Thermal properties of whole and tissue parts of pomegranate (Punica granatum) fruit

  • Matia Mukama
  • Alemayehu Ambaw
  • Umezuruike Linus OparaEmail author
Original Paper


The thermal properties of two pomegranate fruit cultivars (Wonderful and Acco) and their epicarp, mesocarp and arils were experimentally determined. A transient heating probe system was first calibrated and used for accurate measurement of the specific heat capacity, thermal conductivity, and thermal diffusivity over a temperature range of 7–45 °C. The thermophysical properties did not vary significantly between the two cultivars. The density of the whole ‘Wonderful’ and ‘Acco’ fruit was 986.99 ± 23.82 and 1041.23 ± 18.93 kg m−3, respectively. The epicarp of both cultivars had significantly lower density compared to the mesocarp and arils. The values of thermal conductivity and diffusivity of the two pomegranate cultivars increased significantly with increase in tissue temperature. In both cultivars, the aril part was observed to have the highest values of thermal conductivity and specific heat capacity. For ‘Acco’ at 7 °C, values were 0.419 ± 0.047 W m−1 K−1 and 2775.244 ± 298.120 J kg−1 K−1, respectively, compared to the mesocarp (0.352 ± 0.040 W m−1 K−1 and 2560.803 ± 231.028 J kg−1 K−1) and epicarp (0.389 ± 0.030 W m−1 K−1 and 2681.888 ± 135.460 J kg−1 K−1). For both ‘Wonderful’ and ‘Acco’, the in-plane thermal property values (measured along layers of peel slices) were the same as the cross-plane property values (measured through layers of slices).


Thermal conductivity probe Heat exchange Temperature effect Transport phenomena Effective thermal properties 



This work is based upon research supported by the South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation. The project was supported through contract research with Agri-Edge Ltd funded by the Department of Trade and Industry (dti) through the Technology and Human Resources for Industry Programme (THRIP). We acknowledge the award of postgraduate scholarship to Mr M Mukama by DAAD (In-Region Scholarship Programme) and the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM) for support.


  1. 1.
    A.H. Rahmani, M.A. Alsahli, S.A. Almatroodi, Active constituents of pomegranates (Punica granatum) as potential candidates in the management of health through modulation of biological activities. Pharmacognosy J. 9, 689–695 (2017)CrossRefGoogle Scholar
  2. 2.
    M. Erkan, A. Dogan, (2018). Pomegranate/Roma—Punica granatum. In Exotic Fruits (pp. 355–361)Google Scholar
  3. 3.
    CBI Centre for the Promotion of Imports from developing countries, (2010). Exporting fresh pomegranates to Europe. Accessed 21 Nov 2018.
  4. 4.
    POMASA, (2018). Pomegranate Association of South Africa. Accessed 21 Nov 2018. 16/11/18
  5. 5.
    U.L. Opara, M.R. Al-Ani, Y.S. Al-Shuaibi, Physico-chemical properties, vitamin C content, and antimicrobial properties of pomegranate fruit (Punica granatum L.). Food Bioprocess Technol. 2, 315–321 (2009)CrossRefGoogle Scholar
  6. 6.
    O.A. Fawole, U.L. Opara, Effects of storage temperature and duration on physiological responses of pomegranate fruit. Ind. Crops Prod. 47, 300–309 (2013)CrossRefGoogle Scholar
  7. 7.
    E. Arendse, O.A. Fawole, U.L. Opara, Influence of storage temperature and duration on postharvest physico-chemical and mechanical properties of pomegranate fruit arils. CyTA-J. Food 12, 389–398 (2014)CrossRefGoogle Scholar
  8. 8.
    A. Ambaw, M. Mukama, U.L. Opara, Analysis of the effects of package design on the rate and uniformity of cooling of stacked pomegranates: numerical and experimental studies. Comput. Electron. Agric. 136, 3–24 (2017)CrossRefGoogle Scholar
  9. 9.
    M. Mukama, A. Ambaw, T.M. Berry, U.L. Opara, Analysing the dynamics of quality loss during precooling and ambient storage of pomegranate fruit. J. Food Eng. 245, 166–173 (2019)CrossRefGoogle Scholar
  10. 10.
    S.M. Elyatem, A.A. Kader, Postharvest physiology and storage behaviour of pomegranate fruits. Sci. Hortic. 24, 287–298 (1984)CrossRefGoogle Scholar
  11. 11.
    R. Ben-Arie, E. Or, The development and control of husk scald on ‘Wonderful’ pomegranate fruit during storage. J. Am. Soc. Hortic. Sci. 3, 395–399 (1986)Google Scholar
  12. 12.
    A.I. Koksal, Research on the storage of pomegranate (cv. Gok Bahce) under different conditions. Acta Hortic. 258, 295–302 (1989)CrossRefGoogle Scholar
  13. 13.
    A.A. Kader, Postharvest biology and technology of pomegranates, in Pomegranates: Ancient roots to modern medicine, ed. by N.P. Seeram, R.N. Schulman, D. Heber (CRC Press, Boca Raton, 2006), pp. 211–220Google Scholar
  14. 14.
    M. Mukama, A. Ambaw, T.M. Berry, U.L. Opara, Energy usage of forced air precooling of pomegranate fruit inside ventilated cartons. J. Food Eng. 215, 126–133 (2017)CrossRefGoogle Scholar
  15. 15.
    R.P. Singh, Heating and cooling processes for foods, in Handbook of Food Engineering, 2nd edn., ed. by D.R. Heldman, D.B. Lund (CRC Press, Boca Raton, 2006), pp. 397–426Google Scholar
  16. 16.
    J.K. Carson, J. Wang, M.F. North, D.J. Cleland, Effective thermal conductivity prediction of foods using composition and temperature data. J. Food Eng. 175, 65–73 (2016)CrossRefGoogle Scholar
  17. 17.
    N.N. Mohsenin, Thermal properties of food and agricultural materials (Gordon and Breach, New York, 1980), pp. 2–246Google Scholar
  18. 18.
    V.E. Sweat, Thermal properties of foods, in Engineering Properties of Foods, 2nd edn., ed. by M.A. Rao, S.S. Rizvi (CRC Press, Boca Raton, 1994), pp. 99–138Google Scholar
  19. 19.
    O.J. Ikegwu, F.C. Ekwu, Thermal and physical properties of some tropical fruits and their juices in Nigeria. J. Food Technol. 7, 38–42 (2009)Google Scholar
  20. 20.
    R. Espinoza-Guevara, J. Caro-Corrales, C. Ordorica- Falomir, J. Zazueta-Morales, M. Veja-Garcia, K. Cronin, Thermophysical properties of pulp and rind of papaya cv. Maradol. Int. J. Food Properties 13, 65–74 (2009)CrossRefGoogle Scholar
  21. 21.
    F.J. Cuesta, M.D. Alvarez, Mathematical modelling for heat conduction in stone fruits. Int. J. Refrig 80, 120–129 (2017)CrossRefGoogle Scholar
  22. 22.
    H. Lisowa, M. Wujec, T. Lis, Influence of temperature and variety on the thermal properties of apples. Int. Agrophys. 16, 43–52 (2002)Google Scholar
  23. 23.
    V.E. Sweat, Experimental values of thermal conductivity of selected fruits and vegetables. J. Food Sci. 39, 1080–1091 (1974)CrossRefGoogle Scholar
  24. 24.
    A.K. Aremu, O.K. Fadele, Moisture dependent thermal properties of doum palm fruit (Hyphaene Thebaica). J. Emerg. Trends Eng. Appl. Sci. 1, 199–204 (2010)Google Scholar
  25. 25.
    S.K. Modi, B.D. Prasad, M. Basavaraj, The influence of moisture content and density on thermal conductivity of Ficus Carica Linnaus (Fig Fruit) by transient line heat source method. Int. J. Eng. Innov. Technol., 177–180 (2013)Google Scholar
  26. 26.
    A. Farinu, O. Baiik, Thermal properties of sweet potato with its moisture content and temperature. Int. J. Food Prop. 10, 703–719 (2007)CrossRefGoogle Scholar
  27. 27.
    I. Mamani, Modelling of thermal properties of Persian walnut kernel as a function of moisture content and temperature using response surface methodology. J. Food Process. Preserv. 39, 2762–2772 (2015)CrossRefGoogle Scholar
  28. 28.
    J.E. Lozano, M.J. Urbicain, R. Rotstein, Thermal conductivity of apples as a function of moisture content. J. Food Sci. 44, 724–728 (1979)CrossRefGoogle Scholar
  29. 29.
    R.F. Zabalaga, I.A.F. Carla, C.T. Carmen, Experimental determination of thermophysical properties of unripe banana slices (Musa cavendishii) during convective drying. J. Food Eng. 187, 62–69 (2016)CrossRefGoogle Scholar
  30. 30.
    M. Mukama, A. Ambaw, U.L. Opara, Analysis of the thermal and bio-physical properties of pomegranate fruit. Acta Hortic. 1201, 273–280 (2018)CrossRefGoogle Scholar
  31. 31.
    O.K. Owolarafe, M.T. Olabige, M.O. Faborode, Physical and mechanical properties of two varieties of fresh oil palm fruit. J. Food Eng. 78, 1228–1232 (2007)CrossRefGoogle Scholar
  32. 32.
    M. Umeta, C.E. West, H. Fufa, Content of zinc, iron, calcium and their absorption inhibitors in foods commonly consumed in Ethiopia. J. Food Compos. Anal. 18, 803–817 (2005)CrossRefGoogle Scholar
  33. 33.
    F.A. Al-Said, U.L. Opara, R.A. Al-Yahyai, Physico-chemical and textural quality attributes of pomegranate cultivars (Punica granatum L.) grown in the Sultanate of Oman. J. Food Eng. 90, 129–134 (2009)CrossRefGoogle Scholar
  34. 34.
    Z. Li, N. Kobayashi, Determination of moisture diffusivity by thermo-gravimetric analysis under non-isothermal condition. Dry. Technol. 23, 1331–1342 (2005)CrossRefGoogle Scholar
  35. 35.
    Decagon Devices, Inc. KD2 Pro Thermal Properties Analyser Operator’s Manual. 2365 NE Hopkins Court Pullman WA 99163.
  36. 36.
    A. Rozanski, D. Stefaniuk, On the prediction of the thermal conductivity of saturated clayey soils: effect of the specific surface area. Acta Geodyn. Geomater. 13, 184 (2016)Google Scholar
  37. 37.
    A. Różański, M. Sobótka, On the interpretation of the needle probe test results: thermal conductivity measurement of clayey soils. Studia Geotechnica Mechanica 35, 195–207 (2013)CrossRefGoogle Scholar
  38. 38.
    M. Schwarz, K.P. Weiss, R. Heller, W.H. Fietz, Thermal conductivity measurement of HTS tapes and stacks for current lead applications. Fusion Eng. Des. 84, 1748–1750 (2009)CrossRefGoogle Scholar
  39. 39.
    R.L. Costa, V. Vlassov, Evaluation of inherent uncertainties of the homogeneous effective thermal conductivity approach in modelling of printed circuit boards for space applications. J. Electron. Cooling Thermal Control 3, 35–41 (2013)CrossRefGoogle Scholar
  40. 40.
    D. Zhao, X. Qian, X. Gu, S.A. Jajja, R. Yang, Measurement techniques for thermal conductivity and interfacial thermal conductance of bulk and thin film materials. J. Electron. Packag. 138(040802-1-), 040802–040819 (2016)CrossRefGoogle Scholar
  41. 41.
    A. Tehranifar, M. Zarei, Z. Nemati, B. Esfandiyari, M.R. Vazifeshenas, Investigation of physico-chemical properties and antioxidant activity of twenty Iranian pomegranate (Punica granatum L.) cultivars. Sci. Hortic. 126, 180–185 (2010)CrossRefGoogle Scholar
  42. 42.
    X.G. Liang, Y. Zhang, X. Gek, The measurement of thermal conductivities of solid fruits and vegetables. Meas. Sci. Technol. 10, N82–N86 (1999)CrossRefGoogle Scholar
  43. 43.
    S.M.T. Gharibzahedi, M. Ghahderijani, Z.S. Lajevardi, Specific heat, thermal conductivity and thermal diffusivity of red lentil seed as a function of moisture content. J. Food Process. Preserv. 38, 1807–1811 (2014)CrossRefGoogle Scholar
  44. 44.
    Y. Choi, M.R. Okos, Thermal properties of liquid foods—review, in 1983 meeting of the American Society of Agricultural Engineers, Chicago, iii. Paper No. 83-6516, (1983)Google Scholar
  45. 45.
    USDA Nutrient Database for Standard Reference. U.S. Department of Agriculture, Washington, D.C., (1996)Google Scholar
  46. 46.
    M.A. Rao, S.S. Rizvi, A.K. Datta, J. Ahmed, Engineering properties of foods, 4th edn. (CRC Press, Boca Raton, 2014), pp. 223–247CrossRefGoogle Scholar
  47. 47.
    C. Ratti, A.S. Mujumdar, Fixed—bed batch drying of shrinking particles with time varying drying air conditions. Dry. Technol. 11, 1311–1335 (1993)CrossRefGoogle Scholar
  48. 48.
    H.S. Ramaswamy, M.A. Tung, Thermophysical properties of apples in relation to freezing. J. Food Sci. 46, 724–728 (1981)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Matia Mukama
    • 1
  • Alemayehu Ambaw
    • 2
  • Umezuruike Linus Opara
    • 1
    • 2
    Email author
  1. 1.Postharvest Technology Research Laboratory, South African Research Chair in Postharvest Technology, Department of Food Science, Faculty of AgriSciencesStellenbosch UniversityStellenboschSouth Africa
  2. 2.Postharvest Technology Research Laboratory, South African Research Chair in Postharvest Technology, Department of Horticultural Science, Faculty of AgriSciencesStellenbosch UniversityStellenboschSouth Africa

Personalised recommendations