共轭亚油酸对玉米淀粉理化性质的影响

Effect of Conjugated Linoleic Acid on Physical Properties of Corn Starch

摘要:

采用快速黏度分析仪、差示扫描量热仪和动态流变仪研究了共轭亚油酸对3种不同直链淀粉含量的玉米淀粉糊化性质、热学性质和流变学性质的影响。研究表明，添加相同量的共轭亚油酸使普通玉米淀粉的峰值黏度等黏度值增加，对高直链玉米淀粉和蜡质玉米淀粉的糊化性质影响不显著。添加共轭亚油酸使普通玉米淀粉糊化焓值增加，添加量为1%时其糊化焓值增加幅度最大。添加2%的共轭亚油酸使高直链玉米淀粉和蜡质玉米淀粉糊化焓值降低，其中蜡质玉米淀粉糊化焓值降低尤为明显，下降了17%。添加2%的共轭亚油酸，可抑制高直链玉米淀粉的短期老化和长期老化，老化率分别由0.45、0.63降低到0.31、0.55。添加共轭亚油酸增加3种玉米淀粉的表观黏度和稠度系数，增加普通玉米淀粉和高直链玉米淀粉的贮能模量和损耗模量，降低其tanδ值，促进其形成弹性凝胶。

Abstract:

Effect of conjugated linoleic acid on the pasting properties, thermal properties and rheological properties of corn starches with different amylose content were studied by Rapid Viscosity Analyser, Differential Scanning Calorimetry and Dynamic Rheometer. The results showed that with the equal addition of conjugated linoleic acid, the peak viscosity and some other viscosity value of common corn starch was increased. Gelatinization enthalpy of common starch was enhanced and reached the highest with addition of 1% conjugated linoleic acid. With 2% conjugated linoleic acid, gelatinization enthalpy of high-amylose corn starch and waxy corn starch was decreased. Further more, the gelatinization enthalpy of waxy corn starch was decreased significantly. In addition, short-term and long-term retrogradation of high-amylose corn starch was significantly inhibited and the aging rate was decreased from 0.45, 0.63 to 0.31, 0.55 respectively. With the addition of conjugated linoleic acid, apparent viscosity and consistency coefficient of three corn starches were increased. Storage modulus and loss modulus of common corn and high-amylose corn starch were increased, while tanδ was decresed for the addition of conjugated linoleic acid. Therefore, common corn and high-amylose corn starch could form elastic gels.