淀粉-油酸复合物构建及其理化性质研究

Preparation of starch-oleic acid complexes and investigation of their physicochemical property

淀粉-脂肪酸复合物的制备通常采用直链淀粉作为基质,但淀粉中直链淀粉含量较少、且价格高昂,限制了淀粉-脂肪酸复合物在食品工业中的广泛应用。以蜡质玉米淀粉为考察对象,通过利用生物酶法(淀粉蔗糖酶和普鲁兰酶)定向修饰其分子结构,随后与油酸复合构建淀粉-油酸复合物,探究支链淀粉分子结构对淀粉-油酸复合物的构建及其理化性质的影响。结果表明,蜡质玉米淀粉经过淀粉蔗糖酶改性修饰后,其分支链得到显著延长,而普鲁兰酶的改性修饰则特异性地水解淀粉的分支点。晶体衍射和热特性分析显示,淀粉支链延长修饰或分支点水解均促进了V型淀粉-油酸复合物的形成,V型结晶度最高可达33.1%,且复合物的峰值糊化温度达到91.1℃。体外消化表明,淀粉-油酸复合物中的抗性淀粉含量可达49.6%,证明V型结晶结构具有抗酶解特性。

Starch-lipid complexes are normally prepared using amylose as a substrate.However,a low content of amylose in starch,as well as its high cost,limits the application of starch-lipid complexes in the food industry.In this study,waxy corn starch was selected and its molecular structure was directionally modified by enzymes(amylosucrase and pullulanase),followed by complexation with oleic acid to prepare starch-oleic acid complexes,exploring the effects of molecular structure of amylopectin on the preparation and the physicochemical property of starch-oleic acid complexes.Results showed that the branch chains of waxy corn starch were elongated by amylosucrase while the pullulanase specifically hydrolyzed the branching points of starch.XRD and thermal stability analysis suggested that the branch chain elongation and branching points hydrolysis facilitated the formation of V-type starch-oleic acid complexes,and the V-type crystallinity and peak gelatinization temperature were 33.1%and 91.1℃,respectively.In vitro digestion analysis implied that the content of resistant component reached 49.6%,which indicated that the V-type crystalline structure was resistant to amylolytic hydrolysis.