Abstract
This study examined Jeung-pyun(JP) Retrogradation in samples containing 3% whole protein, 7S protein, or 11S protein(w/w) that were stored at $4^{\circ}C$ for 6, 12, 24 and 72 hr. Rheometery and differential scanning calorimetry(DSC) were used in the analysis. The pH of the dough decreased during the fermentation process, but it increased after steaming. The JP prepared with soybean protein isolate(SPI) had higher pH than the control group. During storage the textural characteristics of the JP showed effects according to the additions of SPI. After 6 hr of storage, the JP samples containing soybean flour, whole protein, 7S protein, and 11S protein had lower hardness valuse. From 4 hr to 12 hr, higher springiness values were found in the samples containing whole protein, 7S protein and 11S protein. At 0 hr, the control group had the highest cohesiveness value, but after 24 hr it presented the lowest value. For gumminess, after 6 hr of storage, the control group offered the lowest value. Whereas after 12 hr of storage the whole protein group showed the highest value, and at 24 hr, the whole protein, 7S protein, and 11S protein groups had higher values. According to the DSC results, the 11S protein group had lower enthalpy values(${\bigtriangleup}H$) suggesting that adding 11S protein to JP might improve starch retrogradation. After 72 hr of storage, the control group had the highest onset temperature($T_{o}$) and peak temperature($T_{p}$) whereas the 7S and 11S protein JP samples had higher conclusion temperatures($T_{c}$). Therefore, based on the different analysis result between the control and treatment groups, the addition of SPI to Jp had effects on retrogradation.
