Aroma Components Research Articles

Correlation between pollen morphology, karyotype, floral pigments, and scent components and morphological classification of 15 species and hybrids of Syringa L.

In this paper, the pollen morphology characteristics, chromosome karyotype characteristics, floral pigments, and scents components of 15 species and hybrids of Syringa L. were obtained by means of scanning electron microscopy, root tips quash method, HPLC-MS, and GC-MS, and the 15 species and hybrids of Syringa L. were clustered separately with each index. Results show that the 15 species and hybrids of Syringa L. are clustered into four different groups separately by each index. In morphological taxonomy, S. microphylla Diels and S. microphylla 'ShuangJi', which belong to the Ser. Pubescentes family, original and hybrid species, most varieties of Ser. Syraega are basically cluster into the same group, which is consistent with morphological taxonomy. The findings indicate that the aforementioned four indicators are significantly related to the morphological classification of Syringa L. Among them, the clustering results of pollen morphology were the most consistent with morphological classification. The relationship between the above four aspects and the morphological classification of Syringa L. groups has not been reported in previous related researches, especially indicating the relationship between microscopic morphological indicators, specific physiological components and Syringa morphological classification. The research results have novelty, scientificity and comprehensiveness.

Synthesis of Esters Using Modified Waste Copper Slag: A Sustainable Approach for Waste Valorisation

ABSTRACTThe active sites of waste copper slag were moulded using BaO and used as a catalyst for the esterification reaction without solvent. Various concentrations of BaO were doped over the copper slag and investigated for the esterification of various model components of flavour, fragrance and biofuel. The catalyst was characterised by X‐ray photoelectron spectroscopy, attenuated total reflectance‐Fourier transform infrared spectroscopy, surface area analysis and X‐ray diffraction to examine the impact of BaO addition on the structural and morphological characteristics of BaOX/Cp‐Sl. BaO increases the grain size and enhances the BaOX/Cp‐Sl catalyst's activity and selectivity to flavour, fragrance and biofuel. The BaO2.5%/Cp‐Sl catalyst showed the maximum conversion of oleic acid to the methyl ester. The esterification of various commercially important substrates like geraniol, citronellol, menthol, isoamyl acetate, palmitic acid and waste cooking oil using a catalyst has been explained in detail. The kinetic study of the esterification has been explained with turnover number (TON) and turnover frequency (TOF). The mechanism pathway of the catalyst with various active sites of waste copper slag has been explained using adsorption studies.

Uncovering characteristic and enantiomeric distribution of volatile components in Huangshan Maofeng and Zhejiang baked green teas.

Huangshan Maofeng (HSMF) is a famous baked green tea from the Anhui Province of China, known for its "clean and fresh" flavor. Zhejiang, another major tea-producing province, focuses on the production of green teas. This study aimed to analyze the characteristic aroma components and specific enantiomeric distribution of significant chiral volatile compounds in HSMF and Zhejiang baked green tea (ZJ-BGT) with respect to their origins, cultivars and grades using stir bar sorptive extraction combined with non-targeted gas chromatography-mass spectrometry (GC-MS) and enantiomeric GC-MS approaches. Unique enantiomeric distributions were identified for 2-methylbutanal, γ-nonanolactone, jasmine lactone, α-pinene, cis-linalool oxide (furanoid), and linalool in HSMF and ZJ-BGT. Furthermore, the concentrations of hexanal, cis-3-hexenyl butyrate, geraniol, and the enantiomeric ratio of R-α-terpineol demonstrated a positive correlation with the HSMF grade. Additionally, S-jasmine lactone and R-γ-nonanolactone present in HSMF, along with S-linalool found in ZJ-BGT, significantly contribute to the flavor quality of their respective teas.

Inactivation activity and mechanism of high-voltage pulsed electric fields combined with antibacterial agents against Alicyclobacillus spp. in apple juice.

Alicyclobacillus spp. are crucial factors affecting the quality of fruit juice, so it is very important to control their contamination. In this study, the inactivation activity and mechanism of high-voltage pulsed electric fields (HVPEF) combined with antibacterial agents against Alicyclobacillus spp. in apple juice were investigated. It was found that under the optimal conditions of electric field strength 9.6kV/cm, treatment time 20min, frequency 1000Hz, and duty ratio 50%, HVPEF treatment could reduce bacteria by 1.89-4.76 log CFU/mL. Moreover, the inactivation activities of six antibacterial agents (propyl paraben, glycerol monocaprate, octyl gallate, heptyl paraben, nisin, carvacrol) alone and their combination with HVPEF were further investigated. The results showed that with the combined treatment, the minimum bactericidal concentrations of carvacrol, nisin, and heptyl paraben were reduced by >50% to 1mg/mL, 10IU/mL, and 0.02mg/mL, respectively. Based on this, the most resistant strain of A. acidoterrestris (DSM 3922) was identified to elucidate the inactivation mechanism. It was demonstrated that the antibacterial process could alter the permeability and fatty acid composition of the cell membrane, causing the cells to deform and shrink, leading to leakage of intracellular proteins, and also affect the synthesis of ROS and ATP, ultimately resulting in bacterial death. In addition, the various treatments had no significant effect on the soluble solids content, titratable acid, soluble sugar content, organic acids and aroma components of apple juice. The combination of HVPEF treatment and antibacterial agents could effectively maintain the quality of apple juice.

Development of a Komagataella phaffii cell factory for sustainable production of ( +)-valencene

BackgroundSesquiterpene ( +)-valencene is a characteristic aroma component from sweet orange fruit, which has a variety of biological activities and is widely used in industrial manufacturing of food, beverage and cosmetics industries. However, at present, the content in plant sources is low, and its yield and quality would be influenced by weather and land, which limit the supply of ( +)-valencene. The rapid development of synthetic biology has accelerated the construction of microbial cell factories and provided an effective alternative method for the production of natural products.ResultsIn this study, we first introduced the ( +)-valencene synthase into Komagataella phaffii by CRISPR/Cas9 system, and successfully constructed a ( +)-valencene producer with the initial yield of 2.1 mg/L. Subsequently, the ( +)-valencene yield was increased to 8.2 mg/L by fusing farnesyl pyrophosphate synthase with ( +)-valencene synthase using the selected ligation linker. High expression of key genes IDI1, tHMG1, ERG12 and ERG19 enhanced metabolic flux of MVA pathway, and the yield of ( +)-valencene was further increased by 27%. Besides, in-situ deletion of the promoter of ERG9 increased the yield of ( +)-valencene to 48.1 mg/L. Finally, we optimized the copy number of farnesyl pyrophosphate synthase and ( +)-valencene synthase fusion protein, and when the copy number reached three, the yield of ( +)-valencene achieved 173.6 mg/L in shake flask level, which was 82-fold higher than that of the starting strain CaVAL1.ConclusionsThe results obtained here suggest that K. phaffii has the potential to efficiently synthesize other terpenoids.

Effect of Different Harvest Time and Microwave Aging on Aroma Characteristics of Japanese Apricot Wine.

The aroma and nutrition of Japanese apricot fruit change continuously as the fruit ripens. The differences in fruit aroma and nutrition can affect the resulting wine, which is produced by steeping the Japanese apricot fruit. In this study, we used HS-SPME-GC-MS to examine the aromatic compositions of Japanese apricot fruit and wine produced from its macerated fruit at different levels of ripeness. We employed UPLC to examine the nutritional components such as organic acids, amygdalin, and phenolics to support the identification of the optimal ripening time. The microwave aging technology was also used to treat the steeped mume wine in order to explore the optimal conditions for microwave aging. We found that the optimum aroma period for the 'Nannong Longxia' fruit was 81 d after flowering. Furthermore, the changes in the aroma of mume wine after steeping in 65%vol base wine were closer to those of the fruit than those of 42%vol base wine, and the optimum period for the aroma of mume wine after steeping was the same as the fruit. Analysis showed that the optimum nutritional period for the fruit coincided with the optimum aromatic period. The best aromatic and nutritional components of the finished wine were obtained when the fruit was picked 81 days after flowering and the steeped mume wine was made with a 65%vol base wine. Microwave aging technology can significantly increase the proportion of esters in the aroma composition and reduce the content of acids. Among them, 500 W treatment at 50 °C for 80 min had the best effect on improving aroma components. These findings represent a theoretical foundation for exploring the aroma optimum period for Japanese apricot fruit and steeped mume wine, and for determining the optimum harvest periods for production.

The Scent of Lily Flowers: Advances in the Identification, Biosynthesis, and Regulation of Fragrance Components.

Lilies (Lilium spp.) are renowned for their diverse and captivating floral scents, which are highly valued both commercially and ornamentally. This review provides a comprehensive overview of recent advancements in the identification, biosynthesis, and regulation of fragrance components in lily flowers. Various volatile organic compounds (VOCs) that contribute to the unique scents of different lily species and cultivars, including terpenoids, benzenoids/phenylpropanoids, and fatty acid derivatives, are discussed. The release patterns of these compounds from different floral tissues and at different developmental stages are examined, highlighting the significant role of tepals. Detection methods such as gas chromatography-mass spectrometry (GC-MS) and sensory analysis are evaluated for their effectiveness in fragrance research. Additionally, the biosynthetic pathways of key fragrance compounds are explored, focusing on the terpenoid and benzenoid/phenylpropanoid pathways and the regulatory mechanisms involving transcription factors and environmental factors. This review also addresses the influence of genetic and environmental factors on fragrance production and proposes future research directions to enhance the aromatic qualities of lilies through selective genetic and breeding approaches. Emphasis is placed on the potential applications of these findings in the floral industry to improve the commercial value and consumer appeal of lily flowers.

Comparative bioactivity analysis of latex and water extract of Euphorbia gaillardotii: chemical profile, antioxidant capacity, effects on water quality, in vitro antimicrobial-cytotoxic activities, and in silico molecular docking studies.

The genus Euphorbia, belonging to the family Euphorbiaceae, represents a significant ethnobotanical heritage due to the diverse bioactive properties exhibited. In this study, the phytochemical composition and biological activities of latex and aerial parts of the water extract of Euphorbia gaillardotii were investigated. Phytochemical analyses were performed using gas chromatography-mass spectrometry and high-performance liquid chromatography techniques and total antioxidants, phenolics, sugars, organic acids, and aroma components were quantitatively determined. The effects of the test compounds on physicochemical parameters in aqueous media were evaluated by electrical conductivity, dissolved oxygen concentration, and pH measurements. Antimicrobial activity was evaluated on Gram-positive and Gram-negative bacteria and yeast strains using the disk diffusion method. The cytotoxic activity on the MCF-7 human breast cancer cell line was measured spectrophotometrically using the Cell Counting Kit-8 proliferation/apoptosis detection kit. The results showed that E. gaillardotii latex and aerial parts water extract significantly affected the physicochemical parameters of aqueous media, especially at high concentrations. The test substances displayed antimicrobial activity, with the latex-impregnated disks demonstrating larger inhibition zones than the aerial parts extract. The results showed that both the latex and extract treatments exhibited concentration-dependent effects on MCF-7 cell viability (P < 0.001). Furthermore, in silico docking analyses revealed a robust binding affinity of succinic acid, the most prevalent bioactive compound in the extract, towards the B-cell lymphoma 2 (Bcl-2) molecule, with a binding energy of -6.16 kcal/mol. This may be associated with the observed cytotoxicity. These results suggest that E. gaillardotii may be a valuable source for potential pharmacological applications.

The green method of enriching linseed oil with antioxidants as well as flavour and aroma components from herbs and spices

Abstract The influence of ultrasonic maceration on the extraction of antioxidant and flavour ingredients from cloves and sage directly into linseed oil was investigated. The ingredients were determined by high-performance liquid chromatography. The antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), total polyphenols, flavonoids, oxidation level, and organoleptic quality was examined. The clove macerate had the best antioxidant, flavour, and aroma properties (eugenol 406.9 mg/100 g, DPPH 86%, polyphenols 447.9 mg/100 g, and flavonoids 7.39 mg/100 g). Next in the ranking was sage macerate (carnosic acid 29.58 mg/100 g, carnosol 4.57 mg/100 g, DPPH 21%, polyphenols 109.6 mg/100 g, and flavonoids 5.54 mg/100 g). Ultrasonic extraction from appropriate plant species makes it possible to obtain, in a simple and ecological way, oil macerates rich in phytochemicals, which can be a functional addition to other food or cosmetic products.

Expression Analysis and Functional Validation of DcTPSb1 in Terpene Synthesis of Dendrobium chrysotoxum.

Terpenes are critical components of the floral fragrance component in Dendrobium chrysotoxum, synthesized by terpene synthase (TPS). Analysis of the D. chrysotoxum genome and transcriptional data revealed that the gene DcTPSb1 was significantly up-regulated during flowering periods, showing a strong correlation with the accumulation of aromatic monoterpenes in the floral components of Dendrobium chrysotoxum. Consequently, the DcTPSb1 gene was selected for further analysis. DcTPSb1 exhibited elevated expression levels in flowers among four organs (roots, stems, leaves, flowers) of D. chrysotoxum, with the highest expression observed during the blooming phase, which aligned with the accumulation of volatile terpenes during flowering. DcTPSb1, located in the chloroplasts, was identified as a member of the TPS-b subfamily associated with monoterpenes synthesis, showing close phylogenetic relationships with homologous proteins in related plant species. An analysis of the promoter region of DcTPSb1 indicated that it may be regulated by methyl jasmonate (MeJA) responsiveness. Functionally, DcTPSb1 was shown to catalyze the conversion of geranyl diphosphate (GPP) to linalool, ocimene, and (-)-α-pinitol in vitro. Overexpression of DcTPSb1 in tobacco resulted in a significant increase in terpenoid release during the blooming stage; however, the up-regulated substances did not include their catalytic products. The classification of DcTPSb1 as a terpene synthase capable of producing multiple products provides valuable insights into the complex biosynthesis of terpenes in orchids. These findings enhance our understanding of the functional diversity of DcTPSb1 and the processes involved in terpene biosynthesis in orchids.

Characterization of volatile compounds profiles and identification of key volatile and odor-active compounds in 40 sweetpotato (Ipomoea Batatas L.) varieties

Sweetpotato with different flesh colors exhibits significant differences in flavor. Nevertheless, research on the identification of the key aromatic compounds in sweetpotato is scarce. Therefore, 40 primary sweetpotato varieties with different flesh colors were analyzed by HS-SPME/GC–MS to characterize the volatile compounds. A total of 121 volatile compounds were detected, with aldehydes, furans and terpenes being the most abundant components. Additionally, 35 compounds were identified as the key aromatic compounds by OAV > 1, of which 17 were found in all varieties and hence considered as the major components of sweetpotato aroma. Further analysis demonstrated that the yellow-fleshed sweetpotato had the strongest aroma, which was presumed due to the aldehydes like (E,E)-2,4-heptadienal, nonanal, (E,E)-2,4-decadienal,etc. that were produced during the degradation of unsaturated fatty acids. The unique sweety and floral aroma of orange-fleshed sweetpotato might be attributed to apocarotenoid volatiles (trans-beta-ionone, β-ionone, geranylacetone, etc.), the derivates of carotenoids. The purple-fleshed sweetpotato exhibited weak aroma with a significantly high terpenoids concentration. Overall, these findings may be the main reason for the different aromas of different colored sweetpotatoes and provides insights into sweetpotato aroma and a theoretical basis for improving sweetpotato aroma.

Analysis of the Changes in Volatile Components During the Processing of Enshi Yulu Tea.

Volatile constituents are critical to the flavor of tea, but the changes in Enshi Yulu tea during the processing have not been clearly understood. Using headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS) techniques, we analyze the aroma components of Enshi Yulu tea and changes in them during the processing stages. In total, 242 volatile compounds were identified. From fresh leaves to the shaping process in tea production, there are significant decreases in overall aroma substances, followed by increases after drying. Linalool is the dominant aroma component in Enshi Yulu tea, with a proportion of 12.35%, followed by compounds such as geraniol (7.41%), 2,6-dimethyl-5-heptene (6.93%), phenylmethanol (5.98%), isobutyl acetate (4.16%), hexan-1-ol (3.95%), 2-phenylacetaldehyde (3.80%), and oct-1-ene-3-ol (3.34%). The number of differential volatile components varied by production stage, with 20 up- and 139 down-regulated after steaming, 24 down-regulated after rolling, 60 up- and 51 down-regulated after shaping, and 68 up- and 13 down-regulated after drying. Most variation in expression occurred because of steaming, and the least during the rolling stage. PLS-DA analysis revealed significant differences in aroma components throughout processing and the identification of 100 compounds with higher relative contents, with five distinct change trends. Phenylmethanol, phenylacetaldehyde, (2E)-non-2-enal, oct-1-ene-3-ol, and cis-3-hexenyl hexanoate could exert a profound influence on the overall aroma quality of Enshi Yulu tea during processing. The results offer a scientific foundation and valuable insights for understanding the volatile composition of Enshi Yulu tea and its changes during the processing.

Fermentation of cigar tobacco leaves with citrus flavonoids: changes in chemical, microbiological, and sensory properties

IntroductionFermentation plays a significant role in improving the quality of cigar tobacco leaves. Particularly, fermentation with characteristic additives has been identified as an effective approach to enhance the fermentation process. The objective of this study was to develop new additives and investigate their influence on cigar tobacco leaves.MethodsThe active ingredients extracted from three citrus species were obtained by ultrasonic-assisted extraction followed by solid phase purification. The effects of these ingredients as fermentation additives on the primary chemical components, microbial communities, and sensory quality of cigar tobacco leaves were subsequently analyzed.ResultsResults showed that: (1) Flavonoids were the main components of the prepared citrus extracts. (2) The addition of citrus extracts resulted in a reduced content of amino acids, oxalic acid, and unsaturated fatty acids in cigar tobacco leaves, while increasing the content of citric acid. Besides, the total amount of aroma substances in cigar tobacco leaves increased by 38.15% with the addition of citrus extracts, with notable enhancements in the levels of D-limonene, β-dihydroionone, dihydroactiniolactone, and other representative aroma components. (3) The addition of citrus extracts promoted the succession of the microbial community in cigar tobacco leaves and promoted the enrichment of Pseudomonas and Corynebacterium. (4) The addition of citrus extracts effectively reduced the irritation and improved the aroma richness of cigar tobacco leaves.DiscussionIn this study, the influence of citrus-derived active ingredients on cigar quality was systematically analyzed, providing a reference for the development of characteristic fermentation additives for cigars and the extension of cigar quality enhancement technologies.

Debittering and Improving Flavour of Enzymatic Soy Protein Hydrolysate Using the Maillard Reaction of Arabinose

ABSTRACTThe optimum reaction conditions (temperature 95°C, pH 6.5, time 70 min and cysteine 0.2 g) and significant influence factors were found by response surface model (RSM) experimentation to reduce bitterness and increase overall acceptability of soybean protein hydrolysate (SPH) using the Maillard reaction of arabinose. Three reaction products of different response values and sensory profiles were selected to be investigated further. Fourier transform infrared (FTIR) spectra and UV 294 and 420 nm analyses revealed their different extents of the Maillard reaction. Partial least squares regression analysis (PLSR) for free amino acids and molecular weight distribution and aroma compounds versus the used reaction conditions of the three samples suggested that reaction conditions of higher pH plus less Cys could cause more bitter amino acids (Leu, Val) and 500–1000 Da peptides, while those of more cysteine plus longer times under low temperatures benefitted formation of the umami amino acid of glutamic acid and &gt; 1000 Da peptides. In particular, the reaction conditions of higher temperatures and more cysteine would generate more volatile compounds with roasted and meaty aromas unfavourable for overall acceptability. Furthermore, Pearson coefficient analysis revealed the key taste and aroma components and exposed that the fatty and caramel aromas contributed positively to overall acceptability. This study can provide references for debittering and improving the flavour of SPH.

Characteristic volatile compounds of white tea with different storage times using E-nose, HS-GC-IMS, and HS-SPME-GC-MS.

This paper studied the influence of storage duration on the flavor profile of white tea in detail, with samples produced between 2020 and 2023. Sensory evaluation was performed by quantitative descriptive analysis (QDA), followed by an in-depth aroma components analysis employing an electronic nose (E-nose), headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The QDA findings revealed a gradual transition in the flavor profile of white tea during storage, shifting from sweet, fruity, and floral to more herbal and stale characteristics. E-nose could well distinguish white tea with different storage times. A total of 55 and 53 volatile compounds were identified by HS-GC-IMS and HS-SPME-GC-MS, respectively. The orthogonal partial least squares-discriminant analysis models, based on HS-GC-IMS (R2Y=0.998, Q2=0.987) and HS-SPME-GC-MS (R2Y=0.984, Q2=0.993), successfully distinguished white tea samples stored for different storage times. Furthermore, 14 and 8 key compounds were screened based on the double variable criterion of one-way analysis of variance (p<0.05) and variable importance in projection (VIP) >1.2, and their content changes were also compared. It is the gradual decrease of important aroma components such as 2-hexenal, 2-methyl-2-hepten-6-one, linalool, and geraniol, which are positively correlated with sweet, fruity, and floral aromas, and the gradual increase of hexanoic acid, thiophene, propanoic acid, dimethyl disulfide, and borneyl acetate, which are positively correlated with herbal and stale flavor, that leads to the changes in flavor and aroma of white tea during storage. The results of the study provided a reference for elucidating the aroma characteristics of white tea at different storage times as well as a theoretical basis for the quality control of white tea.

Comparative Analysis of Flavour Profile and Aroma Components of Shanxi Aged Vinegar From China

ABSTRACTShanxi aged vinegar (SAV) is a traditional vinegar produced mainly in southern China from rice and wheat, undergoing prolonged fermentation for maturation, which distinguishes it from other vinegar. To explore its flavour, a selection of 12 SAV varieties was meticulously chosen for in‐depth aroma analysis. Sensory analysis and electronic nose (E‐nose) were used to compare flavour profiles. Volatile components were extracted via liquid–liquid extraction (LLE) with solvent‐assisted flavour evaporation (SAFE), analysed by gas chromatography–mass spectrometry (GC–MS) and gas chromatography olfactometry‐mass spectrometry (GC‐O‐MS). The results revealed 145 volatile compounds, predominantly acids, alcohols, ketones and heterocycles, with acids as the most prevalent (ranging from 960.17 to 1231.78 μg/mL). Additionally, 90 aroma‐active compounds were identified, notably acetic acid, furfuryl alcohol, 2,3‐dimethylpyrazine, lactic acid, phenol, propyl acetate, ethyl propionate and 2(5H)‐furanone. Accordingly, a flavour wheel was constructed highlighting dominant volatile components, featuring acidic, alcohol, tangerine peel‐like and yeasty aromas. Partial least squares regression (PLSR) analysis showed that the acidity note in SAV positively correlates with acetic acid, isovaleric acid, hexanoic acid, phenethyl alcohol and butyric acid. Understanding the flavour composition of SAV provides vital insight for flavour research and product quality control.

Encapsulation Applications and Current Studies in Food Technology

Encapsulation, as a method that provides controlled release and stability of food components, cells, enzymes and different substances in protein or carbohydrate-based mini capsules. In other words, it can also be defined as keeping the active material to be used in nano, micro or millimeter sized coating materials. The encapsulation method has great importance and potential for the food industry. In this method, it is aimed to mask undesirable taste and aroma components, to protect the bioactive compounds used from external factors, to increase the utilization of their functionality, and to control their release during shelf life. Various components such as some valuable food components, essential oils, lipids, aromatic hydrocarbons, vitamins, flavourings, enzymes, colourants, microorganisms, and microbial metabolites can be encapsulated using different methods. In this review, the encapsulation process types, coating materials, application areas in food technology and current studies in the field were investigated in order to understand the method. In the review, general information is given for encapsulation technology and a brief literature summary is intended for new studies to be conducted.

Fatty acid composition and key aroma components of two different cold pressed sesame oils

Fatty acid composition and key aroma components of two different cold pressed sesame oils

Application of ultrasonic pretreatment on fermentation of jujube juice by Lactobacillus plantarum: investigation on physicochemical and volatile aroma components

Application of ultrasonic pretreatment on fermentation of jujube juice by Lactobacillus plantarum: investigation on physicochemical and volatile aroma components

Widely targeted metabolomics and SPME-GC-MS analysis revealed the quality characteristics of non-volatile/volatile compounds in Zheng'an Bai tea.

As albino tea under the geographical protection of agricultural products, Zheng'an Bai tea is not only rich in amino acids, polyphenols and other beneficial components for the human body, but also its leaf color will turn green as the temperature gradually rises, thus causing changes in the quality characteristics of tea leaves. However, these changing characteristics have not yet been revealed. In-depth quality analysis was carried out on the fresh leaves of Zheng'an Bai tea at four different developmental stages and four samples from the processing stage through extensive targeted metabolomics and SPME-GC-MS analysis. In this study, a total of 573 non-volatile metabolites were detected from the fresh leaves and processing samples of Zheng'an Bai tea, mainly including 96 flavonoids, 75 amino acids, 56 sugars and alcohols, 48 terpenoids, 46 organic acids, 44 alkaloids, and 39 polyphenols and their derivatives. In fresh leaves, the most significant differential metabolites (VIP > 1, p < 0.05) among different samples mainly include substances such as ethyl gallate, theaflavin, isovitexin and linalool, while the main differential metabolites of samples in the processing stage include alkaloids, polyphenols and flavonoids such as zarzissine, methyl L-Pyroglutamate, theaflavin 3,3'-digallate, euscaphic acid and ethyl gallate. Overall, substances such as sugars and alcohols, alkaloids and polyphenols show the greatest differences between fresh leaves and the processing process. Meanwhile, 97 kinds of volatile metabolites were detected in these samples, most of which had a higher content in the fresh leaves. Moderate spreading is conducive to the release of the aroma of tea leaves, but fixation causes a sharp decrease in the content of most volatile metabolites. Ultimately, 9 volatile substances including geraniol, linalool, nerolidol, jasmone, octanal, 1-Nonanal, heptaldehyde, methyl salicylate and 1-Octen-3-ol were identified as the key aroma components (OAV >1) of Zheng'an Bai tea. In conclusion, this study has for the first time comprehensively revealed the quality change characteristics of fresh leaves at different developmental stages and during the processing of Zheng'an Bai tea, and provided a foundation for further process improvement.