DSC法研究6种莲子淀粉糊化和老化特性

利用差示扫描量热仪(DSC)结合Avrami 方程研究在4℃、储存两周的条件下，6种莲子淀粉的糊化和老化特性，探讨直链淀粉以及贮存时间对其热力学行为产生的影响，并用SPSS软件计算其相关性。结果表明：6种莲子淀粉的糊化温度、ΔH、老化焓、老化度以及老化速率存在着一定的差异，老化速率的大小顺序为太空莲＞美人红＞大紫红＞武植2号＞鄂莲＞洪湖莲，太空莲淀粉的老化速率是洪湖莲淀粉的1.36 倍；6种莲子淀粉的成核方式均为瞬间成核；4℃条件下贮存两周的莲子淀粉的老化度随着贮存时间的增加而增大；直链淀粉含量与Avrami 指数n值呈负相关，与速率常数k值、ΔH、老化焓以及冰融溶焓呈正相关。

Gelatinization and Retrogradation Characteristics of 6 Kinds of Lotus-seed Starches as Studied by Differential Scanning Calorimetry

The gelatinization and retrogradation characteristics of 6 kinds of lotus-seed starches stored for 2 weeks at 4 ℃ were analyzed by DSC (differential scanning calorimetry). Meanwhile, the Avrami equation was used to explore the effects of amylase content and storage time on the thermodynamics action of lotus-seed starch, and the correlation between the content of amylase and thermodynamics action was evaluated using SPSS Version 17.0. The results showed that significant differences in pasting temperature, ΔH, crystal melting enthalpy, retrogradation degree and aging rate were found among 6 kinds of lotus-seed starches; that the aging rates decreased in the order of Taikonglian, Meirenhong, Dazihong, Wuhzi No 2, Elian and Honghulian, and the aging rate of Taikonglian was 1.36 times higher than that of Honghulian; that 6 kinds of lotus-seed starches all had an instantaneous nucleation; that the degree of retrogradation of seed starches stored for 2 weeks at 4 ℃ increased with storage time prolonged; and that the content of amylase had a negative correlation with the Avrami exponent (n) and a positive correlation with the rate constant (k), ΔH, crystal melting enthalpy and ice melting enthalpy.