Evaluation of Shelf Life of Walnut Kernels Treated by Antioxidants and Different Packaging under Two Temperatures

Document Type: Research Article


1 Department of Horticultural Science and Agronomy, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Engineering Research, West Azerbaijan Agricultural, Education and Natural Resources Research Center, AREEO, Urmia, Iran

3 Department of Horticulture, University of Tehran, Tehran, Iran


In this study, the effects of coatings made of chitosan (Chi) incorporating thyme essential oil (TEO) on lipid oxidation and changing color indexes of walnut kernels were investigated. Chi: pure, in accompany with TEO at concentrations of 500 and 1000 microliter per liter, in an aqueous coating solution, with different packaging methods: Gunny sack, polypropylene and active packaging, compared with control walnut, were used and stored at 4ºC and 25ºC. The study was performed as factorial experiment based on a complete randomized design. The results showed that amounts of color indexes in treated samples decreased. The samples stored at 4°C contained minimum moisture fluctuations in all packaging methods. The peroxide values and conjugated diene values at 4°C were lower than those at 25°C. Treatments did not have positive effect on free fatty acids of walnut kernels. During the storage, shelf life of walnut kernels prolonged with active packaging and chitosan coating at 4ºC.


Ana Rita V, Ferreira Narcisa M, Bandarra Margarida MM, Isabel MC, Vítor DA (2018) Fuco Pol and chitosan bilayer films for walnut kernels and oil preservation.LWT-Food Science and Technology. 91, 34-39.

AOAC (2012) Official Methods of Analysis, 19 th Ed. Arlington, VA, AOAC International, Washington, Dc, USA.

AOCS (2003) American Oil Chemists’ Society. In Official Methods and Recommended Practices of the American Oil Chemists’ Society, 5th ed. (D. Firestone, ed.). AOCS, Champaign. pp.111.

Avramiuc M (2009) The peroxide index evolution of some nonrefined maize and sunflower oils, under the influence of storage conditions. Journal of Agroalimentary Processes and Technologies. 15(3), 382-386.

Brockgreitens J, Abbas A (2016) Responsive food packaging: Recent progress and technological prospects. Comprehensive Reviews in Food Science and Food Safety. 15(1), 3-15.

Chang HL, Chen, YC, Tan FJ) 2011( Antioxidative properties of a chitosan–glucose maillard reaction product and its effect on pork qualities during refrigerated storage. Food Chemistry.124(2), 589-595.

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

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

Cheniany M, Ebrahimzadeh H, Vahdati K, Preece J, Masoudinejad A, Mirmasoumi M (2013) Content of different groups of phenolic compounds in microshoots of Juglans regia cultivars and studies on antioxidant activity. Acta Physiologia Plantarum. 35:443–450.

Eliseeva L, Yurina O, Hovhannisyan N (2017) Nuts as raw material for confectionary industry. Annals of Agrarian Science. 15, 71-74.

Gunstone  FD, Padley FB (1997) Lipid Technologies and Applications. Marcel Dekker Inc., New York. pp.834.

Hill B, Roger T, Vorhagen FW (1997) Comparative Analysis of the Quantization of Color Spaces on the Basis of the CIELAB colordifference formula. Association for Computing Machinery Transactions on Graphics, ACM Transactions on Graphics. 16(2), 109-154.

IUPAC (1992) Standard methods for the analysis of oils fats and derivatives, 1st supplement to 7th edition. International Union of Pure and Applied Chemistry. Pergamon Press, Oxford. pp.151.

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.

Jensen PN, Sorensen G, Engelsen SB, Bertelsen G (2001) Evaluation of quality changes in walnut kernels (Juglans regia L.) by Vis/NIR Spectroscopy. Journal Agriculture Food chemistry. 49(12), 5790-5796.

Kanner J (2007) Dietary advanced lipid oxidation end products are risk factors to human health. Molecular Nutrition & Food Research 51, 1094-1101. Special Issue: Are Dietary AGEs/ALEs a Health?

Leahu A, Damian C, Oroian M, Hretcanu CE (2013) Estimation of biochemical properties of walnuts from the region of Suceava-Romania, Food and Environment Safety. 12 (2), 169-175.

Leahu A, Oroian M, Ropciuc S (2016) The quality and stability of walnut oil under the influence of storage conditions. Article licensed under a Creative Commons Attribution Non Commercial-Share Alike 4.0 International License.

Maftoonazad N, Ramaswamy HS (2005) Postharvest shelf-life extension of avocados using methyl cellulose-based coating. LWT-Food Science and Technology. 38, 617–624.

Maftoonazad N, Ramasway HS, Marcotte M (2008) Shelf life extension of peaches through sodium alginate and methyl cellulose edible coatings. Journal of Food Science Technology. 43, 951- 957.

Maghsoudlou A, Maghsoudlou Y, Khomeiri M, Ghorbani M (2012) Evaluation of anti-fungal activity of chitosan and its effect on the moisture absorption and organoleptic characteristics of pistachio nuts. International Journal of Advanced Science Engineer and Technology. 2, 65–69.

Martinez ML, Penci MC, Ixtaina, V, Ribotta, PD, Maestri D (2013) Effect of natural and synthetic antioxidants on the oxidative stability of walnut oil under different storage conditions. LWT-Food Science and Technology. 51(1), 44-50.

Mate JI, Saltveit E, Krochat JM (1996) Peanut and walnut rancidity: Effect of oxygen concentration and relative humidity. Journal Food Science. 61, 463-465.

Mexis SF, Badeka AV, Riganakos KA, Karakostas KX, Kontominas MG (2009) Effect of packaging and storage conditions on quality of shelled walnuts. Food Control. 20, 743-751.

Nielson SS (2003) Food Analysis Laboratory Manual. New York: Kluwer Academic/Plenum Publishers. pp.108.

Pathare PB, Opara UL, Al-Said FAJ (2013) Color measurement and analysis in fresh and processed foods: a review. Food and Bioprocess Technology. 6, 36-60.

Raal A, Paaver U, Arak E, Orav A (2004) Content and composition of the essential oil of Thymus serpyllum L. growing wild in Estonia. Medicina (Kaunas). 40 (8), 795-799.

Salcedo CL, Lopez de Mishima BA, Nazareno MA (2010) Walnuts and almounds as model system of foods constituted by oxidisable, prooxidant and antioxidant factors. Food Research International. 43, 1187-1197.

Seyed MAR, Taghizadeh M (2007) The specific heat of pistachio nuts as affected by moisture content, temperature, and variety. Journal of Food Engineering. 79, 158–167.

Shah UN, Mir JI,  Ahmed N, Zaid A, Jan S, Fazili KM, Wani SH (2018) Bio-techniques for improvement of qualitative and quantitative traits in walnut (Juglans regia). Advances in Horticulture Science. 32(1), 113-135.

Sze-Tao KWC, Shridhar KS (2000) "Walnuts (Juglans regia L): proximate composition, protein solubility, protein amino acid composition and protein in vitro digestibility. Journal of the Science of Food and Agriculture. 80(9), 1393-1401.

Trandafir I, Cosmulescu S, Nour V (2017) Phenolic profile and antioxidant capacity of walnut extract as influenced by the extraction method and solvent. International Journal of Food Engineering. 13(1), 1-11.

Vaidya B, Eun JB (2013) Effect of roasting on oxidative and tocopherol stability of walnut oil during storage in the dark. European Journal of Lipid Science and Technology. 115(3),348-355.

Vanhanen LP, Savage GP (2006) The use of peroxide value as a measure of quality for walnut flour stored at five different temperatures using three different types of packaging. Food Chemistry. 99(1), 64-69.