Long Jie, Zhang Bao, Li Xingfei, Zhan Xiaobei, Xu Xueming, Xie Zhengjun, Jin Zhengyu
School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China; The State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi 214122, China.
School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China; The State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
Food Chem. 2018 Jan 15;239:276-286. doi: 10.1016/j.foodchem.2017.06.117. Epub 2017 Jun 21.
In this study, pullulanase was firstly immobilized by covalent bonding onto chitosan/FeO nanoparticles or encapsulation in sol-gel after bonding onto chitosan/FeO nanoparticles, and then the immobilized pullulanase was used for the effective production of resistant starch (RS). The highest RS content (35.1%) was obtained under the optimized condition of pH 4.4, enzyme concentration of 10ASPU/g and hydrolysis time of 12h when debranched by free pullulsanase, indicating that RS content was significantly (p<0.05) increased when compared to native starch (4.3%) and autoclaved starch (12.5%). Under these conditions, the immobilized pullulanase (10ASPU/g dry starch) yielded higher RS content compared to free enzyme (10ASPU/g dry starch), especially, the pullulanse immobilized by sol-gel encapsulation yielded the highest RS content (43.4%). Moreover, compared to starches hydrolyzed by free pullulanase, starches hydrolyzed by immobilized pullulanase showed a different saccharide profile of starch hydrolysate, including a stronger peak C (MW=5.0×10), as well as exhibited an additional absorption peak around 140°C. Reusability results demonstrated that pullulanase immobilized by sol-gel encapsulation had the advantages of producing higher RS content as well as better operational stability compared to pullulanase immobilized by cross-linking. The resulting enhanced RS content generated by the process described in this work could be used as an adjunct in food processing industries.
在本研究中，首先通过共价键将支链淀粉酶固定在壳聚糖/FeO纳米颗粒上，或在固定于壳聚糖/FeO纳米颗粒后将其包封在溶胶 - 凝胶中，然后将固定化的支链淀粉酶用于有效生产抗性淀粉（RS）。当用游离支链淀粉酶进行脱支时，在pH 4.4、酶浓度为10ASPU/g和水解时间为12h的优化条件下获得了最高的RS含量（35.1%），这表明与天然淀粉（4.3%）和高压灭菌淀粉（12.5%）相比，RS含量显著（p<0.05）增加。在这些条件下，固定化支链淀粉酶（10ASPU/g干淀粉）比游离酶（10ASPU/g干淀粉）产生更高的RS含量，特别是通过溶胶 - 凝胶包封固定的支链淀粉酶产生了最高的RS含量（43.4%）。此外，与用游离支链淀粉酶水解的淀粉相比，用固定化支链淀粉酶水解的淀粉显示出不同的淀粉水解产物糖谱，包括更强的峰C（MW = 5.0×10），并且在140°C左右还出现了一个额外的吸收峰。可重复使用性结果表明，与通过交联固定的支链淀粉酶相比，通过溶胶 - 凝胶包封固定的支链淀粉酶具有产生更高RS含量以及更好操作稳定性的优点。本工作中所述工艺产生的增强的RS含量可作为食品加工业中的添加剂使用。
