脉冲电场协同酶解提高多孔淀粉制备效率及吸油率

以蜡质玉米淀粉为原料,采用脉冲电场(PEF)协同酶解制备多孔淀粉,探究其对多孔淀粉制备效率及吸油率的影响。结果表明:通过PEF改性后,淀粉水解率达到24.28%时所需的酶解时间缩短一半;在相同加酶量的条件下,通过PEF改性后,淀粉水解率为23.11%,较原淀粉显著提高,表明通过PEF改性可降低加酶量;在酶解6 h和加酶量为0.8×10~(-2) mL/g淀粉干基的条件下,经PEF改性协同酶解制备的多孔淀粉水解率为23.11%、吸油率为145.11%、比表面积为1.25 m~2/g,总孔容为4.31 cm~2/g×10~(-3),原淀粉酶解制备的多孔淀粉上述指标分别为18.38%、119.47%、1.16 m~2/g,4.15 cm~2/g×10~(-3),表明通过PEF改性提高酶解淀粉的水解率、吸油率、比表面积和总孔容。扫描电镜结果显示,PEF改性可使淀粉表面产生凹槽状结构;激光共聚焦显微镜观察显示,PEF改性提高了淀粉颗粒对淀粉酶的敏感性;热力学性质测试结果显示,PEF改性多孔淀粉的焓值低于原淀粉,表明PEF改性破坏了淀粉颗粒内部分致密的结晶区。本项研究揭示了PEF改性对淀粉颗粒及其酶解制备多孔淀粉的构效关系,为高效制备多孔淀粉提供了一个新思路,并拓展了PEF可应用的领域。

Pulsed Electric Field Combined with Enzymatic Hydrolysis Improves the Preparation Efficiency and Oil Absorption of Porous Starch

Porous starch was prepared by pulsed electric field (PEF) combined with enzymatic hydrolysis using waxy corn starch as the raw material, and their effects on the preparation efficiency and oil absorption of porous starch were studied. The results showed that after PEF modification, the hydrolysis time required when the starch hydrolysis rate reaches 24.28% was shortened by half; under the same conditions (enzyme amount and enzymolysis time), after PEF modification, the starch hydrolysis rate is 23.11%, which is significantly higher than that of the original starch. It shows that PEF treatment can shorten the time of enzymolysis and reduce the amount of enzyme added in the enzymolysis process. When PEF treated starch was subjected to enzymatic hydrolysis for 6 h using 0.8×10-2 mL/g of enzyme, the degree of hydrolysis was recorded at 23.11%, degree of oil absorption at 145.11%, specific surface area of 1.25 m2/g and total pore volume of 4.31 cm2/g×10-3. In contrast, when PEF was absent, the same enzymolysis time and amount generated lower degree of hydrolysis at 18.38%, lower degree of oil absorption at 119.47%, lower specific surface area of 1.16 m2/g and lower total pore volume at 4.15 cm2/g×10-3. Scanning electron microscopy results showed that PEF modification can produce a grooved-like structure on the starch surface. Laser confocal electron microscopy observations showed that PEF modification improves the sensitivity of starch granules to enzymes. The thermal results indicated that the enthalpy of gelatinization of PEF modified porous starch was lower than that of native starch, indicating that the PEF treatment possibly destroyed the part dense crystalline area of starch granules. This study reveals the structure-activity relationship of PEF modification on starch granules and the enzymatic hydrolysis of porous starch, provides a new idea for the efficient preparation of porous starch, and expands the application of PEF.