokes shift show the greater photothermal effect. Moreover, when composed of a PVA concentration being 5.0% and a fluorescent concentration being 0.50%, the composites exhibit the maximal photothermal conversion temperature (99.4°C) that is 17.9% higher than that of the solar heat collectors without fluorescent materials. This study proposes creating solar heat collector with modified fluorescent materials, and the new perspective of which demonstrates that the composites have a great potential and application prospect in the solar photothermal field.

Synthesis and antimicrobial activity testing of quaternary ammonium silane compounds

With increasing health awareness of the pathogenic effects of disease-causing microorganisms, interest in and use (of medical textiles, disinfectants in medical devices, etc.) of antimicrobial substances have increased in various applications, such as medical textiles and disinfectants (alcohol-based and nonalcoholic), in medical devices There are several concerns with alcohol-based disinfectants, such as surface deformation of medical devices due to high alcohol content and damage to skin tissue caused by lipid and protein denaturation of cell membranes. Quaternary ammonium compounds (quats) were preferred because they have the potential to prepare water-based disinfectants. In this study, novel (3-chloropropyl)triethoxysilane (CPTMO) and (3-chloropropyl)triethoxysilane (CPTEO) based quaternary ammonium silane compounds (silane-quats) were developed using quats with carbon chain lengths of C12, C14, C16 and C18. Titration (ASTM D2074) was used to calculate the yield of the synthesis and the structures of the products were characterised by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (13C NMR, 1H NMR) and gas chromatography-mass spectrometry (GC–MS).The in vitro antimicrobial activity of the synthesized samples was evaluated against Gram-positive (Staphylococcus aureus (S. aureus), Enterococcus hirae (E. hirae)) and Gram-negative (Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa)) bacteria and fungi (Candida albicans (C. albicans), Aspergillus brasiliensis (A. brasiliensis)) using the minimum inhibitory concentration (MIC) test. According to MIC tests, the silane-quats with the highest antimicrobial effects were dimethylhexadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (SQ3), which had an MIC of < 16 μg/ml (ppm) against E. coli, S. aureus, E. hirae, C. albicans, and A. brasiliensis and 32 μg/ml against P. aeruginosa. The MIC test results also showed antimicrobial activity at least 2 times greater than that of the commercially available disinfectant benzalkonium chloride (BAC). Findings suggest that SQ3 (C16) holds promise as an effective medical disinfectant, presenting a novel approach to combating microbial infections in healthcare settings.

Modelling and optimization of germination and fermentation process conditions during distillation of indigenous alcoholic beverage on the basis of fermented maize grits

This study investigated the effects and optimization of germination time, fermentation period and distillation temperature on the physicochemical properties, mineral and sensory attributes of indigenous alcoholic beverage using Response Surface Methodology. The effects of germination time on the structure of maize grits were also determined by scanning electron microscope, Fourier transmission-Infrared and X-ray diffraction. The maize grits were produced and subsequently processed into indigenous alcoholic beverages by distillation process. Result showed that the micro-structural properties affected by germination and fermentation which cause degradation of starch granules and protein polymers structures. The alcohol content obtained ranged between 1.51 % and 8.30 %. The physicochemical properties, mineral content and sensory attributes of indigenous alcoholic beverage were significantly (p < 0.05) influenced by the processing conditions which gave lower alcohol content. The optimal processing conditions for alcoholic beverages were achieved using germination time of 72 h, fermented at 3 days with distillation temperature of 78.5 °C. These variables are a good source of feasible alternative in the brewing industry.

Kinetic Studies on Ruthenium(III) Chloride‐Catalyzed Oxidation of Benzyl and Homobenzyl Alcohols Using Cerium(IV) Sulfate under Acidic Medium

AbstractThis study investigates the kinetics of oxidative conversion of benzyl and homobenzyl alcohols to carbonyls using cerium(IV) sulfate in the presence of ruthenium(III) complex under mild acidic conditions. The results revealed that the low concentration of both alcohols and cerium(IV) ions drives the reaction to a first‐order kinetics, whereas a higher concentration induces zero‐order kinetics. In addition, the kinetics of the reaction were altered by the additives of hydrogen ions, cerium(III) ions, and chloride ions. We hope this study will be helpful in understanding the reaction kinetics of the oxidation of primary alcohols.

Halal aspect and nutritional potential of telang (Clitoria ternatea L.) flower kombucha

Abstract Public awareness of halal aspects is increasing, especially for foods. Indonesian Ulema Council (MUI) states that fermented drinks are halal if they contain alcohol below 0.5%. Several compounds are produced during the fermentation process in kombucha, including the compound ethanol (alcohol). This research aims to analyze the alcohol content and nutritional content of telang (Clitoria ternatea L.) flower kombucha drinks to fulfil halal aspects and nutritional potential. This research is an experimental study using a Completely Randomized Design (CRD) with one factor, namely storage time at five observation points (0 weeks, 1 week, 2 weeks, 3 weeks, and 4 weeks). The alcohol content was analyzed using a method using Gas Chromatography with Flame Ionization Detection- Head Space (GC-FID). Nutrient content analysis consists of analysis of water, ash, energy, energy from fat and protein content, and carbohydrate analysis carried out by difference. Total sugar content was analyzed using High-Performance Liquid Chromatography (HPLC). The alcohol content increases during the storage period. Alcohol content is in the range of 0.15-0.17%. This content meets halal aspects with a content of &lt;0.5% following MUI regulations. Statistical analysis using ANOVA showed that storage had no significant effect on alcohol content (p&gt;0.05). Telang flower kombucha contains 117.46 calories of energy, 29.37 grams of carbohydrates, 0.02 grams of fat, 0.04 grams of protein, and 16 grams of sugar per 100 ml.

Effect of microwave combined with ultrasonic pretreatment on the flavor of composite stewed soup‐stock

AbstractIn order to increase the content of flavoring components and nutrients in the stock, effects of microwave (MW) combined with ultrasonic pretreatment on water‐soluble proteins, flavor nucleotides, volatile gas constituents and sensory evaluation in the stewed stock were explored. The results showed that, compared with the control group (CK), MW, and ultrasonic (US) pretreatment could significantly promote the degradation of nucleotides and form a large number of 5′‐flavor nucleotides. The combined treatment of MW and US promoted protein hydrolysis and increased the content of water‐soluble protein. The microwave combined ultrasonication pretreated stew stock had the brightest color and the overall sensory score was better than that of the CK. In addition, GC–MS analysis showed that a total of 49 volatile substances were detected in the stock samples. After microwave combined ultrasonication pretreatment, the relative contents of aldehydes and alcohols in the stock increased significantly. The sensor response value of the electronic nose was the highest, indicating that the intensity of flavor characteristics increased. Therefore, MW combined with ultrasonic pretreatment can effectively promote the formation and dissolution of nutrients, and increase the content of flavorful nucleotides and volatile gases.Practical applicationThis study provides a novel processing method for traditional stewed stock. Ultrasonic combined with MW treatment can quickly degrade the protein in the raw material and dissolve it into the stock. At the same time, it promotes the formation of flavor nucleotides and accelerates the Maillard reaction to produce more flavor substances. The technology has the advantages of short processing time, environmental protection and safety. It can be used as a potential pretreatment technology to regulate the flavor of stock‐soup.

Motor vehicle collision characteristics and hospitalization outcomes associated with mild traumatic brain injury and concomitant whiplash injury.

Few large studies have investigated the factors and outcomes related to concomitant injuries occurring alongside mild traumatic brain injury (mTBI) after motor vehicle collisions (MVCs). Thus, the objective of this study was to assess whether MVC characteristics predict which patients with mTBI will have concomitant whiplash injury, and whether concomitant whiplash injury affects care utilization for these patients. This retrospective cohort study included 22,213 patients with mTBI after MVC identified from the American College of Surgeons Trauma Quality Programs dataset. A hierarchical logistic regression model was constructed to investigate patient and MVC factors associated with concomitant whiplash injury. Propensity score matching on whiplash status, in conjunction with a multivariable logistic regression model, assessed if concomitant whiplash affected odds of hospitalization. In the subgroup of patients who were hospitalized, associations with hospital length of stay (LOS) and discharge disposition were investigated. The median (IQR) age was 34 (24-51) years, with a median Glasgow Coma Scale score at presentation of 15 (15-15). Patients with concomitant whiplash were older (median 36 years vs 34 years, p = 0.03) and had higher rates of hospitalization (75% vs 64%, p < 0.001). In the hierarchical model for associations with concomitant whiplash injury, patients with blood alcohol content (BAC) greater than the federal driving limit had lower odds of concomitant whiplash (OR 0.63, 95% CI 0.49-0.81) along with those who had airbag deployment (OR 0.80, 95% CI 0.68-0.95), but seatbelt use was associated with greater odds (OR 1.41, 95% CI 1.16-1.71). After matching, concomitant whiplash was independently associated with increased odds of hospitalization (OR 1.67, 95% CI 1.40-1.99) while seatbelt use was associated with decreased odds (OR 0.88, 95% CI 0.81-0.95). Among hospitalized patients, concomitant whiplash was not associated with hospital LOS or discharge disposition. MVC characteristics such as alcohol consumption and airbag deployment were protective toward development of concomitant whiplash for mTBI patients, while seatbelt use was associated with higher risk. Concomitant whiplash increases the odds of hospitalization for mTBI patients but does not affect hospital LOS or discharge disposition, while seatbelt use is associated with lower rates of hospitalization and a more favorable hospital course. These findings provide context to injury patterns and care provision after a common mechanism of injury.

ROLE OF BIOTECHNOLOGY IN PROCESSING JACKFRUIT SEED WASTE TURNS INTO BIOETHANOL

The jackfruit plant is a type of tropical fruit plant that is multifunctional and can be planted in tropical areas at an altitude of less than 1,000 meters above sea level. Research has been carried out on making bioethanol from waste jackfruit seeds (Artocarpus heterophyllus Lamk). This research aims to find out whether jackfruit seed waste can be used as raw material for making biethanol and to determine the effect of pH on the fermentation process. This research used jackfruit seeds which were hydrolyzed with H2SO, 2.5% for 3 hours at a temperature of 70 °C, then the glucose content was measured and fermented at varying pH = 3, 4, 5, and 6 for 48 hours. The highest bioethanol content of jackfruit seeds was achieved during 4 days of fermentation with an alcohol content of 13.19%.

Cultivating Health: Traditional Alcoholic Drink 'Tuak' as a Potential Functional Drink for Regulating Blood Glucose Levels while Keeping Cultural Significance Intact

This research examines the potential for developing traditional alcoholic drinks using Raru (Cotylelobium melanoxylon Pierre) as an additional ingredient in the fermentation of tuak. Tuak, as a traditional alcoholic drink that is popular in many regions in Indonesia, plays an important cultural role in traditional celebrations. The advantages of palm wine as a traditional alcoholic drink include its natural sweet taste, good nutritional content, low alcohol content and affordable price. By analyzing the potential of Raru as an additional ingredient in making palm wine, this research seeks to develop traditional alcoholic drinks that not only maintain cultural and traditional aspects, but also provide additional health benefits, especially in lowering blood sugar levels, by launching a new product called ' 'RaruReserve: Healthy Tuak”

Definition of halal analysis of formulation of kombucha drink from simplicia of malay apple fruit (Syzygium malaccense)

The wealth of biodiversity and the abundance of native Indonesian germplasm resources have not been optimally utilized domestically. Malay apple, which belongs to the myrtaceae family, has various health benefits. However, its utilization is still limited, thus requiring ideas to increase public interest in this fruit. Therefore, innovation is carried out by transforming malay apple into kombucha fermentation beverages as a step to optimize its utilization. The research aimed to measure the total alcohol content, total acid, and total sugar in the formulation of kombucha beverages derived from malay apple fruit juice, with the goal of developing it into a functional beverage. The research process involved testing alcohol content using gas chromatography, measuring total acid by alkalimetric titration method, and measuring total sugar content by anthrone method. The research results showed that the malay apple kombucha sample the level of alcohol content was 0.0213%, the total acid was 1.38% (&lt;2 g/L), and the total sugar was 0.807 µg. The kombucha malay apple which category halal kombucha.

Drinker driver flyer diver.

Blood alcohol concentrations above defined levels are detrimental to cognitive performance. Empirical and published evidence suggest that nitrogen narcosis is analogous to alcohol intoxication with both impairing prefrontal cortex function. Nitrogen narcosis is also known to have been a factor in fatal accidents. To examine the effects of nitrogen narcosis, a recent publication used the Iowa Gambling Task tool, to simulate dynamic real-life risky decision-making behaviour. If the reported outcomes are corroborated in larger rigorously designed studies it is likely to provide further evidence that divers may well experience the negative effects of a 'narcotic agent', even at relatively shallow depths. These deleterious effects may occur regardless of diving experience, aptitude or professional status. In 1872, English law made it an offence to be 'drunk' whilst in charge of horses, carriages, cattle and steam engines. Understanding the danger was easy, establishing who is 'drunk' in the eyes of the court required a legal definition. Driving above a 'legal limit' for alcohol was made illegal in the United Kingdom in 1967. The limit was set at 80 milligrams of alcohol per 100 millilitres of blood. It took just short of one hundred years to get from first introducing a restriction to specific activities, whilst under the influence of alcohol, to having a clear and well-defined enforceable law. The question surely is whether our modern society will tolerate another century before legally defining safe parameters for nitrogen narcosis?

Wearable Alcohol Monitoring Device for the Data-Driven Transcutaneous Alcohol Diffusion Model.

Wearable alcohol monitoring devices demand noninvasive, real-time measurement of blood alcohol content (BAC) reliably and continuously. A few commercial devices are available to determine BAC noninvasively by detecting transcutaneous diffused alcohol. However, they suffer from a lack of accuracy and reliability in the determination of BAC in real time due to the complex scenario of the human skin for transcutaneous alcohol diffusion and numerous factors (e.g., skin thickness, kinetics of alcohol, body weight, age, sex, metabolism rate, etc.). In this work, a transcutaneous alcohol diffusion model has been developed from real-time captured data from human wrists to better understand the kinetics of diffused alcohol from blood to different skin epidermis layers. Such a model will be a footprint to determine a base computational model in larger studies. Eight anonymous volunteers participated in this pilot study. A laboratory-built wearable blood alcohol content (BAC) monitoring device collected all the data to develop this diffusion model. The proton exchange membrane fuel cell (PEMFC) sensor was fabricated and integrated with an nRF51822 microcontroller, LMP91000 miniaturized potentiostat, 2.4 GHz transceiver supporting Bluetooth low energy (BLE), and all the necessary electronic components to build this wearable BAC monitoring device. The %BAC data in real time were collected using this device from these volunteers' wrists and stored in the end device (e.g., smartphone). From the captured data, we demonstrate how the volatile alcohol concentration on the skin varies over time by comparing the alcohol concentration in the initial stage (= 10 min) and later time (= 100 min). We also compare the experimental results with the outputs of three different input profiles: piecewise linear, exponential linear, and Hoerl, to optimize the developed diffusion model. Our results demonstrate that the exponential linear function best fits the experimental data compared to the piecewise linear and Hoerl functions. Moreover, we have studied the impact of skin epidermis thickness within ±20% and demonstrate that a 20% decrease in this thickness results in faster dynamics compared to thicker skin. The model clearly shows how the diffusion front changes within a skin epidermis layer with time. We further verified that 60 min was roughly the time to reach the maximum concentration, Cmax, in the stratum corneum from the transient analysis. Lastly, we found that a more significant time difference between BACmax and Cmax was due to greater alcohol consumption for a fixed absorption time.

Exploring the Impact of Extended Maceration on the Volatile Compounds and Sensory Profile of Monastrell Red Wine

Volatile organic compounds (VOCs) are crucial to the wine’s overall quality since they define the aromatic profile. The aim of this study was to investigate whether a 146-day extended maceration (EM) treatment positively affects the aromatic and sensory properties of Monastrell red wine. A total of 43 aromatic compounds belonging to different chemical classes were identified using solid-phase microextraction combined with gas chromatography–mass spectrometry (SPME/GC-MS). In general, EM treatment decreased both the number and total relative concentration of VOCs. Specifically, EM decreased the concentration of alcohols, terpenes and sulphur compounds compared to control wines. However certain compounds such as 2-ethyl-1-hexanol, phenylethyl and ethyl decanoate significantly increased with prolonged maceration. Conversely, EM treatment did not significantly affect the total relative concentrations of esters and ketones. From sensorial point of view, the triangular test showed a positive identification of wines (10/18) with a significant preference for EM wines. Moreover, descriptive analysis revealed that EM wines scored lower values in appearance, aroma and taste. Future research should aim to optimize maceration time to enhance the content of VOCs without compromising the sensory quality of the wine.

SURFACE PROPERTIES AND MICELLIZATION OF SODIUM ALKYLSULPHATES IN THE PRESENCE OF LOW-MOLECULAR ALCOHOLS

The process of micellization of sodium alkyl sulfates (SAS : sodium decyl- (SDS) and dodecylsulfate (SDDS)) of formation in aqueous solution without or with alcohols including propanol-1, propanol-2 and butanol-1 and their adsorption behavior at air-liquid interface were investigated with both the tensiometry and the conductometry at 298 K. The effect of chain length of alcohol on micellar and interfacial properties were discussed. Some parameters including surface excess concentration (Γmax), minimum area per surfactant molecule (Smin) at air-liquid interface, degree of ionization of micelle, and standard free energy of adsorption and micellization, etc. are estimated. It was experimentally established that the introduction of 0.5-1.0 mol/dm3 of alcohols into surfactant solutions contributes to the process of micellar formation of SAS and increases the stability of the micellar phase, as evidenced by the observed synergistic effect on the critical micelle concentration (CMC). The addition of different alcohols changes the values of Γmax, Smin, CMC of SDS and SDDS and induces an increase in degree of ionization (β) of micelle relative to that in pure water. When alcohols are introduced into SDS and SDDS solutions, the degree of ionization of micelles at a constant length of the alkyl radical of surfactant moderately increases with increasing alcohol content in the solution and ranges from 0.50-0.73 and 0.38-0.75, respectively. Also, the effect of alcohol was discussed. The obtained thermodynamic parameters were used to confirm these behaviors of interfacial adsorption or micellization. An increase in chain length of alcohol promotes the micellization process. The CMC values decrease with increasing length of the alkyl radical of alcohols. Propanol-1, compared to propanol-2, somewhat reduces the value of SDS and SDDS CMC to a greater extent. Standard free energy of micellization ∆G0mic, also confirms the micellization behavior. Standard free energy of adsorption (∆G0адс) indicates that an increase in the chain length of alcohol in aqueous solution is favorable to the adsorption of SDS and SDDS at air-liquid interface. A comparison of the values of the standard free energy of adsorption and micelle formation in sodium alkyl sulfates – alcohols – water systems showed that adsorption is the most thermodynamically advantageous process in the studies systems, and the packing of surfactant “molecules” in micelles is less dense, compared to packing in a mixed adsorption layer.

Determining the possibility of making mulberry wine by using the osmotic dehydration process

This study aimed to determine the possibility of using osmotic dehydration in the production of mulberry wine. Mulberry fruits (Mórus nígra L.) were mixed with 70 % sucrose solution and osmotic dehydration was carried out (τ=1 h, t=50±5 °C). At the stage of active fermentation, the osmotic solution separated from the fruits was added to the must (10 % by mass). Partially dehydrated mulberry fruits were infused for 12 hours in water at a temperature of 10–15 °C. The formed must was separated from the fruits, mixed with an osmotic solution, and a solution formed during pressing of dehydrated fruits. The mixture was fermented at 20±2 °C for 20 days under static conditions. At the end of fermentation, the young wine was kept at a temperature of 3–5 °C for 1 month. A second transfusion was performed, and its quality indicators were analyzed. It was established that the osmotic solutions formed during the osmotic dehydration of black mulberry fruits contain 42.60±0.25 mg/100 g of anthocyanins, which makes them an effective basis and additive for giving wine the desired sensory characteristics. The high content of anthocyanins in wine (35.8±0.5 mg/100 g) provides for its stable red-ruby color. As a result of hydrolysis, sucrose, which was the main component of the osmotic solution before mulberry dehydration, is transformed into glucose (27.74±0.05 g/100 g) and fructose (28.60±0.05 g/100 g). This significantly increases its biological value and gives the wine a harmonious taste characteristic of fruit wines. The wine made on the basis of mulberry fruit processing products is rated at 7.5 points. It had a pleasant taste and color, but a poorly developed aroma. Mulberry wine was classified as semi-dry because it had a low alcohol content (6±0.5 %), a low concentration of sugars (13.0±0.5 g/dm3), and a high concentration of volatile acids (1.4±0.5 g/dm3)

Alkanols Regulate the Fluidity of Phospholipid Bilayer in Accordance to Their Concentration and Polarity.

In spite of the widespread use of alkanols as penetration enhancers, their effect on vesicular formulations remains largely unexplored. These can affect the stability and integrity of the phospholipid bilayers. In this study, we have investigated the interaction of linear (ethanol, butanol, hexanol, octanol) and branched alkanols (t-amylol and t-butanol) with three phospholipids (soya lecithin, SL; soy L-α-phosphatidylcholine, SPC; and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC). Thermodynamic and structural aspects of these interactions were studied as a function of the alkanol concentration and chain length. Our interpretations are based on isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) experiments. We observed one-site interactions wherein hydroxyl and acyl groups interacted with the polar and nonpolar regions of the phospholipid, respectively. The stability and structural integrity of bilayers appeared to be dependent upon (a) the hydrocarbon chain length and concentration of alcohols, and (b) the degree of unsaturation in the phospholipid molecule. We found that these interactions triggered a reduction in the enthalpy which was compensated by increased entropy, keeping free energy negative. Drop in enthalpy indicates reversible disordering of the bilayer which enables the diffusion of alcohol without triggering destabilization. Ethanol engaged predominantly with the interface, and it resulted in higher enthalpic changes. Interactions became increasingly unfavorable with longer alcohols - a cutoff point was recorded with hexanol. The overall sequence of membrane disordering capability was recorded as follows: ethanol < butanol < octanol < hexanol. Octanol's larger size restricted its penetration in the bilayer, and hence it caused less enthalpic changes relative to hexanol. This could also be verified from the trends in the area ratio of these vesicles obtained from the DLS data. Branched alkanols displayed a lower binding affinity with the phospholipids relative to their linear counterparts. These data are useful while contemplating the inclusion of short-chain alcohols as penetration enhancers in phospholipid vesicles.

Effects of Heterologous Expression of Genes Related L-Malic acid Metabolism in Saccharomyces uvarum on Flavor Substances Production in Wine.

During malolactic fermentation (MLF) of vinification, the harsh L-malic acid undergoes transformation into the milder L-lactic acid, and via decarboxylation reactions it is catalyzed by malolactic enzymes in LAB. The use of bacterial malolactic starter cultures, which usually present challenges in the industry as the suboptimal conditions after alcoholic fermentation (AF), including nutrient limitations, low temperatures, acidic pH levels, elevated alcohol, and sulfur dioxide concentrations after AF, lead to "stuck" or "sluggish" MLF and spoilage of wines. Saccharomyces uvarum has interesting oenological properties and provides a stronger aromatic intensity than Saccharomyces cerevisiae in AF. In the study, the biological pathways of deacidification were constructed in S. uvarum, which made the S. uvarum carry out the AF and MLF simultaneously, as different genes encoding malolactic enzyme (mleS or mleA), malic enzyme (MAE2), and malate permease (melP or MAE1) from Schizosaccharomyces pombe, Lactococcus lactis, Oenococcus oeni, and Lactobacillus plantarum were heterologously expressed. For further inquiry, the effect of L-malic acid metabolism on the flavor balance in wine, the related flavor substances, higher alcohols, and esters production, were detected. Of all the recombinants, the strains WYm1SN with coexpression of malate permease gene MAE1 from S. pombe and malolactic enzyme gene mleS from L. lactis and WYm1m2 with coexpression of gene MAE1 and malate permease gene MAE2 from S. pombe could reduce the L-malic acid contents to about 1 g/L, and in which the mutant WYm1SN exhibited the best effect on the flavor quality improvement.

Correlation between Microorganisms and Volatile Compounds during Spontaneous Fermentation of Sour Bamboo Shoots

Chinese sour bamboo shoot is a traditionally, spontaneous fermented food that is particularly popular due to its complex and distinctive flavor. The volatile compounds of sour bamboo shoot originate mainly from the raw materials and the microbial fermentation. To reveal the correlation between microorganisms and flavor, third-generation sequencing and Gas Chromatography-Ion Mobility Spectrometry were applied to analyze the dynamics of microbial communities at the species level and volatile compounds during sour bamboo shoot fermentation. The abundance of Lactobacillus acetotolerans and Lactobacillus fermentum increased during the fermentation, while Lactobacillus amyloliquefaciens decreased at first but then began to rise. At the end of fermentation, Lactobacillus amyloliquefaciens and Lactobacillus acetotolerans became the predominant species. A total of sixty-seven volatile compounds, which included twenty-three esters, nineteen alcohols, eight ketones, six aldehydes, six aromatic hydrocarbons, four acids and one ether, were identified. These compounds constituted the primary flavor of sour bamboo, which created a complex flavor of sour bamboo shoot. Among them, the contents of acetic acid, propionic acid, and isoamyl alcohol gradually increased during the fermentation process, and they became the main volatile compounds. Furthermore, the correlation between microorganisms and volatile compounds was investigated through two-way Orthogonal Partial Least Squares (O2PLS), which revealed a positive correlation between Lactobacillus amylolyticus and ethyl propanoate. Additionally, the abundance of Lactobacillus acetotolerans and Lactobacillus fermentum was found to be positively correlated with 2-heptenal. These findings provide a theoretical basis for understanding the formation mechanism of sour bamboo shoot flavor and the standardized production of high-quality sour bamboo shoots.

Quality assessment of Gastrodia elata Blume (Tianma) based on Vis-NIR spectroscopy: Discrimination of harvest times and prediction of quality indicator contents

Gastrodia elata Blume (Tianma) is widely cultivated and consumed as a food and herbal material in China. With its increasing use as a functional food, Tianma is gaining popularity in the market. However, during the cultivation process, the harvest time affects its maturity and storage time, while the total content of gastrodin (GAS) and p-hydroxybenzyl alcohol (HA) affects its nutritional value, making it difficult to control the quality of Tianma. In this study, a combination of visible-near-infrared (Vis-NIR) spectroscopy and chemometrics was used to identify the harvest time and determine the quality indicator content. A Vis-NIRRamanNet modeling method based on the architecture of RamanNet was proposed and compared with harvest time discrimination models constructed using partial least squares discriminant analysis (PLS-DA), k-nearest neighbor (KNN), support vector machine (SVM), and one-dimensional convolutional neural network (1D-CNN). The results demonstrated that Vis-NIRRamanNet exhibited superior performance, achieving accuracy rates of 0.995 and 0.973 on the training and testing sets, respectively. Subsequently, Vis-NIR spectroscopy combined with support vector regression (SVR) was employed for quantitative analysis of quality indicator content. Wavelength selection methods such as uninformative variable elimination (UVE), genetic algorithm (GA), and competitive adaptive reweighted sampling (CARS) were utilized to optimize the model. The results indicated that the CARS-SVR model provided the best prediction of quality indicator content, with root mean square error of prediction (RMSEP) and coefficient of determination (Rp2) values of 0.257 and 0.901, respectively. Therefore, the combination of Vis-NIR spectroscopy and chemometrics shows significant potential in assisting the selection of high-quality Tianma.