Rajko BERNIK, Miran LAKOTA and Denis STAJNKO
pp. 3-7

Morphological and physical characteristics of three walnut cultivars (Juglans regia L.) ‘G-139’, ‘Franquette’ and ‘Domači oreh’ were examined in the trial to determine the parameters of centrifugal machine for mechanical crushing of walnuts. Four morphological characteristics (height, diameter, weight and volume) and three physical characteristics (force, shell deformation and energy impact for shell crushing) were measured in the laboratory device. The maximum force (293.14 N) for crushing walnut shells was measured with ‘Franquette’, followed by ‘Domači oreh’ (248.30 N) and ‘G-139’ (202.5 N). The biggest shell deformation during crushing by the height (4.69 mm) was measured with ‘Domači oreh’, 4.62 mm with ‘Franquette’ and 2.58 mm with ‘G-139’, which correlate with the air volume of walnut ‘Domači oreh’ (6.33 %), ‘G-139’ (3.04 %), ‘Franquette’ (4.44 %). The most energy for crushing the shell by the nut height was required for ‘Franquette’ (1.35 J), while for crushing the shell of ‘Domači oreh’ 1.16 J and 0.52 J for ‘G-139’. According to the morphological and mechanical characteristics of the shell, the ‘Franquette’ cultivar was shown to be the most suitable for mechanical crushing on centrifugal nutcracker.

Key words: walnut, phisilogical characteristics, centrifugal nutcracker

REFERENCES

1. Aydin C. Physical properties of hazelnut. Biosystems Engineering. 2002;82/3:297-303.

2. Bernik R. Drobilnik lupinarjev, 2000, Patent št. P–200500303

3. Bernik R, Stajnko D. Usporedba morfoloških i fizikalnih svojstava plodova triju sorata lijeske (Corylus avellana L.) = A Comparison of morphological and physical characteristics of three different haselnut cultivars (Corylus avellana L.). Pomol. Croat. 2008;14/4:221-34.

4. Braga GC, Couto SM, Hara T, Neto CTPA. Mechanical behaviour of macadamia nut under compression loading. J. Agric. Eng. Res. 1999;72:239-45.

5. Dursun IG. Bazı ürünlerin nokta yükü altındaki kabuki kırılma dirençlerinin belirlenmesi [Determination of the shelling resistance of some products under the point load]. Tarımsal Mekanizasyon Ulusal Kongresi, Tokat, Turkey.1997:950-7.

6. Güner M, Dursun E, Dursun G. Mechanical behaviour of hazelnut under compression loading. Biosyst. Eng. 2003;85/4: 485-491.

7. Koyuncu MA, Ekinci K, Savran E. Cracking Characteristic of Walnut. Biosystems Engineering, 2004;87/3:305-11.

8. Ocepek R. Oreh: pridelovanje in uporaba. Ljubljana, ČZD Kmečki glas, 1995; pp 98.

9. Özdemir M, Özilgen M. Comparison of quality of hazelnuts unshelled with different sizing and cracking systems. J. Agric. Eng. Res. 1997;67:219-27.

10. Pliestic S, Dobricevic N, Filipovic D, Gospodaric Z. Physical Properties of Filbert Nut and Kernel, Biosyst. Eng. 2006;93/2:173-8.