Effect of anion type on enzymatic hydrolysis of starch-(thermostable α-amylase)-calcium system in a low-moisture solid microenvironment of bioextrusion
2020
Xu, Enbo | Li, Dandan | Cheng, Huan | Zhao, Huanhuan | Tian, Jinhu | Wu, Zhengzong | Chen, Shiguo | Ye, Xingqian | Liu, Donghong
The effect of six anions (Clˉ, OHˉ, NO₃ˉ, SO₄²ˉ, C₆H₁₀O₆²ˉ and PO₄³ˉ) on a starch (St)-enzyme (thermostable α-amylase, TαA)-calcium (Ca) system was investigated in a low-moisture solid state. Two levels of Ca salts (1 and 10 mmol/100 g St) added to potato starch with and without TαA were analyzed by FT-IR, DSC and SEM. The surface morphologies of the St-Ca complexes were different in the presence of various anions, and the residual Ca salts around the St granules might decrease the enzymatic action. For bioextrusion, TαA (0.5‰ and 1.5‰) were introduced for a relatively low Ca content (1 mmol/100 g). Significant differences in enzyme activity were observed, increasing the activity of TαA by SO₄²ˉ (146.54 %) > C₆H₁₀O₆²ˉ > Clˉ > control > NO₃ˉ > OHˉ ≈ PO₄³ˉ and C₆H₁₀O₆²ˉ (123.20 %) ≈ Clˉ ≈ SO₄²ˉ > control > PO₄³ > OHˉ > NO₃ˉ for the low and high enzyme levels, respectively.
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