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To explore novel methods for improving the gel properties of myofibrillar protein (MP) emulsion gels under low salt condition, pre-emulsified plant oil emulsion was first prepared using the complex of chitin particle (CP) and water-soluble proanthocyanidin (PC), and then mixed with MP to prepare MP emulsion gels. The gel properties of MP emulsion gels were studied under low-salt conditions (0. 3 mol/L NaCl). It was found that under low NaCl conditions, CP and PC could synergistically improve the gel properties of MP emulsion gels. Namely, the gel strength (226. 79 g) and water holding capacity (97. 64%) of the CP-PC(3/2)-MP emulsion gel prepared by combining CP and PC in a ratio of 3:2 were higher than that of other samples. This was because CP-PC (3/2) complex had lower interfacial tension and Zeta-potential, and the droplets stabilized by the complex were smaller than those stabilized by CP alone, resulting in a more compact network structure in the CP-PC (3/2)-MP emulsion gel. Therefore, preparing emulsified plant oil by combining CP and PC was an effective method to improve the quality of emulsified meat products under low-salt conditions.
To explore novel methods for improving the gel properties of myofibrillar protein (MP) emulsion gels under low salt condition, pre-emulsified plant oil emulsion was first prepared using the complex of chitin particle (CP) and water-soluble proanthocyanidin (PC), and then mixed with MP to prepare MP emulsion gels. The gel properties of MP emulsion gels were studied under low-salt conditions (0. 3 mol/L NaCl). It was found that under low NaCl conditions, CP and PC could synergistically improve the gel properties of MP emulsion gels. Namely, the gel strength (226. 79 g) and water holding capacity (97. 64%) of the CP-PC(3/2)-MP emulsion gel prepared by combining CP and PC in a ratio of 3:2 were higher than that of other samples. This was because CP-PC (3/2) complex had lower interfacial tension and Zeta-potential, and the droplets stabilized by the complex were smaller than those stabilized by CP alone, resulting in a more compact network structure in the CP-PC (3/2)-MP emulsion gel. Therefore, preparing emulsified plant oil by combining CP and PC was an effective method to improve the quality of emulsified meat products under low-salt conditions.
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In order to understand the internal mechanism of the difference in the sensory quality of filler tobacco leaves after fermentation in Yunnan, taking the filler tobacco leaves of different grades (B1,X1,C1,C2,C3,C4) after fermentation as the research object. The sensory quality of different grades of filler tobacco leaves was evaluated, and their metabolome were determined with the help of GC-MS technology, and the principal component analysis(PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and KEGG metabolic pathway enrichment analysis were used for comparative analysis of differences between groups. The results showed that the C1 had more aroma, less irritation, and more aftertaste than others. There were 123 kinds of significantly differential metabolites among different grades of filler tobacco leaves, and 35 kinds of significantly differential metabolites among different grades of filler tobacco leaves, mainly heterocyclic compounds, aldehydes, ethers, carboxylic acids and aromatic compounds. Among them, (E)-butyl-2-enonitrile was a highly abundant and significantly differential metabolite in the four comparison groups with the participation of C1, and the three metabolic pathways of cyanoamino acid metabolism, aromatic compound degradation and butyric acid metabolism were significantly different in the comparison groups with the participation of C1. The (E)-buta-2-enonitrile may cause differences in metabolites of different grades of filler tobacco leaves through the accumulation and action of metabolites which related to the above three metabolic pathways, and finally cause differences in the sensory quality of different grades of filler tobacco leaves after fermentation in Yunnan.
In order to understand the internal mechanism of the difference in the sensory quality of filler tobacco leaves after fermentation in Yunnan, taking the filler tobacco leaves of different grades (B1,X1,C1,C2,C3,C4) after fermentation as the research object. The sensory quality of different grades of filler tobacco leaves was evaluated, and their metabolome were determined with the help of GC-MS technology, and the principal component analysis(PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and KEGG metabolic pathway enrichment analysis were used for comparative analysis of differences between groups. The results showed that the C1 had more aroma, less irritation, and more aftertaste than others. There were 123 kinds of significantly differential metabolites among different grades of filler tobacco leaves, and 35 kinds of significantly differential metabolites among different grades of filler tobacco leaves, mainly heterocyclic compounds, aldehydes, ethers, carboxylic acids and aromatic compounds. Among them, (E)-butyl-2-enonitrile was a highly abundant and significantly differential metabolite in the four comparison groups with the participation of C1, and the three metabolic pathways of cyanoamino acid metabolism, aromatic compound degradation and butyric acid metabolism were significantly different in the comparison groups with the participation of C1. The (E)-buta-2-enonitrile may cause differences in metabolites of different grades of filler tobacco leaves through the accumulation and action of metabolites which related to the above three metabolic pathways, and finally cause differences in the sensory quality of different grades of filler tobacco leaves after fermentation in Yunnan.
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Abstract:
To develop a novel tobacco flavoring, low-grade tobacco leaves were enzymatically treated and then co-extracted with dried rose petals. The extract was prepared using an organic solvent heating reflux method. Single-factor and response surface experiments were conducted to optimize the co-extraction parameters, including ethanol volume fraction, mixing ratio of tobacco powder to rose powder, and material ratio. The differences in aroma components between individually extracted and co-extracted samples were compared, and their effects on cigarette flavoring were analyzed. The results showed that the optimal enzymatic hydrolysis conditions for low-grade tobacco leaves were: enzymatic hydrolysis temperature of 50 ℃, enzymatic hydrolysis time of 6 h, and enzyme addition of 150 U / g of tobacco. The factors influencing the content of aroma compounds were ranked as follows: ethanol volume fraction> mixing ratio of tobacco powder to rose powder> material ratio. The optimal extraction conditions were determined as: ethanol volume fraction of 69%, mixing ratio (tobacco powder:rose powder) of 1. 8 ∶1, and material ratio of 1 ∶35. The volatile components detected in the rose sample, tobacco powder sample, and co-extracted sample were 44, 47, and 64, respectively, with total volatile contents of 325. 19 μg / g, 1289. 6 μg / g, and 1642. 89 μg / g, respectively. The co-extracted sample exhibited significantly higher levels of alcohols, esters, aldehydes, and ketones compared to individually extracted samples, while the nicotine content was reduced. When the co-extracted sample under optimal conditions was applied to cigarettes, the sensory quality of the cigarettes improved significantly. The cigarettes displayed enhanced aroma quality with floral and sweet notes, a richer and fuller fragrance, reduced irritation, and a cleaner, more comfortable aftertaste. This study demonstrates the potential of utilizing enzymatically treated low-grade tobacco leaves and rose petals for developing high-quality tobacco flavorings with improved sensory characteristics.
To develop a novel tobacco flavoring, low-grade tobacco leaves were enzymatically treated and then co-extracted with dried rose petals. The extract was prepared using an organic solvent heating reflux method. Single-factor and response surface experiments were conducted to optimize the co-extraction parameters, including ethanol volume fraction, mixing ratio of tobacco powder to rose powder, and material ratio. The differences in aroma components between individually extracted and co-extracted samples were compared, and their effects on cigarette flavoring were analyzed. The results showed that the optimal enzymatic hydrolysis conditions for low-grade tobacco leaves were: enzymatic hydrolysis temperature of 50 ℃, enzymatic hydrolysis time of 6 h, and enzyme addition of 150 U / g of tobacco. The factors influencing the content of aroma compounds were ranked as follows: ethanol volume fraction> mixing ratio of tobacco powder to rose powder> material ratio. The optimal extraction conditions were determined as: ethanol volume fraction of 69%, mixing ratio (tobacco powder:rose powder) of 1. 8 ∶1, and material ratio of 1 ∶35. The volatile components detected in the rose sample, tobacco powder sample, and co-extracted sample were 44, 47, and 64, respectively, with total volatile contents of 325. 19 μg / g, 1289. 6 μg / g, and 1642. 89 μg / g, respectively. The co-extracted sample exhibited significantly higher levels of alcohols, esters, aldehydes, and ketones compared to individually extracted samples, while the nicotine content was reduced. When the co-extracted sample under optimal conditions was applied to cigarettes, the sensory quality of the cigarettes improved significantly. The cigarettes displayed enhanced aroma quality with floral and sweet notes, a richer and fuller fragrance, reduced irritation, and a cleaner, more comfortable aftertaste. This study demonstrates the potential of utilizing enzymatically treated low-grade tobacco leaves and rose petals for developing high-quality tobacco flavorings with improved sensory characteristics.
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Abstract:
To obtain functional acyl sugar acyltransferase NtASAT2 of Nicotiana tabacum L., bioinformatic methods were applied to analyze and predict the sequences and structure of NtASAT2. The gene of NtASAT2 was cloned, prokaryotic expressed, and then purified. T prokaryotic expressed, and then purified. The function of the recombinant protein was verified through enzymatic catalysis. The results showed that in the secondary structure of NtASAT2, α-helices and random coils account for a large proportion with 39. 04% and 41. 13%, respectively. The amino acid sequence of NtASAT2 was highly similar to that of sticky tobacco NacASAT2. The content of soluble NtASAT2 in the recombinant protein expressed by prokaryotic cell BL21 (DE3) was relatively low, and the affinity of NtASAT2 to nickel column was weak. After purification, only a small amount of the target protein was obtained. In enzymatic reaction systems containing substrates, NtASAT2 showed enzyme activity and catalyzed the formation of sucrose diesters. The research results could provide a theoretical basis for the application of acyl sugar acyltransferase in enzymatic synthesis of sucrose esters.
To obtain functional acyl sugar acyltransferase NtASAT2 of Nicotiana tabacum L., bioinformatic methods were applied to analyze and predict the sequences and structure of NtASAT2. The gene of NtASAT2 was cloned, prokaryotic expressed, and then purified. T prokaryotic expressed, and then purified. The function of the recombinant protein was verified through enzymatic catalysis. The results showed that in the secondary structure of NtASAT2, α-helices and random coils account for a large proportion with 39. 04% and 41. 13%, respectively. The amino acid sequence of NtASAT2 was highly similar to that of sticky tobacco NacASAT2. The content of soluble NtASAT2 in the recombinant protein expressed by prokaryotic cell BL21 (DE3) was relatively low, and the affinity of NtASAT2 to nickel column was weak. After purification, only a small amount of the target protein was obtained. In enzymatic reaction systems containing substrates, NtASAT2 showed enzyme activity and catalyzed the formation of sucrose diesters. The research results could provide a theoretical basis for the application of acyl sugar acyltransferase in enzymatic synthesis of sucrose esters.
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Abstract:
Aiming at the key issues of the development and utilization of tobacco biological resources for non-cigarette manufacturing, the current status of foreign technology research and development is sorted out from the aspects of extraction of tobacco active substances and utilization of fiber materials, pointing out that: the active components of tobacco include nicotine, cannabinoid alcohol, polyphenols, proteins, tetraacyl sucrose esters and tobacco tissues (chloroplasts, mitochondria), etc.. Among these, the content and added value of nicotine, chlorogenic acid and cannabinoid alcohol are relatively high, and the extraction technology is more simple. These components have a significant market potential in the fields of pesticides, pharmaceuticals, and tobacco product additives, and have already been widely commercialized abroad. The utilization of fiber materials includes animal feed, fibrous material (paper, fiberboard, particleboard, nitrocellulose), oligosaccharides and biochar fertilizers. The primary directions for large-scale utilization of these materials are the production of biochar-based organic fertilizers, paper, and fiberboard, which are supported by relatively mature technologies. However, the cost associated with these processes remains relatively high, and there have been initial explorations into industrialization.. In the future, in order to further promote the development of the emerging industry of multi-purpose utilization of tobacco, in the scenario of novel tobacco product additives and pharmaceutical use, the extraction of nicotine, cannabinol and aroma-causing components of tobacco is an important research direction; in the scenario of feed application, the cultivation of new varieties of tobacco is an important direction of development; in the scenario of large-scale agricultural application, multi-functional coupling of organic fertilizer based on bio-carbon from tobacco waste resources is an important direction of development. In addition, within the scope of cost permitting, reinforced paper and fiberboard will also be one of the key R&D directions in the future.
Aiming at the key issues of the development and utilization of tobacco biological resources for non-cigarette manufacturing, the current status of foreign technology research and development is sorted out from the aspects of extraction of tobacco active substances and utilization of fiber materials, pointing out that: the active components of tobacco include nicotine, cannabinoid alcohol, polyphenols, proteins, tetraacyl sucrose esters and tobacco tissues (chloroplasts, mitochondria), etc.. Among these, the content and added value of nicotine, chlorogenic acid and cannabinoid alcohol are relatively high, and the extraction technology is more simple. These components have a significant market potential in the fields of pesticides, pharmaceuticals, and tobacco product additives, and have already been widely commercialized abroad. The utilization of fiber materials includes animal feed, fibrous material (paper, fiberboard, particleboard, nitrocellulose), oligosaccharides and biochar fertilizers. The primary directions for large-scale utilization of these materials are the production of biochar-based organic fertilizers, paper, and fiberboard, which are supported by relatively mature technologies. However, the cost associated with these processes remains relatively high, and there have been initial explorations into industrialization.. In the future, in order to further promote the development of the emerging industry of multi-purpose utilization of tobacco, in the scenario of novel tobacco product additives and pharmaceutical use, the extraction of nicotine, cannabinol and aroma-causing components of tobacco is an important research direction; in the scenario of feed application, the cultivation of new varieties of tobacco is an important direction of development; in the scenario of large-scale agricultural application, multi-functional coupling of organic fertilizer based on bio-carbon from tobacco waste resources is an important direction of development. In addition, within the scope of cost permitting, reinforced paper and fiberboard will also be one of the key R&D directions in the future.
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Abstract:
The pea-oat complex protein gel (POPG) was taken as the research object, and the gel strength, water holding capacity (WHC), free sulfhydryl content, disulfide bond content and microstructure were cmeasured to investigate the effects of different enzymes (papain, trypsin, neutral protease, transglutaminase (TG enzyme) and laccase) treatment on the properties of POPG. The ratio of pea protein to oat protein, the mass fraction of complex protein solution and the amount of TG enzyme addition were usel as factors to optimize the formula of POPG by single factor and response surface test. When the addition of TG enzyme was 40 U / g, POPG showed good gel strength (83. 00 g) and WHC (88. 79%). Besides, the above POPG showed lower free sulfhydryl content, higher disulfide bond content, and uniform microstructure. The best formula of complex protein gel was that the ratio of pea protein to oat protein was 1 ∶ 0. 4, the mass fraction of the composite protein solution was 20%, and the TG enzyme addition was 40 U / g. The complex protein gel prepared according to this formula showed a good gel strength (78. 00 g). The POPG prepared in this study holds promise as an animal fat substitnte,offering insights for the processing of green food in the futnre.
The pea-oat complex protein gel (POPG) was taken as the research object, and the gel strength, water holding capacity (WHC), free sulfhydryl content, disulfide bond content and microstructure were cmeasured to investigate the effects of different enzymes (papain, trypsin, neutral protease, transglutaminase (TG enzyme) and laccase) treatment on the properties of POPG. The ratio of pea protein to oat protein, the mass fraction of complex protein solution and the amount of TG enzyme addition were usel as factors to optimize the formula of POPG by single factor and response surface test. When the addition of TG enzyme was 40 U / g, POPG showed good gel strength (83. 00 g) and WHC (88. 79%). Besides, the above POPG showed lower free sulfhydryl content, higher disulfide bond content, and uniform microstructure. The best formula of complex protein gel was that the ratio of pea protein to oat protein was 1 ∶ 0. 4, the mass fraction of the composite protein solution was 20%, and the TG enzyme addition was 40 U / g. The complex protein gel prepared according to this formula showed a good gel strength (78. 00 g). The POPG prepared in this study holds promise as an animal fat substitnte,offering insights for the processing of green food in the futnre.
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Abstract:
In order to develop diversified apple juice concentrate natural flavors and improve the functional focus of the products, the apple juice concentrate was finely processed by using multi-stage membrane separation, and the apple characteristic flavor groups with outstanding characteristics were located by sensory evaluation. The obtained characteristic flavor groups were recombined. The pyrolytic products of recombined products with better sensory effects were analyzed by using Py-GC/MS. The results showed that: 1) four groups were obtained by three stages membrane separation, among which the sensory effects of 50nm retention solution, 50kDa retention solution and 2nm retention solution showed distinct characteristics. 2） By adjusting the proportions of the three characteristic flavor groups, recombinant products can be obtained with an effect superior to that of apple juice concentrate before separation. 3) The pyrolytic products of preferred recombined products are mainly composed of heterocyclic compounds and cyclopentanone derivative, including caramel, sweet, fruit and other aroma types. This study provides a technical reference for the fine processing of natural tobacco flavors.
In order to develop diversified apple juice concentrate natural flavors and improve the functional focus of the products, the apple juice concentrate was finely processed by using multi-stage membrane separation, and the apple characteristic flavor groups with outstanding characteristics were located by sensory evaluation. The obtained characteristic flavor groups were recombined. The pyrolytic products of recombined products with better sensory effects were analyzed by using Py-GC/MS. The results showed that: 1) four groups were obtained by three stages membrane separation, among which the sensory effects of 50nm retention solution, 50kDa retention solution and 2nm retention solution showed distinct characteristics. 2） By adjusting the proportions of the three characteristic flavor groups, recombinant products can be obtained with an effect superior to that of apple juice concentrate before separation. 3) The pyrolytic products of preferred recombined products are mainly composed of heterocyclic compounds and cyclopentanone derivative, including caramel, sweet, fruit and other aroma types. This study provides a technical reference for the fine processing of natural tobacco flavors.
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Abstract:
To make full use of the discarded tobacco leaves, and produce multiple fine processing products, tobacco extract was obtained from discarded tobacco leaves, and the tobacco extract was finely processed using membrane separation and two-dimensional column chromatography separation techniques. Sensory evaluation screened out characteristic flavor groups with prominent style features, and carried out recombination between characteristic flavor groups. Py-GC-MS was used to analyze the recombinant products. The results showed that the yield of tobacco extract obtained by water extraction was the highest and the overall sensory effect was good; A total of 16 groups were obtained through precision processing, among which the sensory effects of membrane separation of 5nm retention solution and column chromatography separation of A1, C1, and E2 fractions showed distinct characteristics, serving as the characteristic flavor groups of tobacco extracts; Among the recombinant products, products 1 and 2 can enhance the characteristics of tobacco aroma, baking aroma, light aroma, and sweet aroma of cigarettes, and have a good overall sensory effect; The thermal decomposition products of recombinant products 1 and 2 are mainly composed of heterocyclic and aromatic compounds, including sweet, light, nutty and other aroma types. This research provided reference to pluralism products preparation of natural flavors.
To make full use of the discarded tobacco leaves, and produce multiple fine processing products, tobacco extract was obtained from discarded tobacco leaves, and the tobacco extract was finely processed using membrane separation and two-dimensional column chromatography separation techniques. Sensory evaluation screened out characteristic flavor groups with prominent style features, and carried out recombination between characteristic flavor groups. Py-GC-MS was used to analyze the recombinant products. The results showed that the yield of tobacco extract obtained by water extraction was the highest and the overall sensory effect was good; A total of 16 groups were obtained through precision processing, among which the sensory effects of membrane separation of 5nm retention solution and column chromatography separation of A1, C1, and E2 fractions showed distinct characteristics, serving as the characteristic flavor groups of tobacco extracts; Among the recombinant products, products 1 and 2 can enhance the characteristics of tobacco aroma, baking aroma, light aroma, and sweet aroma of cigarettes, and have a good overall sensory effect; The thermal decomposition products of recombinant products 1 and 2 are mainly composed of heterocyclic and aromatic compounds, including sweet, light, nutty and other aroma types. This research provided reference to pluralism products preparation of natural flavors.
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Abstract:
The volatile components of navel oranges were extracted using spinning cone column (SCC) and steam distillation (SD) processes. Qualitative and quantitative analysis of the volatile components were performed by gas chromatography-mass spectrometry (GC-MS). Sensory evaluation combined with multivariate statistical analysis methods were used to identify and determine the main differential volatile components obtained by the two processes. The results demonstrated that the extraction rate of volatile components by the SCC process was markedly higher than that of SD. The volatile components extracted by SCC exhibited stronger fruity, sweet, floral, and green notes, whereas those extracted by SD displayed more pronounced fatty and woody notes. There were notable differences in the types and contents of volatile components extracted by the two methods, and a total of 110 volatile components were extracted, with 97 from the SCC process and 68 from the SD process. Based on a P<0. 05 and a variable importance in projection (VIP) value>1, 33 differential volatile components were screened out. Among them, myrcene, palmitoleic acid, (E)-β-ocimene, and ethyl palmitate were strongly correlated with woody and fatty notes, while (Z)-nerolidol, α-terpineol, D-limonene, and valencene were strongly correlated with fruity, floral, and sweet notes. This indicated that the SCC could efficiently extract these components and retain the fresh and natural aroma of navel orange.
The volatile components of navel oranges were extracted using spinning cone column (SCC) and steam distillation (SD) processes. Qualitative and quantitative analysis of the volatile components were performed by gas chromatography-mass spectrometry (GC-MS). Sensory evaluation combined with multivariate statistical analysis methods were used to identify and determine the main differential volatile components obtained by the two processes. The results demonstrated that the extraction rate of volatile components by the SCC process was markedly higher than that of SD. The volatile components extracted by SCC exhibited stronger fruity, sweet, floral, and green notes, whereas those extracted by SD displayed more pronounced fatty and woody notes. There were notable differences in the types and contents of volatile components extracted by the two methods, and a total of 110 volatile components were extracted, with 97 from the SCC process and 68 from the SD process. Based on a P<0. 05 and a variable importance in projection (VIP) value>1, 33 differential volatile components were screened out. Among them, myrcene, palmitoleic acid, (E)-β-ocimene, and ethyl palmitate were strongly correlated with woody and fatty notes, while (Z)-nerolidol, α-terpineol, D-limonene, and valencene were strongly correlated with fruity, floral, and sweet notes. This indicated that the SCC could efficiently extract these components and retain the fresh and natural aroma of navel orange.
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Abstract:
Using commercially availableHongdeng cherries (nine ripe) as the research object, after three kinds of ozone treatment with low, medium and high mass concentrations, and analysed the changes of physicochemical indexes and ultrastructures during the period of low-temperature storage, explored the effects of ozone treatment on the preservation effect of Hongdeng cherries. The results showed that different mass concentrations of ozone treatment effectively improved the storage quality of Hongdeng cherries, slowed down the increasing trend of decay rate, reduced the accumulation of malondialdehyde (MDA), the accumulation of lipid peroxidation products in cell membranes, slowed down the decline of hardness, and increased the anthocyanin content and antioxidant enzyme activities during the storage period. In particular, compared with the control group, the ozone treatment with medium mass concentration (6. 39 mg / m3) at the end of storage reduced the decay rate by 76. 19 %, increased the hardness by 36. 46 %, maintained the delta E (ΔE) and MDA contents at 69. 45 and 6. 83 μmol /g FW, and promoted the increase of anthocyanin content to 0. 581 ΔOD /g and superoxide dismutase (SOD) activity to 69. 31 U / g. At the same time, it induced the stomatal narrowing of the Hongdeng cherries pericarp, effectively controlled the water loss of the fruit, and maintained the cellular tissue structure by delaying the cell wall degradation, which ultimately achieved the purpose of improving the storage quality of Hongdeng cherries, prolonging the supply period of the market, and improving the economic benefits.
Using commercially availableHongdeng cherries (nine ripe) as the research object, after three kinds of ozone treatment with low, medium and high mass concentrations, and analysed the changes of physicochemical indexes and ultrastructures during the period of low-temperature storage, explored the effects of ozone treatment on the preservation effect of Hongdeng cherries. The results showed that different mass concentrations of ozone treatment effectively improved the storage quality of Hongdeng cherries, slowed down the increasing trend of decay rate, reduced the accumulation of malondialdehyde (MDA), the accumulation of lipid peroxidation products in cell membranes, slowed down the decline of hardness, and increased the anthocyanin content and antioxidant enzyme activities during the storage period. In particular, compared with the control group, the ozone treatment with medium mass concentration (6. 39 mg / m3) at the end of storage reduced the decay rate by 76. 19 %, increased the hardness by 36. 46 %, maintained the delta E (ΔE) and MDA contents at 69. 45 and 6. 83 μmol /g FW, and promoted the increase of anthocyanin content to 0. 581 ΔOD /g and superoxide dismutase (SOD) activity to 69. 31 U / g. At the same time, it induced the stomatal narrowing of the Hongdeng cherries pericarp, effectively controlled the water loss of the fruit, and maintained the cellular tissue structure by delaying the cell wall degradation, which ultimately achieved the purpose of improving the storage quality of Hongdeng cherries, prolonging the supply period of the market, and improving the economic benefits.
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Abstract:
Grapefruit peel was used as raw material, and carbon quantum dots (G-CQDs) were prepared by hydrothermal method to construct a green and simple fluorescence biosensor for Pb2+ detection 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.
Grapefruit peel was used as raw material, and carbon quantum dots (G-CQDs) were prepared by hydrothermal method to construct a green and simple fluorescence biosensor for Pb2+ detection 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.
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Abstract:
Electronic nose and head space-solid phase microextraction-gas chromatography mass spectrometry (HSSPME-GC-MS) combined with the odor activity values (OAV) and orthogonal partial least squares discriminant analysis (OPLS-DA) modelwere 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 the juice with more intense floral and fruity aroma. There had 48 and 42 volatile aroma compounds were 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 significantly decreased, and the isopropyl palmitate, citral and nerolidol acetone with floral and fruity aromas were newly formed in fermented jujube juice. The floral flavour of damasone has outstanding contribution to 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 give it a floral and fruity aroma.
Electronic nose and head space-solid phase microextraction-gas chromatography mass spectrometry (HSSPME-GC-MS) combined with the odor activity values (OAV) and orthogonal partial least squares discriminant analysis (OPLS-DA) modelwere 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 the juice with more intense floral and fruity aroma. There had 48 and 42 volatile aroma compounds were 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 significantly decreased, and the isopropyl palmitate, citral and nerolidol acetone with floral and fruity aromas were newly formed in fermented jujube juice. The floral flavour of damasone has outstanding contribution to 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 give it a floral and fruity aroma.
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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, had 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 hours, 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 located in the cell membrane. This study provides a novel strain resource for aroma-producing microorganisms and a theoretical basis 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, had 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 hours, 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 located in the cell membrane. This study provides a novel strain resource for aroma-producing microorganisms and a theoretical basis for the industrial production of apricot pomace flavoring through microbial fermentation.
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
Address：136 Science Avenue, Zhengzhou City, Henan Province, China
Postal Code：450001
Tel：(086)0371-86608635
(086)0371-86608633
