Various proteases were employed to hydrolyze walnut protein, and anti-inflammatory effects of the hydrolysates were evaluated in RAW264.7 cells exposed to lipopolysaccharide. The bromelain hydrolysate, which was further separated using ultrafiltration and RP-HPLC, presented the highest anti-inflammatory effect. A total of 100 peptides were detected using UPLC-Q-Orbitrap-MS2, and novel peptide VLRWPR (VR6) was screened. A DSS-induced colitis model in mice was utilized to assess the anti-inflammatory activity of VR6 in vivo. VR6 markedly reduced the disease activity index score by 66%, reversed the colon-length shortening by 28%, regulated the serum inflammatory index, and alleviated histopathological damage within the colon. VR6 suppressed inflammation by modulating the TLR4-NF-κB axis. Concurrently, VR6 maintained intestinal barrier function by elevating zonula occludens-1, occludin, and claudin-1 levels by 3.43, 1.45, and 2.66 times, respectively. Furthermore, 16S rRNA sequencing analysis indicated that VR6 could reverse the gut microbiota imbalance and improve the production of short-chain fatty acids.

Walnut meal is a protein-rich by-product of oil extraction. The extraction method may influence the quality of the protein within walnut meal and determine its potential application value. However, comparative studies on the characteristics of walnut meal protein under different oil extraction methods, particularly emerging green methods, remain scarce. This study analyzed the structural, functional and digestive properties of walnut protein (WP) isolated from meals defatted using three methods: pressing extraction (PE, traditional), supercritical fluid extraction (SFE, green), and aqueous extraction (AE, green). PE induced extensive structural unfolding and disruption to intermolecular forces, yielding WP with the highest solubility and superior emulsifying properties. In contrast, SFE preserved the native, compact protein structure, yielding WP with superior water-holding capacity and the strongest gelling ability. AE-WP exhibited intermediate structural characteristics and the highest in vitro protein digestibility, indicating that moderate denaturation benefited protein digestion. In terms of peptide release during protein digestion, the looser structures of SFE-WP and AE-WP facilitated the release of low-molecular-weight and bioactive peptides. Furthermore, strong correlations were found between structural characteristics (e.g., surface hydrophobicity, secondary structure, aggregation state and intermolecular forces) and functional/digestive performance, providing a scientific structure-property relationship for the targeted use of proteins in walnut meals.

This study aimed to efficiently valorize protein resources from Juglans sigillata D. by employing ultrasound-shear-assisted enzymatic hydrolysis to generate α-glucosidase-inhibitory peptides. The process parameters were optimized using response surface methodology, and the structural basis underlying this enhanced inhibitory activity was further elucidated through multiscale structural characterization and molecular docking analysis. The optimal conditions were determined as follows: ultrasound treatment time of 21  min, ultrasonic power of 400  W, shear speed of 12000 r/min, and enzyme loading of 12 KU/g. Under these conditions, the α-glucosidase inhibition rate of the hydrolysate reached 54.38 ± 0.77 %, which was significantly higher than that obtained by enzymatic hydrolysis alone, with the latter showing an inhibition rate of 45.82 ± 3.28 % (p < 0.05). Structural analyses indicated that the combined ultrasound-shear treatment modified the conformational structure and increased the surface hydrophobicity of walnut protein, potentially enhancing protease accessibility and facilitating the release of α-glucosidase-inhibitory peptides. In total, 4492 peptides were identified by LC-MS/MS, from which 20 candidate peptides were prioritized using a BIOPEP-aided, two-stage in silico workflow. Molecular docking was subsequently used to compare the predicted binding modes and docking scores of selected peptides with α-glucosidase. The peptides FFPGSP, FGPSQPF, and APSKDAPMF were synthesized and experimentally validated. Their IC50 values were 1745, 5393, and 4090  μM, respectively. These findings show that combining peptide identification, bioinformatics screening, molecular docking, and in vitro validation can help facilitate the preliminary discovery and selection of α-glucosidase-inhibitory peptides. This study provides a basis for the high-value utilization of J. sigillata protein and the development of natural peptides with potential α-glucosidase-inhibitory activity.

Yunxiang 1 is a new small-fruit-type purple kernel walnut variety selected from seedling resources of Juglans sigillata in Ludian County, Yunnan Province. The nut is spherical and uniform, and the shape is beautiful; the average diameter of the nuts is 2.84 cm. The shell features shallow grooves, the shell thickness is 0.87 mm, and the nut weight is 7.32 g. The kernel weighs 4.93 g, exhibits a light purple color, and is plump with an intact extraction rate. The kernel rate is 67.35%. The kernel has a delicate texture and rich aroma without astringency. The walnut kernel has an oil content of 65.1%, and a protein content of 18.5%. The tree vigor is strong, the tree posture is semi-open, and it is naturally open. The 1-year-old dormant branches are purple-brown, with prominent lenticels and sparse density. Mixed bud is triangle with no stalk. There are 9-13 small leaves, and the top leaves are mostly degenerated and spindle-lanceolate. It germinates in early March in Ludian, the male flower disperses in late March, the female flower blooms in early and middle April, the female flower stigma is light red, the flowering habit is protandry, the fruit matures in mid-September, and the leaves fall in late November. The green fruit(husk)is spherical, the fruit surface is covered with yellow fluff, the fruit point is obvious, and the fruit top is not prominent. The clone of this variety blossoms and bears fruit in the second year after the top-working of 4-5 years old tree(3-4 years earlier than that of Yangbi Pao walnut), which has obvious early-fruiting trait. The fruiting branches of the mother tree account for 50.3%, and the fruit branch rate is 70.2%. There are three or four more fruits, with an average of 2.6 fruits per fruiting branch. The average crown projection area produces 0.36 kg·m-2of dried nut. This variety has the characteristics of early fruiting, high yield, round nut shape, uniform and beautiful, full and plump kernel, easiness to take out the whole kernel, light purple kernel, high kernel rate, excellent taste and so on. At the same time, it has good cold, disease and insect resistance. It is a rare new variety of small-fruit-type walnut, which can be applied to the development and utilization of walnut food for kernel, tourism and leisure snacks. It has significant potential in improving quality and efficiency and optimizing variety structure in walnut planting base in Yunnan. The popularization and application of this variety is expected to effectively improve the yield and quality of walnut fruit, enhance market competitiveness, and improve the comprehensive benefits of the industry. It is suitable for Ludian County at an altitude of 1600-2100 m, with an average annual temperature of 12-16℃ and an annual rainfall of 800-1100 mm, ≥10℃active accumulated temperature≥3500℃area and the surrounding similar conditions of planting.

Addressing the poor adaptability of extrusion heads, incomplete shell breaking, and low HGKR in large‑scale processing of Juglans sigillata Dode, this study proposes an adaptive profiling extrusion method. Industrial computed tomography (CT) scanning was used to quantify the shell-kernel gap, identifying transverse as the optimal compression direction. A profiling extrusion device and a drop weight impact test platform were built. The effects of impact energy, profiling depth, and compression displacement on shell breaking and kernel recovery were investigated using one‑time shell breaking rate (OT‑SBR) and HGKR as indicators. Single-factor and Box‑Behnken response surface methodology (RSM) experiments analyzed interactions and established parameter-performance regression models. Optimal parameters for small, medium, and large walnuts were (4.7 J, 3.5 mm, 2.8 mm), (4.5 J, 3.1 mm, 2.7 mm), and (4.4 J, 4.1 mm, 3.9 mm), achieving OT-SBR and HGKR of 90.45

Walnut oil produced by aqueous extraction has the characteristics of higher endogenous antioxidant components, better quality and storability compared with traditional methods. To further study its liposoluble components, a non-targeted metabolomics study was conducted on walnut oil extracted by two methods (hydraulic pressing and aqueous extraction) using ultra performance liquid chromatography-mass spectrometry. The results showed that there are no significant difference in the physicochemical indicators of walnut oil processed by the two methods. A total of 1 006 components were identified in the walnut oil, mainly including lipids and lipid-like molecules (40.56%), phenylpropanoids and polyketides (18.19%), organic acids and derivatives (10.83%), etc. There were a total of 142 different components in the two types of walnut oil. Compared with the hydraulic oil, 82 components were upregulated and 60 components were downregulated of aqueous extracted oil. The metabolic pathways with significant differences had five types: fatty acid metabolism, flavonoid biosynthesis, phenylpropanoid biosynthesis, cutin/suberine/wax biosynthesis, ubiquinone/other terpenoid-quinone biosynthesis. There were a total of 27 key differential components in metabolic pathways, mainly including oxidized fatty acids, polyphenols, tocopherols, branched fatty acid esters of hydroxy fatty acids (FAHFA), etc. In conclusion, compared with the hydraulic oil, the aqueous extracted oil contains more lipid-soluble functional components.

A reasonable branch bending angle is essential for optimizing canopy structure and regulating metabolic distribution in fruit trees. ‘Jinyefoxilan’ is a new olive variety bred by crossing ‘Frantoio’ and Olea cuspidata Wall., characterized by rapid growth and high oil concentration. This study evaluated the physiological and metabolic responses of ‘Jinyefoxilan’ to natural growth (CK), 60°, 90°, and 110° bending. Parameters including leaf morphology, photosynthetic pigments, endogenous hormones, mineral distribution, and fruit quality were analyzed. The results demonstrated that the 60° treatment stimulated leaf gibberellin synthesis. The 90° treatment facilitated the synergistic enrichment of nitrogen and potassium in leaves, resulting in the highest fruit oil concentration, although the yield per plant was the lowest among all treatments. Conversely, 110° bending significantly altered the endogenous hormonal balance, with indole-3-acetic acid concentration reaching 13.3 times that of the CK. This treatment achieved the numerically highest fruit set rate and yield per plant, accompanied by significant accumulations of calcium, magnesium, and phosphorus. However, the 110° angle also induced severe N and K deficits, resulting in the lowest fruit moisture and oil concentration. In conclusion, 90° branch bending represents the optimal strategy for enhancing intrinsic fruit quality and oil accumulation. Although 110° bending maximizes yield, it necessitates supplemental potassium fertilization during fruit development to mitigate metabolic limitations. These findings provide a theoretical and practical basis for canopy management and cultivation of ‘Jinyefoxilan’ olives.

Walnut–Polygonatum kingianum intercropping is a value-added agroforestry strategy that can enhance land-use efficiency and improve forest ecological diversity. However, the relationships among soil nutrients, microbial community structure, and P. kingianum quality under this system remain insufficiently understood. In this study, three walnut–P. kingianum intercropping patterns (IP) with varying light transmission, as well as monoculture systems of P. kingianum (MP) and walnut (MW), were evaluated to examine changes and interactions among P. kingianum quality, soil nutrients, and soil microbial community structure. The results showed that P. kingianum grown under IP conditions exhibited higher quality than that grown under MP conditions, as reflected by the greater net weight and higher contents of total phenolic compounds, polysaccharides, and total flavonoids. Moreover, compared with MW, IP significantly increased soil nutrient levels, particularly soil organic matter, available nitrogen, available phosphorus, and available potassium. Improvements in soil fertility were associated with the accumulation of several beneficial bacterial genera (e.g., Pseudolabrys, Pedomicrobium, and Ilumatobacter) and fungal genera (e.g., Mortierella, Acaulium, and Saitozyma) in IP soils, while the relative abundance of pathogenic genera (e.g., Fusarium) was reduced. Linear discriminant analysis effect size analysis revealed that the IP2 model showed significant enrichment of fungal genera, including Penicillium, Acaulium, and Clonostachys, which may contribute to enhanced soil fertility and the development of high-quality P. kingianum. These findings highlight the interactions among soil fertility, P. kingianum quality, and soil microbial communities within the IP system, providing a scientific basis for cultivating high-quality P. kingianum.

The study utilized zein and apple pectin as matrices with tea polyphenols as functional components to develop three treatment groups for walnut kernels via immersion: a composite zein nanoparticles-pectin coating (composite coating ZNP-P group), multilayer assembled coating pectin-zein nanoparticles-pectin-zein nanoparticles coating (P-ZNP-P-ZNP group), and a sterile water control. After 40 d of cold storage at 4 degrees C, the P-ZNP-P-ZNP group demonstrated superior preservation effects. Specifically, this group maintained significantly higher moisture content (23.66 %), water activity (0.9750), firmness (3217.81 g), total sweet amino acids (0.83 mg/g), and polyunsaturated fatty acid proportion (53.18 %) compared to control (P < 0.05). Conversely, Delta E (3.77), total viable count (4.08 log CFU/g), lipid oxidation, the response increments of E-nose sensors to sulfide compounds and ammonia/amines, hexanal content (19.27 mu g/100g), lipoxygenase activity (13.67 U/g), peroxidase activity (1.71 U/g), and polyphenol oxidase activity (5.11 U/g) were significantly lower than both the ZNP-P group and control. These results indicate that the P-ZNP-P-ZNP multilayer coating creates a gradient barrier that effectively delays physiological metabolism and quality deterioration in walnut kernels, offering a novel technological approach for cold chain preservation.

The formation mechanism of fibrosis in walnut meal protein (WMP) was investigated using high-moisture extrusion technology, and also explored the improved texture and color properties of the extruded product by mixing with soybean protein isolate (SPI) and wheat gluten (WG) in various proportions. The results indicated that significant changes occurred in the protein molecules during the extrusion process, and the die and cooling zone outside the barrel were the key regions for the development of fibrosis in WMP extrudate. The hydrogen bonds and disulfide bonds interactions were essential in maintaining the extrudate fibrous structure, with the protein secondary structure being beta-turn > beta-sheet > alpha-helix > random coil. High-water extrusion enhanced the free amino acid content of WMP. When the ratio of WMP, SPI, and WG was set at 8:1:1, the texturization degree of the excluded compound proteins was 1.92, and the texture of the extruded WMP complex was comparable to that of chicken breast. This work provides a basis for the comprehensive utilization of walnut by-products and contributes to the enrichment of resources in plant protein-based products.

Walnut protein was hydrolyzed by different enzymes, and bromelain protein hydrolysate (W-Bromelain) showed the highest dipeptidyl peptidase-IV (DPP-IV) inhibitory activity. W-Bromelain was fractionated, and three novel tetrapeptides (LPQF, LPSF, and VPFP) were identified. In vitro evaluation showed that LPQF exhibited the highest DPP-IV inhibitory activity with an IC50 value of 99.34 μM. Evaluation of the absorption, distribution, metabolism, excretion, and toxic properties of LPQF showed high absorption and nontoxicity. Molecular docking showed that LPQF could interact with the active residues of DPP-IV through seven hydrogen bonds and five hydrophobic interactions. Molecular dynamics simulation further confirmed the stability of the LPQF-DPP-IV complex. LPQF showed high stability in in vitro gastrointestinal digestion. LPQF ameliorated the type 2 diabetes mellitus-like phenotype and reduced the degree of oxidative stress and intestinal barrier damage in a Drosophila melanogaster model of insulin resistance. Furthermore, the RNA-seq analysis showed that LPQF may exert hypoglycemic effects by regulating the Wnt, MAPK, and FoxO pathways.

Legume proteins have recently gained significant interest in the food industry for their eco-friendliness and nutritional qualities. Research shows that the replacement of specific animal protein sources with legume proteins presents sustainability and economic benefit. Nonetheless, legume proteins frequently exhibit inferior functional properties and palatability compared to animal proteins. Various non-thermal technologies, including high hydrostatic pressure, ultrasound, cold plasma, pulsed electric field, and dynamic high-pressure microjet, had been investigated to enhance the functional properties of legume proteins without loss of nutritional and sensory properties. Although these technologies show potential, no systematic study has been conducted to summarize and compare their effects on different legume proteins. This review aims to fill this gap by addressing the most promising approaches of non-thermal technologies for the modification of functional properties of legume proteins. New insights are discussed, elaborating the effect of non-thermal technologies on the structural and functional behavior of proteins.

Dayao No. 1 walnut is a new variety of walnut, characterized by late maturity, high yield, sweet and fragrant flavor, and delicate texture, which was selected and bred from the seedling population of deeply-ribbed walnuts in Yunnan. It is highly popular among the markets and consumers, and is in high demand in the production areas, bringing good economic benefits. The walnut kernel is spherical in shape, with flat shoulders and a slightly convex base. The suture lines are slightly raised and moderately close together. The seed tip is bluntly pointed, and the shell is relatively smooth. The average diameter of the three axes is 3.40 cm, classifying it as a medium-sized fruit variety. The shell thickness is 1.08 mm, with a degenerated inner fold and a membranous septum, making it easy to extract the kernel. The average weight of a single nut is 12.20 g, with a kernel weight of 6.84 g, resulting in a kernel extraction rate of 56.07%. The kernel is plump and light in color. The walnut kernel contains 1.7 g of reducing sugars per 100 g, and has an oil content of 64.7% and a protein content of 17.1%. The tree has a strong growth vigor and a spherical canopy. Each compound leaf consists of 10 to 13 leaflets, with 11 leaflets being the most common. The leaflets are oblong in shape. The mixed buds are round without bud stalks. The branching rate of shoots is 185%, the branch formation rate is 100%, and the fruit-bearing branch rate is 95%. The tree has unisexual flowers with protandry (male flowers open before female flowers). The male inflorescences are 5.0 to 10.0 cm long. On average, each fruit-bearing branch has 3 to 4 female flowers, often more than 3, and the average fruit set is 3 to 4, often more than 3. The fruit is round, with a smooth surface and without no pubescence, and is green in color. In Dayao County, the tree buds and leaves come out in mid-to-late April and leaves shed in mid-November, with a growing period of about 214 days. The tree mainly bears fruit from the terminal buds and the lower 2 to 3 lateral buds of the fruit-bearing branches. The fruits mature in mid-October, about 20 days later than the control variety Dayao Santai walnut. The tree has good growth and fruiting conditions, with no significant alternate bearing. Molecular marker analysis shows that Dayao No. 1 walnut plants differ from Dayao Santai walnut plants at the molecular level. It exhibits good cold resistance, ability to avoid late frosts, and resistance to pests and diseases. Dayao No. 1 walnut can be cultivated in the mid-to-high altitude regions of Yunnan. The breeding of this variety fills the gap in Yunnan for late-maturing walnut cultivars suitable for mid-to-high altitude, and it has a promising future for production and promotion.

In this study, zein/apple pectin/tea polyphenol layer-by-layer assembled cling film prepared by solution casting was characterized, and the preservation effect of composite coatings, double, triple, and quadruple multilayer layer-by-layer assembly coatings on fresh walnut kernels at 4 degrees C was evaluated. As the number of assembly layers increased, the water vapor barrier increased, and the lower the film's UV transmittance. The assembled film's antioxidant and antibacterial activities were significantly higher than composite film. The moisture, color, and texture of the fresh walnut kernels treated with the assembled coatings were less different from 0 d fresh walnut kernels after 40 d of storage at 4 degrees C. The acid value, peroxide value, and total number of bacterial colonies of the fresh walnut kernels with 4-layer assembled coatings were significantly lower than those of the composite coatings. Overall, zein/apple pectin/tea polyphenol layer-by-layer assembled coating is an effective way to the fresh walnut kernel preservation.

Juglans sigillata is an economically valuable nut crop renowned for its nutritional richness, including essential nutrients, antioxidants, and healthy fats, which boost human cardial, brain and gut health. Despite its importance, the lack of a complete genome assembly has been a stumbling block in its biological breeding process. Therefore, we generated deep coverage ultralong Oxford Nanopore Technology (ONT) and PacBio HiFi reads to construct a telomere-to-telomere (T2T) genome assembly. The final assembly spans 537.27 Mb with no gaps, demonstrating a remarkable completeness of 98.1%. We utilized a combination of transcriptome data and homologous proteins to annotate the genome, identifying 36 018 protein-coding genes. Furthermore, we profiled global cytosine DNA methylations using ONT sequencing data. Global methylome analysis revealed high methylation levels in transposable element (TE)-rich chromosomal regions juxtaposed with comparatively lower methylation in gene-rich areas. By integrating a detailed multi-omics data analysis, we obtained valuable insights into the mechanism underlying endopleura coloration. This investigation led to the identification of eight candidate genes (e.g. ANR) involved in anthocyanin biosynthesis pathways, which are crucial for the development of color in plants. The comprehensive genome assembly and the understanding of the genetic basis of important traits like endopleura coloration will open avenues for more efficient breeding programs and improved crop quality.

Walnut oil (WO) is rich in nutrients; however, it is susceptible to oxidative rancidity caused by external factors during storage. This susceptibility is also related to its own lipid composition, metabolism, and other factors. At present, no comprehensive study has investigated lipid group changes during the oxidation process of WO. Lipid changes in WO over 24 d of accelerated oxidation were dynamically monitored via high-performance liquid chromatography-triple quadrupole tandem mass spectrometry, revealing 354 lipids across 15 subclasses. Among these lipids, ceramide, phosphatidylcholine, triglyceride, diglycerides, and total ester exhibited significantly decreased levels (P < 0.05), while phosphatidylinositol and phytoceramide yielded significantly increased contents (P < 0.05). Using multivariate statistical analysis, 22 differential lipids (variable importance in projection >1, P < 0.05) were screened as markers to identify the degree of WO oxidation. Through Kyoto Encyclopedia of Genes and Genomes pathway analysis, seven major metabolic pathways were elucidated to investigate the underlying oxidative mechanisms. This study offers novel insights into and lays a theoretical foundation for exploring the storage stability of WO and the mechanisms underlying lipid oxidation.

Background Non-alcoholic fatty liver disease (NAFLD) is a metabolic syndrome associated with obesity and type 2 diabetes mellitus. Currently, there are no effective drugs to treat NAFLD. Palmitoleic acid (PA) has demonstrated therapeutic potential in managing various metabolic diseases and inflammation. Although ferroptosis is known to play a critical role in the NAFLD development, it remains unclear whether PA can alleviate NAFLD by inhibiting ferroptosis. Methods Thirty C57BL/6 mice were divided into three groups: standard diet, high-fat diet (HFD), and HFD with PA. The experiment lasted 16 weeks. Results PA alleviated liver injury, hepatitis, and dyslipidemia in HFD-induced NAFLD mice. It improved insulin resistance, downregulated genes and proteins related to fat synthesis, and upregulated genes and proteins linked to lipolysis and fat oxidation. Mechanistically, bioinformatics enrichment revealed the involvement of ferroptosis in NAFLD. PA mitigated oxidative stress and reduced liver iron content in NAFLD. It downregulated acyl-CoA synthetase long-chain family member 4 (ACSL4) expression while upregulating glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression, thereby inhibiting ferroptosis. Conclusion PA exerts a protective effect against liver lipotoxicity by inhibiting lipid metabolism-mediated ferroptosis. These findings provide new insights into preventive and therapeutic strategies for the pathological processes of NAFLD.

Multidrug-resistant (MDR) bacterial infections have become a significant threat to global healthcare systems. Here, we developed a highly efficient antimicrobial hydrogel using environmentally friendly garlic carbon dots, pectin, and acrylic acid. The hydrogel had a porous three-dimensional network structure, which endowed it with good mechanical properties and compression recovery performance. The hydrogel could adhere closely to skin tissues and had an equilibrium swelling ratio of 6.21, indicating its potential as a wound dressing. In particular, the bactericidal efficacy following 24-h contact against two MDR bacteria could exceed 99.99 %. When the hydrogel was applied to epidermal wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) on mice, a remarkable healing rate of 93.29 % was observed after 10 days. This was better than the effectiveness of the traditionally used antibiotic kanamycin, which resulted in a healing rate of 70.36 %. In vitro cytotoxicity testing and hemolysis assay demonstrated a high biocompatibility. This was further proved by the in vivo assay where no toxic side effects were observed on the heart, liver, spleen, lung, or kidney of mice. This eco-friendly and easy-to-prepare food-inspired hydrogel provides an idea for the rational use of food and food by-products as a wound dressing to control MDR bacterial infections.

This study investigated the physicochemical properties, flavor substances, and metabolites of three major cultivated walnut kinds Xixiang walnut kernels (XXWK), Santai walnut kernels (STWK), and Yangbipao walnut kernels (YBWK) in China Yunnan. The lowest oil content and the highest protein content were found in the YBWK. The total content of 17 amino acids, including threonine, valine, and lysine, in YBWK was significantly higher than those of XXWK and STWK. The unsaturated fatty acid contents of XXWK, STWK, and YBWK were 85.92%, 86.78%, and 87.58%, respectively. The flavor compounds with the highest OAV values were hexanal, trans-2-nonenal, and trans-2-nonenal in XXWK, STWK, and YBWK, respectively. A total of 156 metabolites with significant differences were identified, the highest content of lipids and lipid-like molecules. Vitamin B6 metabolism, alpha-linolenic acid metabolism, and purine metabolism were the important metabolic pathways in walnut kernels. Hexanol and methyl hexanoate showed a highly significant positive correlation with icariside E5, and 1-nonanal, decyl aldehyde showed a highly significant positive correlation with 8 amino acids, including leucine, isoleucine, and phenylalanine. This study provided a theoretical basis for understanding the characteristics of main cultivated walnuts and developing walnut products in Yunnan.

To select the appropriate extraction process of Yunnan walnut oil,with the main cultivars of walnut in Yunnan as raw materials,walnut oil was prepared by hydraulic pressing,screw pressing and aqueous method respectively,and the physicochemical indexes and functional active ingredients of walnut oil obtained by three oil production methods were compared.The functional active ingredients of walnut oil extracted by aqueous method from three main cultivars'Yangpao''Santai''Xixiang'in Yunnan were compared with six commercial walnut oils.The results showed that the acid value,peroxide value,iodine value,saponification value,moisture and volatile matter content and fatty acid composition and content of the walnut oils extracted by aqueous method,hydraulic pressing and screw pressing were all in line with the requirements of the national standard.The contents of α-tocopherol,γ-tocopherol,squalene and β-sitosterol in walnut oil obtained by aqueous method were significantly higher than those in hydraulic pressed and screw pressed oils.The contents of α-tocopherol,γ-tocopherol,squalene,β-sitosterol,melatonin and β-carotene in walnut oil obtained by aqueous method were significantly higher than those in commercial walnut oils.Walnut oil with good quality and high functional active ingredients content can be obtained by aqueous method,and aqueous method can be used for the extraction of walnut oil from main cultivars in Yunnan.