Mechanical behaviour of hazelnuts used for table consumption under compression loading

• Published in: Journal of the science of food and agriculture Vol. 86; no. 8; pp. 1257 - 1262
• Main Authors: Valentini, N, Rolle, L, Stevigny, C, Zeppa, G
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-06-2006; Wiley; John Wiley and Sons, Limited
• Subjects: Biological and medical sciences; compressors; Corylus avellana; Corylus avellana L; cultivars; deformation; dimensions; Energy; energy content; Food industries; food quality; Food science; forces; Fracture toughness; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; hazelnut; hazelnuts; hulls; in-shell nuts; loads; mechanical behaviour; mechanical stress; modulus of rupture; Nuts; rupture energy and deformation; rupture force; rupture force, rupture energy and deformation; Shear loading; shear strength; shear stress; strength (mechanics); texture; texture analysis; Italy; Texture analysis; Compression; Deformation; Nuts; Use; Hazelnut; Rupture; rupture energy and deformation; Energy; Loading; Dicotyledones; Angiospermae; Corylus avellana; Spermatophyta; Betulaceae; Corylus avellana L.; hazelnut; in-shell nuts; texture analysis; mechanical behaviour; rupture force
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.2486

Nuts of four hazelnut varieties and five new selections used for table consumption were compressed at the moisture content of 6% wet basis to measure shell resistance to breakage. Rupture force, rupture energy and nut specific deformation were measured under three compression loading positions. Physical parameters of nuts were also evaluated to relate them to the data obtained by compression test measurements. Rupture force and nut specific deformation are the most discriminant parameters that can be used to describe the behaviour under compression, while rupture energy values show fewer differences among the considered varieties. The values of force required to break nut shell ranged from 322.2 to 769.3 N. The lowest values of force were generally obtained along the y-axis, the transverse axis containing the major dimension at right angles to the longitudinal axis. Nut specific deformation ranged from 3.35 to 11.76%. Correlations between physical and texture parameters showed that values of force, energy and deformation were dependent on different parameters that varied in the three considered axis. The most used varieties, Ennis and Barcelona, showed high mean values of force rupture to break shell and low deformability, while Tonda Giffoni and Tonda Bianca were easy to break. Among the new selections, L35 and B6, with mean values of force rupture less than 428 N and values of nut specific deformation higher than 8%, were suitable for table consumption.