Study on the Production of Puffed Corn Snack with Glycerol Mono Stearate and Acid Modified Starch as Additive by Single-Screw Extruder

• Main Authors: Cheng-Kuo Wu, 吳正國
• Other Authors: 龔鳴盛
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/16669189386656272935

碩士 === 國立海洋大學 === 食品科學系碩士在職專班 === 90 === This research was to study the production of puffed corn snack by single-screw extruder. At the fixed raw material feed rate 150kg/hr, a set of fifteen of produce quality indices was tested to evaluate of extrusion upon changing the main screw speed (250-350rpm) and the amount of additive glycerol mono stearate（0-1%） or acid modified starch（0-20%）. Experiment results showed at the speed from 300 to 250 rpm without any additive, the content of yellowish residue of on ungelatinized corn starch as well as unevenness of cell homogeneity were increased. When the screw speed was increased from 300 to 350 rpm, the product expansion, whiteness and cell homogeneity were all increased. However, in the mean time, water solubility index and deformation at break, reflecting the tendency to develop stickiness in chewing as well as the loss of crispiness reaction, were increased. At around 300 rpm, although the expansion, whiteness and homogeneity of extrudate as good as those obtained at higher screw speed were not favorable. Product with most acceptable crispiness and inhibited stickiness in chewing, were accounted. In addition, the mechanical energy consumption and machine wears were reaching their minima. Thus, the screw speed at around 300 rpm seemed to be the optimized operation condition. Glycerol mono stearate additions to the raw material although would cast the depletion in expansion and whiteness of its extruded. However, 0.5% addition of its at screw speed of 300 rpm could offer most significant improvement in crispness and inhibited stickiness in chewing, the increasing hardness and brittle, as well as depressed stickiness mouth-feel by the inhibition of water solubility index. This addition of acid modified starch at level above 10% could improve cell size homogeneity of extrudates. However the significant increased of water solubility index by its addition would cause increased tendency to develop the unfavorable stickiness mouth-feel. In general, the additions of glycerol mono stearate and acid modified starch could modify their products texture toward hard/brittle and soft/brittle respectively.