Effect of Soybean Protein Isolate on the Baking Qualities of Bread

분리 대두단백질의 첨가가 제빵적성에 미치는 영향

This study was conducted to investigate the effect of soybean protein isolate (SPI) on the baking qualities of bread which was made of composite flour blended with SPI extracted at acidic (pH 2.0, 3.0), neutral (pH 7.0) and alkaline (pH 10.0, 12.0) conditions. The mixogram showed that water absorption of composite flour dough blended with SPI extracted at pH 2.0 and 12.0 was higher than that of 100% wheat flour dough, and mixing time was shorter than that of 100% wheat flour dough. No differences were found between the composite flour blended with SPI at level of 5% and 100% wheat flour on the loaf volume of bread. The loaf volume of bread made of composite flour blended with $SPI_2\;AND\;SPI_3$ at level of 10% was lower than that of 100% wheat flour, but that of $SPI_7,\;SPI_{10},\;and\;SPI_{12}$, which had higher emulsion capacity than $SPI_2,\;SPI_3$ was similar to that of 100% wheat flour. No differences were found between the composite flour blended with SPI at level of 5% and that of 100% wheat flour on springiness, chewiness, cohesiveness, gumminess, adhesiveness and hardness of bread. The composite flour blended with SPI at level of 10% was similar to 100% wheat flour on springiness, chewiness, cohesiveness, gumminess, adhesiveness and hardness of bread except for chewiness, gumminess and hardness of $SPI_2,\;and\;SPI_{12}$ which were significantly higher than that of 100% wheat flour (P<0.05).

산성, 중성 및 알칼리성 영역에서 각각 추출된 SPI를 첨가시킨 복합분의 제빵적성에 미치는 영향을 조사하였으며 제빵적성은 빵의 용적과 조직감을 측정하여 판정하였다. Mixograph를 이용하여 측정된 SPI-밀가루 복합분 반죽의 물리적 성질에서 pH 2.0과 12.0에서 추출된 SPI를 첨가한 복합분 반죽의 수분흡수율이 100% 밀가루 반죽의 수분흡수율보다 컸으며 SPI-밀가루 복합분의 반죽형성시간은 100% 밀가루 반죽에 비해 SPI의 종류에 관계없이 모두 감소하였다. 5% SPI-빵의 용적은 100% 밀가루로 만들어진 빵과 차이가 없었으며, 10% SPI-빵의 경우 $SPI_2$와 $SPI_3$-빵의 용적은 대조구보다 감소하였으나 $SPI_7,\;SPI_{10}$ 및 $SPI_{12}$-빵의 용적은 차이가 없었다. 또한 유화형성력이 큰 $SPI_7,\;SPI_{10},\;SPI_{12}$-빵의 용적이 유화형성력이 작은 $SPI_2,\;SPI_3$-빵 보다 크게 나타났다. 5% SPI-빵의 탄성, 씹힘성, 응집성, 껌성, 부착성 및 견고성은 대조구와 큰 차이를 나타내지 않았으며, 10% SPI-빵의 경우 $SPI_2$와 $SPI_{12}$-빵의 씹힘성, 껌성, 견고성에 있어 유의차를 보이며 증가하였고(P< 0.05) 대조구에 비해 전체적으로 큰 차이를 보이지 않았다.