Chung H-J, Liu Q
Guelph Food Research Centre, Agriculture and Agri-Food Canada, Guelph, ON, Canada.
J Food Sci. 2009 Jun;74(5):C353-61. doi: 10.1111/j.1750-3841.2009.01159.x.
Carboxyl content and amylose leaching of gamma-irradiated corn starch increased and swelling factor decreased with increasing radiation dose. The apparent amylose content decreased gradually from 28.7% for native starch to 20.9% for 50 kGy irradiated starch. The proportion of short amylopectin branch chains (DP 6 to 12) increased, while the proportion of longer branch chains (DP > or = 37) decreased with increasing radiation dose. The relative crystallinity and the degree of granule surface order decreased from 28.5% and 0.631 in native starch to 26.9% and 0.605 in 50 kGy irradiated starch, respectively. Pasting viscosity and gelatinization temperatures decreased with an increase in radiation dose. At a high dose (50 kGy), melting of amylose-lipid complex in DSC thermogram was not observed. The rapidly digestible starch (RDS) content slightly decreased up to 10 kGy but increased at 50 kGy. The resistant starch (RS) content slightly decreased at 2 kGy and then increased up to 50 kGy. The slowly digestible starch (SDS) content showed the opposite trend to RS content. Slower irradiation dose rate reduced carboxyl content, swelling factor, and amylose leaching. The apparent amylose content and amylopectin chain length distribution were not significantly affected by dose rate of gamma irradiation. However, the relative crystallinity and gelatinization enthalpy increased with slower dose rate. Slower dose rate decreased RDS and SDS contents, and increased RS content.
随着辐照剂量增加，γ辐照玉米淀粉的羧基含量和直链淀粉浸出率增加，膨胀因子降低。表观直链淀粉含量从天然淀粉的28.7%逐渐降至50 kGy辐照淀粉的20.9%。随着辐照剂量增加，短支链支链淀粉（聚合度6至12）的比例增加，而长支链（聚合度≥37）的比例降低。相对结晶度和颗粒表面有序度分别从天然淀粉的28.5%和0.631降至50 kGy辐照淀粉的26.9%和0.605。糊化粘度和糊化温度随着辐照剂量的增加而降低。在高剂量（50 kGy）下，差示扫描量热图中未观察到直链淀粉-脂质复合物的熔化。快速消化淀粉（RDS）含量在10 kGy之前略有下降，但在50 kGy时增加。抗性淀粉（RS）含量在2 kGy时略有下降，然后在50 kGy时增加。缓慢消化淀粉（SDS）含量呈现与RS含量相反的趋势。较低的辐照剂量率降低了羧基含量、膨胀因子和直链淀粉浸出率。γ辐照的剂量率对表观直链淀粉含量和支链淀粉链长分布没有显著影响。然而，相对结晶度和糊化焓随着剂量率降低而增加。较低的剂量率降低了RDS和SDS含量，并增加了RS含量。
