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Comparing Physical and Biochemical Properties of Dried and Fresh Kernels of Persian Walnut

Vergleich der physikalischen und biochemischen Eigenschaften getrockneter und frischer Kerne der persischen Walnuss-Sorten

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Abstract

Information about qualitative changes of walnut properties is very important for processing units of walnuts. In the present study, the physical and biochemical characteristics of fresh walnut kernels from four cultivars (Hartley, Ronde de Montignac, Damavand, and Pedro) were evaluated for 2 years. Also, biochemical and physical characteristics of kernels dried at 20 ± 1 °C, 30 ± 1 °C, and via sun drying were compared with fresh kernels for 2 consecutive years. The results showed significant variability among the studied cultivars regarding nut weight, kernel percentage (the ratio of kernel weight to nut weight × 100), fill, plumpness, weight, color, and shrivel of kernels. The oil content in fresh walnut kernels ranged from 51.11% to 45.62%, while the protein content of the kernel was 15.42–10.51 mg/g kernel. The peroxide value of the extracted oil from fresh walnut kernels varied between 0.37 meq/kg and 0.22 meq/kg oil. Kernels dried at temperatures of 20 ± 1 °C and 30 ± 1 °C as well as those that were sun dried showed significant deterioration in physical and chemical properties in comparison with fresh kernels. Damavand, a commercial Iranian cultivar, was superior with regard to most of the studied characteristics. Fresh kernels showed higher quality compared with dried ones; however, kernels dried at 20 ± 1 °C were better than those exposed to two other drying methods in terms of maintaining kernel quality. Therefore, it is recommended to do kernel drying at lower temperatures.

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Acknowledgements

The authors thank the Iran National Science Foundation, the Center of Excellence of Walnut Improvement and Technology of Iran, and the University of Tehran for their financial support.

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Authors and Affiliations

  1. Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran

    Susan Pakrah & Kourosh Vahdati

  2. Department of Horticulture, Faculty of Agriculture, Shiraz University, Shiraz, Iran

    Majid Rahemi

  3. Horticultural Science Research Institute, Agricultural Research, Education and Extension Organizations, Temperate Fruits Research Center, Karaj, Iran

    Roohallah Haghjooyan

  4. Agricultural Research, Education and Extension Organization, Rice Research Institute of Iran, Amol, Mazandaran, Iran

    Alireza Nabipour

  5. Department of Horticulture, Faculty of Agriculture, Zanjan University, Zanjan, Iran

    Farshad Kakavand

  6. Department of Horticulture, Faculty of Agriculture, Tabriz University, Tabriz, Iran

    Fatemeh Zahedzadeh

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  1. Susan Pakrah
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  2. Majid Rahemi
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  3. Roohallah Haghjooyan
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  4. Alireza Nabipour
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  5. Farshad Kakavand
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  6. Fatemeh Zahedzadeh
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  7. Kourosh Vahdati
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Correspondence to Kourosh Vahdati.

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S. Pakrah, M. Rahemi, R.H. Jooyan, A. Nabipour, F. Kakavand, F. Zahedzadeh, and K. Vahdati declare that they have no competing interests.

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Pakrah, S., Rahemi, M., Haghjooyan, R. et al. Comparing Physical and Biochemical Properties of Dried and Fresh Kernels of Persian Walnut. Erwerbs-Obstbau 64, 455–462 (2022). https://doi.org/10.1007/s10341-022-00643-4

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  • DOI: https://doi.org/10.1007/s10341-022-00643-4

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