银杏脱支淀粉-月桂酸复合物的结构及发酵特性

Structure and Fermentation Properties of Ginkgo Starch-Lauric Acid Complex

将提取的银杏淀粉用普鲁兰酶进行脱支,得到银杏脱支淀粉。而后将银杏脱支淀粉与月桂酸(lauric acid,LA)复合得到银杏脱支淀粉-月桂酸复合物(ginkgo starch-lauric acid complex,GSL)。采用扫描电子显微镜、分子对接、傅里叶变换红外光谱、X-射线衍射对GSL的结构进行表征,研究发现GSL扫描电子显微镜观察结果为不规则块状结构,且表面呈致密的层状结构;分子对接结果表明月桂酸可通过氢键和疏水作用进入右旋单螺旋淀粉的螺旋腔;短程有序性和长程有序性均有所增强,结晶度提高,内部结构更加致密。体外消化结果表明GSL的消化率降低约20%,抗酶解能力的提高可能是由于抗性淀粉含量显著升高,快速消化淀粉含量显著降低。肠道菌群的发酵处理,发现GSL的pH值明显降低,且产生的短链脂肪酸显著增加。综上,银杏脱支淀粉-月桂酸复合物的低消化和益生元特性,使其有望成为淀粉基新型营养食品的重要来源。

The extracted ginkgo starch was debranched using Prulanase,yielding debranched ginkgo starch.The debranched ginkgo starch was later complexed with lauric acid(lauric acid,LA)to yield the debranched ginkgo starch-lauric acid complex(ginkgo starch-lauric acid complex,GSL).The GSL complex was characterized by scanning electron microscopy,molecular docking,Fourier transform infrared spectroscopy,and Xray diffraction,it was found that the GSL had an irregular blocky structure with a dense lamellar surface as observed by scanning electron microscopy.,molecular docking results indicated that lauric acid could enter the helical cavity of the right-handed single helix starch through hydrogen bonding and hydrophobic interactions,and both short-range and long-range molecular orders were enhanced,with increased crystallinity and a denser internal structure.The in vitro digestion results showed that the digestibility of the GSL was reduced by approximately 20%.This diminished digestibility likely stems from a marked increase in the content of resistant starch coupled with a notable decrease in the content of rapidly digestible starch,enhancing the complex’s resistance to enzymatic digestion.The fermentation treatment of the intestinal flora revealed a significant reduction in the pH of the GSL and a significant increase in the production of short-chain fatty acids.In summary,the low digestibility and prebiotic properties of the GSL position it as a promising source for new starch-based nutritional foods.