Studies on Mechanical Properties of Agricultural Products (II)

On Menchanical Strength of the Tomato During Growing, Ripening and Storage

Abstract

In 1958, this experiment was conducted on mechanical properties of tomatoes (FUKUJU NO. 2) during growing, ripening and storage.
A series of compression creep and relaxation tests was run at 10mm/min. on a commercial testing machin, the Tensilon Model UTM-4 (Fig. 1 on the part 14), with a flat disk 6mm in dia meter plunger and a disk 150mm in dia meter. to measure certain mechanical properties of it.
The following tendencies were found.
1) Rupture force of tomatoes by plunger compression continues to decrease during growing, ripening and storage, but the amount of deformation upto the rupture point continues to increase.
2) Toughness of tomatoes tends to be the largest at about the harvest time throughout the period of growing, ripening and storage.
The higher storage temperatures, the faster the over-ripening rate.
4) In creep and relaxation tests, the behavier of the products could be represented by a 4-element model with springs and dashpots.
5) Unripening flesh had such large viscocity that the recovery in creep and recovery test was conducted perfectly, and was disregarded. η₃ Therefore, the behavier of green flesh in relaxation test also might be represented by a 3-element model (Fig. 9-a).