School of Biological Science and Biotechnology, Minnan Normal University, 36 Xianqianzhi Street, Zhangzhou 363000, Fujian, People's Republic of China; Key Laboratory of Agro-products Processing Technology at Jilin Provincial Universities, Changchun University, 6543 Weixing Road, Changchun 130022, Jilin, People's Republic of China.
Key Laboratory of Agro-products Processing Technology at Jilin Provincial Universities, Changchun University, 6543 Weixing Road, Changchun 130022, Jilin, People's Republic of China.
Food Chem. 2019 Mar 30;277:1-5. doi: 10.1016/j.foodchem.2018.10.092. Epub 2018 Oct 22.
We describe a novel method for enzymatic production of slowly digestible starch (SDS) at 100 °C. A hyperthermophilic amylopullulanase from archaeon Staphylothermus marinus (SMApu) was expressed in a generally recognised as safe (GRAS) microorganism, Bacillus subtilis. Purified SMApu at 80-240 U/g substrate was incubated with 0.1 g/mL of corn starch in a boiling water bath for 2 h. SDS content of the SMApu-modified starch increased significantly from 17.4 to 42.7% (P < 0.05). Molecular weight and amylopectin branch chains A (DP 6-12) of SMApu-modified starch were significantly lower, and amylose content and amylopectin branch chains B1 (DP 13-24) significantly higher (P < 0.05), than those of natural corn starch. These changes in molecular structure partially explained the reduced digestibility. High optimal temperature of SMApu facilitated the simultaneous gelatinisation and hydrolysis of cereal starch. These results demonstrate that SMApu has potential applications in the production of SDS during thermal processing of cereal foods.
我们描述了一种在 100°C 下酶法生产缓慢消化淀粉 (SDS) 的新方法。一种来自古细菌葡萄球菌（SMApu）的嗜热淀粉 pullulanase 在被普遍认为安全（GRAS）的微生物枯草芽孢杆菌中表达。纯化的 SMApu 在 80-240 U/g 底物的条件下，在沸水浴中孵育 2 小时，与 0.1 g/mL 的玉米淀粉一起。SMApu 改性淀粉的 SDS 含量显著增加（P<0.05），从 17.4%增加到 42.7%。SMApu 改性淀粉的分子量和支链 A（DP 6-12）显著降低，直链淀粉含量和支链 B1（DP 13-24）显著升高（P<0.05），与天然玉米淀粉相比。这些分子结构的变化部分解释了消化率的降低。SMApu 的高最适温度促进了谷物淀粉的同时糊化和水解。这些结果表明，SMApu 在谷物食品热加工过程中生产 SDS 方面具有潜在的应用价值。
