Abstract:For dark tea and white tea with good storage value, a moderate storage period can improve their quality. The author sorts out the research results of correlation analysis between aroma components and aroma types of white tea and black tea in recent years and summarizes the research progress in aroma type and aroma component changes of different grades and forms of white tea and different types of black tea during storage. Furthermore, this paper discusses the difficulties in the study of the aromas of black tea and white tea and makes an outlook on the future research directions.

Abstract:A substantial quantity of waste is generated during the processing of citrus fruits. Such waste is rich in diverse bioactive compounds, including flavonoids, phenols, essential oils, carotenoids, and pectin. The efficient extraction and resource utilization of these compounds hold significant importance in managing the processing pollution and propelling the development of a circular economy. The author presents a comprehensive review of the functional properties and application status of the major bioactive compounds in citrus fruit processing waste. Additionally, it expounds on the principles, advantages, and application outcomes of extraction technologies such as microwave-assisted extraction, supercritical fluid extraction, ultrasound-assisted extraction, and enzymatic hydrolysis methods.

Abstract:Aptamers and DNAzymes, both belonging to the functional nucleic acids (FNAs) family, can form complexes with gold nanoparticles (AuNPs) to synergistically achieve molecular recognition with signal amplification, significantly enhancing their performance in sensor applications. These complexes have been extensively applied in food safety testing, environmental monitoring, and biomedical diagnostics, demonstrating exceptional application value. The author systematically summarizes the discovery and development of aptamers, DNAzymes, and AuNPs, elaborates on the formation mechanisms and assembly strategies of functional nucleic acid-AuNP complexes, and highlights recent advances in biosensors based on colorimetry, fluorescence, and electrochemical signals for the detection of heavy metal ions and pathogens.

Abstract:Objective This study aimed to screen high-yield ectoine-producing strains from the strains isolated from the Jintan salt cavern and optimize their culture conditions to enhance ectoine production. Method High-performance liquid chromatography (HPLC) was employed for quantitative analysis and liquid chromatography-mass spectrometry (LC-MS) for qualitative analysis. The ectoine-producing strains were screened. The effects of pH and mass concentrations of KCl, MgSO₄, L-glutamate sodium (MSG), acid-hydrolyzed casein (CA), and NaCl on ectoine production were investigated via a single-factor approach. Response surface methodology was then adopted to establish a mathematical model between ectoine production and key influencing factors (mass concentrations of KCl, acid-hydrolyzed casein, and NaCl). Result A high-yield ectoine-producing strain, DJA10, was successfully screened and identified as Marinobacter through systematic characterization. Under the optimized culture conditions (MgSO₄ 12.0 g/L, L-glutamate sodium 6.8 g/L, NaCl 56.6 g/L, KCl 37.3 g/L, and acid-hydrolyzed casein 10.5 g/L, pH 8.5), the ectoine titer of the strain significantly increased by 134%, from (195.30±2.06) mg/L to (458.51±1.08) mg/L. Conclusion This study successfully screened a high-yield ectoine-producing strain, DJA10, and significantly enhanced its ectoine production through culture condition optimization, providing an excellent microbial resource for the industrial production of ectoine.

Abstract:Objective This study aimed to investigate the regulatory mechanism of white light-induced anthocyanin synthesis in postharvest Taoxingli plum fruits. Method With dark treatment as the control, the effect of white light treatment on the mass fraction of anthocyanins in Taoxingli plum fruits was measured. Weighted gene co-expression network analysis (WGCNA) was performed to screen co-expression modules and core genes related to anthocyanin synthesis. Reverse transcription real-time quantitative PCR (RT-qPCR) was employed to validate gene expression levels. Yeast one-hybrid (Y1H) assay was employed to verify the interactions between transcription factors and the PsANS promoter. Result White light treatment significantly increased the mass fraction of anthocyanins in Taoxingli plum fruits. WGCNA results revealed that the MEdarkred and MElightcyan1 modules were significantly correlated with anthocyanin synthesis, containing 12 anthocyanin synthesis-related genes, among which PsANS was identified as the core gene. RT-qPCR results confirmed the upregulated expression of PsANS gene and selected transcription factors. Y1H assay results demonstrated that transcription factors (PsbHLH2, PsbZIP4, PsGRAS1, and PsMYB1) could bind to the PsANS promoter. Conclusion White light promotes postharvest anthocyanin accumulation in Taoxingli plum fruits by activating the PsANS-centered transcriptional regulatory network.

Abstract:Objective This study used the exopolysaccharides (EPS) secreted by lactic acid bacteria to enhance the textural and gel properties of fermented goat yogurt, aiming to alleviate syneresis and improve the yogurt quality. Method Five EPS-producing strains of lactic acid bacteria were isolated from traditionally fermented vegetables. The influences of fermentation with different lactic acid bacteria strains on the microstructure, textural properties, and rheological behavior of fermented goat yogurt were studied. Result Strains S4, N4, S1, C1, and C4 were identified by 16S rDNA sequencing as Lactiplantibacillus plantarum, among which strains C1 and C4 showed EPS-producing capability. The fermented goat yogurt samples prepared with strains C1 and C4 capable of producing EPS showed denser gel network with smaller gaps, higher hardness, higher cohesiveness, higher consistency, and higher viscosity than those prepared with strains S4, N4, and S1 without the capability of producing EPS. Compared with the fermentation with strain S1, the fermentation with strains C1 and C4 enhanced the modulus of elasticity of fermented goat yoghurt, which reduced the damage caused by shear stress to fermented goat yoghurt. Water-holding capacity and low-frequency NMR (LF-NMR) results showed that the fermented goat yogurt prepared with Lactiplantibacillus plantarum C4 exhibited higher water-holding capacity, with the water-holding rate of (58.37±1.66)% and T₂₃ value of (167.16±13.14)%. Conclusion This study suggests that EPS-producing Lactiplantibacillus plantarum can significantly enhance the water-holding capacity and viscosity of fermented goat yogurt, thus improving the comprehensive quality of fermented goat yoghurt.

Abstract:Objective This study aimed to investigate the effects of different drying methods on the physicochemical quality and functional properties of Gastrodia elata (G.elata) and to elucidate the molecular mechanisms underlying the inhibition of acetylcholinesterase (AChE) by the active components of G. elata. Method G. elata samples were processed by hot air drying (HAD), vacuum freeze drying (FD), vacuum drying (VD), far-infrared drying (FIRD), and vacuum freeze-hot air combined drying. The variations in the physicochemical quality of G. elata were systematically evaluated. The components responsible for AChE inhibition were screened Overcoming the limitations of single method drying, the FD12-HAD3 combined drying process significantly promoted the conversion of parishins into gastrodin and p-hydroxybenzyl alcohol, increasing the mass fraction of the two compounds by 8.19% compared with the vacuum freeze drying group. The AChE inhibition rate of G. elata processed with the combined drying process reached 60.84%, which was significantly higher than those in other drying groups. The molecular dynamics simulations revealed that small molecules (p-hydroxybenzyl alcohol and gastrodin) precisely anchored the catalytic active site of AChE, while macromolecules (parishins) sterically blocked the peripheral anionic site, thereby establishing a network of multi-target synergistic competitive inhibition. Conclusion The FD12-HAD3 combined drying process exhibits outstanding efficacy in both enriching active components and enhancing AChE-inhibitory functions, providing a robust scientific basis for the high-quality processing of G. elata.

Abstract:Objective This study aimed to develop a catalytic system utilizing immobilized enzyme coupling glycosyltransferase for the synthesis of salidroside. Method The prokaryotically expressed glycosyltransferase UGT85AF8 and sucrose synthase GmSUS were immobilized on nickel-chelated polyacrylic acid resin. The immobilized UGT85AF8 was used to catalyze tyrosol glycosylation, and the immobilized GmSUS was used for the regeneration of uridine diphosphate glucose (UDPG). The reaction system conditions, including temperature, pH, enzyme loading, and substrate concentration, were optimized. The reusability of immobilized enzymes was investigated, and salidroside was separated and purified via the macroporous resin LSA-30. Result Under optimal conditions, the reaction for 12 h achieved a salidroside titer of 11.87 g/L. Moreover, the average molar conversion rate was 88.47% in six consecutive reaction batches. After purification, the purity of salidroside exceeded 99%, with a crystallization recovery rate of 51.49%. Conclusion The immobilized enzyme coupling catalytic system demonstrates promising potential for industrial-scale production of salidroside.

Abstract:ObjectiveThis study aimed to decipher the mechanism through which wheat flour components influenced the deterioration of frozen streamed bread after re-steaming. Method The composite wheat flour samples with different formulations were used to prepare steamed bread, which was then frozen. The specific volume, texture, glutenin macropolymer (GMP) mass, free sulfhydryl molality, and relative molecular mass of proteins were measured after re-steaming of frozen steamed bread. Result The protein mass fraction in the composite wheat flour significantly influenced the thermomechanical properties of dough and the frozen storage stability of steamed bread. The MF1 formulation, with higher protein mass fraction, produced dough with greater water absorption, development time, and stability. Its gluten network structure is more intact, exhibited higher GMP mass and lower mass fraction of SDS-extractable proteins, which better preserved the specific volume and textural properties of steamed bread during frozen storage. As the frozen storage time prolonged, the gluten network underwent significant depolymerization, as manifested by the decreases of 1.67%~15.12% in GMP mass, increases of 2.44%~37.68% in free sulfhydryl molality, and increases of 9.56%~48.84% in mass fraction of SDS-extractable proteins. Correspondingly, the streamed breed exhibited decreased specific volume, deteriorated texture, and uneven pore distribution. Pearson correlation analysis revealed the intrinsic relationships between macroscopic quality indicators, protein structural parameters, and dough rheological properties at different frozen storage stages. Conclusion The deterioration of frozen steamed bread after re-steaming is related to the differences in wheat flour components. In the composite wheat flour systems used, gluten protein mass fraction and complete GMP structure are significantly associated with textural properties of frozen steamed bread after re-steaming. Maintaining the integrity of the gluten network structure plays an important role in slowing down the quality deterioration of frozen streamed bread after re-steaming. This study provides a theoretical basis for improving frozen wheat flour-based products.

Abstract:Objective This study comprehensively analyzed the bioactive components in the pomace of large-fruited and small-fruited sea buckthorn (Hippophae rhamnoides L.), aiming to determine their nutritional utilization value. Method The pomace samples of different fruit types of sea buckthorn were selected as the research objects. Detection methods such as gas chromatography, liquid chromatography, and inductively coupled plasma-mass spectrometry were employed to identify the main bioactive components including total flavonoids, total polyphenols, vitamin C, vitamin E, amino acids, and mineral elements in the pomace. Cluster heatmap analysis, orthogonal partial least squares-discriminant analysis (OPLS-DA), and principal component analysis (PCA) were performed to comprehensively analysis 44 nutritional and bioactive components. Result The pomace samples of both large-fruited and small-fruited sea buckthorn were rich in flavonoids and polyphenols. The mass fractions of vitamin E and β-carotene in the pomace of large-fruited sea buckthorn were higher than those in the pomace of small-fruited sea buckthorn. Seventeen amino acids, including 7 essential amino acids and 10 non-essential amino acids, were detected in both pomace samples. Seven trace elements and four major elements essential for the human body were detected, and 11 and 10 fatty acids were detected in the pomace of large-fruited and small-fruited sea buckthorn, respectively. In addition, some amino acids (such as aspartic acid and leucine), fatty acids (such as linoleic acid and erucic acid), flavonoids, polyphenols, and mineral elements (such as K and Fe) can be used as marker components for the pomace of large-fruited and small-fruited sea buckthorn.Conclusion The sea buckthorn pomace is rich in bioactive components and can be applied in the food or health product industries in the form of food additives. The results of this study provide a theoretical basis for the comprehensive utilization of sea buckthorn pomace resources.

Abstract:Objective This study aimed to solve the issue of poor nutritional and sensory quality of Gastrodia elata fermented by single strains, this study explored the improving effects of mixed strain fermentation on the nutritional quality and flavor of Gastrodia elata. Method Strains that could improve the flavor of Gastrodia elata liquid were screened, and the mixed strain fermentation process was optimized. The nutritional and flavor quality were compared between the Gastrodia elata liquids fermented by mixed strains and single strains.Result The optimized process was as follows: eight suitable strains (Weissella halotolerans, Lactobacillus farciminis, Lactiplantibacillus plantarum, Lactobacillus brevis, Lactobacillus mucosae reuteri, Pediococcus pentosaceus, Lactococcus acidophilus, and Enterococcus faecalis) were mixed in equal proportions, fermentation for 3 d, an inoculation volume fraction of 2.25%, and a fermentation temperature of 37 ℃. The red-yellow degree of the Gastrodia elata liquid fermented by mixed strains increased, the mass concentration of total acids was (4.81±0.39) g/mL and the mixed strain fermentation group showed the mass concentration of flavonoids (1.28±0.03) mg/mL. Compared with the control group, the DPPH free radical scavenging rate increasing by 47.96%, being significantly better than single strain fermentation. The mass concentrations of gastrodin and p-hydroxybenzyl alcohol were (434.53±14.11) μg/mL and (289.94±0.11) μg/mL, respectively. The mass concentration of polyphenols decreased by 6.70%, and that of soluble solids also decreased. The data indicated that mixed strain fermentation outperformed single strain fermentation. The analysis of the fermented Gastrodia elata liquid by an electronic nose showed that the response values of the W1W and W5S sensors decreased. The main off-flavor components were sulfides, terpenes, and nitrogen oxides, and the coordination effect of mixed strain fermentation on off-flavors was better, which was consistent with the results of sensory evaluation.Conclusion The mixed strain fermentation has a synergistic acid production effect, producing the Gastrodia elata liquid with a relatively high retention rate of polyphenols and flavonoids, an enhanced antioxidant activity, and improved flavor quality and demonstrating the value of popularization and application.