• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.260-265
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• 2007

In this study, the quality characteristics of retort Tteok (Korean rice cake) prepared with various dextrinization times were investigated during storage. The moisture content of the retort Tteok made with dextrinized rice was 43.19-43.34% at 0 day and there were no differences in the samples during storage. As dextrinization time increased, the L value of the retort Tteok decreased, and the a and b values increased. Again there were no differences in the samples during storage. In the texture profiles, the hardness, gumminess and chewiness of the retort Tteok increased with increasing dextrinization time for all the samples, except the ones that were dextrinized for 32 minutes. The adhesiveness of the retort Tteok increased with decreasing dextrinization time, and springiness and cohesiveness did not differ among the samples. Also, the quality characteristics showed no differences after 15 days of storage. In the sensory evaluation, color, smell and delicate taste were significantly different between the retort Tteok made with rice dextrinized over 16 minutes and that made with no dextrinized rice. The retort Tteok with rice dextrinized for 16 minutes showed the highest score in the softness. Storage times up to 120 days made no differences in the sensory evaluation measurements. These results indicate that a dextrinization time of 16 minutes seems to give the best quality to retort Tteok made with dextrinized rice.

• Food Engineering Progress
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• v.13 no.4
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• pp.289-296
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• 2009

The purpose of this study was to investigate the effect of dextrinization methods (dry oven and roaster) and the ratio of dextrinized rice on the quality of Backsulgi during storage. The moisture content significantly increased with increasing the amount of dextrinized rice regardless of dextrinization methods. As the ratio of dextrinized rice increased, the L value of the Backsulgi decreased, but the a and b values increased. The a and b values of dry oven method were higher than those of roaster method due to their thermal denaturalization. However, there were no significant pattern's change in sample's colors during storage. In the texture profiles, the hardness, cohesiveness, gumminess and chewiness significantly decreased with increasing the amount of dextrinized rice depending on the dextrinization methods and the ratios. The time constant (1/k) of the Backsulgi with dextrinized rice comparatively higher than that of control and appeared to be the highest in the Backsulgi formulated by 100% of dextrinized rice. In the sensory evaluation, Backsulgi with dextrinized rice over 30% after 1day storage showed higher value in overall quality and lower value in hardness than control. The addition of 30% dextrinized rice made by roaster showed the most effective on the quality and retrogradation of Backsulgi.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.463-469
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• 1988

The effects of moisture content and particle size of rice flour on the physical properties of the extrudate were examined by using a autogeneous single screw extruder. The moisture contents tested were in the range of 17-28% and the particle sizes were 18-60mesh and 60-120mesh. Samples were taken at different temperatures from the start-up period to the steady state operation. The expansion ratio increased and bulk density decreased as the moisture content and particle size of the flour decreased. The cutting force decreased and the air cell size became uniform as the moisture content and particle size of the flour decreased. As the moisture content increased, the yellowness of the extrudate powder decreased, while the lightness increased, the apparent viscosity increased and the water soluble index decreased. Gelatinization and partial dextrinization were apparent during the extrusion process, and the degree of dextrinization was appeared to be influenced by the levels of moisture content and particle size of rice flour.

• YAKHAK HOEJI
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• v.6 no.2
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• pp.18-22
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• 1962

Purified preparation of .betha.-amylase is obtained from radish root by the means of fractional precipitation with ammonium sulfate. Purified preparation saccharifies the starch, .betha.-maltose being formed. Dextrinization in the true sense does not take place. Hydrolysis ceases when approximately 50% of the theoretical yield of maltose is obtained and there remains a substance (to be .betha.-limit dextrin) which gives a blue-violet with iodine, no glucose being formed. Stability of preparation is optimal at pH 4-9 and more completely inactivated at 65.deg. in fifteen minutes. .betha.-Amylase of radish exhibits optimal activity at and near pH 5.0, which varied depending upon the buffer. Calcium and chloride ions do not effect the activities of enzyme. The results of experiments with oxidizing, alkylating and mercaptide-forming reagents which have been reported to be specific for sulfhydryl groups confirm that free sulfhydryl groups are essential to the activity of .betha.-amylase from radish.