酶法改性对米糠蛋白溶液流变性影响

利用NDJ-5S型粘度计,对米糠蛋白溶液(RBP-S)与酶法改性米糠蛋白溶液(EMRBP-S)流变特性进行对比研究。结果表明,EMRBP-S和RBP-S均为非牛顿流体,与RBP-S相比,EMRBP-S流变性发生改变;在不同浓度下,EMRBP-S粘度均小于RBP-S,当浓度在100 g/L以上时,差异显著(ρ<0.05);EMRBP-S粘度在不同转速下均明显低于RBP-S(ρ<0.05);在不同温度下,EMRBP-S粘度均明显低于RBP-S(ρ<0.05),尤其当温度为100℃时,RBP-S粘度急剧下降,而前者变化不明显,两者粘度差异非常显著(ρ<0.01)。当pH=pI时,EMRBP-S粘度明显大于RBP-S(ρ<0.05),而在其它pH值时后者粘度均明显大于前者(ρ<0.05);在整个24 h存放过程中,EMRBP-S粘度显著低于RBP-S(ρ<0.05);RBP-S经冻融后其粘度明显下降(ρ<0.05),而EMRBP-S经冻融后,其粘度变化不明显(ρ>0.05)。研究表明,酶法改性有利于改善米糠蛋白溶液流变学性能。

Effects of enzymatic modification on rheological properties of rice bran protein solution

In this paper,the rheological differences of rice bran protein solution(RBP-S ) and enzymatic modified rice bran protein solution(EMRBP-S ) were studied taking viscosity as indicator assayed by NDJ-5S viscometer.The results showed that both RBP-S and EMRBP-S belonged to non-Newtonian fluid.The rheology of EMRBP-S,however,changed in several aspects compared with that of RBP-S.The EMRBP-S' viscosity was less than that of RBP-S at different concentrations, and the differences were significant(p<0.05 ) when the concentration was more than 100 g/L;The viscosity of EMRBP-S was lower than that of RBP-S(p<0.05 ) at different speeds;At different temperature,the viscosity of EMRBP-S was obviously less than that of RBP-S(p<0.05 ).The latter showed a sharp decrease when the temperature reached 100℃or more,while the former did not change significantly,and the difference in viscosity was very signific ant(p<0.01 );When the pH value was equivalent to the value of pi,the EMRBP-S' viscosity was higher than that of RBP-S(p<0.05 ), however,the latter'viscosity was larger than the former'(p<0.05 ) at other pH values;During the 24 h storage,the viscosity of EMRBP-S was obviously smaller than that of RBP-S(p < 0.05 );The viscosity of RBP-S decreased significantly(p<0.05 ) after it was frozen and then was thawed,while the EMRBP-S' viscosity did not change obviously(p>0.05 ).Based on the studies of this work,it could be concluded that enzymatic modification could improve the rheological properties of rice bran protein.