摘要
为阐明薏米淀粉的结构和糊化特征以6份薏米为实验材料,在粳(非糯)、糯性鉴定的基础上比较了不同胚乳类型薏米淀粉在淀粉粒度、分子质量、链长分布、结晶度及糊化热力学等结构和理化特征.碘试剂染色和淀粉含量结果显示,3份糯性材料的胚乳染色呈棕红色,直链淀粉质量分数为1.54％～2.34％;非糯薏苡胚乳染色呈蓝色,直链淀粉质量分数为9.55％～22.92％,而且粳、糯性性材料之间均差异显著.淀粉颗粒扫描电镜和粒度分析结果表明,粳、糯性薏苡淀粉颗粒排列的紧实度存在品种差异,但是淀粉颗粒形貌相似,主要呈多面体和球形,外表往往具小孔、空腔或凹陷;粒径范围为4.03～35.30 pm,重均分子质量(Mw)、流体力学半径(Rw)分别为80 254.8～159 438.4 ku和122.3～233.7 nm;淀粉链长呈单峰分布,B1链数量占绝对优势,平均聚合度为17.17～17.53.6份薏米淀粉在X射线衍射角(2θ)15.0°、17.0°、18.0°和23.5°均出现强衍射峰,其晶体类型均为A型,而且粳性薏米的淀粉结晶度显著高于糯性薏米;在近红外光谱波数995、1 022、1 045、1 047 cmr-1处均有吸收峰,以QY02的1 045cm-1/1022 cm-1比值最高.薏米淀粉的糊化焓、起糊温度、衰减值和回生值范围分别为 9.582～11.210 J/g、78.95～79.85 ℃、450.00～1 071.00 cP 和 121.00～912.00 cP,相比之下,糯性薏米淀粉比粳性薏米淀粉更易糊化而不易老化.
Abstract
In order to clarify the structure and pasting properties of adlay starch,six adlay cultivars were used as the materials to test their starch grain size,molecular weight,chain distribution,crystallinity,thermal and pasting properties.The results were that three cultivars were dyed reddish brown,and the others were blue by I2-KI reagent staining,whereas amylose content were differed significantly in waxy and normal adlay that their contents were 1.54％-2.34％and 9.55％-22.92％scope,respectively.Although the arrangement and packing of starch gran-ule differed in cultivars,the surface morphology of granule was similar with polyhedral or spheriform shape,and small holes,cavities,or depressions always existed;grain size ranged from 4.03-35.30 pm,weight-average molecular weight(M)and hydrodynamic radius(Rw)were 80 254.8-159 438.4 ku and 122.3-233.7 nm.Chain length have unimodal distribution with a DP(degree of polymerization)of 17.17-17.53,and B1 chains were absolutely superior in quantitative.Six accessions had X-ray diffraction peaks in 15.0°、17.0°、18.0° and 23.5° of 2θ that their crystal were A pattern,while the crystallinity of normal accessions were significant higher than waxy type;be-sides that,absorption peaks were found at near-infrared wave number 995,1 022,1 045 and 1 047 cm-1,and QY02 accession had a maximum value of 1 045 cm-1/1 022 cm-1.Values of pasting enthalpy(△H)and tempera-ture,breakdown and setback viscosity were ranged9.582-11.210 J/g,78.95-79.85 ℃,450.00-1 071.00 cP,121.00-912.00 cP,respectively;then the waxy adlay starch could be gelatinized easier but more difficult to set-back than normal type.
基金项目
贵州省级财政种业发展项目(黔财农[2022]45号)
贵州省级财政种业发展项目(黔财农[2023]2号)
维普
万方数据