【作者】 缪铭； 江波；

【Author】 Ming Miao Bo Jiang (State Key Laboratory of Food Science and Technology,Jiangnan University,Wxui 214122)

【机构】 江南大学食品科学与技术国家重点实验室；

【摘要】 本实验旨在研究酶部分脱支-重结晶处理对玉米淀粉分子结构及消化性能的影响。结果显示,异淀粉酶脱支-老化处理糊化玉米淀粉后,淀粉营养片断的比例与结构发生了改变。增加异淀粉酶液浓度与减少酶脱支时间可得到高含量慢消化淀粉(SDS);在4℃储藏有利于晶核形成,SDS含量则增多。因此,玉米淀粉经高浓度酶液(20U/g)部分脱支处理3 h,在4℃储藏2d后可获得较多SDS。富含SDS的淀粉样品X-衍射图谱显示为B型晶体结构,增加储藏时间与温度使晶体结构转变为B+V型。相比糊化淀粉,经酶部分脱支-重结晶处理后高密度、表面多孔的不规则、多棱角状淀粉碎片被观察到;在DSC图谱上也显示出To、Tp、Tc与△H逐渐增加。依据这些变化可推断SDS由一小部分双螺旋部分堆积有序结晶区和大部分无定型区构成。更多还原

【Abstract】 Impact of isoamylase debranching and aging treatment on the structure and digestibility change of maize starch were investigated.When gelatinized starch was treated with higher enzyme concentration and less debranching time,higher SDS was formed while resistant starch(RS) increased with time.The maximum SDS content was obtained by debranching for 3 hours with higher concentration of pullulanase (20U/g) then storing at 4℃for 2 days.X-ray diffraction pattern of treated starch at optimal conditions was similar to the B-type in which illuminated treated starches contain partially ordered crystalline structures. Scanning electron micrographs showed the treated starch had more irregular angular shapes with a higher crystallinity structure and pitted surface as debranching and aging time increased.In differential scanning calorimetry themograms,the melting temperature and enthalpy of treated starches were gradually enhanced,resulting from reforming of double helix structure by low temperature recrystallization following debranching.These changes showed that SDS mainly consists of a partially ordered double helix crystallite structure with short amylopectin chains and amorphous regions.更多还原