Role of skin in compression of berry-like fruits between two plates
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Department of Physics, University of Agriculture, 16521 Praha 6 - Suchdol, Czech Republic
Publication date: 2021-08-17
Int. Agrophys. 1994, 8(3): 381–387
Berry-like fruits of cultural plants (currant, vine grapes, aronia) and natural growing plants (lilac elder, rowan berry, bilberry, cowberry, cranberry) were tested by compression between two plates in time of their maturity. Moreover, currant berries were compressed repeatedly for five weeks (before and after the picking maturity). It was found that compression curves are composed from two simple parts, that can be described by power relations a=aEn, where a and n are parameters, typical for every different part, different berries and different stage of maturity. Strength of berries generally decreases in time of maturity and in the same time the maximal relative deformation of the tested berries increases at first and decreases later (Em=0.35-0.47). The strength of the tested berries has been taken as a basis for estimation of maximum meridian stress in the berries skin. The obtained results are comparable with the strength of a tomato skin, that have been determined in direct tension test of samples prepared from the skin by cutting.