Examining Effects of Storage Duration on the Different Forms of Tocopherol and Peroxide Value in Walnut Kernel and Powder

الموضوعات :

Amir Hosseinvand ¹ , Bouchra Ikram Adja ²

1 - Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Yekaterinburg, 620002, Russia
2 - Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Yekaterinburg, 620002, Russia

تاريخ الإرسال : 27 الإثنين , رجب, 1446 تاريخ التأكيد : 17 الثلاثاء , شوال, 1446 تاريخ الإصدار : 06 الجمعة , ربيع الأول, 1447

الکلمات المفتاحية: Kernel walnut, Nut, Peroxide value, time, Tocopherol,

ملخص المقالة :

The walnut kernel (WK), which has high oil content and contains many polyunsaturated fatty acids (FFA), is considered a valuable nut with a protective effect against cardiovascular diseases. This product is sensitive to oxidation and has a short shelf life. Fat oxidation is the crucial parameter that reduces the economic value and has a negative side for consumers during storage time. The objective of present research was the evaluation of Vit E types (  and peroxide indexes during storage time (6 months) for walnut kernel and walnut powder (WP). The analysis of peroxide indicated that during storage time of this parameter increased to kernel and powder, significantly (  Moreover, testifier samples had the highest total tocopherol value. According to the results of the statistical analysis, the effect of the storage time on the tocopherol and peroxide index was bilateral. Meanwhile, there is a direct relationship between the reduction of tocopherol content and the increase of peroxide value.

المصادر:

Akbari G (2020) Molecular Mechanisms Underlying Gallic Acid Effects Against Cardiovascular Diseases: An Update Review. Avicenna Journal of Phytomedicine. 10(1), 11–23.
Asadi F, Tavan, Z, Zeidabadi, H (2022) Effect of the humidity on the peroxidation of the kerenel pistachio. Journal of Agriculture and Sustainable Environment Research. 3(3), 41-47.
Chatrabnous N, Yazdani N, Tavallali V, Vahdati K (2018) Preserving quality of fresh walnuts using plant extracts. LWT 91, 1-7.
Chatrabnous N, Yazdani N, Vahdati K (2018) Determination of nutritional value and oxidative stability of fresh walnut. Journal of Nuts. 9(1), 11-20.
Cui P, Zhou J, Xiao X, Qi B, Li S, Chen Z, Ma A, Jia Y (2025) Preparation and Properties of Walnut Oil Microcapsules. Available at SSRN 5080919.
Emami Sh, Damirchi S, Peyghambardut H (2011) Iranian standard organization council.
Habibie A, Yazdani N, Saba MK, Vahdati K (2019) Ascorbic acid incorporated with walnut green husk extract for preserving the postharvest quality of cold storage fresh walnut kernels. Scientia Horticulturae 245, 193-199.
Habibi A, Yazdani N, Chatrabnous N, Koushesh Saba M, Vahdati K (2022) Inhibition of browning via aqueous gel solution of Aloe vera: a new method for preserving fresh fruits as a case study on fresh kernels of Persian walnut. Journal of Food Science and Technology 59, 2784–2793.
Habibi A, Yazdani N, Koushesh Saba M, Chatrabnous N, Molassiotis A, Sarikhani S, Vahdati K (2023) Natural preservation and improving lipid oxidation inhibition of fresh walnut. Horticulture, Environment, and Biotechnology. 64, 133–142.
Habibie A, Yazdani N, Saba MK, Vahdati K (2021) Limitation of access to oxygen for inhibition of browning in fresh walnut kernels. Acta Horticulturae 1318, 137-140.
Habibi A, Yazdani N, Koushesh Saba M, Vahdati K (2021) Ascorbic acid preserved phenolic compounds of cold stressed fresh walnut kernels. Acta Horticulturae 1315, 665-668.
Hassankhah A, Vahdati K, Rahemi M, Hassani D, Sarikhani Khorami S (2017) Persian walnut phenology: effect of chilling and heat requirements on budbreak and flowering date. International Journal of Horticultural Science and Technology. 4(2), 259-271.
Ifeh C, Okolo C, Odoh EN (2024) Quality evaluation of biscuits produced from wheat, high-quality cassava, and african walnut composite flours. Journal of Scientific and Engineering Research. 11(1), 32-40.
Jahanbani R, Ghaffari SM, Salami M, Vahdati K, Sepehri H, Namazi Sarvestani N, Sheibani N, Moosavi-Movahedi AA (2016) Antioxidant and anticancer activities of walnut (Juglans regia L.) protein hydrolysates using different proteases. Plant Foods and Human Nutrition. 71, 402-409.
Jahanbani R, Ghaffari SM, Vahdati K, Salami M, Khalesi MR, Sheibani N, Moosavi-Movahedi AA (2018) Kinetics study of protein hydrolysis and inhibition of angiotensin converting enzyme by peptides hydrolysate extracted from walnut. International Journal of Peptide Research and Therapeutics. 24(1), 77-85.
Jahanbani R, Bahramnejad E, Rahimi N, Shafaroodi H, Sheibani N, Moosavi-Movahedi AA, Dehpour A, Vahdati K (2021). Anti-seizure effects of walnut peptides in mouse models of induced seizure: The involvement of GABA and nitric oxide pathways. Epilepsy Research, p.106727.
Kornsteiner M, Karl-Heinz W, Ibrahim E (2006) Tocopherols and phenolics in 10 different nut types. Food Chemistry. 98, 381-387.
Martínez E, Pardo JE, Álvarez-Ortí M, Martínez-Navarro M.E, Rabadán A (2025) Sensory and Lipid Profile Optimization of Functional Brownies Through Cold-Pressed Nut Oil Substitution for Butter. Applied Sciences. 15(1), 454.
Nosirov B, Qobulova M, Raxmonova B, Shermatov O, Xojiboyev M (2024) Ways to improve the efficiency of nut production in terms of food safety. Science Promotion. 10(1), 502-507.
Park SK, Page GP, Kim K, Allison DB, Meydani M, Weindruch R, Prolla TA (2008) Alpha- and gamma-tocopherol prevent age-related transcriptional alterations in the heart and brain of mice. Journal of Nutrition. 138, 1010-1018
Pakrah S, Rahemi M, Nabipour A, Zahedzadeh F, Kakavand F, Vahdati K (2021) Sensory and nutritional attributes of Persian walnut kernel influenced by maturity stage, drying method, and cultivar. Journal of Food Processing and Preservation, e15513.
Pakrah S, Rahemi M, Haghjooyan R, Nabipour A, Kakavand F, Zahedzadeh F, Vahdati K (2022) Comparing physical and biochemical properties of dried and fresh kernels of Persian walnut. Erwerbs-Obstbau, 1-8
Pal A, Suresh S, Khan A, Kuo LH, Chi LT, Ganguly A, Kao CY, Sharma MK, Wang TSA, Kang DY, Lin ZH (2025) Metal-organic frameworks as thermocatalysts for hydrogen peroxide generation and environmental antibacterial applications. Science Advances. 11(2), eads4711.
Pascoalino LA, Pires TC, Pinela J, Rodrigues MÂ, Ferreira IC, Barros L, Barreira JC, Reis FS (2025) Foliar application of biostimulants improves nutritional and bioactive quality of walnuts. Journal of the Science of Food and Agriculture. 105(2), 1138-1146.
Qingyang L, Shuting W, Ruohui W, Danyu S, Runhong M, Fubin T, Yihua L (2024) Comparative investigation on the phenolic compounds and antioxidant capacity of walnut kernel from different drying methods. Food Production, Processing and Nutrition. 61, 41-48.




Rabadán A, Pardo JE, Gómez R.,Álvarez-Ortí M (2018) Evaluation of physical parameters of walnut and walnut products obtained by cold pressing. Lwt. 91, 308-314.

Rashki M, Ghasemzadeh R, Boskabady MH (2025) Nutritional Advantages of Walnut (Juglans regia L.) for Cardiovascular Diseases: A Comprehensive Review. Food Science & Nutrition. 13(1), p.e4526.
Richard D, K Kefi, U Barbe, P Bausero, F Visioli (2008) Polyunsaturated Fatty Acids as Antioxidants. Pharmacological Research. 57(6), 451–455.
Roozban MR, Mohamadi N and Vahdati K (2006) Fat content and fatty acid composition of four Iranian pistachio varieties grown in Iran. Acta Horticulturae. 726, 573-577.
Sarikhani S, Vahdati K, Ligterink W (2021) Biochemical properties of superior persian walnut genotypes originated from southwest of Iran. International Journal of Horticultural Science and Technology. 8(1), 13-24.
Schwartz H, Ollilainen V, Piironen V, Lampi AM (2008) Tocopherol, tocotrienol and plant sterol contents of vegetable oils and industrial fats. Journal of Food Composition and Analysis. 21, 152-16.
Tahmasbian I, Wallace HM, Gama T, Bai SH (2021) An automated non-destructive prediction of peroxide value and free fatty acid level in mixed nut samples. LWT. 143, 110893.
Zhang X, Zhan X, Liu W, Wang T, Zhang T, Wei C(2025) Prolonging the oxidative stability of walnut oil by endogenous antioxidants: Phytosterol compounding for improved antioxidant capacity. Journal of Food Composition and Analysis. 137, 106931.

نص كامل:



 

 

 

ORIGINAL ARTICLE 

 

Examining Effects of Storage Duration on the Different Forms of Tocopherol and Peroxide Value in Walnut Kernel and Powder

Amir Hosseinvand*, Bouchra Ikram Adja

Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Yekaterinburg, 620002, Russia 

Introduction

 

K E Y W O R D S		A B S T R A C T
Kernel walnut; Nut; Peroxide value; time; Tocopherol		The walnut kernel (WK), which has high oil content and contains many polyunsaturated fatty acids (FFA), is considered a valuable nut with a protective effect against cardiovascular diseases. This product is sensitive to oxidation and has a short shelf life. Fat oxidation is the crucial parameter that reduces the economic value and has a negative side for consumers during storage time. The objective of present research was the evaluation of Vit E types ( and peroxide indexes during storage time (6 months) for walnut kernel and walnut powder (WP). The analysis of peroxide indicated that during storage time of this parameter increased to kernel and powder, significantly ( Moreover, testifier samples had the highest total tocopherol value. According to the results of the statistical analysis, the effect of the storage time on the tocopherol and peroxide index was bilateral. Meanwhile, there is a direct relationship between the reduction of tocopherol content and the increase of peroxide value.

*Corresponding author: Email address: [e-mail]  Received: 27 January 2025; Received in revised form: 16 November 2024; Accepted: 15 April 2025 DOI: 10.60680/10.60680/jon.2025.1197772

Walnut have bioactive compounds, including caffeic acid, ferulic acid, and phenolic compounds like juglon, which have been demonstrated to improve lipid profiles, blood pressure, endothelial function, inflammation, oxidative stress, and thrombosis (Jahanbani et al., 2016, 2018, 2021). The kernel of walnuts has a high nutrient value food because of its high concentration of proteins, unsaturated fatty acids, triglycerides, tocopherols, vitamins minerals, and phenolic acids such as Gallic acid (Hassankhah et al., 2017; Habibie et al., 2019, 2021a, 2021b; Sarikhani et al., 2021; Habibi et al., 2022, 2023; Quyingyang et al., 2024). Carbohydrates such as pectic compounds and other polyphenols are abundant in these nuts, contributing to their overall nutritional profile (Rashki et al., 2025). Unsaturated fatty acids in walnuts have been shown to provide health benefits, such as cardio-protective effects including lowering blood cholesterol levels and providing antioxidant protection (Richard et al. 2008). Peroxide number is measured as the amount of peroxide in the oil (Chatrabnous et al., 2018, 2019). Heat, oxygen, and metal (Cu) are among the factors that intensify oxidation and it also found that this index shows a good correlation with organoleptic properties (Pal et al., 2025). There various research papers indicated that application of walnut powder as a novel, functional and rich in nutrition value natural ingredient to apply in food formulations to enhances physicochemical and sensory evaluation properties (Nosirov et al., 2024; Ifeh et al., 2024; ). In the case of study, Scientifics stated that the peroxide number of butter replacement by walnut powder showed lower values than the standard of the Iranian organization (Emami, et al., 2011; Pakrah et al., 2021, 2022). Therefore, this study  was performed to the effect of different walnut types (kernel and powder) on tocopherol and peroxide number properties, during storage time at laboratory temperature (20 for 180 days).

Materials and Methods

Tocopherol measurement

About  of the extracted oil was dissolved in  of heptane and 10 ml was injected into the HPLC device. Tocopherol with a particle size of  and a mobile phase mixture of Lichrosphere 100  filled with LichroCART 250-4 column of Heptane: Tert butyl ether and Methanol: tetrahydrofuran (0.2:0.89; 20:79) at a speed of  separated per minute. For determination, the fluorescence detector was used at the wavelength of 294 nm and  respectively for excitation and emission. Based on the retention time of tocopherol in the oil samples, the foreign standard method was used to determine the amount.

Peroxide number

 Of the sample was weighed in an Erlenmeyer sandblasted lid.  chloroform acetic acid mixture and then  of saturated potassium iodide solution were added to it and placed in a cover after adding potassium iodide, the resulting mixture was kept in the dark for 1 minute. After this step,  of distilled water and  of starch solution were added and titrated with sodium thiosulfate. The peroxide number was calculated using the following equation (Pascoalino et al., 2025). 

Peroxide number = (1)

Where N is the volume of the sodium thiosulphate used a sample in ml and m is the mass of the walnut sample in g. Measurements (in triplicate) were conducted within the period 6 months (Tahmasbian et al., 2021).

Statistical analysis

Each experiment was carried out in triplicates with at least 3 independent cultures with comparable results. Data are reported as mean± SD in at least three experiments. Comparisons between groups were made by student test  was considered statistically significant.

Results

Analysis of tocopherols

The results of tocopherol and peroxidate value of WK and WP during storage times are displayed in Tables 1 - 5. Compared to testifiers before storage times, the concentration of tocopherols decreased by increasing storage of time and differences were significant ( 

 

 

Table1. α-Tocopherol concentration during storage time.

Different letters within the same row represent significant differences (p<0.05).Means ±standard deviation

 

 

 

Table 2. β-Tocopherol concentration during storage time.

	Before storage	30 Days	60 Days	90 Days	120 Days	150 Days	180 Days
Walnut kernel	375a	370.1a	367.27b	360.14±0.36b	351.41±0.33c	340.40±0.20c	329.60±0.11d
Walnut powder	369.11±0.22a	360.47±0.27a	359.78±0.33b	349.10±0.10b	338.11±0.24c	329.20±0.33c	316.11±054d

Different letters within the same row represent significant differences (p<0.05).Means ±standard deviation

 

Table 3. γ-Tocopherol concentration during storage time.

	Before storage	30Days	60 Days	90 Days	120 Days	150 Days	180 Days
Walnut kernel	20.99±0.22a	1910±0.97a	18.17±0.36a	17.87±0.39a	15.22±0.36b	14.12±0.39b	13.28±058b
Walnut powder	18.33±0.35a	17.77±0.99a	16.90±0.37a	15.97±0.64a	14.44±0.49b	13.11±0.98b	11.10±0.39b

Different letters within the same row represent significant differences (p<0.05).Means ±standard deviation

 

Table 4. δ-Tocopherol concentration during storage time.

	Before Storage	30 Days	60 Days	90 Days	120 Days	150 Days	180 Days
Walnut kernel	17. 22±0.88a	16.55±0.21a	15.77±0.25a	14.25±087b	13.58±0.55b	12.22±0.98c	10.11±0.25c
Walnut powder	15.50±0.59a	14.40±0.32a	13.30±0.19a	12.20±0.80b	11.10±0.98b	9.30±0.39b	7.20±0.39c

	δ-Tocopherol
	Before storage	30 Days	60 Days	90 Days	120 Days	150 Days	180Days
Walnut kernel	27.11±0.22a	20.11±0.10a	17.22±0.23b	14.11±011b	12.32±0.28c	11.11±0.65c	10.24±0.74d
Walnut powder	25.02±0.30a	19.13±0.79a	16.25±0.69a	14.98±0.35a	11.21±0.25c	9.98±0.20c	8.99±0.25d

Different letters within the same row represent significant differences (p<0.05).Means ±standard deviation

 

Table 5. Total tocopherol concentration during storage time.

	Total- Tocopherol
	Before storage	30 Days	60 Days	90 Days	120 Days	150 Days	180 Days
Walnut kernel	408.01±0.02a	403.02±0.01a	393.02±0.41b	389.50±0.09b	380.77±0.21c	370.14±0.71c	361.17±0.11d
Walnut powder	405.25±0.10a	400.08±0.2a	392.11±0.91b	387.29±0.81c	377.22±0.01c	366.36±0.50c	356.67±0.31d

Different letters within the same row represent significant differences (.Means standard deviation

 

Peroxide number

 

Table 6 shows the peroxide value of treatments after 6 months of storage. Results of the current study showed that there was a continued increase in tocopherol peroxide level during storage time. WK and WP samples before storage had the lowest peroxide value compared to samples after storage time. Significant differences (p > 0.05) among treatments at each time point of the storage time. So, the increase in peroxide value attributed to temperature and storage time. 

 

 

Table 6. Peroxide value of WK and WP during storage time

	Peroxide value
	Before storage	30 Days	60 Days	90 Days	120 Days	150 Days	180 Days
Walnut kernel	1.70±0.22a	2.22±0.29a	2.90±0.59a	3.19±0.87a	3.90±0.17a	4.19±0.98b	4.59±22b
Walnut Powder	1.90±0.29a	2.23±0.88a	2.99±0.47a	3.59±0.29b	4.19±0.87b	5..49±0.78b	6.10±0.80c

Different letters within the same row represent significant differences (p<0.05).Means ±standard deviation

 

 

Discussion

 

Tocopherols, especially α and γ tocopherols, are the most abundant natural antioxidants in vegetable oils (Park et al., 2008). The data in the tables indicated that walnut kernel had the excellent amount of tocopherol and amount of this vitamin was from 408 -361 g g-1 for kernel walnut and 405-356 g g-1 for walnut powder during storage time. These values are higher than those reported with researchers in other walnut varieties (Akbari & Shahidi, 2008). Moreover, present results were in good agreement by previous scientific research (Schwrtzet al., 2008 and Kornsteiner et al, 2006). Scientific reports stated that in France and the USA, the content of Vit E in walnuts decreased during storage time. They emphasized contents of β tocopherol and γ tocopherol reduced in fresh and stored kernels for 3 momth at 4℃. They found that gamma-tocopherol is the major tocopherol in walnut oil. The quantity of tocopherol depends on some parameters such as variety and cultivation conditions in agriculture like genotype and mutation. Meanwhile, researchers pointed out that some phenomena like cultivation in the warm season (spring and summer) could positively affect the tocopherol concentrations in almonds by warmer temperatures. In addition, the increase in tocopherol concentration content might be attributed to the preservation of plant oxidation damage in drought conditions (Kodad et al., 2018). The present study tries to investigate the effort of different parameters on the peroxide value of WK and WP samples. In WP samples, moisture enters the oil from oxygen and accelerates the oxidation.An Oxygen molecule acts as an electron acceptor in oxidation and causes the transfer of electrons from oils, which leads to the formation of free radicals of atoms with extra electron. Present radicals, react with other chemical compounds in walnut unsaturated fatty acids (Linoleic acid and oleic acid) and can begin oxidation chains. In brief, humidity is one of the most important factors affecting the oxidation of nuts. One of the substances produced by the oxidation of fats are peroxides, which are compounds containing two oxygen molecules that can react with fats and fatty acids in cells and produce a substance called Malondialdehyde (MDA), which is a Diketone compound it’s one of the common mutagen and cancer factors for health (Roozban et al., 2006). In addition, peroxide values in vegetable oils are 10(Asadi et al, 2022). The present results were in good agreement with the scientific report.

Conclusions 

Walnut oils are made up of a myriad of fatty acids, which include polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), and saturated fatty acids (SUFA). In summation, the storage period of walnuts hurts their quality in terms of an increase in peroxide values and a decrease in the tocopherol content. Walnuts also possess multiple health-related bioactive compounds, including anticancer, antibacterial, cardiovascular, and antibiotic activities. Simultaneously, in the field of agricultural science, several natural and environmental factors like genotype, cultivar, and cultivation origin directly influence physicochemical properties of the end product. Further, a remarkable variation exists in terms of quality and quantity regarding the composition of tocopherol and fatty acid among different varieties.

Conflict of interests

No conflict.

References

Akbari G (2020) Molecular Mechanisms Underlying Gallic Acid Effects Against Cardiovascular Diseases: An Update Review. Avicenna Journal of Phytomedicine. 10(1), 11–23.

Asadi F, Tavan, Z, Zeidabadi, H (2022) Effect of the humidity on the peroxidation of the kerenel pistachio. Journal of Agriculture and Sustainable Environment Research. 3(3), 41-47. 

Chatrabnous N, Yazdani N, Tavallali V, Vahdati K (2018) Preserving quality of fresh walnuts using plant extracts. LWT 91, 1-7.

Chatrabnous N, Yazdani N, Vahdati K (2018) Determination of nutritional value and oxidative stability of fresh walnut. Journal of Nuts. 9(1), 11-20.

Cui P, Zhou J, Xiao X, Qi B, Li S, Chen Z, Ma A, Jia Y (2025) Preparation and Properties of Walnut Oil Microcapsules. Available at SSRN 5080919.

Emami Sh, Damirchi S, Peyghambardut H (2011) Iranian standard organization council.

Habibie A, Yazdani N, Saba MK, Vahdati K (2019) Ascorbic acid incorporated with walnut green husk extract for preserving the postharvest quality of cold storage fresh walnut kernels. Scientia Horticulturae 245, 193-199.

Habibi A, Yazdani N, Chatrabnous N, Koushesh Saba M, Vahdati K (2022) Inhibition of browning via aqueous gel solution of Aloe vera: a new method for preserving fresh fruits as a case study on fresh kernels of Persian walnut. Journal of Food Science and Technology 59, 2784–2793.

Habibi A, Yazdani N, Koushesh Saba M, Chatrabnous N, Molassiotis A, Sarikhani S, Vahdati K (2023) Natural preservation and improving lipid oxidation inhibition of fresh walnut. Horticulture, Environment, and Biotechnology. 64, 133–142.

Habibie A, Yazdani N, Saba MK, Vahdati K (2021) Limitation of access to oxygen for inhibition of browning in fresh walnut kernels. Acta Horticulturae 1318, 137-140.

Habibi A, Yazdani N, Koushesh Saba M, Vahdati K (2021) Ascorbic acid preserved phenolic compounds of cold stressed fresh walnut kernels. Acta Horticulturae 1315, 665-668.

Hassankhah A, Vahdati K, Rahemi M, Hassani D, Sarikhani Khorami S (2017) Persian walnut phenology: effect of chilling and heat requirements on budbreak and flowering date. International Journal of Horticultural Science and Technology. 4(2), 259-271.

Ifeh C, Okolo C, Odoh EN (2024) Quality evaluation of biscuits produced from wheat, high-quality cassava, and african walnut composite flours. Journal of Scientific and Engineering Research. 11(1), 32-40.

Jahanbani R, Ghaffari SM, Salami M, Vahdati K, Sepehri H, Namazi Sarvestani N, Sheibani N, Moosavi-Movahedi AA (2016) Antioxidant and anticancer activities of walnut (Juglans regia L.) protein hydrolysates using different proteases. Plant Foods and Human Nutrition. 71, 402-409.

Jahanbani R, Ghaffari SM, Vahdati K, Salami M, Khalesi MR, Sheibani N, Moosavi-Movahedi AA (2018) Kinetics study of protein hydrolysis and inhibition of angiotensin converting enzyme by peptides hydrolysate extracted from walnut. International Journal of Peptide Research and Therapeutics. 24(1), 77-85.

Jahanbani R, Bahramnejad E, Rahimi N, Shafaroodi H, Sheibani N, Moosavi-Movahedi AA, Dehpour A, Vahdati K (2021). Anti-seizure effects of walnut peptides in mouse models of induced seizure: The involvement of GABA and nitric oxide pathways. Epilepsy Research, p.106727.

Kornsteiner M, Karl-Heinz W, Ibrahim E (2006) Tocopherols and phenolics in 10 different nut types. Food Chemistry. 98, 381-387.

Martínez E, Pardo JE, Álvarez-Ortí M, Martínez-Navarro M.E, Rabadán A (2025) Sensory and Lipid Profile Optimization of Functional Brownies Through Cold-Pressed Nut Oil Substitution for Butter. Applied Sciences. 15(1), 454.

Nosirov B, Qobulova M, Raxmonova B, Shermatov O, Xojiboyev M (2024) Ways to improve the efficiency of nut production in terms of food safety. Science Promotion. 10(1), 502-507.

Park SK, Page GP, Kim K, Allison DB, Meydani M, Weindruch R, Prolla TA (2008) Alpha- and gamma-tocopherol prevent age-related transcriptional alterations in the heart and brain of mice. Journal of Nutrition. 138, 1010-1018

Pakrah S, Rahemi M, Nabipour A, Zahedzadeh F, Kakavand F, Vahdati K (2021) Sensory and nutritional attributes of Persian walnut kernel influenced by maturity stage, drying method, and cultivar. Journal of Food Processing and Preservation, e15513.

Pakrah S, Rahemi M, Haghjooyan R, Nabipour A, Kakavand F, Zahedzadeh F, Vahdati K (2022) Comparing physical and biochemical properties of dried and fresh kernels of Persian walnut. Erwerbs-Obstbau, 1-8

Pal A, Suresh S, Khan A, Kuo LH, Chi LT, Ganguly A, Kao CY, Sharma MK, Wang TSA, Kang DY, Lin ZH (2025) Metal-organic frameworks as thermocatalysts for hydrogen peroxide generation and environmental antibacterial applications. Science Advances. 11(2), eads4711.

Pascoalino LA, Pires TC, Pinela J, Rodrigues MÂ, Ferreira IC, Barros L, Barreira JC, Reis FS (2025) Foliar application of biostimulants improves nutritional and bioactive quality of walnuts. Journal of the Science of Food and Agriculture. 105(2), 1138-1146.

Qingyang L, Shuting W, Ruohui W, Danyu S, Runhong M, Fubin T, Yihua L (2024) Comparative investigation on the phenolic compounds and antioxidant capacity of walnut kernel from different drying

 

methods. Food Production, Processing and Nutrition. 61, 41-48.

Rabadán A, Pardo JE, Gómez R.,Álvarez-Ortí M (2018) Evaluation of physical parameters of walnut and walnut products obtained by cold pressing. Lwt. 91, 308-314.

 

Rashki M, Ghasemzadeh R, Boskabady MH (2025) Nutritional Advantages of Walnut (Juglans regia L.) for Cardiovascular Diseases: A Comprehensive Review. Food Science & Nutrition. 13(1), p.e4526.

Richard D, K Kefi, U Barbe, P Bausero, F Visioli (2008) Polyunsaturated Fatty Acids as Antioxidants. Pharmacological Research. 57(6), 451–455.

Roozban MR, Mohamadi N and Vahdati K (2006) Fat content and fatty acid composition of four Iranian pistachio varieties grown in Iran. Acta Horticulturae. 726, 573-577.

Sarikhani S, Vahdati K, Ligterink W (2021) Biochemical properties of superior persian walnut genotypes originated from southwest of Iran. International Journal of Horticultural Science and Technology. 8(1), 13-24.

Schwartz H, Ollilainen V, Piironen V, Lampi AM (2008) Tocopherol, tocotrienol and plant sterol contents of vegetable oils and industrial fats. Journal of Food Composition and Analysis. 21, 152-16.

Tahmasbian I, Wallace HM, Gama T, Bai SH (2021) An automated non-destructive prediction of peroxide value and free fatty acid level in mixed nut samples. LWT. 143, 110893.

Zhang X, Zhan X, Liu W, Wang T, Zhang T, Wei C(2025) Prolonging the oxidative stability of walnut oil by endogenous antioxidants: Phytosterol compounding for improved antioxidant capacity. Journal of Food Composition and Analysis. 137, 106931.

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