Showing papers by "Malcolm C. Bourne published in 2007"
TL;DR: In this article, three snappy foods (cookie, beet, carrot) were fashioned into bars of rectangular or circular cross-section in lengths varying from 2.0 to 5.8 cm and they were snapped in two by mounting them in a horizontal plane on two fixed vertical supports and applying force to fracture by means of a descending beam centered between the supports in a snapping rig mounted in an Instron Universal Testing machine.
Abstract: . According to well-known formulae for the mechanics of flexure stresses, the force required to snap a test specimen of uniform rectangular cross-section is inversely proportional to its length and directly proportional to the width and the square of the thickness. For a specimen of circular cross-section, the snapping force is directly proportional to the cube of its radius and inversely proportional to its length. In order to test the validity of the theoretical models for foodstuffs, three snappy foods (cookie, beet, carrot) were fashioned into bars of rectangular or circular cross-section in lengths varying from 2.0 to 5.8 cm. The rectangular bars ranged from 0.4 to 1.0 cm in thickness and 1.5 to 3.0 cm in width. The cylindrical bars ranged from 0.253 to 0.578 cm in diameter. The bars were snapped in two by mounting them in a horizontal plane on two fixed vertical supports and applying force to fracture by means of a descending beam centered between the supports in a snapping rig mounted in an Instron Universal Testing machine. Experimental data for the commodities tested were in satisfactory agreement with the theoretical model.
35 citations
TL;DR: In this article, the authors investigated the kinetics of softening of every sample and found that the initial rapid softening followed by progressively slower softening until, after about 3h, there was little change in firmness.
Abstract: Summary
Whole soybeans and dehulled soybean cotyledons were soaked in water at ambient temperature for 0, 8 and 12h then cooked in boiling water at atmospheric pressure for up to 6h. In every case there was an initial rapid rate of softening followed by progressively slower softening until, after about 3h, there was little change in firmness. The kinetics of softening of every sample was consistent with the two substrate theory of thermal softening. The firmness ranking in descending order after 15 min cooking was no soak, whole beans > 12h, soak cotyledons > no soak, cotyledons > 8h soak, whole beans > 12h soak, whole beans. This ranking was maintained for the entire cooking period. For whole beans the soaked samples were less firm than the unsoaked samples while for the cotyledons the soaked samples were more firm than the unsoaked. This reversal in behaviour may be caused by the seed coat (skin) retarding the imbibition of water in the whole beans thus delaying the onset of enzyme activity in the bean tissue.
13 citations