摘要
将玉米淀粉和马铃薯淀粉分别在35℃条件下用浓度为2 4mol/L的HCl处理不同时间,采用碘量法、X射线衍射(X ray)分析和差热分析(DTA)等对酸解后的淀粉颗粒进行了结构和性能表征。结果表明,马铃薯淀粉的酸解过程可分为3个阶段,酸解速率常数分别为2 78(t<24h),0 94(24h<t<144h)和0 39(144h<t<384h);玉米淀粉的酸解过程分为两个阶段,其酸解速率常数分别为2 27(t<96h)和0 15(t>96h)。在比较分析了玉米和马铃薯淀粉酸解前后的一些物理化学性质及结构变化与酸解时间的相互联系后,认为酸首先水解淀粉的无定型区,提高淀粉颗粒结晶度、热稳定性和酶解速率;而后随着酸解时间的延长,淀粉结晶结构遭到侵蚀,热稳定性降低。酸解时间为4d时,玉米淀粉和马铃薯淀粉颗粒的结晶最完美,热稳定性最佳,结晶转变温度分别为87 0℃和93 5℃。
Maize and potato starch were treated with 2.4 mol/L hydrochloric acid at 35 ℃ in different time period.The remaining starch granules after acid hydrolysis were analyzed for the increment of aldehyde group by iodine titration,the crystallinity by X-ray diffraction,and the thermal stability by DTA.The results indicated that the acid hydrolysis of potato starch occurred in three steps,the hydrolysis rate constants being 2.78( t <24 h),0.94(24 h< t <144 h)and 0.39(144 h< t <384 h),respectively;but acid hydrolysis of maize starch followed two distinct steps,with hydrolysis rate constants 2.27( t <96 h) and 0.15( t >96 h),respectively.This study was conducted to compare the differences in some physicochemical properties of native and acid-hydrolyzed maize and potato starches,and the relation between their structures and hydrolysis time.The results suggested that firstly a quick degradation of the amorphous areas occurres with the increasing of crystallinity,thermal stability and the speed of enzyme hydrolysis;and then thermal stability decreases with the increasing of hydrolysis time and disintegration of crystalline structure.In the fourth day,the crystallinity was perfect and thermal stability was the best.The crystalline transition temperature was 87.0 ℃ and 93.5 ℃ for maize starch and potato starch,respectively.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2004年第3期202-205,共4页
Fine Chemicals
关键词
马铃薯淀粉
玉米淀粉
酸解
物理化学性质
potato starch
maize starch
acid hydrolysis
physicochemical property
