Submitted Successfully!
To reward your contribution, here is a gift for you: A free trial for our video production service.
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1 -- 2254 2023-07-19 22:21:14 |
2 update references and layout Meta information modification 2254 2023-07-20 03:21:05 |

Video Upload Options

Do you have a full video?

Confirm

Are you sure to Delete?
Cite
If you have any further questions, please contact Encyclopedia Editorial Office.
Kithi, L.; Lengyel-Kónya, �.; Berki, M.; Bujdosó, G. Green Husks of Persian Walnut. Encyclopedia. Available online: https://encyclopedia.pub/entry/47000 (accessed on 19 June 2024).
Kithi L, Lengyel-Kónya �, Berki M, Bujdosó G. Green Husks of Persian Walnut. Encyclopedia. Available at: https://encyclopedia.pub/entry/47000. Accessed June 19, 2024.
Kithi, Laurine, Éva Lengyel-Kónya, Mária Berki, Géza Bujdosó. "Green Husks of Persian Walnut" Encyclopedia, https://encyclopedia.pub/entry/47000 (accessed June 19, 2024).
Kithi, L., Lengyel-Kónya, �., Berki, M., & Bujdosó, G. (2023, July 19). Green Husks of Persian Walnut. In Encyclopedia. https://encyclopedia.pub/entry/47000
Kithi, Laurine, et al. "Green Husks of Persian Walnut." Encyclopedia. Web. 19 July, 2023.
Green Husks of Persian Walnut
Edit

Green husks are the outer layer of walnut fruits. They form part of the agro-residues discarded away upon nut maturity in the walnut industry. A total of 83 individual phenolic compounds were identified in walnut husks, mainly consisting of naphthoquinones, flavonols, and hydroxycinnamic acids.

antioxidants husk nut phenology walnut cultivars

1. Introduction

Persian or English walnut is one of the most important nut tree crops grown for its nutritious nuts, timber, and landscaping. It provides a source of employment and income to farming households and other value-chain players [1]. Walnut production is found in regions between latitudes 30–55° and 30–40° in the Northern and Southern Hemisphere, respectively. They include countries in Asia, Europe, North America, North Africa, South Africa, Australia, New Zealand, Chile, and Argentina [1].
In 2009, the total walnut production was estimated at 2.28 million tons of dried nuts with shells. A decade later, production had increased to 4.49 million tons. The top five producers include China, the United States of America, Iran, Turkey, and Mexico. China produced more than 50% of the total global production. The United States of America and Iran produced 592,390 tons and 321,074 tons of dried nuts with shells, respectively [1][2]. Annual production is steadily increasing in Central Europe [3]. In 2019, statistics show that Hungary’s production was estimated at 6820 tons of dried nuts with shells [2].
Walnuts are mainly grown for their kernels and wood to a lesser extent; the other parts (hard shell, green husk) are produced as waste. The main products of walnuts are dried nuts with shells and kernels due to their nutritional value [4]. However, the walnut green husk is also a valuable part of the fruit due to its high phenolic compounds.

2. Botany of Walnut

Walnuts are large deciduous trees in the Juglandaceae family, arguably native to some countries in the Balkan Peninsula and Central Asia [5]. Mature trees are anchored on deep root systems, with big tap roots [6] and heavy, close-grained stems that produce valuable hardwood suitable for furniture. The trunk has large brown/copper glabrous branches with characteristically many-chambered pith. They also have broad canopies of about 18-m wide and 13-m high, and elongated pinnate compound leaves of 5–23 leaflets. Walnuts are commonly propagated vegetatively with grafting and budding, including in vitro culture [7]. Sexually propagated trees take 8–12 years to mature and produce nuts with many variations [8].
Flower differentiation and anthesis start, bearing monoecious flowers [9]. After meeting the chilling requirements that vary from 400 to 1500 h in temperatures between 0 °C and 7 °C [10][11]. This occurs from mid-April for early cultivars to mid-May for late-blooming cultivars [12]. Petal-less male drooping catkins develop on older branches, and clusters of 2–5 female flowers are borne on new terminal shoots or lateral spurs [13][14]. The flowers are heterodichogamous, some cultivars are protogynous, and others are protandrous. Imperfect overlap between pollen shedding and female flower receptivity necessitates the presence of two complementary cultivars to pollinate each other [1].
Walnut fruits consist of a kernel, seed coat, shell, and pericarp, commonly called green husk [15]. The semi-fleshy green pericarp covers a hard corrugated shell enclosing a four-celled edible nut. Walnut husks are composed of the epicarp, mesocarp, and endocarp supplying nutrients for the seed’s growth [16]. The pericarp dehisces allow the seed to fall upon the maturity of nuts. The walnut seed contains two cotyledons enclosed in the shell with a thin lining called the pellicle. Selections of English walnuts are diverse, ranging from round to very elongated shapes, pea-sized to more than 50-mm shell diameter [8].

3. Nut Characteristics

3.1. Physical Characteristics of Kernel

Physical and phytochemical studies show significant kernel variations across walnut cultivars. Walnut fruits come in different dimensions, shapes, and kernel appearances, and have different content of chemical compounds. The main physical quality features are kernel weight and colour, shell shape and size, kernel ratio, and cracking ratio [17]. Others include sphericity, porosity, volume, bulk and true densities, coefficient of friction, and terminal velocity [18][19].

3.2. Chemical Compounds in Kernel

Walnuts contain numerous phytochemical constituents such as polyphenols, fatty acids, mineral elements, vitamins, digestible proteins, amino acids, carbohydrates, and dietary fibre in their bark, roots, leaves, and fruits [20][21][22][23][24][25].
Polyphenolic compounds are secondary metabolites characterized by phenolic rings synthesized by plants as a defence against stress factors such as radiation, pest, and diseases. Classification of these compounds is based on their chemical structure. They include flavonoids, phenolic acids, stilbenes, lignans, and others [26][27]. A total of 83 phenolic compounds were identified in walnut husks, mainly consisting of naphthoquinones, flavonols, and hydroxycinnamic acids [28]. A related study by Medic et al. [29] identified and quantified 91 individual phenolic compounds. Forty-one of these were in root tissues, and others in petiole, bark, buds, and leaf tissue. They comprised 28 hydroxybenzoic acids, 22 naphthoquinones, 20 flavonols, 11 flavanols, 8 hydroxycinnamic acids, and 2 coumarins.
Kernels are rich in monounsaturated and polyunsaturated fatty acids such as alpha-linolenic acid (ALA), an omega-3 fatty acid, and linoleic acid (LA), an omega-6 fatty acid [30], oleic acid, and small amounts of saturated fatty acids. Studies show that its oil content ranges from 45.6% to 79.4% [5][15][18][21][25][31][32], with unsaturated fatty acids, tocopherols, and phytosterols being the most dominant. The main fatty acids present in walnuts include linoleic, oleic, linolenic, palmitic, and stearic acids [33][34][35][36][37]. Palmitoleic acid, arachidic acid, and eicosenoic acid are present in small amounts [34].
Kernels contain a significant amount of protein ranging from 10.6 to 25.0% [5][18][23][32][38]. Gu et al. [39] reported 40.0–45.0% protein content in J. sigillata kernels. Glutelin is the most abundant protein (72.1%); others (globulin, albumin, and prolamin) are present in smaller amounts [23]. These proteins come with various free amino acids, notably alanine, arginine, and glutamate [40].
Other biochemicals present in walnut kernels include carbohydrates (5.0–24.0%); minerals (phosphorus, potassium, and traces of sulphur); micro-elements (Ca, Mg, Fe, Cu, Zn, and I); vitamins: E, C, B1, B2, and A [5]; dietary fibre [25].

4. Walnut Green Husks

The green husk is a fleshy outer layer enclosing the shell of a nut [41]. Upon nut ripening, the husk gradually darkens. As a by-product, it is considered waste upon harvesting [13]. Sebahattin et al. [42] report that the average fresh husks-biomass to total walnut-biomass ratio is 57.15%. Husks are therefore produced in large amounts, and poor disposal lead to environmental pollution. However, they are a natural source of bioactive compounds, which can be used for diverse purposes.

4.1. Phenolic Compounds in Walnut Green Husks

Similar to other parts of the tree, numerous bioactive polyphenolic compounds associated with antioxidant and antimicrobial properties have been identified in green husks [43]. These compounds, as secondary metabolites, cover a large group of heterogeneous bioactive compounds. Their synthesis is regulated by different enzymes in different metabolic pathways, and they have several roles in fruit growth processes. The amount of these compounds depends on the genotype, environmental and climatic conditions as well as geographical conditions. Furthermore, it depends on the development stage of the fruit. It is necessary to follow up on these changes and consider the date of extraction when the amount reaches its maximum concentration [44]. The open green husks have higher antioxidant capacity and polyphenol content than the closed ones [45].
The basis of walnut husk utilization could be the high antioxidant activity of these phenolic compounds. The isolated and identified phenolic compounds are divided into different groups according to their chemical structure. Ellagic acid and tannic acid belong to hydrolyzable tannins, both present in walnut husks. Naphthoquinones, naphthoquinone glycosides, and naphthalenes are also isolated in green husks and widely studied. Juglone, the most important phenolic compound in the husk, is a naphthoquinone. Derivatives of juglone are also present. Other compound groups are α-tetralones, α-tetralones glycosides, and α-tetralones dimers. The most significant hydroxybenzoic acids in husk are gallic acid, protocatechuic acid, syringic acid, vanillic acid, salicylic acid, 3,4-dihydroxybenzoic acid and 2,3-dihydroxybenzoic acid, and benzoic acid. Caffeic acid, ferulic acid, chlorogenic acid, p-coumaric acid, sinapic acid, chlorogenic acid, and trans-ferulic acid are also characterized in green husks, which make the group of hydroxycinnamic acids. Flavonoids are represented in the husk by (+)-catechin, (−)-epicatechin, myricetin, quercetin, sudachitin, cirsilineol, and 5,6,4′-trihydroxy-7,3′-dimethoxy-flavone, apigenin, eriodictyol, kaempferol, rutin. Other secondary metabolites, such as diarylheptanoids, are isolated and identified as well, e.g., rhoiptelol, juglanin A, juglanin B, and juglanin C [15].

4.2. Extraction Methods of Phenolic Compounds

The choice of extraction solvent is a critical consideration because of its chemical variability and complexity. Many research groups have investigated the effects of different extraction solvents and how the development stage affects the content of phenolics as well. A negative correlation was established between growth and the concentration of the phenolic compounds [44]. According to the investigation by Zhang [46], extraction by methanol, ethanol, and acetone shows the highest content of phenolic compounds and antioxidant activity compared to ethyl-acetate and water. Hexane yielded the least number of phenolic compounds. Fernandez-Agulló et al. [43] investigated the extraction yield of methanol, ethanol, methanol/water 50/50, and ethanol/water 50/50. It was established that ethanol/water 50/50 resulted in higher bioactivity and that the antioxidant properties depend on the concentration of the extraction solvent. In a related study, Hama et al. [47] used methanol (80%) for phenolic extraction with chloroform, ethyl acetate, and n-butanol. Ethyl acetate yielded the highest amount of phenolics, followed by chloroform and n-butanol, respectively.
A comparative study of antioxidant activity and individual phenolic compounds in green husk extracts using three different solvents (70% ethanol, 40% ethanol, and 40% ethanol/sugar 50/50) was performed by Cosmolescu and co-workers [48]. In the case of 70% ethanol, it was found that the concentrations of gallic, vanillic, chlorogenic, caffeic, syringic, salicylic, ellagic acids, juglone, catechin, epicatechin, myricetin, and quercetin were the highest. In the case of 40% ethanol, ferulic acid and rutin were more, compared to the other compounds mentioned above. Forty per cent ethanol and sugar (the traditional way of walnut liqueur production) resulted in the highest amount of rutin. Jakopic and co-workers [49] examined the effect of different ethanol concentrations on total phenolic concentration and the number of individual compounds. Generally, they found that increasing ethanol concentration resulted in increased phenolic concentrations. However, in some cases (gallic, chlorogenic, vanillic, and syringic acid, (+)-catechin, and juglone), they achieved better extraction yield with 40% ethanol. In another study, methanol gave better extraction for juglone, (+)-catechin, gallic, protocatechuic, and chlorogenic acids, whereas ethanol resulted in higher amounts of ellagic and sinapic acids [50].
Barekat et al. [51] established that phenolic compounds in walnut husks could have significant antioxidant power ranging from 256.5 to 746.8 score g−1 dry weight (DW) by using the PAOT (total antioxidant power) method. This method uses two specific electrodes to measure the changes in the electrochemical potential in the reaction medium. These changes are in correlation with the antioxidant properties, and results are expressed in PAOT score (total antioxidant power) per gram of dw walnut husk. The identified phenolic compounds include tannins, flavonoids, stilbenes, lignans, quinones, diarylheptanoids, and phenolic acids [20][27][52][53].
Ghasemi et al. [54] observed variances in phenolic and flavonoid content in husks with changes in altitude and temperature. A positive correlation between total phenolic and flavonoid content with altitude was observed; however, the correlation with the temperature was negative [54]. Ghesami’s team attributed the significant differences in phenolic and flavonoid content to the differences in geographical and climatic conditions where samples were obtained.
Mikulic-Petkovsek et al. [55] observed a decline in total phenolic content concerning the physiological stage of the nuts. However, it was noted that the biosynthesis of phenolic compounds in healthy plants may be triggered by pathological infections. Xanthomonas arboricola pv. juglandis infected tissues of the husk exhibited higher content of hydroxycinnamic acids, gallic acid, quercetin, and catechin than uninfected tissues. Similar observations were made by Sheng et al. [20]. The total phenolic and flavonoid content in husks declined with increased maturity to subsequent ripening of the walnut fruit. The differences in phenolic content reported by the research groups [20][55] may be related to the sample origin, the genotype, the ripening status of the samples, the applied solvent, and measurement methods.

4.3. Uses of Walnut Husks

Despite being underutilized, green husks remain an important agricultural by-product and a natural source of bioactive compounds. Like other parts of the walnut tree, the green husk has been used in traditional medicine to relieve pain and treatment of cancer, diabetes, microbial infections and skin and heart diseases [15][41]. The walnut green husk is a source of glucans and pectins, which are useful in human pathology treatment and induce defence mechanisms to respond to wounding [15]. The husks contain juglone, which is a natural dye used in the textile and wood industry, as well as tanning leather [45][56]. Allelopathic compounds in husks serve as pesticides and herbicides [57][58]. It is also important to note that green husks are used in making wine, traditional liqueur, and jam [59][60], whereas green nuts are used in pharmaceuticals and cosmetics [43].

4.4. Effects of Walnut Green Husk Biochemical Compounds on Abiotic and Biotic Factors

The numerous bioactive compounds present in walnut husks are associated with both positive and negative effects on abiotic and biotic factors such as soil, water, microorganisms, and insects, including herbivores. They play a significant role in human, animal, and plant health because these compounds have antioxidant and antiradical properties. They exhibit anticarcinogenic, antimutagenic, anti-inflammatory, cardioprotective, astringent, antiseptic, anthelmintic, and antiaging effects that are beneficial to human and animal health [21][61][62][63][64][65].
According to the literature, these compounds have antimicrobial and antifungal properties that prevent and control plant diseases [66]. They inhibit the initiation and progress of X. arboricola pv. juglandis, the walnut blight disease-causing bacteria [3] and pathogenic fungi such as Botrytis cinerea, Alternaria alternata, Fusarium culmorum, Rhizoctonia solani, and Phytophthora cactorum [67]. Both 4-coumaric acid and p-hydroxybenzoic acid, at minimum concentrations of 1 gL−1 and 2 gL−1, respectively, inhibit the growth of Colletotrichum gloeosporioides fungi responsible for walnut anthracnose disease [66]. Maleita et al. [68] established that at 50 ppm, 1,4-Naphthoquinone can cause 42% mortality in the juvenile root-knot nematode (Meloidogyne hispanica), thus a potential alternative to synthetic nematicides. Walnut and tea intercrops improved the availability of soil micronutrients such as potassium, nitrogen, phosphorus, and organic matter, including enhanced microbial diversity [69].

References

  1. Vahdati, K.; Arab, M.M.; Sarikhani, S.; Sadat-Hosseini, M.; Leslie, C.A.; Brown, P.J. Advances in Persian Walnut (Juglans regia L.) Breeding Strategies. In Advances in Plant Breeding Strategies: Nut and Beverage Crops; Al-Khayri, J.M., Jain, S.M., Johnson, D.V., Eds.; Springer Nature Switzerland AG: Cham, Switzerland, 2019; Volume 4, pp. 401–472.
  2. Oğuz, H.; Oğuz, İ. Walnut (Juglans regia L.) Breeding and Walnut Breeding Criteria. In Walnut; Gundesli, M.A., Ed.; Iksad Publications: Ankara, Turkey, 2021; pp. 203–230.
  3. Bujdosó, G.; Lengyel-Kónya, É.; Berki, M.; Végh, A.; Fodor, A.; Adányi, N. Effects of Phenolic Compounds on Walnut Bacterial Blight in the Green Husk of Hungarian-Bred Cultivars. Plants 2022, 11, 2996.
  4. Tomer, V.; Kumar, A.; Gupta, K.; Shukla, S.; Rafiq, S. Walnut. 10. In Antioxidants in Vegetables and Nuts—Properties and Health Benefits; Nayik, G.A., Gull, A., Eds.; Springer Nature, Singapore Pte Ltd.: Singapore, 2020; pp. 385–422.
  5. Iordanescu, O.A.; Radulov, I.P.; Buhan, I.; Cocan, I.; Berbecea, A.A.; Popescu, I.; Posta, D.S.; Camen, D.; Lalescu, D. Physical, Nutritional, and Functional Properties of Walnuts Genotypes (Juglans regia L.) from Romania. Agronomy 2021, 11, 1092.
  6. de Rigo, D.; Enescu, C.M.; Houston Durrant, T.; Tinner, W.; Caudullo, G. Juglans regia in Europe: Distribution, habitat, usage, and threats. In European Atlas of Forest Tree Species; San-Miguel-Ayanz, J., de Rigo, D., Caudullo, G., Houston Durrant, T., Mauri, A., Eds.; Publications Office of the EU: Luxembourg, 2016; p. 103.
  7. Vahdati, K.; Sadeghi-Majd, R.; Sestras, A.F.; Licea-Moreno, R.J.; Peixe, A.; Sestras, R.E. Clonal Propagation of Walnuts (Juglans spp.): A Review on Evolution from Traditional Techniques to Application of Biotechnology. Plants 2022, 11, 3040.
  8. Stonehouse, W. The Effects of Walnuts (Juglans regia) on the Characteristics of the Metabolic Syndrome. In Nuts and Seeds in Health and Disease Prevention; Victor, R.P., Ronald, R.W., Vinood, B.P., Eds.; Academic Press: Amsterdam, The Netherlands, 2011; pp. 1141–1148. ISBN 9780123756886.
  9. Hassankhah, A.; Rahemi, M.; Ramshini, H.; Sarikhani, S.; Vahdati, K. Flowering in Persian walnut: Patterns of gene expression during flower development. BMC Plant Biol. 2020, 20, 136.
  10. Aslamarz, A.A.; Vahdati, K.; Rahemi, M.; Hassani, D. Estimation of Chilling and Heat Requirements of Some Persian Walnut Cultivars and Genotypes. HortScience 2009, 44, 697–701.
  11. Chandler, W.H.; Kimball, M.H.; Phillip, G.L.; Tufts, W.P.; Weldon, G.P. Chilling requirements for opening of buds on deciduous orchard trees and some other plants in California. Univ. Cal. Agr. Expt. Bull. 1937, 611, 3–62.
  12. Bujdosó, G.; Illes, B.; Varjas, V.; Cseke, K. Is “Esterhazy II”, an Old Walnut Variety in the Hungarian Gene Bank, the Original Genotype? Plants 2021, 10, 854.
  13. Britannica, The Editors of Encyclopaedia. “Walnut”. Encyclopedia Britannica. Available online: https://www.britannica.com/plant/walnut-tree-and-nut (accessed on 8 June 2023).
  14. Wilkinson, J. Nut Grower’s Guide. In The Complete Handbook for Producers and Hobbyists; Landlinks Press: Collingwood, Australia, 2005; ISBN 0 643 06963 1.
  15. Jahanban-Esfahlan, A.; Ostadrahimi, A.; Tabibiazar, M.; Amarowicz, R. A Comprehensive Review on the Chemical Constituents and Functional Uses of Walnut (Juglans spp.) Husk. Int. J. Mol. Sci. 2019, 20, 3920.
  16. Wu, G.L.; Liu, Q.L.; Teixeira da Silva, J.A. Ultrastructure of pericarp and seed capsule cells in the developing walnut (Juglans regia L.) fruit. S. Afr. J. Bot. 2009, 75, 128–136.
  17. Bujdosó, G.; Cseke, K. The Persian (English) walnut (Juglans regia L.) assortment of Hungary: Nut characteristics and origin. Sci. Hort. 2021, 283, 110035.
  18. Pakrah, S.; Rahemi, M.; Haghjooyan, R.; Nabipour, A.; Kakavand, F.; Zahedzadeh, F.; Vahdati, K. Comparing Physical and Biochemical Properties of Dried and Fresh Kernels of Persian Walnut. Erwerbs-Obstbau 2022, 64, 455–462.
  19. Altuntas, E.; Erkol, M. Physical properties of shelled and kernel walnuts as affected by the moisture content. Czech J. Food Sci. 2010, 28, 547–556.
  20. Sheng, F.; Hu, B.; Jin, Q.; Wang, J.; Wu, C.; Luo, Z. The Analysis of Phenolic Compounds in Walnut Husk and Pellicle by UPLC-Q-Orbitrap HRMS and HPLC. Molecules 2021, 26, 3013.
  21. Li, X.; Guo, M.; Chi, J.; Ma, J. Bioactive Peptides from Walnut Residue Protein. Molecules 2020, 25, 1285.
  22. Jahanban-Esfahlan, A.; Ostadrahimi, A.; Tabibiazar, M.; Amarowicz, R. A Comparative Review on the Extraction, Antioxidant Content and Antioxidant Potential of Different Parts of Walnut (Juglans regia L.) Fruit and Tree. Molecules 2019, 24, 2133.
  23. Mao, X.; Hua, Y.; Chen, G. Amino acid composition, molecular weight distribution and gel electrophoresis of walnut (Juglans regia L.) proteins and protein fractionations. Int. J. Mol. Sci. 2014, 15, 2003–2014.
  24. Ros, E. Health Benefits of Nut Consumption. Nutrients 2010, 2, 652–682.
  25. Savage, G.P. Chemical composition of walnuts (Juglans regia L.) grown in New Zealand. Plant Foods Hum. Nutr. 2001, 56, 75–82.
  26. Bolling, B.W.; Chen, C.Y.; McKay, D.L.; Blumberg, J.B. Tree nut phytochemicals: Composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios, and walnuts. Nutr. Res. Rev. 2011, 24, 244–275.
  27. Pandey, K.B.; Rizvi, S.I. Plant polyphenols as dietary antioxidants in human health and disease. Oxid. Med. Cell. Longev. 2009, 2, 270–278.
  28. Medic, A.; Jakopic, J.; Solar, A.; Hudina, M.; Veberic, R. Walnut (J. regia) Agro-Residues as a Rich Source of Phenolic Compounds. Biology 2021, 10, 535.
  29. Medic, A.; Zamljen, T.; Hudina, M.; Veberic, R. Identification and Quantification of Naphthoquinones and Other Phenolic Compounds in Leaves, Petioles, Bark, Roots, and Buds of Juglans regia L., Using HPLC-MS/MS. Horticulturae 2021, 7, 326.
  30. Carey, A.N.; Fisher, D.R.; Bielinski, D.F.; Cahoon, D.S.; Shukitt-Hale, B. Walnut-Associated Fatty Acids Inhibit LPS-Induced Activation of BV-2 Microglia. Inflammation 2020, 43, 241–250.
  31. Chamorro, F.; Carpena, M.; Lourenço-Lopes, C.; Taofiq, O.; Otero, P.; Cao, H.; Xiao, J.; Simal-Gandara, J.; Prieto, M.A. By-Products of Walnut (Juglans regia) as a Source of Bioactive Compounds for the Formulation of Nutraceuticals and Functional Foods. Biol. Life Sci. Forum. 2022, 12, 35.
  32. Liu, B.; Liang, J.; Zhao, D.; Wang, K.; Jia, M.; Wang, J. Morphological and Compositional Analysis of Two Walnut (Juglans regia L.) Cultivars Growing in China. Plant Foods Hum. Nutr. 2020, 75, 116–123.
  33. Yang, H.; Xiao, X.; Li, J.; Wang, F.; Mi, J.; Shi, Y.; He, F.; Chen, L.; Zhang, F.; Wan, X. Chemical Compositions of Walnut (Juglans spp.) Oil: Combined Effects of Genetic and Climatic Factors. Forests 2022, 13, 962.
  34. Wang, R.; Zhong, D.; Wu, S.; Han, Y.; Zheng, Y.; Tang, F.; Ni, Z.; Liu, Y. The phytochemical profiles for walnuts (J. regia and J. sigillata) from China with protected geographical indications. Food Sci. Technol. 2021, 41, 695–701.
  35. Bouabdallah, I.; Bouali, I.; Martinez-Force, E.; Albouchi, A.; Perez Camino, M.C.; Boukhchina, S. Composition of fatty acids, triacylglycerols, and polar compounds of different walnut varieties (Juglans regia L.) from Tunisia. Nat. Prod. Res. 2014, 28, 1826–1833.
  36. Poggetti, L.; Ferfuia, C.; Chiabà, C.; Testolin, R.; Baldini, M. Kernel oil content and oil composition in walnut (Juglans regia L.) accessions from north-eastern Italy. J. Sci. Food Agric. 2018, 98, 955–962.
  37. Gao, P.; Jin, J.; Liu, R.; Jin, Q.; Wang, X. Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China. J. Am. Oil Chem. Soc. 2018, 95, 825–834.
  38. Yerlikaya, C.; Yucel, S.; Erturk, Ü.; Korukluoğlu, M. Proximate Composition, Minerals and Fatty Acid Composition of Juglans regia L. Genotypes and Cultivars Grown in Turkey. Braz. Arch. Biol. Technol. 2012, 55, 677–683.
  39. Gu, M.; Chen, H.P.; Zhao, M.M.; Wang, X.; Yang, B.; Ren, J.Y.; Su, G.W. Identification of antioxidant peptides released from defatted walnut (Juglans Sigillata Dode) meal proteins with pancreatin. LWT Food Sci. Technol. 2015, 60, 213–220.
  40. Mapelli, S.; Brambilla, I.; Bertani, A. Free amino acids in walnut kernels and young seedlings. Tree Physiol. 2001, 21, 1299–1302.
  41. La Torre, C.; Caputo, P.; Plastina, P.; Cione, E.; Fazio, A. Green Husk of Walnuts (Juglans regia L.) from Southern Italy as a Valuable Source for the Recovery of Glucans and Pectins. Fermentation 2021, 7, 305.
  42. Yilmaz, S.; Akça, Y.; Saçlik, S. Green Husk and Inshell Biomass Production Capabilities of Six Walnut Cultivars. Agric. Food 2017, 5, 389–397. Available online: https://www.scientific-publications.net/en/article/1001431 (accessed on 20 June 2023).
  43. Fernández-Agulló, A.; Pereira, E.; Freire, M.S.; Valentão, P.; Andrade, P.B.; González-Álvarez, J.; Pereira, J.A. Influence of solvent on the antioxidant and antimicrobial properties of walnut (Juglans regia L.) green husk extracts. Ind. Crop. Prod. 2013, 42, 126–132.
  44. Solar, A.; Colaric, M.; Usenik, V.; Stampar, F. Seasonal variations of selected flavonoids, phenolic acids, and quinones in annual shoots of common walnut (Juglans regia L.). Plant Sci. 2006, 170, 453–461.
  45. Soto-Madrid, D.; Gutiérrez-Cutiño, M.; Pozo-Martínez, J.; Zúñiga-López, M.C.; Olea-Azar, C.; Matiacevich, S. Dependence of the Ripeness Stage on the Antioxidant and Antimicrobial Properties of Walnut (Juglans regia L.) Green Husk Extracts from Industrial By-Products. Molecules 2021, 26, 2878.
  46. Zhang, Q. Effects of Extraction Solvents On Phytochemicals and Antioxidant Activities of Walnut (Juglans Regia L.) Green Husk Extracts. Eur. J. Food Sci. Technol. 2015, 3, 15–21.
  47. Hama, J.R.; Omer, R.A.; Rashid, R.S.M.; Mohammad, N.E.A.; Thoss, V. The Diversity of Phenolic Compounds along Defatted Kernel, Green Husk and Leaves of Walnut (Juglans regia L.). Anal. Chem. Lett. 2016, 6, 35–46.
  48. Cosmulescu, S.N.; Trandafir, I.; Nour, V. Influence of the extraction solvent on antioxidant capacity and total phenolic in currant fruits. J. Appl. Bot. Food Qual. 2014, 87, 206–209.
  49. Jakopič, J.; Solar, A.; Colaric, M.; Hudina, M.; Veberič, R.; Stampar, F. The influence of ethanol concentration on content of total and individual phenolics in walnut alcoholic drink. Acta Aliment. 2008, 37, 233–239.
  50. Jakopič, J.; Veberič, R.; Stampar, F. Extraction of phenolic compounds from green walnut fruits in different solvents. Acta Agric. Slov. 2009, 93, 11–15.
  51. Barekat, S.; Nasirpour, A.; Keramat, J.; Dinari, M.; Meziane-Kaci, M.; Paris, C.; Desobry, S. Phytochemical Composition, Antimicrobial, Anticancer Properties, and Antioxidant Potential of Green Husk from Several Walnut Varieties (Juglans regia L.). Antioxidants 2023, 12, 52.
  52. Bolling, B.W.; McKay, D.L.; Blumberg, J.B. The phytochemical composition and antioxidant actions of tree nuts. Asia Pac. J. Clin. Nutr. 2010, 19, 117–123.
  53. Croitoru, A.; Ficai, D.; Craciun, L.; Ficai, A.; Andronescu, E. Evaluation and Exploitation of Bioactive Compounds of Walnut, (Juglans regia). Curr. Pharm. Des. 2019, 25, 119–131.
  54. Ghasemi, K.; Ghasemi, Y.; Ehteshamnia, A.; Nabavi, S.M.; Nabavi, S.F.; Ebrahimzadeh, M.A.; Pourmorad, F. Influence of environmental factors on antioxidant activity, phenol and flavonoids contents of walnut (Juglans regia L.) green husks. J. Med. Plant Res. 2011, 5, 1128–1133.
  55. Mikulic-Petkovsek, M.; Slatnar, A.; Veberic, R.; Stampar, F.; Solar, A. Phenolic response in green walnut husk after the infection with bacteria Xanthomonas arboricola pv. juglandis. Physiol. Mol. Plant Pathol. 2011, 76, 159–165.
  56. Zakaria Nizam, M.H.; Al Mamun, M.; Yousuf, M.; Ali, R.; Rahman, L.; Miah, M. Dyeing of S/J Cotton Knit Fabric with Natural Dye Extracts from Green Walnut Shells: Assessment of Mordanting Effect on Fastness Properties. J. Text. Sci. Technol. 2017, 3, 17–30.
  57. Islam, A.K.M.M.; Widhalm, J.R. Agricultural Uses of Juglone: Opportunities and Challenges. Agronomy 2020, 10, 1500.
  58. Sun, M.; Wang, Y.; Song, Z.; Fang, G. Insecticidal activities and active components of the alcohol extract from green peel of Juglans mandshurica. J. For. Res. 2007, 18, 62–64.
  59. Liu, S.; Cheng, S.; Jia, J.; Cui, J. Resource efficiency and environmental impact of juglone in Pericarpium Juglandis: A review. Front. Environ. Sci. 2022, 10, 999059.
  60. Stampar, F.; Solar, A.; Hudina, M.; Veberic, R.; Colaric, M.; Fabcic, J. Phenolics in walnut liqueur. Acta Hortic. 2007, 744, 451–454.
  61. Lockyer, S.; de la Hunty, A.E.; Steenson, S.; Spiro, A.; Stanner, S.A. Walnut consumption and health outcomes with public health relevance—A systematic review of cohort studies and randomized controlled trials published from 2017 to present. Nutr. Rev. 2023, 81, 26–54.
  62. Wang, P.; Zhong, L.; Yang, H.; Zhu, F.; Hou, X.; Wu, C.; Zhang, R.; Cheng, Y. Comparative analysis of antioxidant activities between dried and fresh walnut kernels by metabolomic approaches. LWT Food Sci. Technol. 2022, 155, 112875.
  63. Pop, A.; Fizeșan, I.; Vlase, L.; Rusu, M.E.; Cherfan, J.; Babota, M.; Gheldiu, A.M.; Tomuta, I.; Popa, D.S. Enhanced Recovery of Phenolic and Tocopherolic Compounds from Walnut (Juglans regia L.) Male Flowers Based on Process Optimization of Ultrasonic Assisted-Extraction: Phytochemical Profile and Biological Activities. Antioxidants 2021, 10, 607.
  64. Wang, G.; Han, Q.; Yan, X.; Feng, L.; Zhang, Y.; Zhang, R.; Zhang, Y. Polyphenols-rich extracts from walnut green husk prevent non-alcoholic fatty liver disease, vascular endothelial dysfunction, and colon tissue damage in rats induced by a high-fat diet. J. Funct. Foods 2021, 87, 104853.
  65. Sagawa, H.D.C.; Assis, d.A.B.R.; Zaini, P.A.; Wilmarth, P.A.; Phinney, B.S.; Moreira, L.M.; Dandekar, A.M. Proteome Analysis of Walnut Bacterial Blight Disease. Int. J. Mol. Sci. 2020, 21, 7453.
  66. Xu, H.; Wang, G.; Zhang, J.; Zhang, M.; Fu, M.; Xiang, K.; Zhang, M.; Chen, X. Identification of phenolic compounds and active antifungal ingredients of walnut in response to anthracnose (Colletotrichum gloeosporioides). Postharvest Biol. Technol. 2022, 192, 112019.
  67. Wianowska, D.; Garbaczewska, S.; Cieniecka-Roslonkiewicz, A.; Dawidowicz, A.L.; Typek, R.; Kielczewska, A. Influence of the Extraction Conditions on the Antifungal Properties of Walnut Green Husk Isolates. Anal. Lett. 2020, 53, 1970–1981.
  68. Maleita, C.; Esteves, I.; Chim, R.; Fonseca, L.; Braga, E.M.M.; Abrantes, I.; de Sousa, C.H. Naphthoquinones from Walnut Husk Residues Show Strong Nematicidal Activities against the Root-knot Nematode (Meloidogyne hispanica). ACS Sustain. Chem. Eng. 2017, 5, 3390–3398.
  69. Bai, Y.-C.; Li, B.-X.; Xu, C.-Y.; Raza, M.; Wang, Q.; Wang, Q.-Z.; Fu, Y.-N.; Hu, J.-Y.; Imoulan, A.; Hussain, M.; et al. Intercropping Walnut and Tea: Effects on Soil Nutrients, Enzyme Activity, and Microbial Communities. Front. Microbiol. 2022, 13, 852342.
More
Information
Subjects: Horticulture
Contributors MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register : , , ,
View Times: 311
Revisions: 2 times (View History)
Update Date: 20 Jul 2023
1000/1000
Video Production Service