A study of extrusion processing of defatted soybean flour by an indigenous single-screw extruder with different dies

• Main Authors: Chang, Jian-Jhih, 張建智
• Other Authors: Lin, Jenshinn
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/583k4m

碩士 === 國立屏東科技大學 === 食品科學系所 === 105 === Recently, some studies about high moisture texturized vegetable proteins were focused on increasing the moisture content of production. The product with texturization permutation of proteins has not been studied and able to develop into one direction to texturization of the product. Therefore, a specially designed cylindrical cooling die (182 mm long, 48 mm ϕ) with rectangular channel was used in this study. The channel dimensions are length, width and height of 155, 18 and 12 mm to be inserted with 3 levels but four rows small pieces of die-insert. There are two types of die-insert: external dimensions are length 40 mm × width 18 mm × height 4 mm of die-insert. One without opening, the other one has five mesh openings with width and height of 2 mm, spacing 1 mm. Die-insert filling the channel, here are nine combinations of opening in total. The purpose of the study was to explore the possibility of producing one direction texturized soybean protein by using the indigenous single-screw extruder with different mesh opening of combination of die-inserts. In preliminary experiments before the formal extrusion test, in the extruder operation have many encountered problems such as: the material was sticking on the screw of the extruder and lead to feeding hindered; Or further after the feeding problem was solved, the materials could not move forward and heating time was too long on the third barrel and occurred coking phenomenon; When the internal pressure of the third barrel was too high (due to the stuck die), the material was spray from the gap between the discharge barrel and the third barrel. By adjusting the material formulation, extruder operating conditions (barrel temperature, feed moisture content, feed rate), in order to make the material pass through the 3 layer×3 row of five mesh opening die more smoothly, soy protein isolate was used to instead of the defatted soybean flour. Successfully extruded 5 strips and 3 rows of one direction of the texturization of soybean protein extrudate when feed moisture content could achieved to 80%. According to the results of the final successful test, the moisture content, cooking loss, L-value, a-value, WI-value, and water retention of the extrudate increased with increasing feed moisture content, whereas a-value was decreased. No difference on protein solubility of extrudate was found. Reducing the feed moisture content contributed to the formation of internal structure of extrudate. In contrast, feed moisture content increase in extrudate improved color appearance. The results of the cutting forces in the vertical and parallel directions of the extrudate affected by the feed moisture content. The texturization strength of the product change by the decreased the feed moisture content. In the same extrudate vertical and parallel cutting strength, there are significant differences, the vertical cutting strength was greater than the parallel. The microstructure of the extrudate was observed by SEM at 40x, 100x, and 1,000x magnification. The extrudate found in Runs 46-2 and 46-3 were more similar in internal structure and preferred.