• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.98-102
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• 1995

Popped popcorn generally have a regular popping direction and typical shape. But the reason and mechanism are not clear yet. This experiment was carried out to investigate the shape moulding factor of popped popcorn. Pericarp thickness of tip-cap section of kernels is slightly thicker than that of top section and this fact provides the important information to the reason. Popping starts when the moisture pressure of heated popcorn is increased and reaches at the critical pressure. Therefore, in the same moisture pressure conditions, top sections are bursted first because their pericarp section is thinner than that of tip-cap section. At the very moment tip-cap sections pull down the top sections of peri carp as bi-metal does. So kernels which removed tip-cap section showed the irregular popping shape because they lost the tip-cap pericarp function. How-ever, kernels which removed embryo showed the typical popping shape but their popping volume was small due to emition and shortage of critical moisture pressure. But kernels which removed the whole pericarp and top pericarp were not popped at all because moisture was entirely emitting out of kernels. These results suggest that the shape moulding factor of popped popcorn is the pericarp thickness differences between the top and tip-cap section of kernels.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.617-624
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• 1990

Proper processing condition of Yukwa(oil popped rice snack) for mass production and pop-ping mechanism of it were tested with Shinsun (waxy, Japonica type rice) which was excellent for Yukwa making. Optimum steaming time of dough was 15 min among 4 to 60 min and reasonable moisture content of the dough before steaming was 4895 among 48 to 53% which had good and fine texture. Acceptable stirring time of steamed dough was not significantly different among 1 to 4 min, but no stirring with much larger volume was shown very poor and too soft in texture. At the simplification test of milling method, wet milling was better then dry milling in expansion rate and high temperature treatment of dough at 6$0^{\circ}C$ gave negative effect on their quality. Extending high temperature treatment of dough, reducing sugars in the dough increased and it might be caused of starch degradation. In addition of some other protein sources to dough, Yukwa quality were in proportion to the protein content of the beans. At the long term storage of the Yukwa base, moisture absorption was different depending upon RH of atmosphere and the quality of Yukwa was inferior by storage time. By addition of some alcoholic beverage, such as Makkoli, Soju and Chungju, expansion rate and their texture were somewhat improved by increasing addition amount of them from 15% to. 30％ on dough (w/w).