| Summary: | 碩士 === 國立中興大學 === 農業機械工程學系 === 85 === waste carrot pulps was used as the additive in corn grits to
produce a highdietary fiber snack food by using a single-screw
extruder. The operationvariables were die temperature,screw
speed,and carrot pulps content. Theresponse surface methodlogy
was used to investigate the effects of operationvariables on
extrudate''s physical and chemical properties, such as
expansionratio, hardness, color values,β-carotene content,
total dietary fiber content,water solubility index, and water
absorption index.Results indicated that:1.Increasing the die
temperature, screw speed, and the ratio of carrot pulpsraised
the longitudinal expansion ratio, but decreased the expansion
ratio.Also, increasing the ratio of carrot pulps weakened the
extrudate''s structurelowered the hardness, and lifted the
redness.2.The extrudate''s β-carotene content was increased with
increasing the carrotpulps ratio, however, it was decreased with
raising the die temperature.Lifting the die temperature and
screw speed both resulted the increase of dietary fiber content.
Furthermore, the increase of the die temperature resultedin an
increase of the water solubility index. However, the increase of
the screwspeed resulted in a decrease of the water solubility
index. Water absorptionindex was independent of the screw speed
and was minimun under the conditionsof 96-99℃ die temperature
and 9.6% carrot pulps ratio.3.The optimum operation conditions
for producing the high dietary fiber snackfood by using a
single-screw extruder were as following: 98.4-103.2℃ die
temperature, 1000 rpm screw speed, and 6.8-7.2% ratio of carrot
pulps. The extrudate''s dietary fiber content was 14-15% under
the optimum operation condition.
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