Effect of anion type on enzymatic hydrolysis of starch-(thermostable α-amylase)-calcium system in a low-moisture solid microenvironment of bioextrusion

The effect of six anions (Cl-, OH-, NO₃-, SO₄²-, C₆H₁₀O₆²- and PO₄³-) 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 SO₄²- (146.54 %) > C₆H₁₀O₆²- > Cl- > control > NO₃- > OH- ≈ PO₄³- and C₆H₁₀O₆²- (123.20 %) ≈ Cl- ≈ SO₄²- > control > PO₄³ > OH- > NO₃- for the low and high enzyme levels, respectively.

Keywords: Anion; Bioextrusion; CID: 5284359, calcium chloride (CaCl(2)); Calcium; Low-moisture solid microenvironment; PubChem CID: 13144, calcium lactate (C(6)H(10)O(6)Ca); PubChem CID: 24456, calcium phosphate (Ca(3)(PO(4))(2)); PubChem CID: 24497, calcium sulfate (CaSO(4)); PubChem CID: 24963, calcium nitrate (Ca(NO(3))(2)); PubChem CID: 6093208, calcium hydroxide (Ca(OH)(2)); Starch; Thermostable α-amylase.