Effects of Rice Bran Dietary Fiber Extract on Gelatinization and Retrogradation of Wheat Flour

미강 식이섬유 추출물이 밀가루의 호화 및 노화에 미치는 영향

Rapid visco-analyzer (RVA) and differential scanning calorimetry (DSC) were used to study the effect of rice bran dietary fiber extract on gelatinization and retrogradation of wheat flour. The addition of rice bran dietary fiber extracts from various heat treated bran into wheat flour caused to increase the pasting temperature, peak viscosity and final viscosity of RVA measurements. For gelatinization measured with DSC, mixtures of wheat flour and rice bran dietary fiber extract had slightly higher To (onset temperature) and Tp (peak temperature) values than those of control (wheat flour), and wheat flour/defatted rice bran dietary fiber extract mixture had the lowest enthalpy value. In comparison with gelatinization, the retrogradation endotherm of mixtures stored at $4^{\circ}C$ up to 4 weeks occurred at about $20^{\circ}C$ lower temperatures than gelatinization endotherm with broader shape and well-defined thermograms with storage time. The retrogradation of wheat flour was retarded greatly by addition of rice bran dietary fiber extract, and there was no big difference between 5% and 10% additions.

미강 식이섬유 추출물이 밀가루의 호화 및 노화에 미치는 영향을 조사하기 위하여 여러방법으로 열처리한 미강 식이섬유 추출물을 첨가하여 호화 및 노화현상을 RVA와 DSC로 측정하여 조사하였다. 그결과 미강 식이섬유 추출물 첨가는 대조구에 비해 호화온도, 최고점도 및 최종점도를 증가시켰다. 미강 식이섬유 추출물을 첨가한 시료들을 DSC로 측정했을 때 To, Tp 및 ${\triangle}H$값들은 탈지미강 식이섬유 추출물을 첨가한 시료에 영향을 받지 않았다. 노화시 나타난 endothermic peak는 호화시보다 약 $15{\sim}20^{\circ}C$ 낮은 온도에서 폭이 넓은 형태로 나타났으며, 저장기간이 길어질수록 뚜렷한 endothermic peak를 보였다. 미강 식이섬유 추출물을 첨가한 시료들은 노화지연 효과를 보였으며, 5%와 10% 첨가시료들 사이에는 큰 차이가 없었다.