Current Articles
2025, 40(2)
:1-12.
doi: 10.12187/2025.02.001
Abstract:
To develop apricot pomace flavoring, the most effective aroma-producing strain was isolated and screened from apricot orchard soil. The process conditions for microbial fermentation of apricot pomace by this strain were optimized using single-factor experiments and Box-Behnken response surface methodology, and the key enzyme was preliminarily identified. The results showed that the strain LY13, identified as Wickerhamomyces, exhibited the best aroma-producing effect. After fermentation of apricot pomace by this strain, the resulting product exhibited rich sweet, fruity, and floral aromas, with a high total content of alcohols, esters, and ketones in the fermentation liquid. The optimal fermentation conditions were a stirring speed of 145 r/min, a fermentation time of 49 h, a fermentation temperature of 31℃, and an initial pH of 7.1. Under these conditions, the total content of volatile aromatic compounds in the fermented product reached 135.38 μg/g, and the key enzyme responsible for aroma production was mainly present in the cell membrane. This study provides a novel strain resource for aroma-producing microorganisms and lays a theoretical forndation for the industrial production of apricot pomace flavoring through microbial fermentation.
To develop apricot pomace flavoring, the most effective aroma-producing strain was isolated and screened from apricot orchard soil. The process conditions for microbial fermentation of apricot pomace by this strain were optimized using single-factor experiments and Box-Behnken response surface methodology, and the key enzyme was preliminarily identified. The results showed that the strain LY13, identified as Wickerhamomyces, exhibited the best aroma-producing effect. After fermentation of apricot pomace by this strain, the resulting product exhibited rich sweet, fruity, and floral aromas, with a high total content of alcohols, esters, and ketones in the fermentation liquid. The optimal fermentation conditions were a stirring speed of 145 r/min, a fermentation time of 49 h, a fermentation temperature of 31℃, and an initial pH of 7.1. Under these conditions, the total content of volatile aromatic compounds in the fermented product reached 135.38 μg/g, and the key enzyme responsible for aroma production was mainly present in the cell membrane. This study provides a novel strain resource for aroma-producing microorganisms and lays a theoretical forndation for the industrial production of apricot pomace flavoring through microbial fermentation.
2025, 40(2)
:13-22.
doi: 10.12187/2025.02.002
Abstract:
Electronic nose and head space-solid phase microextraction-gas chromatography mass spectrometry (HS-SPME-GC-MS) combined with the odor activity values (OAV) and orthogonal partial least squares discriminant analysis (OPLS-DA) model were used to study the effects of Lactobacillus plantarum CICC 20022 fermentation on volatile aroma compounds in jujube juice. The results showed that fermented jujube juice contained more terpenes, sulfur compounds, aromatic compounds and organosulfur than unfermented jujube juice, and these compounds contribute to the juice a more intense floral and fruity aroma. There were 48 and 42 volatile aroma compounds identified with the total mass concentrations of 4 479.54 μg/L and 6 943.14 μg/L for unfermented and fermented jujube juice, respectively. The mass concentration of acid compounds in fermented jujube juice increased significantly, with decanoic acid increasing by 193.68%, while the types of ester compounds were decreased significantly, and new compounds such as the isopropyl palmitate, citral and nerolidol acetone with floral and fruity aromas were formed in fermented jujube juice. The floral flavour of damascone made the most signiticant contribution the fragrance of fermented jujube juice. The seven main different volatile aroma components were benzaldehyde, capric acid, benzyl alcohol, nonanoic acid, damastone, lauric acid and caproic acid. Therefore, fermentation with L.plantarum could enhance the overall flavor of jujube juice and imparted a floral and fruity aroma to it.
Electronic nose and head space-solid phase microextraction-gas chromatography mass spectrometry (HS-SPME-GC-MS) combined with the odor activity values (OAV) and orthogonal partial least squares discriminant analysis (OPLS-DA) model were used to study the effects of Lactobacillus plantarum CICC 20022 fermentation on volatile aroma compounds in jujube juice. The results showed that fermented jujube juice contained more terpenes, sulfur compounds, aromatic compounds and organosulfur than unfermented jujube juice, and these compounds contribute to the juice a more intense floral and fruity aroma. There were 48 and 42 volatile aroma compounds identified with the total mass concentrations of 4 479.54 μg/L and 6 943.14 μg/L for unfermented and fermented jujube juice, respectively. The mass concentration of acid compounds in fermented jujube juice increased significantly, with decanoic acid increasing by 193.68%, while the types of ester compounds were decreased significantly, and new compounds such as the isopropyl palmitate, citral and nerolidol acetone with floral and fruity aromas were formed in fermented jujube juice. The floral flavour of damascone made the most signiticant contribution the fragrance of fermented jujube juice. The seven main different volatile aroma components were benzaldehyde, capric acid, benzyl alcohol, nonanoic acid, damastone, lauric acid and caproic acid. Therefore, fermentation with L.plantarum could enhance the overall flavor of jujube juice and imparted a floral and fruity aroma to it.
2025, 40(2)
:23-30.
doi: 10.12187/2025.02.003
Abstract:
The set yoghurt was prepared by incorporating skim milk powder into an aqueous solution of oat β-glucan (OBG) at varying concentrations. The pH value, acidity, rheological properties, water holding capacity (WHC), and viable counts of lactic acid bacteria were assessed to investigate the impact of OBG on the fermentation characteristics and storage quality of set yoghurt. The results indicated that, compared to the control group, OBG had no significant effect on pH value during fermentation (P>0.05). However, it significantly reduced the acidity of set yoghurt during late fermentation (6~8 h) and 24 hours post-ripening (P<0.05), and significantly increased the WHC of yoghurt after 24 hours post-ripening (P<0.05). The energy storage modulus (G') and loss modulus (G″) for set yoghurt containing 0.4% OBG after 24 hours post-ripening were optimal, it had better viscoelasticity and sensory quality. As storage time extended, the viable counts of lactic acid bacteria in both experimental and control groups initially increased before subsequently decreasing. And the viable counts of lactic acid bacteria in the yoghurt from the 0.4% OBG group maintained the highest (9.12 log CFU/mL) by day 15. Therefore, incorporating an appropriate amount of OBG not only could enhance the fermentation performance of set yoghurt but also significantly improve its overall quality while protecting lactic acid bacteria within the product.
The set yoghurt was prepared by incorporating skim milk powder into an aqueous solution of oat β-glucan (OBG) at varying concentrations. The pH value, acidity, rheological properties, water holding capacity (WHC), and viable counts of lactic acid bacteria were assessed to investigate the impact of OBG on the fermentation characteristics and storage quality of set yoghurt. The results indicated that, compared to the control group, OBG had no significant effect on pH value during fermentation (P>0.05). However, it significantly reduced the acidity of set yoghurt during late fermentation (6~8 h) and 24 hours post-ripening (P<0.05), and significantly increased the WHC of yoghurt after 24 hours post-ripening (P<0.05). The energy storage modulus (G') and loss modulus (G″) for set yoghurt containing 0.4% OBG after 24 hours post-ripening were optimal, it had better viscoelasticity and sensory quality. As storage time extended, the viable counts of lactic acid bacteria in both experimental and control groups initially increased before subsequently decreasing. And the viable counts of lactic acid bacteria in the yoghurt from the 0.4% OBG group maintained the highest (9.12 log CFU/mL) by day 15. Therefore, incorporating an appropriate amount of OBG not only could enhance the fermentation performance of set yoghurt but also significantly improve its overall quality while protecting lactic acid bacteria within the product.
2025, 40(2)
:31-40.
doi: 10.12187/2025.02.004
Abstract:
To deeply explore the characteristics of Tianzhu Tibetan-flavor Daqu and its role in the Baijiu brewing process, the diversity of microbial communities was analyzed by using metagenomic technology, and its functional genes were annotated. The results showed that the microorganisms identified from Tianzhu Tibetan-flavor Daqu belonged to 53 phyla and 835 genera, of which the dominant phyla included Firmicutes, Actinobacteria and Mucoromycota, and the dominant genera included Saccharopolyspora, Virgibacillus, Lentibacillus, Lichtheimia, Desmospora, Oceanobacillus, Bacillus, Syncephalastrum and Streptomyces. A total of 22 metabolic pathways were annotated at the secondary level of KEGG database, among which carbohydrate metabolism and amino acid metabolism were the most prominent. Moreover, glycolysis/gluconeogenesis and glycine, serine and threonine metabolism were the most vigorous. Glycosyl transferase and glycoside hydrolase annotated the most genes by the CAZy database, accounting for 40.49% and 39.09% of the total number of genes, respectively.
To deeply explore the characteristics of Tianzhu Tibetan-flavor Daqu and its role in the Baijiu brewing process, the diversity of microbial communities was analyzed by using metagenomic technology, and its functional genes were annotated. The results showed that the microorganisms identified from Tianzhu Tibetan-flavor Daqu belonged to 53 phyla and 835 genera, of which the dominant phyla included Firmicutes, Actinobacteria and Mucoromycota, and the dominant genera included Saccharopolyspora, Virgibacillus, Lentibacillus, Lichtheimia, Desmospora, Oceanobacillus, Bacillus, Syncephalastrum and Streptomyces. A total of 22 metabolic pathways were annotated at the secondary level of KEGG database, among which carbohydrate metabolism and amino acid metabolism were the most prominent. Moreover, glycolysis/gluconeogenesis and glycine, serine and threonine metabolism were the most vigorous. Glycosyl transferase and glycoside hydrolase annotated the most genes by the CAZy database, accounting for 40.49% and 39.09% of the total number of genes, respectively.
2025, 40(2)
:41-50.
doi: 10.12187/2025.02.005
Abstract:
In order to improve the quality of proso millet Niaodoubao, 287 strains of lactic acid bacteria were studied as research subjects. Through growth, acid production ability, antioxidant activity, exopolysaccharide synthesis capability, and in situ fermentation experiments, excellent lactic acid bacteria fermentation agents were selected for proso millet Niaodoubao. The results showed that 9 strains of lactic acid bacteria had good ability of growth, acid production, antioxidant activity, and extracellular polysaccharide synthesis ability, and had excellent fermentation characteristics in proso millet sourdough. Compared with naturally fermented Niandoubao, all 9 strains of lactic acid bacteria could significantly improve the texture, brightness, and sensory quality of proso millet Niandoubao, among which the texture properties of strains 2P01 and 22P07 were the best, the brightness (L*66.82) of strains 24M07 was the highest, and the strain 2P01 has the highest consumer acceptance (sensory score 85.17). Among them, strain 2P01 not only had better growth, acid production ability and antioxidant activity, but also produced proso millet Niandoubao with better hardness, viscosity, chewiness and sensory scores, making it the best starter strain for making.proso millet Niandoubao.
In order to improve the quality of proso millet Niaodoubao, 287 strains of lactic acid bacteria were studied as research subjects. Through growth, acid production ability, antioxidant activity, exopolysaccharide synthesis capability, and in situ fermentation experiments, excellent lactic acid bacteria fermentation agents were selected for proso millet Niaodoubao. The results showed that 9 strains of lactic acid bacteria had good ability of growth, acid production, antioxidant activity, and extracellular polysaccharide synthesis ability, and had excellent fermentation characteristics in proso millet sourdough. Compared with naturally fermented Niandoubao, all 9 strains of lactic acid bacteria could significantly improve the texture, brightness, and sensory quality of proso millet Niandoubao, among which the texture properties of strains 2P01 and 22P07 were the best, the brightness (L*66.82) of strains 24M07 was the highest, and the strain 2P01 has the highest consumer acceptance (sensory score 85.17). Among them, strain 2P01 not only had better growth, acid production ability and antioxidant activity, but also produced proso millet Niandoubao with better hardness, viscosity, chewiness and sensory scores, making it the best starter strain for making.proso millet Niandoubao.
2025, 40(2)
:51-60.
doi: 10.12187/2025.02.006
Abstract:
Based on near-infrared spectroscopy technology, combined with different preprocessing and characteristic wavelength screening methods, partial least squares(PLS)prediction models and overall prediction model were established for indicators such as damaged starch content, falling number, water absorption rate, stability time, stretching area, extensibility and maximum resistance. The results showed that detrend (DT) was the best preprocessing method for the prediction model of damaged starch content and water absorption rate, savitzky-gloay(SG) convolutional smoothing was the best preprocessing method for the prediction model of falling number and stretching area, and standard normal variable transformation (SNV) was the best preprocessing method for the prediction model of extensibility and maximum resistance. Competitive adaptive reweighted sampling (CARS) could effectively improve the prediction accuracy of models for damaged starch content, falling number, water absorption rate, stretching area and maximum resistance, with prediction determination coefficients of 0.964 1, 0.714 0, 0.975 5, 0.943 4 and 0.828 3, respectively, successive projections algorithm (SPA) had improved the performance of stability time and extensibility prediction models, with prediction determination coefficients of 0.713 5 and 0.953 0, respectively. The overall prediction model had improved its predictive performance for stability time, stretching area and maximum resistance, their residual predictive deviation increased from 1.86, 4.27 and 2.51 to 2.43, 5.26 and 3.11, respectively. In summary, near-infrared spectroscopy technology was effective and feasible for a non-destructive and rapid detection of the quality characteristics of wheat flour.
Based on near-infrared spectroscopy technology, combined with different preprocessing and characteristic wavelength screening methods, partial least squares(PLS)prediction models and overall prediction model were established for indicators such as damaged starch content, falling number, water absorption rate, stability time, stretching area, extensibility and maximum resistance. The results showed that detrend (DT) was the best preprocessing method for the prediction model of damaged starch content and water absorption rate, savitzky-gloay(SG) convolutional smoothing was the best preprocessing method for the prediction model of falling number and stretching area, and standard normal variable transformation (SNV) was the best preprocessing method for the prediction model of extensibility and maximum resistance. Competitive adaptive reweighted sampling (CARS) could effectively improve the prediction accuracy of models for damaged starch content, falling number, water absorption rate, stretching area and maximum resistance, with prediction determination coefficients of 0.964 1, 0.714 0, 0.975 5, 0.943 4 and 0.828 3, respectively, successive projections algorithm (SPA) had improved the performance of stability time and extensibility prediction models, with prediction determination coefficients of 0.713 5 and 0.953 0, respectively. The overall prediction model had improved its predictive performance for stability time, stretching area and maximum resistance, their residual predictive deviation increased from 1.86, 4.27 and 2.51 to 2.43, 5.26 and 3.11, respectively. In summary, near-infrared spectroscopy technology was effective and feasible for a non-destructive and rapid detection of the quality characteristics of wheat flour.
Analysis and antioxidant activity study of different extraction liquid from Pinus massoniana needles
2025, 40(2)
:61-71.
doi: 10.12187/2025.02.007
Abstract:
To analyze the chemical composition and antioxidant activity of Pinus massoniana needles, the main components of essential oils, aqueous extracts, and alcoholic extracts were studied using gas chromatography-mass spectrometry (GC-MS) coupling method. Additionally, network pharmacology was utilized to investigate the active components, and free radical scavenging experiments were conducted to evaluate their antioxidant activities. The results revealed that 60 compounds, accounting for 95.13% of the total, were identified in the essential oils, primarily consisting of terpenes. The aqueous and alcoholic extracts contained 10 and 16 compounds, respectively, mainly consisting of ketones. Significant differences were observed in the composition distribution among different extraction methods. VIP analysis identified six potential candidate differential compounds: pinene (VIP=1.31), 1-caryophyllene (VIP=1.47), L-β-pinene (VIP=1.80), α-pinene (VIP=3.32), 3-nitro-1-phenylpropyl-1-ketone (VIP=7.86), and 2-ethoxyphenyl isothiocyanate (VIP=1.13). These compounds may exert effects on oxidative stress and free radical scavenging pathways through interactions with proteins such as aldehyde reductase (AR). In the evaluation of antioxidant activity, when the DPPH scavenging rate reached 80%, the mass concentrations of alcoholic extract, aqueous extract, and essential oil were 0.2 mg/mL, 0.9 mg/mL, and 80 mg/mL, respectively. When the ABTS+ scavenging rate reached 80%, the concentrations of alcoholic extract, aqueous extract, and essential oil were 0.07 mg/mL, 0.2 mg/mL, and 10 mg/mL, respectively. When the hydroxyl radical scavenging rate reached 80%, the concentration of alcoholic extract was 3.5 mg/mL, while the scavenging abilities of aqueous extract and essential oil were relatively low and unstable. At the mass concentration of the extract liquid was 1.00 mg/mL, the alcoholic extract exhibited the strongest total reducing power.Therefore, Pinus massoniana needles possess significant antioxidant potential, with various components exhibiting antioxidant activities obtainable through different extraction methods.
To analyze the chemical composition and antioxidant activity of Pinus massoniana needles, the main components of essential oils, aqueous extracts, and alcoholic extracts were studied using gas chromatography-mass spectrometry (GC-MS) coupling method. Additionally, network pharmacology was utilized to investigate the active components, and free radical scavenging experiments were conducted to evaluate their antioxidant activities. The results revealed that 60 compounds, accounting for 95.13% of the total, were identified in the essential oils, primarily consisting of terpenes. The aqueous and alcoholic extracts contained 10 and 16 compounds, respectively, mainly consisting of ketones. Significant differences were observed in the composition distribution among different extraction methods. VIP analysis identified six potential candidate differential compounds: pinene (VIP=1.31), 1-caryophyllene (VIP=1.47), L-β-pinene (VIP=1.80), α-pinene (VIP=3.32), 3-nitro-1-phenylpropyl-1-ketone (VIP=7.86), and 2-ethoxyphenyl isothiocyanate (VIP=1.13). These compounds may exert effects on oxidative stress and free radical scavenging pathways through interactions with proteins such as aldehyde reductase (AR). In the evaluation of antioxidant activity, when the DPPH scavenging rate reached 80%, the mass concentrations of alcoholic extract, aqueous extract, and essential oil were 0.2 mg/mL, 0.9 mg/mL, and 80 mg/mL, respectively. When the ABTS+ scavenging rate reached 80%, the concentrations of alcoholic extract, aqueous extract, and essential oil were 0.07 mg/mL, 0.2 mg/mL, and 10 mg/mL, respectively. When the hydroxyl radical scavenging rate reached 80%, the concentration of alcoholic extract was 3.5 mg/mL, while the scavenging abilities of aqueous extract and essential oil were relatively low and unstable. At the mass concentration of the extract liquid was 1.00 mg/mL, the alcoholic extract exhibited the strongest total reducing power.Therefore, Pinus massoniana needles possess significant antioxidant potential, with various components exhibiting antioxidant activities obtainable through different extraction methods.
2025, 40(2)
:72-79.
doi: 10.12187/2025.02.008
Abstract:
Carbon quantum dots (G-CQDs) were prepared by hydrothermal method using grapefruit peel and fluorescence biosensor for Pb2+ detection was constructed in honeysuckle. The morphology, structure and optical properties of G-CODs were characterized by circular dichroism spectroscopy, transmission electron microscopy,ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy. The experimental conditions of the fluorescent biosensor were optimized and its detection performance was analyzed. The results showed that the G-CQDs were spherical and uniformly distributed. The average particle size was 2.41 nm, and the optimal excitation wavelength was 350 nm. The suitable experimental conditions for the fluorescence biosensor were as follows: Hemin concentration of 60 μmol/L, reaction time of 30 min, reaction temperature of 25 ℃, K+ concentration of 10 mmol/L and pH value of 6.5. Compared with other metal ions (Ag+, Zn2+, Cd2+, Cu2+ and Hg2+), the fluorescence biosensor had higher selectivity for Pb2+, and its fluorescence intensity increased with the increase of Pb2+ mass concentration. In the linear range of 0.1~5.0 μg/mL, the linear relationship between the two was good, R2 was 0.998 0, and the detection limit was 0.063 9 μg/mL. Compared with the conventional method (ICP-MS method), the fluorescence biosensor had good accuracy, and had the advantages of green environmental protection, economical and effective, simple operation and so on.
Carbon quantum dots (G-CQDs) were prepared by hydrothermal method using grapefruit peel and fluorescence biosensor for Pb2+ detection was constructed in honeysuckle. The morphology, structure and optical properties of G-CODs were characterized by circular dichroism spectroscopy, transmission electron microscopy,ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy. The experimental conditions of the fluorescent biosensor were optimized and its detection performance was analyzed. The results showed that the G-CQDs were spherical and uniformly distributed. The average particle size was 2.41 nm, and the optimal excitation wavelength was 350 nm. The suitable experimental conditions for the fluorescence biosensor were as follows: Hemin concentration of 60 μmol/L, reaction time of 30 min, reaction temperature of 25 ℃, K+ concentration of 10 mmol/L and pH value of 6.5. Compared with other metal ions (Ag+, Zn2+, Cd2+, Cu2+ and Hg2+), the fluorescence biosensor had higher selectivity for Pb2+, and its fluorescence intensity increased with the increase of Pb2+ mass concentration. In the linear range of 0.1~5.0 μg/mL, the linear relationship between the two was good, R2 was 0.998 0, and the detection limit was 0.063 9 μg/mL. Compared with the conventional method (ICP-MS method), the fluorescence biosensor had good accuracy, and had the advantages of green environmental protection, economical and effective, simple operation and so on.
2025, 40(2)
:80-89.
doi: 10.12187/2025.02.009
Abstract:
To explore the effects of salicylic acid (SA) on the total flavonoid content of tobacco (Nicotiana tabacumL.) and the expression of flavonoid synthesis-related genes, SA was applied to the one-month tobacco seedlings for 0 h, 1 h, 4 h and 12 h, and the total flavonoid content of the whole tobacco plant was detected and transcriptomic analysis was performed. The results of transcriptome analysis were verified by fluorescence quantitative PCR. The experimental results showed as follows: Compared with 0 h treated sample (SA0), the total flavonoid content of 1 h treated sample (SA1) was significantly up-regulated, and higher than that of 4 h treated sample (SA4) and 12 h treated sample (SA12). Analysis of differentially expressed genes (DEGs) showed that 1272 overlapping genes among SA1, SA4 and SA12 were significantly upregulated by SA treatment, GO functional annotation and KEGG metabolic pathway enrichment dispalyed that most of the genes significantly upregulated in SA1 encoded catalytic enzymes related to phenylpropanoid metabolism and isoflavone metabolism pathway, which could promote the biosynthesis of flavonoids such as lignin and its derivatives, flavins and anthocyanins. Fluorescence quantitative PCR analysis showed that the relative expression changes of differential genes were consistent with the corresponding differential gene expression trends in transcriptome analysis. This study provides clues and basis for seeking the genes involved in SA-induced flavonoids synthesis in tobacco and elucidating the regulatory network between SA and flavonoid biosynthetic pathway.
To explore the effects of salicylic acid (SA) on the total flavonoid content of tobacco (Nicotiana tabacumL.) and the expression of flavonoid synthesis-related genes, SA was applied to the one-month tobacco seedlings for 0 h, 1 h, 4 h and 12 h, and the total flavonoid content of the whole tobacco plant was detected and transcriptomic analysis was performed. The results of transcriptome analysis were verified by fluorescence quantitative PCR. The experimental results showed as follows: Compared with 0 h treated sample (SA0), the total flavonoid content of 1 h treated sample (SA1) was significantly up-regulated, and higher than that of 4 h treated sample (SA4) and 12 h treated sample (SA12). Analysis of differentially expressed genes (DEGs) showed that 1272 overlapping genes among SA1, SA4 and SA12 were significantly upregulated by SA treatment, GO functional annotation and KEGG metabolic pathway enrichment dispalyed that most of the genes significantly upregulated in SA1 encoded catalytic enzymes related to phenylpropanoid metabolism and isoflavone metabolism pathway, which could promote the biosynthesis of flavonoids such as lignin and its derivatives, flavins and anthocyanins. Fluorescence quantitative PCR analysis showed that the relative expression changes of differential genes were consistent with the corresponding differential gene expression trends in transcriptome analysis. This study provides clues and basis for seeking the genes involved in SA-induced flavonoids synthesis in tobacco and elucidating the regulatory network between SA and flavonoid biosynthetic pathway.
2025, 40(2)
:90-99.
doi: 10.12187/2025.02.010
Abstract:
In order to solve the problems of poor aroma and strong irritation of Sino-cigar tobacco leaves, milky flavor-producing microbial strain isolated from tobacco leaves was screened through smell evaluation in this study. The bacterium was identified by microscopic characteristics and 16S rDNA sequence analysis. The liquid fermentation conditions were optimized by sensory evaluation of flavoring in machine-made cigar and OD600 of bacterial turbidity. The key aroma components of the fermentation broth were determined by GC-MS analysis. Flavoring effects of the Bacillus strain on the sensory quality of cigar tobacco leaves were also studied. The results showed that one bacterium strain F2A was screened out, which was identified as B.subtilis. The preferred conditions for liquid fermentation were temperature of 32 ℃, time of 24 h, carbon sources of glucose, and inorganic salts of CaCl2. The main milky and sweet aroma component in the fermentation broth was identified as 2-hydroxy-3-methyl-2-cyclopentenone with a high content of 7.58 μg/mL. After fermentation by B.subtilis F2A, the contents of milky and sweet flavor components such as vanillin, coumarin, 6-ethyl-5,6-dihydropyran-2-one, and 2-hydroxy-3-methyl-2-cyclopentenone in fermented Chexue 14 cigar tobacco leaves were significantly increased, which significantly enhanced milky and sweet aromas. And the enhancement of tabanone, 3-hydroxy-β-damascone, and neophytadiene could improve freshness and floral smell. After fermentation, the milky and sweet aromas of cigars produced by Chexue 14 tobacco leaves were significantly improved, and the irritation was reduced. This study suggested B.subtilis F2A could produce 2-hydroxy-3-methyl-2-cyclopentenone and other flavor compounds, which provides a new way and theoretical support for the quality improvement of cigar tobacco leaves.
In order to solve the problems of poor aroma and strong irritation of Sino-cigar tobacco leaves, milky flavor-producing microbial strain isolated from tobacco leaves was screened through smell evaluation in this study. The bacterium was identified by microscopic characteristics and 16S rDNA sequence analysis. The liquid fermentation conditions were optimized by sensory evaluation of flavoring in machine-made cigar and OD600 of bacterial turbidity. The key aroma components of the fermentation broth were determined by GC-MS analysis. Flavoring effects of the Bacillus strain on the sensory quality of cigar tobacco leaves were also studied. The results showed that one bacterium strain F2A was screened out, which was identified as B.subtilis. The preferred conditions for liquid fermentation were temperature of 32 ℃, time of 24 h, carbon sources of glucose, and inorganic salts of CaCl2. The main milky and sweet aroma component in the fermentation broth was identified as 2-hydroxy-3-methyl-2-cyclopentenone with a high content of 7.58 μg/mL. After fermentation by B.subtilis F2A, the contents of milky and sweet flavor components such as vanillin, coumarin, 6-ethyl-5,6-dihydropyran-2-one, and 2-hydroxy-3-methyl-2-cyclopentenone in fermented Chexue 14 cigar tobacco leaves were significantly increased, which significantly enhanced milky and sweet aromas. And the enhancement of tabanone, 3-hydroxy-β-damascone, and neophytadiene could improve freshness and floral smell. After fermentation, the milky and sweet aromas of cigars produced by Chexue 14 tobacco leaves were significantly improved, and the irritation was reduced. This study suggested B.subtilis F2A could produce 2-hydroxy-3-methyl-2-cyclopentenone and other flavor compounds, which provides a new way and theoretical support for the quality improvement of cigar tobacco leaves.
2025, 40(2)
:100-107.
doi: 10.12187/2025.02.011
Abstract:
To enhance the potential application of aromatic amino acid transaminase (AAT) in the synthesis of auxin (IAA) and promotion of crop growth, bioinformatics methods were applied to analyze and predict the structure of AAT from Enterobacter tabaci strain β7. Then, this AAT was cloned, expressed and purified in Escherichia coli, and the enzymatic properties of recombinant AAT were determined. The bioinformatics analysis results revealed that the length of this AAT protein is composed of 396 amino acids. The key residue in the active center of this AAT was Lys246. The molecular weight of the recombinant AAT expressed in E.coli was approximately 43 kDa. The optimal substrate for recombinant AAT was tryptophan, at a temperature of 50 ℃ and a pH value of 8.0. Cu2+ had a certain activating effect on enzyme activity, and recombinant AAT showed good tolerance to the organic solvent ethanol. These results provided a theoretical basis for the AAT enzyme modification and the construction of high-yield auxin engineering bacteria.
To enhance the potential application of aromatic amino acid transaminase (AAT) in the synthesis of auxin (IAA) and promotion of crop growth, bioinformatics methods were applied to analyze and predict the structure of AAT from Enterobacter tabaci strain β7. Then, this AAT was cloned, expressed and purified in Escherichia coli, and the enzymatic properties of recombinant AAT were determined. The bioinformatics analysis results revealed that the length of this AAT protein is composed of 396 amino acids. The key residue in the active center of this AAT was Lys246. The molecular weight of the recombinant AAT expressed in E.coli was approximately 43 kDa. The optimal substrate for recombinant AAT was tryptophan, at a temperature of 50 ℃ and a pH value of 8.0. Cu2+ had a certain activating effect on enzyme activity, and recombinant AAT showed good tolerance to the organic solvent ethanol. These results provided a theoretical basis for the AAT enzyme modification and the construction of high-yield auxin engineering bacteria.
2025, 40(2)
:108-115.
doi: 10.12187/2025.02.012
Abstract:
In order to study the effect of membrane separation technology on the volatile components and sensory quality of low-grade tobacco leaf extract, 0.1 μm microfiltration membrane, 300 kDa and 10 kDa ultrafiltration membranes were used to separate low-grade tobacco leaf extract, and gas chromatography-mass spectrometry (GC-MS) combined with principal component analysis and cluster analysis were used to explore the differences in volatile components of the separated components and then the cigarette flavoring test was carried out. The results showed that: 1) A total of 71 volatile components were detected in unseparated fraction (M0), 0.1 μm permeable solution (M1), 0.1 μm interceptor solution (M2), 300 kDa permeable solution (M3), 300 kDa permeable solution (M4), 10 kDa permeable solution (M5) and 10 kDa retentate (M6),and most of the volatile components were enriched in M6. 2) The seven membsrane-separated components could be divided into 3 categories, the volatile components of M0 and M1 components were similar, the volatile components of M2, M4, M5 and M6 components were similar, and M3 was significantly different from the other 6 components. 3) M3 had the best flavoring effect, combined with GC-MS detection and analysis, the content of volatile components such as megastigmatrienone, neophytadiene and furfural, which played an important role in cigarette sensory, was significantly higher than that of M4, M5 and M6, enhancing the aroma quality, aroma intensity, sweetness and smoke concentration of cigarettes.
In order to study the effect of membrane separation technology on the volatile components and sensory quality of low-grade tobacco leaf extract, 0.1 μm microfiltration membrane, 300 kDa and 10 kDa ultrafiltration membranes were used to separate low-grade tobacco leaf extract, and gas chromatography-mass spectrometry (GC-MS) combined with principal component analysis and cluster analysis were used to explore the differences in volatile components of the separated components and then the cigarette flavoring test was carried out. The results showed that: 1) A total of 71 volatile components were detected in unseparated fraction (M0), 0.1 μm permeable solution (M1), 0.1 μm interceptor solution (M2), 300 kDa permeable solution (M3), 300 kDa permeable solution (M4), 10 kDa permeable solution (M5) and 10 kDa retentate (M6),and most of the volatile components were enriched in M6. 2) The seven membsrane-separated components could be divided into 3 categories, the volatile components of M0 and M1 components were similar, the volatile components of M2, M4, M5 and M6 components were similar, and M3 was significantly different from the other 6 components. 3) M3 had the best flavoring effect, combined with GC-MS detection and analysis, the content of volatile components such as megastigmatrienone, neophytadiene and furfural, which played an important role in cigarette sensory, was significantly higher than that of M4, M5 and M6, enhancing the aroma quality, aroma intensity, sweetness and smoke concentration of cigarettes.
2025, 40(2)
:116-126.
doi: 10.12187/2025.02.013
Abstract:
To investigate the differences in volatile components of tobacco leaves from Yongzhou, Hunan, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was employed to analyze volatile components in tobacco leaves with various parts and maturity levels. Differences of relative content were evaluated using principal component analysis, hierarchical cluster analysis, and orthogonal partial least squares regression analysis. The results showed a total of 69 volatile components were identified from tobacco leaves of different parts and maturity levels. Additionally,noticeable variations were observed in the volatile components among different tobacco leaves, with clear regional affiliations. The total 2b distinct volatile components were identified. Among these, the relative concentrations of 2-hexanone, isoamyl formate, furfural, 2,6-dimethylpyrazine, 2-methoxy-3-isobutylpyrazine, ethyl acetate, and geraniol exhibited significant variation in tobacco leaves depending on their stark positions within the plant. Concurrently, the relative concentrations of tetrahydrothiophene, 2-hexanone, isoamyl formate, nonanal, acetic acid, indole, salicylaldehyde, and isobutanol showed significant variation in tobacco leaves at different stages of maturity. These findings could be used to distinguish tobacco leaves from different parts and maturity stages.
To investigate the differences in volatile components of tobacco leaves from Yongzhou, Hunan, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was employed to analyze volatile components in tobacco leaves with various parts and maturity levels. Differences of relative content were evaluated using principal component analysis, hierarchical cluster analysis, and orthogonal partial least squares regression analysis. The results showed a total of 69 volatile components were identified from tobacco leaves of different parts and maturity levels. Additionally,noticeable variations were observed in the volatile components among different tobacco leaves, with clear regional affiliations. The total 2b distinct volatile components were identified. Among these, the relative concentrations of 2-hexanone, isoamyl formate, furfural, 2,6-dimethylpyrazine, 2-methoxy-3-isobutylpyrazine, ethyl acetate, and geraniol exhibited significant variation in tobacco leaves depending on their stark positions within the plant. Concurrently, the relative concentrations of tetrahydrothiophene, 2-hexanone, isoamyl formate, nonanal, acetic acid, indole, salicylaldehyde, and isobutanol showed significant variation in tobacco leaves at different stages of maturity. These findings could be used to distinguish tobacco leaves from different parts and maturity stages.
Journal Information
Founded in 1986， bimonthly
Administered by：The Education Department Henan Province
Sponsored by：Zhengzhou University of Light Industry
Editor-in-chief：Wei Shizhong
Executive Editor-in-Chief：Zou Lin
Deputy Editor-in-Chief：Qu Shuanghong
Edited & published by：Editorial Department of Journal of Light Industry
CN 41-1437/TS
ISSN 2096-1553
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