Mechanical properties of potato starch modified by moisture content and addition of lubricant

Abstract

A b s t r a c t. Laboratory testing was conducted to deliver a set of characteristics of structure and mechanical properties of pure starch and starch with an addition of a lubricant -magnesium stearate. Considerable influence of moisture content of potato starch was found in the case of density, parameters of internal friction, coefficients of wall friction and flowability. Elasticity was found to be strongly influenced by water content of the material. Addition of magnesium stearate affected density and parameters of flowability, internal friction and elasticity. Bulk density increased from 604 to 774 kg m -3 with decrease in moisture content of potato starch from 17 to for 6%. Addition of magnesium stearate resulted in approximately 10% decrease in bulk density. Angle of internal friction obtained for 10 kPa of consolidation stress decreased from 33 to 24º with increase in moisture content, and to approximately 22º with addition of the lubricant. With an increase of moisture content from 6 to 18% and with addition of the lubricant, the modulus of elasticity during loading decreased from approximately 1.0 to 0.1 MPa. Modulus of elasticity during unloading was found in the range from 19 to 42 MPa and increased with increase of moisture content and amount of lubricant.

Breaking tester for examining strength of consolidated starch

“…The presented results showed that the new method for determination of breaking force allows the estimation of strength of potato, wheat and maize starches at three levels of moisture content and with the addition of a lubricant. The obtained results reflected different behaviour of potato starch compared to wheat and maize starches, which has been observed earlier in standard tests (Stasiak et al, 2013(Stasiak et al, , 2014. …”

“…The relationship s c (s 1 ), characterises the ability of a powder to flow and is termed the flow function of the material, FF (Jenike, 1961;Molenda et al, 2006). Mechanical properties of potato starch given in this article are cited from our earlier work (Stasiak et al, 2014).…”

Physicochemical properties of starch obtained from Curcuma karnatakensis - A new botanical source for high amylose content

“…However, the maximum recommended moisture content for safe storage is 13% (ISI, 1970;Radley, 1976). Moisture content has been found to strongly influence the density of potato starch (Statsiak et al, 2014). Climatic factors play an important role in regulation of moisture content.…”

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].…”