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vol. 2, nr. 3 (2003)
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Chosen physical features of matured fruits of walnut
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Katarzyna Majewska1, Justyna Kopytowska1, Romuald E. Łojko2, Ryszard Zadernowski1
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1 Chair of Food Plant Chemistry and Processing, University of Warmia and Mazury, Plac Cieszyński 1, 10-957 Olsztyn |
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2 Belarusian Research Institute for Fruit Growing, Minsk, Byelorussia |
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vol. 2 (2003), nr. 3,
pp. 597-609
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abstract:
The aim of the present study was to determine some chosen physical properties of mature walnut (Juglans regia L.) fruit. Thirty walnut samples harvested in the North-East and South-East of Poland, Byelorussia, Moldavia, Uzbekistan and Azerbaijan were used as study material. Morphological features of the walnuts studied were evaluated by the determination of their average weight, height, width, thickness in seam, roundness index nutshell weight, bulkheads and seed. Walnut hardness was determined by compression and penetration tests using an Instron 4301 Universal Testing Machine. The walnuts studied were characterized by significant differences in their morphological features, especially an average nut weight and also nutshell, bulkhead and seed weight. Most of the walnuts were distinguished by a medium or high endocarp mass. Only in the case of 5 samples, seed content was higher than 45% of the whole fruit mass. On the basis of walnut hardness test results it was concluded that over 36.7% of the samples studied was characterized by a small and middle nutshell resistance to compression, 23.3% of the samples had a hard nutshell and only 3.3% of the samples were characterized by a very high nutshell resistance to compression. Positioning of the walnut for the compression test influenced the maximum compression load. Results of the hardness measurement of the nutshell inner part by the penetration test were characterized by less differentiation as compared to the results obtained during the compression test.
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keywords:
walnuts, morphological features, hardness, compression and penetration tests
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original in:
Polish
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