Abstract:Active natural products have diverse structures and activities and can be a major source of small molecule drugs. Given the emergence of multi-drug resistant bacteria and superbacteria, there is an urgent need to develop new active natural products. Large fragment cloning has been an important tool for the discovery of active natural products in recent years, and it has demonstrated obvious advantages in obtaining the biosynthetic gene clusters of active natural products. This approach, combined with efficient cluster-targeted screening methods, has significantly accelerated the discovery of active natural products. This review summarizes a wide variety of active natural products. Furthermore, this paper elaborates on the principles and applications of several large fragment cloning technologies, including artificial chromosome technology, Red/ET recombination system, and TAR technology coupled with the CRISPR-Cas9 system. This paper compares the advantages, disadvantages, and application scopes of different technologies and envisions their future prospects, aiming to provide theoretical guidance for the research and development of active natural products.

Abstract:[Objective]This study explores the unique flavor characteristics and volatile compounds of black tea produced from the large-leaf variety in northern Guangxi, aiming to reveal the material basis of aroma formation of this variety.[Method]Sensory evaluation, determination of biochemical parameters, headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and odor activity value (OAV) analysis were performed in combination with chemometrics analysis to analyze the flavor characteristics and volatile compounds of the black tea.[Result]The black tea samples produced from the large-leaf variety in northern Guangxi had similar aroma properties and were characterized by distinct floral and fruity aromas. A total of 88 volatile compounds including alcohols, esters, aldehydes, ketones, and acids were identified from the black tea samples. The mass concentrations of esters, aldehydes, and ketones were higher. Six key aroma components were selected by the chemometrics analysis, with the criteria of variable importance in the projection (VIP)>1 and OAV>1.0. Among them, linalool, geraniol, and α-myrcene were the characteristic aroma compounds conferring the floral and fruity aromas of the black tea. Nonanal, methyl salicylate, and β-ionone were the characteristic aroma compounds conferring the floral aroma, the mint aroma, and the strong floral and creamy aroma, respectively. These components were considered to be the key factors for the aroma formation of the black tea produced from the large-leaf variety in northern Guangxi.[Conclusion]The black tea produced from the large-leaf variety in northern Guangxi is characterized by floral and fruity aromas. The key aroma compounds are linalool, geraniol, α-myrcene, nonanal, methyl salicylate, and β-ionone, which together constitute the unique aroma characteristics of the black tea in this area.

Abstract:[Objective]This study aims to explore the cilium assembly of the radial spoke protein RSP10 and develop a highly specific polyclonal antibody to RSP10.[Method]Firstly, the prokaryotic expression vector pMal-C2X-rsp10 was constructed, and the expression of MBP-labeled RSP10 was induced in Escherichia coli BL21 (DE3). After the fusion protein was purified, and the MBP label was excised. The obtained protein was used to immunize New Zealand male white rabbits, and the antibody titer in the anti-serum was determined by indirect ELISA.[Result]The rabbit anti-Chlamydomonas reinhardtii RSP10 antibody with high specificity and high sensitivity was obtained after purification of Protein A and antigen antibody. The immunofluorence assay showed that RSP10 was mainly located in the kinetosome. The isolation of ciliary components showed that a large amount of RSP10 was detected in the axial filament and a small amount in the matrix of cilia.[Conclusion]This finding provides strong data support for the subsequent study of the assembly of RSP complex and the molecular mechanism underpinning its influence on cilium movement.

Abstract:[Objective]This study aims to improve the dispersion and utilization of caffeic acid phenethyl ester (CAPE) in aqueous solutions.[Method]CAPE-loaded hordein (CAPE-HD) nanoparticles were constructed via an anti-solvent precipitation method. The physicochemical properties of the nanoparticles were characterized, and the antioxidant properties of the nanoparticles within Caco-2 cells were investigated.[Result]The components within the CAPE-HD nanoparticles interacted through non-covalent bonds, such as hydrogen bonding, resulting in an altered state of CAPE upon nanoparticle formation. The CAPE-HD nanoparticles exhibited near-spherical morphology with an average particle size of 193.93 nm, an average polydispersity index (PDI) of 0.26, and average Zeta potential of 14.50 mV. These nanoparticles remained stable over 28 days and demonstrated favorable encapsulation efficiency, drug loading capacity, and biocompatibility. Antioxidant assays revealed that the CAPE-HD nanoparticles exhibited remarkable antioxidant activity, in terms of both DPPH free radical scavenging ability and within the Caco-2 cell model.[Conclusion]This nano-delivery system provides a promising platform and strategy for enhancing the bioavailability and clinical application of poorly water-soluble drugs such as CAPE.

Abstract:[Objective]This study explored the bacterial diversity in milk and traditional fermented dairy products in Balin Right Banner, aiming to lay a foundation for the development and utilization of bacterial resources in the milk and traditional fermented dairy products in this region.[Method]A total of 32 samples of cow milk, milk tofu, and sour fermentation supernatant of milk tofu were collected from Balin Right Banner, and their bacterial diversity was analyzed by 16S rRNA high-throughput sequencing.[Result]The diversity and abundance of bacterial communities varied among the milk and traditional fermented dairy products in Balin Right Banner. The dominant bacterial phyla were Firmicutes and Proteobacteria in cow milk, milk tofu, and sour fermentation supernatant of milk tofu, while their relative abundance varied among different samples (P<0.001). The dominant bacterial genus in cow milk was Lactococcus (91.53%), and those in the sour fermentation supernatant of milk tofu were Lactobacillus (72.68%) and Acetobacter (25.54%). The dominant bacterial genera in milk tofu were Lactococcus (33.88%), Lactobacillus (15.41%), Acetobacter (11.89%), Streptococcus (8.99%), Pediococcus (6.50%), Enterobacter (5.65%), Gluconobacter (3.88%), Weissella (2.98%), Enterococcus (2.30%), and Escherichia-Shigella (2.22%). Bacterial genera were richer in milk tofu than in the sour fermentation supernatant of milk tofu and cow milk. The prediction of bacterial gene functions revealed that metabolism was the gene function with the highest relative abundance of bacteria in milk and traditionally fermented dairy products at the pathway level 1, and global and overview maps had the highest relative abundance at the pathway level 2.[Conclusion]The bacterial communities were significantly different among milk and traditional fermented dairy products in Balin Right Banner, and the bacterial richness was the highest in milk tofu. The dominant phyla of the three kinds of sample were the same, while the dominant genera were different. The acidic environment was an important factor affecting bacterial diversity. Although the bacterial communities are different, the bacterial gene functions are similar.

Abstract:[Objective]To evaluate the antimicrobial resistance and transmission risk of foodborne Escherichia coli in wet markets, this study isolated E. coli from pork, aquatic products, vegetables, and wastewater collected from three wet markets in Hangzhou, Zhejiang.[Method]The isolates were identified by 16S rRNA sequencing, and their antimicrobial resistance phenotypes were determined via the disk diffusion method. PCR was employed to detect antimicrobial resistance genes and integrons in the isolates. The antimicrobial resistance characteristics of E. coli were analyzed, and conjugation experiments were performed to assess the potential for horizontal transfer of antimicrobial resistance genes. Co-occurrence network analysis was conducted to evaluate the transmission risk of antimicrobial resistance among the isolates.[Result]A total of 68 E. coli strains were isolated from 180 samples. The Kirby-Bauer (K-B) test revealed that most E. coli isolates were multidrug-resistant (MDR). The resistance rates to amoxicillin, tetracycline, and sulfisoxazole exceeded 50%. PCR amplification revealed that the tetracycline resistance gene tetA had the highest detection rate, followed by sul1, blaTEM, and tetB. Moreover, E. coli isolates from the wet market B exhibited higher prevalence of antimicrobial resistance genes than those from wet markets A and C. The detection rate of the integrase gene intI1 was the highest at 30.88%, and eight intI1-positive strains carried gene cassettes. Conjugation experiments demonstrated that in three donor strains, tetA could be transferred via plasmid-mediated conjugation into the recipient strain EC600. Co-occurrence network analysis revealed a strong co-transmission relationship between antimicrobial resistance genes and mobile genetic elements among E. coli isolates.[Conclusion]The author investigates the antimicrobial resistance profiles and dissemination risk of E. coli isolated from three wet markets in Hangzhou, Zhejiang, providing a theoretical basis for ensuring the food safety in wet markets.

Abstract:[Objective]This study aims to develop a rapid and accurate method for detecting epidermal growth factor (EGF).[Method]4-Formylphenylboronic acid (4-FPBA) was covalently anchored to the surface of aminocarbon nanotubes (NH₂-MWCNTs) to synthesize nanocomposites (NH₂-MWCNTs@4-FPBA), and NH₂-MWCNTs@4-FPBA was modified on a glassy carbon electrode. When EGF was present, 4-FPBA captured the EGF template through benzaldehyde, and then the electrode was immersed in pyrrole solution to electropolymerize to form a pyrrole molecularly imprinted layer. Finally, after dissociation and removal of the EGF template in an acidic solution, a three-dimensional cavity complementary to the EGF template was formed.[Result]The sensor had a wide linear range of 0.45~500.00 pg/mL and a low detection limit of 0.45 pg/mL, with excellent selectivity, reproducibility, and stability.[Conclusion]The measurement using this molecularly imprinted electrochemical sensor showed that the mass concentration of EGF was 3.67 pg/mL in yoghurt and 29.03 pg/mL in ultra-high temperature transiently sterilized cow milk.

Abstract:[Objective]The aim was to construct an electrochemical sensor based on a metal-organic framework-modified electrode for the highly sensitive detection of glucose solution in beverages.[Method]An electrochemical sensor based on ZIF-8 composite carbon nanotubes and immobilizing glucose oxidase (GOx) was prepared by in-situ synthesis and immobilized enzyme technology. The microstructure and morphology of the material were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, and infrared spectrometry (IR). The electrochemical performance of the electrode immobilizing enzyme was tested by electrochemical workstation.[Result]The prepared electrode immobilizing enzyme showed excellent detection performance for glucose solution, with a limit of detection being 1.395 μmol/L.[Conclusion]The sensor has a good application prospect in the field of food detection.

Abstract:[Objective]This study aims to compare Ziziphus jujuba polysaccharide (ZJP) and its degradation products in terms of their chemical composition and bioactivities.[Method]ZJP was degraded by α-L-rhamnosidase, cellulase, snail enzyme, and trifluoroacetic acid to prepare different degradation products (ZJP-R, ZJP-C, ZJP-S, and ZJP-T), and the chemical composition and degradation effects were compared. On the basis of in vitro antioxidant and probiotic activities, the in vivo antioxidant, anti-aging, anti-stress, and neuroprotective activities of ZJP and its degradation products were compared with Caenorhabditis elegans as a model system.[Result]The mass fraction of reducing sugar and average degree of polymerization of ZJP showed significant variations among different degradation treatments. In addition, Sephadex G-50 gel chromatography elution profile showed that ZJP-S had more oligosaccharide fragments with different relative molecular mass. In vitro assays demonstrated that degradation treatments significantly enhanced the free radical scavenging ability and total reducing power of ZJP and the growth activity of probiotics exposed to ZJP. In vivo assays in C. elegans revealed that the treatments with ZJP and its degradation products significantly reduced the reactive oxygen species (ROS) accumulation, enhanced the superoxide dismutase (SOD) activity, and decreased the malondialdehyde (MDA) molality of C. elegans under oxidative stress. Furthermore, the treatments prolonged the lifespan, reduced the lipofuscin accumulation, and enhanced the resistance to heat stress and acute oxidative stress. ZJP demonstrated improved bioactivity after degradation, with ZJP-S exhibiting the most significant effects across multiple indicators. Additionally, both ZJP-S and ZJP-C showed significant neuroprotective activity in the C. elegans models of Huntington disease and Alzheimer’s disease.[Conclusion]Degradation treatment enhanced the bioactivity of ZJP. The greater bioactivity of ZJP-S might be associated with the more abundant oligosaccharides and reducing sugars from snail enzyme degradation. The findings provide a reference for the development and utilization of Z. jujuba resources.

Abstract:[Objective]The aim of this study was to analyze the compositional changes of the alcohol extracts of Acanthopanax senticosus (Rupr. et Maxim.) Harms (APS)-Ganoderma applanatum (Pers.) Pat. (GA) before and after compounding at a mass ratio of 5∶1 (m_APS∶m_GA=5∶1) and to investigate the immunomodulatory effects and marker components of the extracts.[Method]The mouse models of compromised immunity and delayed-type hypersensitivity (DTH) were established with cytoxan (CTX) and 2, 4-dinitrochlorobenzene (DNCB), respectively, to investigate the effects of the alcohol extracts on the immune system. Ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) was used to analyze the changes of the active ingredients before and after compounding. Differential thermal analysis was performed to determine whether new substances were generated after compounding. Single solvent extraction was employed to qualitatively analyze the chemical components.[Result]The alcohol extract of A. senticosus-G. applanatum compounding at a mass ratio of 5∶1 possessed strong immunomodulatory effects. UHPLC-MS showed that the mass fractions of the active ingredients in the alcohol extract were directly proportional to the mass of the two drugs. The differential thermal analysis showed that new compounds different from those in A. senticosus and G. applanatum were generated after the compounding of the two drugs, mainly including tannins, oxygen-containing heterocyclic anthraquinones, polysaccharides, volatile oils, and lipids.[Conclusion]The strong immunomodulatory effects of the alcohol extract of A. senticosus-G. applanatum compounding at a mass ratio of 5∶1 are presumably related to the co-action of new compounds produced by the compounding, and these compounds could be used as maker components for the quality evaluation of A. senticosus-G. applanatum.

Abstract:[Objective]This study aims to investigate the effects and differences of the natural antioxidant (+)-catechin and its isomer (-)-epicatechin on the antioxidant activity of HEK293T cells based on the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway.[Method]The effects of (+)-catechin and (-)-epicatechin on the viability of HEK293T cells were investigated via the methyl thiazolyl tetrazolium (MTT) assay. Reporter genes were employed to investigate the regulatory effects on the activation of ARE. The effects of (+)-catechin and (-)-epicatechin on the mRNA and proteins levels of the downstream factors [glutamate-cysteine ligase modifier subunit (GCLM), NAD(P)H quinone dehydrogenase 1 (NQO1), and heme oxygenase-1 (HO-1)] of the Nrf2-ARE signaling pathway were explored by RT-PCR and Western blot, respectively.[Result]The expression of reporter genes showed that ARE-mediated transcriptional activation was significantly induced by (+)-catechin and (-)-epicatechin at 20 μmol/L and 10 μmol/L, respectively. RT-PCR and Western blot results showed that (+)-catechin at 40 μmol/L significantly up-regulated the mRNA levels of GCLM, NQO1, and HO-1, and (-)-epicatechin at the same concentration significantly up-regulated the mRNA levels of NQO1 and HO-1. At 10 μmol/L, (+)-catechin up-regulated the protein levels of GCLM, NQO1, and HO-1, and (-)-epicatechin up-regulated the protein levels of GCLM and HO-1.[Conclusion](+)-Catechin and (-)-epicatechin have different minimum effect concentrations on cells. Both of them have the ability to activate the Nrf2-ARE signaling pathway, and the required concentration of (-)-epicatechin to activate the pathway is lower than that of (+)-catechin. In addition, the two compounds have different effects on the expression of genes and proteins downstream of the Nrf2-ARE signaling pathway, with (+)-catechin outperforming (-)-epicatechin at the same concentration.

Abstract:[Objective]This study aims to investigate the effects of α-amylase addition on the characteristics of infant rice flour.[Method]Infant rice flour samples with different α-amylase addition were prepared. The basic composition, relative molecular mass of starch, gelatinization properties, hydration properties, texture properties, in vitro digestion characteristics, and microstructure of infant rice flour were determined. Furthermore, the correlations between the physicochemical characteristics and quality characteristics of infant rice flour were analyzed.[Result]The weight-averaged molecular weight and the number-averaged molecular weight of starch in infant rice flour decreased with the increase in α-amylase addition. The gelatinization curve of infant rice flour with α-amylase addition was relatively gentle, and the gelatinization properties of infant rice flour without α-amylase addition were higher than those of infant rice flour supplemented with this enzyme (P<0.05). The water absorption index and swelling power decreased with the increase in α-amylase addition. Infant rice flour with α-amylase addition of 1.8 U/L had the highest sensory scores. The texture properties decreased with the increase in α-amylase addition. The infant rice flour with α-amylase addition showed small and numerous starch granules and denser pores on the surface. The mass fraction of ready digestible starch increased and that of resistant starch decreased in the infant rice flour with α-amylase addition. The sensory scores of infant rice flour were negatively correlated with the valley viscosity (P<0.01). The mass fraction of resistant starch, hardness, consistency, cohesion, and adhesion were positively correlated with the relative molecular mass of starch, water absorption index, and gelatinization properties (P<0.01), and they were negatively correlated with water solubility index (P<0.01).[Conclusion]The characteristics of infant rice flour are significantly improved by α-amylase addition, and the comprehensive quality of infant rice flour with the addition of 1.8 U/L is the best.

Abstract:[Objective]This study aims to investigate the effects of spices on the microbial community structure and volatile flavor compounds of Fuling pickled mustard tuber and explore the correlations between dominant microbial genera and volatile components.[Method]The effects of spices on microbial community structure and volatile flavor components of Fuling pickled mustard tuber were investigated by high-throughput sequencing and headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Pearson correlation coefficients were calculated to reveal the correlations between dominant microbial genera and volatile components. The mass fractions of total acids, nitrite, and reducing sugar were determined.[Result]The dominant microbial genera in the pickled mustard tuber without spices addition (control) were Lactobacillus (35.61%), Halomonas (15.13%), Leuconostoc (10.40%), Debaryomyces (77.51%), etc. In the pickled mustard tuber with spices addition, Lactobacillus (80.49%), Debaryomyces (43.17%), and unclassified_k_Fungi (28.33%) were dominant. A total of 60 volatile flavor compounds were detected in the control group, with the total mass fraction of 1 286.94 μg/kg, mainly including esters, organic sulfides, and acids. 84 volatile flavor compounds were detected in the spices addition group, with the total mass fraction of 14 304.21 μg/kg, mainly including alcohols, ethers, and acids. The pickled mustard tuber with spices addition had higher total acid mass fraction (10.95 g/kg vs. 7.14 g/kg) and higher nitrite mass fraction (5.57 mg/kg vs. 3.13 mg/kg) than the control group. Lactobacillus showed positive correlations with alcohols, ethers, alkenes, acids, ketones, and phenols (P<0.001) and negative correlations with organic sulfides (P<0.001). Debaryomyces, Halomonas, and Leuconostoc showed negative correlations with most volatile flavor components (P<0.05).[Conclusion]Spices can increase the acidity of pickled mustard tuber, the relative abundance of Lactobacillus, and the number of dominant fungi. By regulating the abundance of Lactobacillus, Wallemia, and Alternaria during the fermentation process, spices help improve the flavor of pickled mustard tuber.

Abstract:[Objective]This study investigated the effects of shaping and baking processes on the antioxidant activity of round roasted green tea, aiming to provide theoretical support and practical reference for improving the quality and optimizing the processing techniques of green tea.[Method]The influences of different processing stages and key procedures such as shaping and baking on the antioxidant activity of round roasted green tea were studied. A zebrafish model (in vivo) and multiple indexes including DPPH radical scavenging rate, ABTS? radical scavenging rate, and ferric ion reducing antioxidant power (FRAP) were employed for comprehensive evaluation of the antioxidant activity.[Result]Shaping and baking conditions significantly affected the antioxidant activity of green tea. The effect of shaping temperature varied under different baking temperatures. For example, under baking at 75 ℃ for 20 min (twice), the DPPH radical scavenging rate of green tea shaped at 90 ℃ was significantly higher than that at 120 ℃ and 150 ℃. In the case of shaping at 90 ℃ for 50 min, the FRAP of green tea baked at 105 ℃ was significantly better than that baked at 75 ℃. Through process optimization, the best combination was determined as shaping at 90 ℃ for 50 min + baking at 90 ℃ for 20 min (twice), under which the DPPH radical scavenging rate increased by 43.54% compared with that of conventional factory processes.[Conclusion]Optimizing shaping and baking processes can significantly enhance the antioxidant activity of round roasted green tea. This study provides scientific support for the refined processing and quality improvement of green tea.

Abstract:[Objective]This study aims to explore the lipid-lowering effects of the phytosterol-oil bodies emulsion (POE).[Method]Caenorhabditis elegans was taken as a model to evaluate the effects of POE on lipid metabolism, physiological indexes, and expression of genes associated with oxidative stress and fat metabolism.[Result]Compared with the control group, different mass concentrations of POE reduced the mass fraction of fat (P<0.01) and the relative content of triglycerides (P<0.05), without toxicity to the growth and development of C. elegans (P<0.01). At the same time, it significantly reduced the level of reactive oxygen species and increased the levels of antioxidant enzymes. In addition, POE affected the expression levels of genes related to fat metabolism. qPCR results showed that POE up-regulated the mRNA level of sbp-1, while down-regulating the mRNA levels of fat-2, nhr-80, and fat-5 (P<0.05).[Conclusion]POE may improve lipid metabolism by slowing fat deposition, regulating the fat peroxidation pathway, and alleviating oxidative stress in C. elegans.

Abstract:[Objective]This study aims to increase the caproic acid yield of Aneurinibacillus JXN-1.[Method]First, a Plackett-Burman design was employed to screen the significant factors affecting caproic acid yield from eight medium components. Subsequently, the path of steepest ascent method was used to determine the optimal concentration ranges of these significant factors. Finally, a Box-Behnken design was utilized to establish a quadratic polynomial regression model, and the interactions among the significant factors were analyzed to predict the optimal medium composition.[Result]The Plackett-Burman design identified the mass concentrations of sodium acetate and calcium folinate and the volume fraction of ethanol as significant influencing factors. The regression model established by the Box-Behnken design was highly significant (P<0.01). The predicted optimal medium composition was as follows: sucrose mass concentration of 7.50 g/L, yeast extract mass concentration of 1.00 g/L, magnesium sulfate heptahydrate mass concentration of 0.20 g/L, sodium acetate mass concentration of 4.08 g/L, ammonium sulfate mass concentration of 0.45 g/L, calcium folinate mass concentration of 2.88 mg/L, dipotassium hydrogen phosphate mass concentration of 0.60 g/L, and ethanol volume fraction of 2.53%. Under these conditions, the actual caproic acid yield was in high agreement with the model predicted value, representing an increase of 212.47% compared with the pre-optimization level.[Conclusion]This study successfully optimizes the fermentation medium for caproic acid production by Aneurinibacillus JXN-1. The optimized medium significantly enhances the caproic acid yield, providing a theoretical basis and technical reference for the practical application of this strain in Baijiu brewing.

Abstract:[Objective]This study is intended to optimize the preparation process of Jinxuan black tea cream, enhance the content of tea polyphenols, and compare the effects of different processing methods on the volatile components of the tea cream.[Method]With dried Jinxuan black tea as the raw material, response surface methodology was adopted to examine the impacts of tea-to-water ratio, enzyme dosage, ultrasonic power, and ultrasonic duration on the mass fraction of tea polyphenols in the black tea cream. Furthermore, headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was employed to detect and analyze the volatile components in the black tea cream samples processed via three distinct methods: vacuum freeze concentration (NP), enzyme-assisted vacuum freeze concentration (WB), and rotary evaporation concentration combined with vacuum freeze concentration (B).[Result]The optimal process conditions for the black tea cream were determined as follows: a tea-to-water ratio of 1 g∶20 mL, an enzyme dosage of 30 mg/g, ultrasonic power of 514 W, and ultrasonic duration of 21 min. Under these optimal conditions, the mass fraction of tea polyphenols in the Jinxuan black tea cream attained 269.34 mg/g. A total of 103, 107, and 84 volatile components were identified from NP, WB, and B samples, respectively. Among them, volatile components with floral and fruity aromas, including linalool, benzyl alcohol, 3-methylbutanal, benzaldehyde, phenylacetaldehyde, myrcene, and pyrrole, were detected in all the three samples (NP, WB, and B). After enzymatic hydrolysis, the mass fraction of volatile components in the WB sample was 4 014.39 μg/kg higher than that in the NP sample. The volatile components with floral and fruity aromas, such as 3,7-dimethyl-1,5,7-octatriene-3-ol, limonene, and pyrazines, were not detected in sample B.[Conclusion]Enzymatic hydrolysis combined with vacuum freeze-drying can effectively increase the mass fraction of volatile components in black tea cream.