Section E Quality and Post-harvest Processing Fine Structure and Water Solubility of Tartary Buckwheat Materials Processed in Different Methods

Abstract: This study is conducted to prepare high quality raw materials for food processing by processing different parts of Tartary buckwheat in different methods. Fine structure and water solubility were compared among different materials processed in different ways. Young sprouts(9 days-old), whole grains, and matured stems of Tartary buckwheat were used in this experiment. The materials were dried in a far infrared drier at 60 "(; to less than 8 % in water content(Wb) ' Three kinds of raw materials were processed in three kinds of methods: hyperfinely grinded powder, roasted powder, and extruded powder. Fine structure of each raw material processed differently was observed by Field Emission Scanning Electron Microscope(S4300, HITACHI, Japan). Water ' Solubility Index (WSI) was measured by centrifuging mixture of milled powder Ig and water 20 ml in 1452Orpm(2000 x g) speed for 10min and by calculating percent ratio of the supernatant to weight of powder tested. In sprout-derived and stem-derived powder, extruded one was finest; 13.677 ImI in sprout and 18.2121m1 in stem. Fine structure of seed-derived powder was spherical type in hyperfinely grinded powder but blocky type in roasted powder, which seems to be attributed to gelatinization of starch by heat during the roasting. Extruded powder showed a blocky type structure of which surface are enclosed with a number of small crystal structures due to starch gelatinization. Water solubility of sprout-derived powder was respectively 15.74%, 16.17%, and 23.70 % in hyperfinely grinded powder, roasted powder, and extruded powder obtained from sprouts, seeds, and stems of Tartary buckwheat