Degree Of Fermentation Research Articles

Chemometrics for estimating the fermentation and quality properties of kimchi based on hyperspectral image analysis

Kimchi is a traditional Korean dish made from fermenting vegetables. The fermentation process is crucial for enhancing its quality and flavor during storage. Approaches such as hyperspectral imaging (HSI) and chemometrics (PLS, partial least square; SVR, support vector regression) including principal component analysis (PCA), and 2-dimensional correlation spectroscopy (2D-COS) can detect key physical and chemical components and changes in total soluble solids (TSS), pH, titratable acidity (TA), salinity, and lactic acid bacteria (LAB). Multivariate analytical models were developed to predict the quality properties using full and characteristic wavelengths and preprocessed data. The results showed that the ratio of prediction to deviation (RPD) values of the PLS prediction model constructed using the full wavelengths of TSS, salinity, pH, TA, and LAB were 1.57, 2.33, 2.79, 2.91, and 2.73, respectively. The Savitzky Golay 1st derivative preprocessed SVR model established based on characteristic wavelengths (951, 1020, 1139, 1174, 1216, 1321, and 1384 nm) extracted by PCA and a 2D-COS matrix showed the best results and increased efficiency in predicting pH (Rp2 = 0.9166, RPD = 3.281) and the number of LAB (Rp2 = 0.8488, RPD = 2.466). Additionally, the visualization process accurately illustrated the distribution of various quality indicators of kimchi across different periods. These results demonstrate that our proposed HSI strategy successfully assessed the degree of kimchi fermentation.

Enzymatic and Enzyme‐Free Electrochemical Lactate Sensors: A Review of the Recent Developments

ABSTRACTLactate is a useful analytical indicator in various fields. The lactate monitoring benefits from evaluating the body's condition, as excessive muscle use or fatigue can result in injury. Further, it is useful for alerting to emergencies like haemorrhage, hypoxia, respiratory distress, and sepsis. Additionally, the determination of the food's lactate level is very important in examining freshness, storage stability, and fermentation degree. Given such benefits, the determination of lactate in various samples has been widely explored, especially using electrochemical sensor technology. Despite enzymatic sensors being the focus of numerous studies, enzyme‐free platforms have gained focus over the last few years to address the matter of enzyme stability. This review article respectfully offers an overview of the concepts, applications, and recent advances of electrochemical lactate detection platforms. A comparison of hot research for enzymatic and enzyme‐free lactate sensors in terms of electrode surface engineering, enzymes and their immobilisation matrices, and several analytical parameters, including linear dynamic range, the limit of detection, sensitivity, and stability, have been discussed. In addition, future perspectives have been highlighted in this review.

B-294 Case report: Postmortem ethanol production following traumatic injury

Abstract Background Ethanol is the most commonly encountered psychoactive substance in forensic toxicology. Accurate interpretation of ethanol concentrations from postmortem samples is fraught with potential hurdles, including decomposition, redistribution, and postmortem production of ethanol. Through the fermentation of substrates like glucose, pyruvate, lactate, and amino acids, microorganisms present in the gut and/or environment can generate ethanol in contaminated human tissues, especially following traumatic injury. The degree of fermentation varies widely depending on the time between death and autopsy, temperature, humidity, tissue glucose concentrations, and the specimen type. Vitreous humor (VH) is the preferred specimen for postmortem toxicological analysis of ethanol because it accurately reflects the antemortem ethanol concentration in serum while being resistant to microbial contamination. This case highlights the utility of VH in an extreme instance of postmortem ethanol production. Methods Postmortem toxicological analysis of liver tissue and VH (NMS Labs, Horsham, PA) was performed by headspace-gas chromatography (HS-GC) Results Case presentation: A man in his sixties with a history of type 1 diabetes mellitus and hypertension was involved in a fatal mining accident while operating heavy machinery in which the equipment fell down a cliff, causing the man to be ejected onto the ground nearby. The decedent was discovered hours after the fall with extensive traumatic injuries to the left side of his body and head. Seven days later, an autopsy was performed by the medical examiner’s office. Postmortem toxicological analysis of liver tissue by HS-GC revealed ethanol at a concentration of 690 mg/100g. The liver tissue also tested positive for amlodipine, nicotine, cotinine, and caffeine. A vitreous humor (VH) sample tested negative (<10 mg/dL) for ethanol. Conclusions The toxicological findings reported herein are inconsistent with antemortem alcohol consumption and are instead an example of severe postmortem ethanol production by microbial contamination. Several factors likely led to the stark discrepancy between the concentrations of ethanol in VH and liver tissue. First, the decedent suffered traumatic injuries, creating conditions favorable for extensive microbial contamination. Second, the time between death and autopsy was seven days, allowing ample time for fermentation to occur, even under refrigerated conditions. Third, postmortem glycogenolysis in addition to the patient’s underlying T1DM likely provided a high concentration of glucose to fuel postmortem fermentation. Ultimately, this case underscores the importance of forensic specimen selection in accurately interpreting toxicology findings following traumatic injury.

Information fusion of hyperspectral imaging and self-developed electronic nose for evaluating the degree of black tea fermentation

Fermentation is a crucial step in the processing of black tea. Currently, the evaluation of the fermentation degree of black tea relies mainly on manual experience, which suffers from subjectivity and lacks quantifiability. This study proposed the fusion of hyperspectral imaging and electronic nose to evaluate the degree of black tea fermentation. The self-developed electronic nose was used to acquire aroma information, while hyperspectral imaging was used to obtain color and spectral information during the fermentation process. The samples were collected at different fermentation time including insufficient, moderate, and excessive fermentation. Then, the classification models were constructed based on individual types of information. Subsequently, the electronic nose data were fused with the hyperspectral data using different information fusion strategies (low-level, middle-level, high-level) and the classification models were built accordingly. Six types of classifiers were established. Results showed that with deeper levels of fusion, the accuracy of the model on the test set gradually improved. In the high-level fusion, the accuracy of the test set reached 100 %, with improvements of 10.34 % and 8.62 % compared with that solely based on electronic nose and hyperspectral imaging, respectively. This indicates that the proposed information fusion method is highly effective, providing state-of-the-art insights into and technologies for the evaluation of black tea fermentation degree.

Mashing Isothermally at High Temperature Compared to Infusion Mashing for the Production of Full-Bodied, Alcohol-Reduced Beer

The objective of this study was to investigate the influence of the mashing temperatures on alcohol content and taste of bottom-fermented Pilsner style beers and to ascertain whether these beers exhibit comparable sensorial properties. For this purpose, three beers brewed with three different mashing procedures were compared. The worts produced were sampled during mashing and after boiling, and subsequently analysed for their original gravity, fermentable sugars, and free amino nitrogen. The beers were analysed for their alcohol content, aroma compounds, apparent degree of fermentation, pH value, foam, and bitterness units as well as being evaluated sensorially according to DLG (= “Deutsche Landwirtschafts-Gesellschaft - German Agricultural Society”) grading in the categories: odour, purity of taste, body, carbonation, quality of bitterness. Overall it was shown, that the isothermal mashing procedure yielded less fermentable but more unfermentable sugars than the two more traditional mashing procedures, leading to a comparable original wort of 11.6°P in the final beer and lower alcohol content of 2.8% v/v in comparison to the more traditional mashing procedures (“high-short” and “simplified high-short” mashing procedure) with original worts of 12.1°P and alcohol contents of 4.5% v/v and 5.0% v/v, respectively. The DLG-rating showed that the beers derived from the different mashing procedures were all classified similarly with scores above 4.5 on average (out of 5.0) in all categories with no significant differences.

Lightweight CNN combined with knowledge distillation for the accurate determination of black tea fermentation degree

Black tea is the second most common type of tea in China. Fermentation is one of the most critical processes in its production, and it affects the quality of the finished product, whether it is insufficient or excessive. At present, the determination of black tea fermentation degree completely relies on artificial experience. It leads to inconsistent quality of black tea. To solve this problem, we use machine vision technology to distinguish the degree of fermentation of black tea based on images, this paper proposes a lightweight convolutional neural network (CNN) combined with knowledge distillation to discriminate the degree of fermentation of black tea. After comparing 12 kinds of CNN models, taking into account the size of the model and the performance of discrimination, as well as the selection principle of teacher models, Shufflenet_v2_x1.0 is selected as the student model, and Efficientnet_v2 is selected as the teacher model. Then, CrossEntropy Loss is replaced by Focal Loss. Finally, for Distillation Loss ratios of 0.6, 0.7, 0.8, 0.9, Soft Target Knowledge Distillation (ST), Masked Generative Distillation (MGD), Similarity-Preserving Knowledge Distillation (SPKD), and Attention Transfer (AT) four knowledge distillation methods are tested for their performance in distilling knowledge from the Shufflenet_v2_x1.0 model. The results show that the model discrimination performance after distillation is the best when the Distillation Loss ratio is 0.8 and the MGD method is used. This setup effectively improves the discrimination performance without increasing the number of parameters and computation volume. The model’s P, R and F1 values reach 0.9208, 0.9190 and 0.9192, respectively. It achieves precise discrimination of the fermentation degree of black tea. This meets the requirements of objective black tea fermentation judgment and provides technical support for the intelligent processing of black tea.

Non-destructive determination of volatile compounds and prediction of amino acid nitrogen during sufu fermentation via electronic nose in combination with machine learning approaches

Electronic nose along with different machine learning approaches was tested as tool to predict degree of sufu fermentation, with amino acid nitrogen content as marker. Consistent increase in E-nose signal values and amino acid nitrogen content were noted with fermentation time. The number of volatile compounds in sufu increased from 19 to 61 upon fermentation, with 46 compounds identified as major aroma contributors. Among them, acetone, ethyl palmitate and indole demonstrated strong correlations with amino acid nitrogen content. Three prediction models, i.e., partial least-squares regression, support vector machine, and artificial neural network, were tested for abilities to predict amino acid nitrogen content. All models were capable of quantitatively predicting the content of amino acid nitrogen, with ANN-based model demonstrating the highest prediction accuracy (RP2 = 0.968, RMSE = 5.49 × 10−8). Electronic nose along with appropriate prediction model is noted as a promising tool for evaluating the degree of sufu fermentation.

An improved 3D-SwinT-CNN network to evaluate the fermentation degree of black tea

Fermentation is a key process in forming the flavor quality of black tea. Evaluating the degree of fermentation during black tea processing is difficult. This paper proposes an improved 3D-SwinT-CNN network for the end-to-end processing of black tea's hyperspectral images to evaluate the degree of fermentation. The model incorporates dilated convolution and a shifted window self-attention mechanism, expanding the network's receptive field and capturing both local spatial-spectral and global features of black tea hyperspectral images. The accuracy is 98.13% on the test set. Compared to manual feature extraction methods, the accuracy improved by 3.45%. Compared to baseline 3D-CNNs, 3D-SwinT-CNN demonstrates superior spatial-spectral feature extraction, achieving an average accuracy improvement of 10.17%. Ablation experiments were conducted to further verify the effectiveness of the introduced modules. The proposed 3D-SwinT-CNN aims to establish a research foundation for online evaluation of black tea's fermentation degree.

Intensification of high-gravity brewer’s wort fermentation process with the use of microelements

In high-gravity brewing, conditions arise that adversely affect the yeast. These are high osmotic pressure, high fermentation temperature, high ethanol content. As a result of these unfavorable factors, the intensity of yeast reproduction and the rate of fermentation decrease, the duration of the process increases, the degree of fermentation decreases, which leads to a change in the taste and aroma profile of the drink. Cofactors of important enzymes and stress modulators are microelement ions, the optimal content of which can be provided by adding appropriate salts to the wort. In this work, the influence of calcium and zinc on the fermentation of high-gravity beer wort with the participation of Saccharomyces cerevisiae yeast strain Saflager W-34/70 was investigated. The optimal dosage of CaCl2 and ZnSO4 salts was determined, which is 5.0 and 0.1 mg/dm3, respectively. It was established that adding CaCl2 to the wort leads to an increase in the rate of fermentation by 21.9 %, the apparent and actual degree of fermentation by 17.8 and 17.0 %, respectively. At the same time, the ethanol content in young beer increases by 19.1 %, the content of visible and actual extract decreases by 28.8 and 17.5 %, respectively, and the biomass of yeast accumulated during fermentation increases by 14.0 %. When using ZnSO4, the changes in the values of all these indicators are significantly smaller and lie in the range of 3.2‒5.8 %. Other physical-chemical parameters of the studied samples of young beer, namely acidity, pH value, content of vicinal diketones, do not undergo significant changes. To enhance the growth and metabolism of yeast under adverse conditions that occur during high-gravity brewing, it is recommended to add CaCl2 to beer wort in the amount of 5.0 mg/dm3. This will make it possible to reduce the duration of fermentation of wort with a dry matter content of 18 % at a temperature of 15 ℃ by 1.5 days (21 %)

Rapid fluorescence detection of black tea fermentation degree based on cobalt ion mediated carbon quantum dots

Fermentation is key to the quality of black tea, and traditional sensory evaluation methods are too slow and subjective for reliable, large-scale evaluation during fermentation. To address this problem, this study formulated a sensing system based on cobalt ions-doped carbon quantum dots emitting bright blue fluorescence. In evaluation experiments, this system was found to work stably for 90 min and accurately determine fermentation quality in real time. In fluorescence spectra results, fluorescence intensity decreased sharply with the concentrations of catechins, theaflavins, and gallic acid and this relationship was highly linear at concentrations from 0.01 to 50 μg/mL; R2 was >97% and the limit of detection was <0.046 μg/mL. A least-squares support vector machine model was established, and it had a 100% accuracy rate in discriminating between degrees of fermentation. Therefore, this quantum-dot-based system serves as an accurate and efficient means of measuring the fermentation quality of black tea.

Exploring the Nutritional Impact of Sourdough Fermentation: Its Mechanisms and Functional Potential.

Sourdough fermentation is one of the oldest traditional methods in food technology and occurs as a result of fermentation of flour prepared from grains. The nutritional role of sourdough is related to the final composition of fermented foods prepared through sourdough fermentation, and recently, sourdough has become an important application to improve nutrition characteristics of bread. Thanks to lactic acid bacteria (LAB) presented in sourdough microflora and metabolites partially produced by yeasts, technological and important nutritional features of the bread improve and an increase in shelf life is achieved. In addition, sourdough bread has a low glycemic index value, high protein digestibility, high mineral and antioxidant content, and improved dietary fiber composition, making it more attractive for human nutrition compared to regular bread. When the sourdough process is applied, the chemical and physical properties of fibers vary according to the degree of fermentation, revealing the physiological importance of dietary fiber and its importance to humans' large intestine microbiota. Therefore, taking these approach frameworks into consideration, this review highlights the benefits of sourdough fermentation in increasing nutrient availability and contributing positively to support human health.

Online System for Monitoring the Degree of Fermentation of Oolong Tea Using Integrated Visible-Near-Infrared Spectroscopy and Image-Processing Technologies.

During the fermentation process of Oolong tea, significant changes occur in both its external characteristics and its internal components. This study aims to determine the fermentation degree of Oolong tea using visible-near-infrared spectroscopy (vis-VIS-NIR) and image processing. The preprocessed vis-VIS-NIR spectral data are fused with image features after sequential projection algorithm (SPA) feature selection. Subsequently, traditional machine learning and deep learning classification models are compared, with the support vector machine (SVM) and convolutional neural network (CNN) models yielding the highest prediction rates among traditional machine learning models and deep learning models with 97.14% and 95.15% in the prediction set, respectively. The results indicate that VIS-NIR combined with image processing possesses the capability for rapid non-destructive online determination of the fermentation degree of Oolong tea. Additionally, the predictive rate of traditional machine learning models exceeds that of deep learning models in this study. This study provides a theoretical basis for the fermentation of Oolong tea.

Quality Evaluation of Fermented Pre Gelatinized Unripe Plantain and Soybean Based Complementary Foods 1: Physicochemical, Sensory and Rheological Properties

Aims: This study aimed at evaluating the effect of the degree (%) of starch gelatinization (G) and fermentation (F) on the physicochemical characteristics of the flours and also the sensory and flow properties of the gruels of unripe plantain fruits and soybean seeds based complementary foods. Study Design: Completely randomized design Place and duration of the Study: This study was carried out in Makurdi, Benue State, Nigeria, between January and November 2023. Methodology: Plantain slices heated to obtain 10% to 100% starch gelatinization were subjected to accelerated natural fermentation followed by drying and milling to yield fermented (F) flours. Non-gelatinized (NG) and nonfermented (NF) lots served as controls. The flours were each combined with soybean flour to obtain 16 g protein/100 g of each mixture based on the proximate compositions of the inputs using material balancing technique. The flours’ oil absorption capacities (OAC), water absorption capacities (WAC), packed bulk densities (PBD), sensory attributes (taste, mouth feel, appearance, overall acceptability) and flow properties of their gruels were evaluated using standard methods. Significant differences and separation of the data means were achieved by Duncan multiple range and Turkey’s tests using an SPSS package, respectively. Results: Gelatinization and fermentation increased WAC and OAC, but decreased packed bulk density (PBD) of the flours with concomitant reduction in pH, viscosities and improved sensory attributes of the gruels. Generally, viscosities increased with increase in slurry concentration and decreased with increase in temperature and shear rates. The flow behavior indices ranged from 0.27 to 0.64, with lower values in gelatinized and fermented samples, showing more pseudoplastic behavior in pretreated samples. Conclusion: Gelatinization and natural fermentation are therefore adaptable technologies, especially at rural levels, to improve acceptability and bulk reduction of resistant starch-based complementary foods.

Skin Anti-Aging Potential through Whitening and Wrinkle Improvement Using Fermented Oil Derived from Hermetia illucens Larvae.

As the aging population increases, so has interest among emerging seniors in anti-aging ingredients that enhance functionality by incorporating fermentation with natural materials. In this study, fermentation conditions for enhancing the functionality of Hermetia illucens larvae oil (HIO) were established, and its anti-aging potential was evaluated. First, the lipase activity and amount of lipid degradation products of the fermentation strains were measured in order to select Lactobacillus gasseri and Lactiplantibacillus plantarum as the strains with high fermentation ability. A fermentation period of 28 d and a fermentation method that uses only the strain culture medium were established by evaluating the fermentation degree after fermenting HIO with the selected strains. The whitening functionality test results of fermented HIO (FHIO) showed an increase of approximately 20% in extracellular tyrosinase inhibition activity compared with HIO. Additionally, within melanocytes, there was a 12% increase in tyrosinase inhibition activity and a 26% enhancement in melanin production inhibition ability. For wrinkle-improving functionality, it was observed that, for fibroblasts, there was a 10% increase in collagen production, a 9% increase in collagenase inhibition ability, and an 8% increase in elastase inhibition ability. Therefore, FHIO was confirmed to be an effective cosmetic raw material, with high functionality for anti-aging within the senior generation. This is achieved through increased whitening and wrinkle-improving functionality.

Impact of Fermentation on the Phytochemical Content and Biological Properties of Moringa oleifera Lam. Shoot Teas.

This work examined the variation in chemical and biological properties of Moringa oleifera Lam. shoot (MOS) teas prepared under different degrees of fermentation, viz: non-fermented, semi-fermented and fermented. The chemical composition was ascertained via FTIR, GC-MS, total phenolic and total flavonoid content. Also determined were the biological properties, including antioxidant, antimicrobial and alpha-amylase inhibitory activities. The data confirmed that MOS teas were rich in phenolic and flavonoid compounds, with fermented MOS tea displaying the highest phenolic and flavonoid contents. With respect to antioxidant property, all tea extracts exhibited good radical scavenging activities against DPPH⋅, ABTS⋅+ and NO⋅, and the radical scavenging capacity was in the order of non-fermented>semi-fermented>fermented MOS teas. The same trend was also observed for the antimicrobial activities against Staphylococcus aureus and Staphylococcus epidermidis. In contrast, the fermented MOS tea exhibited better α-amylase inhibitory activity compared to the non-fermented and semi-fermented MOS teas.

Straw with different fermentation degrees mediate Se/Cd bioavailability by governing the putative iron reducing bacteria

Straw returning is a crucial agronomic practice in fields due to its various benefits. However, effects and mechanisms of straw with different fermentation degrees on Se and Cd bioavailability have not been sufficiently investigated. In this study, straw with different fermentation degrees were applied to a Cd-contaminated seleniferous soil to investigate their effects on Se and Cd bioavailability. Results revealed that the effects of straw application on Se/Cd bioavailability in soil depended on the fermentation degrees of straw. Both original and slightly fermented straw had pronounced impacts on microbial iron reduction compared to fully fermented straw, and thus led to a significant increase in Se and Cd bioavailability. The linear discriminant analysis effect size (LEfSe) showed that norank_f_Symbiobacteraceae, Micromonospora, WCHB1-32, Ruminiclostrdium, and Cellulomonas were the major biomarkers at genus level in straw application soils, additional network analysis and random forest analysis suggested that Ruminiclostrdium and Cellulomonas might be implicated in microbial iron reduction. Furthermore, the microbial iron reduction had negative effects on mineral-associated Se with coefficient of −0.81 and positive effects on mineral-associated Cd with coefficient of 0.72, while Mn fractions exhibited positive effects on mineral-associated Se with a coefficient of 0.53 and negative effects on mineral-associated Cd. In conclusion, straw with different fermentation degrees governed Se and Cd mobility by regulating abundance of Ruminiclostrdium and Cellulomonas, subsequently affecting Fe and Mn fractions and consequently influencing Se and Cd bioavailability.

Use of unmalted cereals with enzyme preparations in brewing

The use of unmalted grain is one of the methods for improving quality, reducing production costs, and creating new types of beer. However, the enzymatic activity of such raw materials is zero, so the use of enzyme preparations is relevant. The purpose of the study was to compare the quality indicators of 100% malt beer and beer with the replacement of malt with unmalted barley using enzymes. Methods of technical and chemical analysis were used to determine the organoleptic and physico-chemical parameters of beer. Recommendations have been developed for intensifying the preparation of wort using various types of grain raw materials – unmalted barley and rice grits with the addition of enzyme preparations from Novozymes (Denmark) at different stages of brewing were developed. When testing new enzyme preparations (β-glucanase complex, xylanase), the filtration time, wort viscosity, and the content of β-glucans and arabinoxylans decreased by about 20% compared to the control samples. The use of a new enzyme preparation resulted in better breakdown of substances, which affected the quality and duration of filtration. This leads to an improvement of wort quality, reducing the duration of the process and reducing the cost of raw materials. To ensure the required ratio of substances in the wort, it is necessary to introduce complex enzyme preparations – peptidhydrolase, α-amylase, endo-β-glucanase (Ceremis Plus). Preparations containing endo-β-glucanase (Ultraflo Max) should be used at the beginning of mashing to improve the rheological properties of the wort and reduce its viscosity, which improves the filtration process. To obtain beer with the required degree of fermentation during mashing, it is better to use new enzyme preparations (glucoamylase). The practical significance of the study lies in the use of large amounts of unmalted grain together with exoenzymes such as Ultraflo Max and Ceremis Plus, which will allow brewers to produce wort and beer of the same composition and quality as premium wort and beer, using only malt

Research Progress on the Effect and Mechanism of Tea Products with Different Fermentation Degrees in Regulating Type 2 Diabetes Mellitus.

A popular non-alcoholic beverage worldwide, tea can regulate blood glucose levels, lipid levels, and blood pressure, and may even prevent type 2 diabetes mellitus (T2DM). Different tea fermentation levels impact these effects. Tea products with different fermentation degrees containing different functional ingredients can lower post-meal blood glucose levels and may prevent T2DM. There are seven critical factors that shed light on how teas with different fermentation levels affect blood glucose regulation in humans. These factors include the inhibition of digestive enzymes, enhancement of cellular glucose uptake, suppression of gluconeogenesis-related enzymes, reduction in the formation of advanced glycation end products (AGEs), inhibition of dipeptidyl peptidase-4 (DPP-4) activity, modulation of gut flora, and the alleviation of inflammation associated with oxidative stress. Fermented teas can be used to lower post-meal blood glucose levels and can help consumers make more informed tea selections.

The antifungal substance from Bacillus velezensis B-3 improved the malt quality against premature yeast flocculation induced by Fusarium graminearum infection.

Malt produced from barley contaminated with Fusarium graminearum can cause premature yeast flocculation (PYF) in beer fermentation, which ultimately affects the production efficiency and flavor quality of beer. In this study, a strain of Bacillus velezensis B-3 that was isolated from soil displayed strong antifungal activity against F. graminearum. The antifungal substances were extracted and separated by ammonium sulfate fractional precipitation and semipreparative high-performance liquid chromatography to obtain fraction VI with the strongest antifungal activity. Ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry was used to identify that the fraction contained lipopeptides such as iturin A, surfactant B, and surfactant C. The minimum inhibitory concentration of the fraction was 0.2mg/mL, and confocal laser scanning microscopy showed that the morphology of F. graminearum hyphae was obviously abnormal, with most of them were dead. Antifungal fraction VI could inhibit the growth of F. graminearum and avoid the production of PYF factor during malting but did not affect other qualities of malt. Therefore, the development of antimicrobial agents against Fusarium provides an effective potential strategy to control the production of PYF factors for malt-manufacturing enterprises. PRACTICAL APPLICATION: Antifungal fraction VI could inhibit the growth of F. graminearum and the formation of DON during malting but did not affect other qualities of malt. The levels of soluble nitrogen, free amino nitrogen, and color experienced a substantial reduction compared to the malt infected by F. graminearum. The PYF phenomenon was significantly improved, the number of suspended yeast cells and the degree of fermentation were increased, and the level of residual extract in the wort was low, close to that of control malt.

Comparison of fat determination methods and analysis of fatty acids in tea

Comparative analysis of two method for determining fat and analysis of fatty acid content in tea samples. The content of freefatand total fat in tea was determined by Soxhlet extraction method and acid hydrolysis method, and the content of fatty acids were determined by gas chromatography. The composition and content of fatty acids in 21 tea samples from 5 regions were analyzed. The freefat content of tea determined by Soxhlet extraction method was significantly lower than that determined by acid hydrolysis method. The totalfat content in tea determined by acid hydrolysis method was consistent with the total amount of fatty acids determined by gas chromatography, and their content conformed to the logical relationshipsimultaneously. The totalfat content in tea ranged from 0.6 to 4.1 g/100 g, which in green tea, white tea, yellow tea, and black tea were 2.2, 1.8, 1.6 and 0.6 g/100 g, respectively. The content of free fat in tea was less than 58%, with 42%-80% of the fat existing in a bound form. The fatty acids in tea were mainly unsaturated fatty acids, accounting for 67.52%-99.03% of the total fatty acids. There were differences in the composition of fatty acids in different types of tea, with the proportion of unsaturated fatty acids in yellow tea accounting for 98.84% of the total fatty acids, which was significantly higher than that of green tea, white tea, and black tea. The fatty acids with high content in green tea(except Tang chi xiaolan tea, Bawangjian green tea and Liuxi yuye tea)were α-linoleic acid, linoleic acid, and palmitic acid. Theacid hydrolysis method is more suitable for the determination of fat in tea samples. The composition and content of fat and fatty acids in tea vary depending onfactors such as the type of tea and the degree of fermentation.