摘要
建立了分离三种薯类(马铃薯、红薯、木薯)淀粉颗粒外壳的不完全糊化方法,并利用环境扫描电子显微镜、X-射线衍射仪、高效分子筛色谱和高效阴离子色谱等对淀粉颗粒外壳的性质和分子结构进行分析.结果表明,马铃薯、红薯和木薯淀粉在淀粉乳浓度0.5%,最高处理温度分别为低于它们糊化温度5℃、2℃、5℃时,经13min加热处理可分离出较完整的淀粉颗粒外壳.此时淀粉的糊化程度在37%~57%之间.三种薯类淀粉颗粒外壳均呈现口袋状,表面有孔洞和褶皱.相较于原淀粉,三种薯类淀粉颗粒外壳的直链淀粉含量及相对结晶度较低,分子量相近(4.4×107~5.2×107 g/moL).具有较长侧链(DP>25)的支链淀粉参与了颗粒外壳的组成.
An insufficient gelatinization method on separating the outer shells of three tuber starches(potato,sweet potato,tapioca)was established.The properties and molecular structure of starch granule outer shells were analyzed by environmental scanning electron microscope(ESEM),X-ray diffractometer(XRD),high performance molecular sieve chromatography(HPSEC)and high performance anion chromatography(HPAEC).The results showed that the outer shells of potato,sweet potato and tapioca starch can be separated after 13 min heating at 0.5% starches concentration,and the highest treatment temperatures were 5 ℃,2 ℃ and 5 ℃lower than their gelatinization temperatures,respectively.The outer shells of three tuber starch granules were all pocket-like,with holes and folds on the surface.The gelatinization degrees were between 37% and 57%.Compared with the native starch,the amylose content and relative crystallinity of the outer shell were lower,the molecular weight of the shells were similar(4.4×107~5.2×107 g/moL).The amylopectin with long side chains(DP>25)participated in the shell composition.
引文
[1]Obanni M,Bemiller J N.Ghost microstructures of starch from different botanical sources[J].Cereal Chemistry,1996,73(3):333-337.
[2]Huang J,Wei N,Li H,et al.Outer shell,inner blocklets,and granule architecture of potato starch[J].Carbohydrate Polymers,2014,103(1):355-358.
[3]Zhang B,Dhital S,Flanagan B M,et al.Mechanism for starch granule ghost formation deduced from structural and enzyme digestion properties[J].Journal of Agricultural&Food Chemistry,2014,62(3):760-761.
[4]付良绅.四个品质马铃薯乙酰化淀粉及其残存颗粒性质的研究[D].西安:陕西科技大学,2011.
[5]严青.不完全糊化法研究淀粉颗粒的外壳和小体结构[D].西安:陕西科技大学,2015.
[6]Huang J,Wei M,Ren R,et al.Morphological changes of blocklets during the gelatinization process of tapioca starch[J].Carbohydrate Polymers,2017,163:324-329.
[7]Atkin N J,Abeysekera R M,Robards A W.The events leading to the formation of ghost remnants from the starch granule surface and the contribution of the granule surface to the gelatinization endotherm[J].Carbohydrate Polymers,1998,36(2-3):193-204.
[8]Jane J,Craig S A S,Seib P A,et al.Characterization of granular cold water-soluble starch[J].Starch-Strke,2010,38(8):258-263.
[9]Chen J,Jane J.Preparation of granular cold-water-soluble starches by alcoholic-alkaline treatment[J].Cereal Chemistry,1994,71(6):618-622.
[10]Jane J L,Shen J J.Internal structure of the potato starch granule revealed by chemical gelatinization[J].Carbohydr Res,1993,247(36):279-290.
[11]李玥,钟芳,麻建国.大米直链淀粉分子量分布及分子旋转半径的研究[J].农业工程学报,2007,23(11):36-41.
[12]黄强,罗发兴,杨连生.淀粉颗粒结构的研究进展[J].高分子材料科学与工程,2004,20(5):19-23.
[13]Zhu F.Composition,structure,physicochemical properties,and modifications of cassava starch[J].Carbohydrate Polymers,2015,122:456-480.
[14]Prentice R D M,Stark J R,Gidley M J.Granule residues and‘ghost’remaining after heating A-type barley-starch granules in water[J].Carbohydrate Research,1992,227(3):121-130.
[15]魏毛毛.淀粉糊化过程中小体形态变化和不完全糊化颗粒性质研究[D].西安:陕西科技大学,2017.
[16]缪铭,张涛,江波.高效排阻色谱-多角度激光散射分析淀粉分子特征[J].食品科学,2009,30(21):119-122.
[17]Eliasson A C.Starch in food:Structure,function and applications[M].New York:Woodhead Publishing Limited and CRC Press LLC,2004:57-96.
[18]于轩,李才明,顾正彪,等.淀粉分子结构与α-淀粉酶酶解性能的相关性[J].食品与发酵工业,2013,39(6):1-6.