Effects of molecular characteristics of on konjac glucomannan glass transitions of potato amylose, amylopection and their mixtures.
Effects of molecular characteristics of on konjac glucomannan glass transitions of potato amylose, amylopection and their mixtures.
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DOI：
10.1002/jsfa.4247
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发表时间：
2011-03
影响因子：
4.1
通讯作者：
Li Guo;Qin Liang;Xianfeng Du
中科院分区：
文献类型：
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作者：
Li Guo;Qin Liang;Xianfeng Du
背景本研究旨在进一步探讨魔芋葡甘聚糖（KGM）在淀粉类食品中的功能。以直链淀粉/支链淀粉/魔芋葡甘聚糖混合体系为模型进行了实验。采用高速差示扫描量热法（hyper-DSC）、高效体积排阻色谱（HPSEC）、多角度激光散射（MALLS）、示差折光率（RI）、X射线衍射（XRD）和粘度法研究了魔芋葡甘聚糖（KGM）对不同直/支链淀粉比例混合物玻璃化转变温度（T（g）s）的影响。结果超差示扫描量热法（Hyper-DSC）结果表明，随着魔芋葡甘聚糖浓度的增加，直链淀粉、支链淀粉及其混合物的T（g）s均降低。基于KGM的分子特性，HPSEC-MALLS-RI、黏度测定和XRD结果表明，KGM的摩尔质量范围为1.023 × 10（6）~ 1.329 × 10（6）g mol（-1），均方根半径分布在110.5 ~ 129.6 nm，M（w）/M（n）为1.017。魔芋葡甘聚糖在溶液中为无规卷曲线型分子，结晶度为0.00%。结论魔芋葡甘聚糖的加入对直链淀粉和支链淀粉的结构有增塑作用，使直链淀粉和支链淀粉链的自由体积增大，分子运动增加，从而降低了直链淀粉和支链淀粉的T（g）s。
BACKGROUND The purpose of this study was to explore further the functions of konjac glucomannan (KGM) in starch-based foods. Experiments were carried out using the mixed amylose/amylopectin/KGM system as a model. High-speed differential scanning calorimetry (hyper-DSC) with the support of high-performance size exclusion chromatography (HPSEC) equipped with multi-angle laser light scattering (MALLS) and differential refractive index (RI), X-ray diffractometry (XRD) and viscosimetry was used to investigate the effects of KGM on glass transition temperatures (T(g) s) of mixtures with different amylose/amylopectin ratios. RESULTS Hyper-DSC results showed that the T(g) s of amylose, amylopection and their mixtures decreased with increasing concentration of KGM. Based on the molecular characteristics of KGM, HPSEC-MALLS-RI, viscosimetry and XRD results showed that the molar masses of KGM ranged from 1.023 × 10(6) to 1.329 × 10(6) g mol(-1) ; the root mean square (RMS) radii were distributed from 110.5 to 129.6 nm, and M(w) /M(n) was 1.017. KGM was a linear molecule with random-coil conformation in solution and the crystallinity was 0.00%. CONCLUSION It is suggested that the addition of KGM has plasticizing effects on the structures of amylose and amylopectin, which can increase free volume and molecular movement of amylose and amylopectin chains, resulting in a decrease in their T(g) s.