A comparative study on the nutritional composition, protein structure and effects on gut microbiota of 5 fermented soybean products (FSPs).

In this study, we conducted an analysis of the differences in nutrient composition and protein structure among various fermented soybean products and their impacts on the gut microbiota of rats. Conventional physicochemical analysis was employed to analyze the fundamental physicochemical composition of the samples. Additionally, we utilized high-performance liquid chromatography and ELISA techniques to quantify the presence of antinutritional compounds. Fourier infrared spectroscopy was applied to delineate the protein structure, while 16 s rRNA gene sequencing was conducted to evaluate alterations in gut microbiota abundance. Subsequently, KEGG was utilized for metabolic pathway analysis. Our findings revealed that fermented soybean products improved the nutritional profile of soybeans. Notably, Douchi exhibited the highest protein content at 52.18 g/100 g, denoting a 26.58 % increase, whereas natto showed a 24.98 % increase. Douchi and natto demonstrated the most substantial relative amino acid content, comprising 50.86 % and 49.04 % of the total samples, respectively. Moreover, the levels of antinutritional factors markedly decreased post-fermentation. Specifically, the α-helix content in doujiang decreased by 13.87 %, while the random coil content in soybean yogurt surged by 132.39 %. Rats that were fed FSP showcased notable enhancements in gut microbiota and associated metabolic pathways. A strong correlation was observed between nutrient composition, protein structure, and gut microbiota abundance. This study furnishes empirical evidence supporting the heightened nutritional attributes of FSPs.

Enhancing the nutritional and bioactive benefits of faba bean flour by combining preprocessing and thermoplastic extrusion: A comprehensive study on digestion-resistant peptides.

This research assessed how three preprocessing techniques [soaking (S), soaking and reconstitution (SR), and soaking and dehulling (SD)] impact the protein digestibility and bioactivity of faba bean flours when combined with thermoplastic extrusion. Samples were compared against a control (C) of extruded faba bean flour without preprocessing. Applying preprocessing techniques followed by extrusion diminished antinutrient levels while enhancing protein hydrolysis and in vitro bioactivity in higher extent compared to C. Specifically, SD combined with extrusion was the most effective, achieving an 80% rate of protein hydrolysis and uniquely promoting the release of gastric digestion-resistant proteins (50-70 kDa). It also resulted in the highest release of small peptides (<3kDa, 22.51%) and free amino acids (15.50%) during intestinal digestion. Moreover, while all preprocessing techniques increased antioxidant (ABTS radical-scavenging), antidiabetic, and anti-hypertensive activities, SD extruded flour displayed the highest levels of dipeptidyl peptidase inhibition (DPP-IVi, IC50=13.20 µg/mL), pancreatic α-amylase inhibition (IC50=8.59 mg/mL), and angiotensin I-converting enzyme inhibition (ACEi, IC50=1.71 mg protein/mL). As a result, it was selected for further peptide and in silico bioactive analysis. A total of 24 bioactive peptides were identified in intestinal digests from SD extruded flour, all with potential DPP-IVi and ACEi activities, and six were also predicted as antioxidant peptides. VIPAGYPVAIK and GLTETWNPNHPEL were highlighted as resistant bioactive peptides with the highest antidiabetic and antioxidant potential. Our findings demonstrated that combining preprocessing (particularly SD) and thermoplastic extrusion enhances protein digestibility in faba beans and promotes the release of beneficial bioactive peptides in the intestine.

Two Debaryomyces hansenii strains as starter cultures for improving the nutritional and sensory quality of dry-cured pork belly.

Dry-cured meat products are gaining attention owing to their distinctive sensory characteristics and health benefits. In this study, two Debaryomyces hansenii strains were investigated for their potential as starter cultures for dry-cured pork belly products. After preliminary screening, these D. hansenii strains, namely, S20 and S26, both exhibiting with excellent aroma-producing capacity in a dry-cured meat model, were selected as single-strain starter cultures. For comparison, a non-inoculated control was also evaluated. In S20- and S26-inoculated pork belly, yeast dominated the microbiota and improved microbiological safety by suppressing Enterobacteriaceae growth. Compared with the non-inoculated control, the inoculated pork belly yielded higher hardness and redness (a*) values. Starter culture inoculation accelerated proteolysis in pork belly, improving the content of total free amino acids (TFFAs) and several essential free amino acids (Thr, Val, Met, Ile, Leu, and Phe) at the end of processing. Moreover, the inoculated samples exhibited higher levels of fat oxidation-derived aldehydes as well as esters, acids, alcohols and other compounds than the non-inoculated control at the end of the 95-day ripening period. Overall, these findings provide new insights into the application of D. hansenii isolated from dry-cured ham to dry-cured pork belly.

Exploring free amino acid profiles in Crimean-Congo hemorrhagic fever patients: Implications for disease progression.

This study investigated the intricate interplay between Crimean-Congo hemorrhagic fever virus infection and alterations in amino acid metabolism. The primary aim is to elucidate the impact of Crimean-Congo hemorrhagic fever (CCHF) on specific amino acid concentrations and identify potential metabolic markers associated with viral infection. One hundred ninety individuals participated in this study, comprising 115 CCHF patients, 30 CCHF negative patients, and 45 healthy controls. Liquid chromatography-tandem mass spectrometry techniques were employed to quantify amino acid concentrations. The amino acid metabolic profiles in CCHF patients exhibit substantial distinctions from those in the control group. Patients highlight distinct metabolic reprogramming, notably characterized by arginine, histidine, taurine, glutamic acid, and glutamine metabolism shifts. These changes have been associated with the underlying molecular mechanisms of the disease. Exploring novel therapeutic and diagnostic strategies addressing specific amino acids may offer potential means to mitigate the severity of the disease.

Revealing core functional microorganisms in the fermentation process of Qicaipaojiao (Capsicum annuum L.) based on microbial metabolic network.

Paojiao, a typical Chinese traditional fermented pepper, is favored by consumers for its unique flavor profile. Microorganisms, organic acids, amino acids, and volatile compounds are the primary constituents influencing the development of paojiao's flavor. To elucidate the key flavor compounds and core microorganisms of Qicaipaojiao (QCJ), this study conducted a comprehensive analysis of the changes in taste substances (organic acids and amino acids) and volatile flavor compounds during QCJ fermentation. Key flavor substances in QCJ were identified using threshold aroma value and odor activity value and the core microorganisms of QCJ were determined based on the correlation between dominant microorganisms and the key flavor substances. During QCJ fermentation, 16 key taste substances (12 free amino acids and 4 organic acids) and 12 key aroma substances were identified. The fermentation process involved 10 bacteria and 7 fungal genera, including Lactiplantibacillus, Leuconostoc, Klebsiella, Pichia, Wickerhamomyces, and Candida. Correlation analysis revealed that the core functional microorganisms encompassed representatives from 8 genera, including 5 bacterial genera (Lactiplantibacillus, Weissella, Leuconostoc, Klebsiella, and Kluyvera) and 3 fungal genera (Rhodotorula, Phallus, and Pichia). These core functional microorganisms exhibited significant correlations with approximately 70 % of the key flavor substances (P < 0.05). This study contributes to an enhanced understanding of flavor formation mechanisms and offers valuable insight into flavor quality control in food fermentation processes.

Efficacy of amino acids in sports nutrition- review of clinical evidences.

The efficacy of amino acids as popular sports supplements has triggered debates, with their impact on athletic performance varying across sports disciplines due to diversity and heterogeneity in clinical trials. This review evaluates the ergogenic potential of amino acids, by critical appraisal of results of clinical trials of Branched chain amino acids (BCAAs), arginine, glutamine, citrulline, ß-alanine, and taurine, performed on elite sportsmen from various land and water sports. Clinical trials reviewed here confirm notable physiological benefits thereby supporting the claim that BCAA, citrulline and arginine in various doses can have positive effects on endurance and overall performance in sportsperson. Furthermore, results of clinical trials and metabolomic studies indicate that in future it would be more beneficial to design precise formulations to target the requirement of specific sports. For instance, some combinations of amino acids may be more suitable for long term endurance and some others may be suitable for short burst of excessive energy. The most important insights from this review are the identification of three key areas where research is urgently needed: a) Biomarkers that can identify the physiological end points and to distinguish the specific role of amino acid as anti-fatigue or reducing muscle soreness or enhancing energy b) In-depth sports-wise clinical trials on elite sportsperson to understand the ergogenic needs for the particular sports c) Design of precision formula for similar types of sports instead of common supplements.

Differential accumulation patterns of flavor compounds in Longjing 43 and Qunti fresh leaves and during processing responding to altitude changes.

Variations in cultivars and cultivation altitudes have significant impacts on tea flavour compounds however lack of comprehensive understanding. This study provided insights into differential accumulation of crucial flavour compounds in response to cultivars, cultivation altitudes, and processing. Twelve flavonoids (262.4 âˆ¼ 275.4 mg•g-1) and 20 amino acids (AAs) (56.5 âˆ¼ 64.8 mg•g-1) were comparative analyzed in 'Longjing 43' and 'Qunti' fresh leaves harvested at low (80 m, LA) and high (500 m, HA) altitudes. Additionally, an in-depth correlation unravelling of 31 alkaloids, 25 fatty acids, 31 saccharides, 8 organic acids, and 7 vitamins and flavonoids/AAs during green tea (GT) and black tea (BT) processing was performed. Enhenced flavonoid accumulation alongside higher AAs and saccharides in HA GT promoted a sweet/mellow flavour. Abundant flavonoids, AAs, and saccharides derivates in LA BT gave rise to a sweet aftertaste. The study presents an integrated illustration of major flavour compounds' differential accumulation patterns and their interrelations, providing new insights into the influence of cultivation conditions on tea flavour.

The impact of extraction processes on the physicochemical, functional properties and structures of bamboo shoot protein.

This study aimed to extract bamboo shoot protein (BSP) using different extraction approaches and compare their functional and physicochemical properties with commercial protein ingredients, including whey protein and soy protein isolates. The extraction methods including alkali extraction (AE), salt extraction (SE), and phosphate-aided ethanol precipitation (PE) were used. An enhanced solvent extraction method was utilized in combination, resulting in a significant improvement in the protein purity, which reached 81.59 %, 87.36 %, and 67.08 % respectively. The extraction methods had significant effects on the amino acid composition, molecular weight distribution, and functional properties of the proteins. SE exhibited the best solubility and emulsification properties. Its solubility reached up to 93.38 % under alkaline conditions, and the emulsion stabilized by SE with enhanced solvent extraction retained 60.95 % stability after 120 min, which could be attributed to its higher protein content, higher surface hydrophobicity, and relative more stable and organized protein structure. All three BSP samples demonstrated better oil holding capacity, while the SE sample showed comparable functional properties to soy protein such as foaming and emulsifying properties. These findings indicate the potential of BSP as an alternative plant protein ingredient in the food industry.

Amino acid analogues provide multiple plausible pathways to prebiotic peptides.

Prebiotic peptide synthesis has consistently been a prominent topic within the field of the origin of life. While research predominantly centres on the 20 classical amino acids, the synthesis process encounters significant thermodynamic barriers. Consequently, amino acid analogues are being explored as potential building blocks for prebiotic peptide synthesis. This review delves into the pathway of polypeptide formation, identifying specific amino acid analogues that might have existed on early Earth, potentially participating in peptide synthesis and chemical evolution. Moreover, considering the complexity and variability of the environment on early Earth, we propose the plausibility of coevolution between amino acids and their analogues.

Comparative studies of hair shaft components between healthy and diseased donors.

Globally, the rapid aging of the population is predicted to become even more severe in the second half of the 21st century. Thus, it is expected to establish a growing expectation for innovative, non-invasive health indicators and diagnostic methods to support disease prevention, care, and health promotion efforts. In this study, we aimed to establish a new health index and disease diagnosis method by analyzing the minerals and free amino acid components contained in hair shaft. We first evaluated the range of these components in healthy humans and then conducted a comparative analysis of these components in subjects with diabetes, hypertension, androgenetic alopecia, major depressive disorder, Alzheimer's disease, and stroke. In the statistical analysis, we first used a student's t test to compare the hair components of healthy people and those of patients with various diseases. However, many minerals and free amino acids showed significant differences in all diseases, because the sample size of the healthy group was very large compared to the sample size of the disease group. Therefore, we attempted a comparative analysis based on effect size, which is not affected by differences in sample size. As a result, we were able to narrow down the minerals and free amino acids for all diseases compared to t test analysis. For diabetes, the t test narrowed down the minerals to 15, whereas the effect size measurement narrowed it down to 3 (Cr, Mn, and Hg). For free amino acids, the t test narrowed it down to 15 minerals. By measuring the effect size, we were able to narrow it down to 7 (Gly, His, Lys, Pro, Ser, Thr, and Val). It is also possible to narrow down the minerals and free amino acids in other diseases, and to identify potential health indicators and disease-related components by using effect size.

A real-world cross-sectional study evaluating the role of an oral amino acid-based supplement in nutrient intake by preschoolers on a cow's milk elimination diet.

INTRODUCTION AND OBJECTIVES: Food allergy has several negative nutritional consequences and may persist beyond the first year of lives. This study aimed to assess the role of a complete oral amino acid-based supplement in the diet of children on cow's milk protein elimination diet because of food allergy. MATERIALS AND METHODS: This study included two groups of children aged 1-5 years paired by age and socioeconomic status: (1) study group, on cow's milk protein elimination diet plus an oral amino acid-based supplement, and (2) control group, on cow's milk protein elimination diet. Sociodemographic, clinical, anthropometric, and dietary data were obtained through online interviews. Two 24-h dietary recalls were collected on nonconsecutive days. Both groups comprised mostly boys. RESULTS: The study group presented lower values of body mass index. The frequency of feeding difficulties was similar between groups. The study group had a higher intake of energy, protein, carbohydrates, calcium, iron, zinc, phosphorus, magnesium, copper, selenium, vitamins D, E, B1, B2, B6, and B12, niacin, and folic acid compared to the control group. A higher proportion of children in the study group had adequate intake according to the recommendations made for energy, carbohydrates, iron, phosphorus, selenium, vitamins A, D, E, B1, B2, and B6, and folic acid. CONCLUSIONS: The use of a complete oral amino acid-based supplement has a positive effect on the diet quality of preschoolers on cow's milk elimination diet because of food allergy, promoting higher intake of energy, calcium, vitamin D, and other essential nutrients.

Amino acid bites: Microbial snacking influences host metabolism.

The gut microbiota has the capacity to metabolize food-derived molecules. In this issue of Cell Host & Microbe, Li et al. explore how some bacterial species of the gut microbiota can deplete amino acids in the gut lumen, modulating the amino acid landscape and energy metabolism of the host.

Characterization of Key Aroma Compounds and Main Contributing Amino Acids in Hot-Pressed Oil Prepared from Various Peanut Varieties.

The production of peanut oil in the industrial sector necessitates the utilization of diverse raw materials to generate consistent batches with stable flavor profiles, thereby leading to an increased focus on understanding the correlation between raw materials and flavor characteristics. In this study, sensory evaluations, headspace solid-phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV) calculations, and correlation analysis were employed to investigate the flavors and main contributing amino acids of hot-pressed oils derived from different peanut varieties. The results confirmed that the levels of alcohols, aldehydes, and heterocyclic compounds in peanut oil varied among nine different peanut varieties under identical processing conditions. The OAVs of 25 key aroma compounds, such as methylthiol, 3-ethyl-2,5-dimethylpyrazine, and 2,3-glutarone, exceeded a value of 1. The sensory evaluations and flavor content analysis demonstrated that pyrazines significantly influenced the flavor profile of the peanut oil. The concentrations of 11 amino acids showed a strong correlation with the levels of pyrazines. Notably, phenylalanine, lysine, glutamic acid, arginine, and isoleucine demonstrated significant associations with both pyrazine and nut flavors. These findings will provide valuable insights for enhancing the sensory attributes of peanut oil and selecting optimal raw peanuts for its production.

Reactive Force Field Molecular Dynamics Investigation of NH3 Generation Mechanism during Protein Pyrolysis Process.

The mechanism of ammonia formation during the pyrolysis of proteins in biomass is currently unclear. To further investigate this issue, this study employed the AMS 2023.104 software to select proteins (actual proteins) as the model compounds and the amino acids contained within them (assembled amino acids) as the comparative models. ReaxFF molecular dynamics simulations were conducted to explore the nitrogen transformation and NH3 generation mechanisms in three-phase products (char, tar, and gas) during protein pyrolysis. The research results revealed several key findings. Regardless of whether the model compounds are actual proteins or assembled amino acids, NH3 is the primary nitrogen-containing product during pyrolysis. However, as the temperature rises to higher levels, such as 2000 K and 2500 K, the amount of NH3 decreases significantly in the later stages of pyrolysis, indicating that it is being converted into other nitrogen-bearing species, such as HCN and N2. Simultaneously, we also observed significant differences between the pyrolysis processes of actual proteins and assembled amino acids. Notably, at 2000 K, the amount of NH3 generated from the pyrolysis of assembled amino acids was twice that of actual proteins. This discrepancy mainly stems from the inherent structural differences between proteins and amino acids. In proteins, nitrogen is predominantly present in a network-like structure (NH-N), which shields it from direct external exposure, thus requiring more energy for nitrogen to participate in pyrolysis reactions, making it more difficult for NH3 to form. Conversely, assembled amino acids can release NH3 through a simpler deamination process, leading to a significant increase in NH3 production during their pyrolysis.

Exploring the Key Amino Acid Residues Surrounding the Active Center of Lactate Dehydrogenase A for the Development of Ideal Inhibitors.

Lactate dehydrogenase A (LDHA) primarily catalyzes the conversion between lactic acid and pyruvate, serving as a key enzyme in the aerobic glycolysis pathway of sugar in tumor cells. LDHA plays a crucial role in the occurrence, development, progression, invasion, metastasis, angiogenesis, and immune escape of tumors. Consequently, LDHA not only serves as a biomarker for tumor diagnosis and prognosis but also represents an ideal target for tumor therapy. Although LDHA inhibitors show great therapeutic potential, their development has proven to be challenging. In the development of LDHA inhibitors, the key active sites of LDHA are emphasized. Nevertheless, there is a relative lack of research on the amino acid residues around the active center of LDHA. Therefore, in this study, we investigated the amino acid residues around the active center of LDHA. Through structure comparison analysis, five key amino acid residues (Ala30, Met41, Lys131, Gln233, and Ala259) were identified. Subsequently, the effects of these five residues on the enzymatic properties of LDHA were investigated using site-directed mutagenesis. The results revealed that the catalytic activities of the five mutants varied to different degrees in both the reaction from lactic acid to pyruvate and pyruvate to lactic acid. Notably, the catalytic activities of LDHAM41G and LDHAK131I were improved, particularly in the case of LDHAK131I. The results of the molecular dynamics analysis of LDHAK131I explained the reasons for this phenomenon. Additionally, the optimum temperature of LDHAM41G and LDHAQ233M increased from 35 °C to 40 °C, whereas in the reverse reaction, the optimum temperature of LDHAM41G and LDHAK131I decreased from 70 °C to 60 °C. These findings indicate that Ala30, Met41, Lys131, Gln233, and Ala259 exert diverse effects on the catalytic activity and optimum temperature of LHDA. Therefore, these amino acid residues, in addition to the key catalytic site of the active center, play a crucial role. Considering these residues in the design and screening of LDHA inhibitors may lead to the development of more effective inhibitors.

Comparing the biological activity and composition of Cerebrolysin with other peptide preparations.

Neurological disorders, ranging from acute forms such as stroke and traumatic brain injury to neurodegenerative diseases like dementia, are the leading cause of disability-adjusted life years (DALYs) worldwide. A promising approach to address these conditions and promote nervous system regeneration is the use of the neuropeptide preparation Cerebrolysin, which has been shown to be effective in both clinical and preclinical studies. Despite claims of similar clinical efficacy and safety by several peptide preparations, concerns regarding their generic composition and efficacy have been previously raised. Based on these reports, we analyzed the peptide composition and neurotrophic activity of several peptide preparations allegedly similar to Cerebrolysin and approved in some countries for treating neurological diseases. Our results demonstrate that these preparations lack relevant biological activity and that the peptide composition is significantly different from Cerebrolysin. peptide.

Seleno-amino Acid Metabolism Reshapes the Tumor Microenvironment: from Cytotoxicity to Immunotherapy.

Selenium (Se) is an essential trace element for biological processes. Seleno-amino acids (Se-AAs), known as the organic forms of Se, and their metabolic reprogramming have been increasingly recognized to regulate antioxidant defense, enzyme activity, and tumorigenesis. Therefore, there is emerging interest in exploring the potential application of Se-AAs in antitumor therapy. In addition to playing a vital role in inhibiting tumor growth, accumulating evidence has revealed that Se-AA metabolism could reshape the tumor microenvironment (TME) and enhance immunotherapy responses. This review presents a comprehensive overview of the current progress in multifunctional Se-AAs for antitumor treatment, with a particular emphasis on elucidating the crosstalk between Se-AA metabolism and various cell types in the TME, including tumor cells, T cells, macrophages, and natural killer cells. Furthermore, novel applications integrating Se-AAs are also discussed alongside prospects to provide new insights into this emerging field.

Dynamic alterations of flavor, functional nutrients, and microbial community during fermentation of different animal milk kefirs.

Kefir is a traditional dairy beverage, usually made from cow or goat milk fermented with kefir grains, and has many health benefits. To elucidate the fermentation patterns of animal milk kefirs during the fermentation process and find the optimal milk types, cow, camel, goat, and donkey milk were fermented with kefir grains for 0, 1, 3, 5, and 7 days. Volatile and non-volatile metabolites and microbial changes were dynamically monitored. The results showed that volatile flavor substances were massively elevated in four kefirs on days 1-3. Lipids and carbohydrates gradually decreased, while amino acids, small peptides, and tryptophan derivatives accumulated during fermentation in four kefirs. Besides, four kefirs had similar alterations in Lactobacillus and Acetobacter, while some distinctions existed in low-abundance bacteria. Association analysis of microorganisms and volatile and non-volatile metabolites also revealed the underlying fermentation mechanism. This study found that appropriately extending the fermentation time contributed to the accumulation of some functional nutrients. Furthermore, goat and donkey milk could be the better matrices for kefir fermentation.

Contribution of mono- and co-culture of Pseudomonas paralactis, Acinetobacter MN21 and Stenotrophomonas maltophilia to the spoilage of chill-stored lamb.

Exploring the contribution of common microorganisms to spoilage is of great significance in inhibiting spoilage in lamb. This work investigated the extent of protein degradation and profile changes of free amino acids (FAAs), free fatty acids (FFAs) and volatile organic compounds (VOCs) in lamb caused by single- and co-culture of the common aerobic spoilage bacteria, P. paralactis, Ac. MN21 and S. maltophilia. Meanwhile, some key VOCs produced by the three bacteria during lamb spoilage were also screened by orthogonal partial least square discriminant analysis and difference value in VOCs content between inoculated groups and sterile group. Lamb inoculated with P. paralactis had the higher total viable counts, pH, total volatile base nitrogen and TCA-soluble peptides than those with the other two bacteria. Some FAAs and FFAs could be uniquely degraded by P. paralactis but not Ac. MN21 and S. maltophilia, such as Arg, Glu, C15:0, C18:0 and C18:1n9t. Co-culture of the three bacteria significantly promoted the overall spoilage, including bacterial growth, proteolysis and lipolysis. Key VOCs produced by P. paralactis were 2, 3-octanedione, those by Ac. MN21 were 1-octanol, octanal, hexanoic acid, 1-pentanol and hexanoic acid methyl ester, and that by S. maltophilia were hexanoic acid. The production of extensive key-VOCs was significantly and negatively correlated with C20:0, C23:0 and C18:ln9t degradation. This study can provide a basis for inhibiting common spoilage bacteria and promoting high-quality processing of fresh lamb.

Identification and quality evaluation of Lushan Yunwu tea from different geographical origins based on metabolomics.

The relationship between the chemical composition and quality of Lushan Yunwu tea (LYT) from different geographical origins is not clear. Sensory evaluation, metabolomics analyses combined with chemometrics were conducted on LYT from 8 different geographical origins, and altitude was identified as the main factor responsible for the differences among LYT. A total of 32 non-volatile and 27 volatile compounds were identified as marker metabolites to distinguish the origins of high altitudes from those of low altitudes. LYT samples from higher altitude areas contained more free amino acids, sugars, and organic acids, and less catechins, which may contribute to the reduction of bitterness and astringency and the enhancement of umami. The contents of geranylacetone, ethyl hexanoate, ethyl caprylate, 3-carene, d-cadinene, linalool, nerol, and nerolidol in high altitude areas were higher than those in low altitude areas, indicating that LYT from high altitude had strong floral and fruity aroma. The altitudes were positively correlated with pH value, total flavonoids, soluble protein, total free amino acids, and the antioxidant capacities of the LYT. This study provided a theoretical basis for the study of the effect of altitude on tea quality.