Abstract
A novel prototype of a modified centrifugal sheller was evaluated in terms of undamaged kernels, damaged kernels, fragments of kernels and unbroken nuts. Trials were carried out with walnut varieties ‘Elit’, ‘Franquette’ and ‘G-139’. First, morphological characteristics (fruit height, width, thickness), relative moisture content and walnut shell strength was measured on randomly selected samples. The maximum force was measured at constant weight of dried nuts perpendicular to the longitudinal axis in ‘Elit’ (287.38 ±107.09 N) followed by ‘Franquette’ (223.36 ±101.00 N) and ‘G-139’ (98.08 ±30.76 N). Shelling walnuts with the centrifugal sheller resulted best output in ‘Franquette’ with 78.05% of whole undamaged kernels, 8.76% of damaged kernels and 7.15% of fragments, while 6.05% remains unbroken; ‘Elit’ only 76.42% of whole kernels, 10.02% of damaged kernels, 9.48% of fragments and 4.08% unbroken nuts. ‘G-139’ gave significantly poorer quality with 60.05% of whole kernels, 21.43% of damaged kernels and 13.63% of fragments and 4.89% unbroken nuts. The output of whole kernels yielded by modified centrifugal sheller is in significant correlation with the walnut thickness of particular variety.
Zusammenfassung
Ein neuer Prototyp eines modifizierten Zentrifugalschälers wurde in Bezug auf unbeschädigte Kerne, beschädigte Kerne, Kernfragmente und ungebrochene Nüsse bewertet. Versuche wurden mit den Walnusssorten ‘Elit‘, ‘Franquette‘ und ‘G-139’ durchgeführt. Zuerst wurden die morphologischen Eigenschaften (Fruchthöhe, -breite, -dicke), der relative Feuchtigkeitsgehalt und die Walnussschalenfestigkeit an zufällig ausgewählten Proben gemessen. Die maximale Kraft wurde bei konstantem Gewicht der getrockneten Nüsse senkrecht zur Längsachse bei ‘Elit’ (287,38 ±107,09 N) gefolgt von ‘Franquette’ (223,36 ±101,00 N) und ‘G-139’ (98,08 ±30,76 N) gemessen. Walnüsse, die mit dem Zentrifugalschäler geschält wurden, ergaben mit 78,05 % unbeschädigter Kerne, 8,76 % geschädigter Kerne und 7,15 % Fragmenten den besten Ertrag bei ‘Franquette’, während 6,05 % ungebrochen blieben; während ‘Elit’ nur 76,42 % ganze Kerne, 10,02 % beschädigte Kerne, 9,48 % Fragmente und 4,08 % ungebrochene Nüsse erbrachte. ‘G-139’ ergab eine signifikant schlechtere Qualität mit 60,05 % ganzen Kernen, 21,43 % beschädigten Kernen und 13,63 % Fragmenten und 4,89 % ungebrochenen Nüssen. Die Ausbeute an ganzen Kernen, die durch einen modifizierten Zentrifugalschäler erreicht werden, steht in signifikanter Korrelation zum Fruchtdurchmesser einer Sorte.
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The authors acknowledges the financial grant from Biotechnical Faculty and Faculty of Mechanical Engineering, University of Ljubljana, Slovenia
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R. Bernik, D. Stajnko and I. Demšar declare that they have no competing interests.
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Bernik, R., Stajnko, D. & Demšar, I. Comparison of the Kernel Quality of Different Walnuts (Juglans regia L.) Varieties Shelled with Modified Centrifugal Sheller. Erwerbs-Obstbau 62, 213–220 (2020). https://doi.org/10.1007/s10341-020-00473-2
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DOI: https://doi.org/10.1007/s10341-020-00473-2