CHARACTERIZATION OF TEXTURE AND MECHANICAL-PROPERTIES OF STARCH GELS

Gels of various starches, potato (PO), tapioca (TA), corn (CO), wheat (WH) were prepared under various conditions by combinations of starch concentrations (three levels) and temperatures of aging to set a gel (5 or 20-degrees-C). The mechanical parameters of the gels were measured using a compression-decompression test. The parameters of force (F) and compression work (CW) exhibited a tendency to increase as the starch concentration increased. On the other hand, resiliency (RS) and compressibility (CM) were not dependent on starch concentration and varied depending on the starch species. For PO and TA as a root (or tuber) starch, the RS value was small and the CM value was large. For CO and WH as a cereal starch, the RS value was large and CM value was small. The mechanical properties of the gels were affected by the aging temperature, where F, CW and RS generally exhibited higher values at 5-degrees-C than at 20-degrees-C, and CM somewhat lower values at 5-degrees-C. Factor analysis was performed to determine mechanical parameter data. The gels were represented by three-dimensional diagrams through their scores. This made it possible to discriminate and characterize the texture of the starch species gels.