摘要
To study the characteristics of tuber starchgranules,firstly,three kinds of common tuber starches were separated and characterized by gravitational field-flow fractionation(GrFFF)instrument,and the ratios of large and small starch granules A/B were calculated.Then,the liquid of peak A and peak B was collected and observed by scanning electron microscope(SEM)to verify the separation result of GrFFF.Secondly,the particle size distribution and crystal characteristics were characterized by particle size analyser,X-ray diffraction(X-ray)and fourier transform infrared spectroscopy(FT-IR).Three kinds of tuber starches all had the bimodal distribution in GrFFF.Peak A contained large particles,and peak B contained small particles.For yam starch,the ratio of starch granules A/B was much higher than 1;for sweet potato starch the ratio was approximately equal to 1;for tapioca starch,the ratio was much lower than 1.Moreover,the starch granules of sweet potato and tapioca were both A-type crystallinity,while yam starch granules were C-type crystallinity.GrFFF could be used to characterize and separate large and small granules of tuber starches and estimate the ratio of starch granules A/B.Yam starch was suitable for the development of slowly digestible starch(one kind of functional food),which could delay the occurrence of metabolic syndrome,diabetes and cardiovascular diseases.Tapioca starch was suitable for plant capsules,which were safer than gelatin capsule and could prevent the"poison capsule"incident from happening.
本文利用重力场流分离等技术探究山药、红薯、木薯淀粉的颗粒性质及应用。首先,应用重力场流分离系统(GrFFF)对3种淀粉的大小颗粒进行分离和表征,并计算其大小颗粒数目比例。并将A、B峰对应的液体接出,在扫描电镜(SEM)下观察,以验证GrFFF的分离效果。其次,利用粒度仪、X-射线衍射(X-ray)和傅里叶红外光谱(FT-IR)表征其粒度分布和晶体性质。结果发现,3种淀粉在GrFFF表征下均呈双峰分布。A峰包含大颗粒,B峰包含小颗粒。山药淀粉大颗粒远多于小颗粒,红薯淀粉大、小颗粒数目近似相等,木薯淀粉小颗粒数目显著多于大颗粒。红薯淀粉与木薯淀粉颗粒是A型晶体结构,山药淀粉颗粒是C型晶体结构。由此可知,GrFFF能有效地分离和表征薯类淀粉大小颗粒,且能够估算大小颗粒数目比例。山药淀粉适用于功能食品—慢消化淀粉的开发,可以延缓代谢综合征、糖尿病和心血管疾病的发生。木薯淀粉适用于淀粉胶囊的制作,代替明胶胶囊,提高安全性,防止"毒胶囊"事件再次发生。
