Breaking tester for examining strength of consolidated starch

Abstract

A b s t r a c t. A new method based on the measurement of force required to break by bending a vertical column of consolidated powder was elaborated, and its results were compared with the ones obtained from the Jenike shear test. A new apparatus was built based on a vertical cylindrical chamber divided into two cylinders connected with a horizontal hinge. The apparatus was tested with samples of potato, maize and wheat starches with moisture content of 6, 12 and 17% and with the addition of a lubricant. Results of testing revealed significant differences in measured force required to rotate the upper part of the cylinder away from the lower one. The average force varied from 0.138 N for maize starch to 0.143 N for potato starch, while, for various moisture contents, the measured force varied from 0.135 N for 6% to 0.143 N for 17% mc. The results were compared with the results of a direct shear test.

Removal of turbidity from water by using modified starch of achira, Canna edulis Ker Gawl. (Cannaceae)

“…A moisture content lower than 10% is convenient to avoid the deterioration of starches during storage [12]. Although moisture contents have been found higher to 10% in other studies [12], commercial potato starch had presented 6, 12 and 17% of moisture content [13,14]; in other results, the maize and wheat starch and potato starch presented moisture content of 6% and 4%, respectively [15]. Similar results were founded to starch of rose and white cargamanto bean, the moisture contents were 3.68 % and 6.29 %, respectively [10].…”

Determination of the Strength of Consolidated Powder Materials with a Pull-Based Tester

“…Based on the shear test, new instruments are being developed to examine the properties of granular materials at various levels of consolidation [7][8][9]. However, the assessment of powder flowability with the Jenike tester is time-consuming and complicated, and the analysis of the results provided by the apparatus is difficult and requires highly qualified staff [10]. Therefore, there is an urgent need to search for new and less complicated devices for assessing the flowability and caking properties of powders.…”

“…The tensile strength of a lumpy sample is defined as the stress required to break the two halves of the split cylinder containing the caked material [18]. A similar technique has been used by Stasiak et al [10], where the breaking strength of a column of consolidated starches was determined in a divided cylinder. Salehi et al [19] have developed a new Greenwich Caking Tester for powders characterized by low lumps and low hardness.…”