Abstract High amylose (HA) maize starch, rich in amylose (more than 55%), belongs to the category of resistant starch type 2 (RS2), and therefore has a specific structure resistant to digestion. The purpose of this study was to modify HA maize starch, reducing its particle size. A mechanical treatment was used, applying high-pressure homogenization (HPH) at different pressure conditions 140, 200 and 250 MPa and treatment cycles, ranging from 1 to 4. The impact of HPH on starch structure, including size, morphology and crystallinity as well as on the amylose content was investigated. The granule particle size was measured by Dynamic Light Scattering (DLS), their morphology using Scanning Electron Microscopy (SEM) and the degree of crystallinity by X-ray diffraction (XRD). According to the results the smallest particle size, 540 nm, was achieved after 4 cycles of homogenization at 250 MPa. It was found that the pressure applied was more significant to reduce granules’ size than the time of treatment. Αt intense pressure the granules structure has changed as pores, deep slots and aggregates were observed. The amylopectin structure was destroyed resulting in an increase in amylose:amylopectin ratio. However, size reduction was not accompanied by any structure conversion and HA maize starch remained a B-type starch. According to the information found a further understanding of the effect of HPH on modifying HA starch was achieved. Physically modified RS could result to different food applications.

中文翻译：

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高压均质处理对抗性淀粉纳米颗粒的改性

摘要 高直链淀粉（HA）玉米淀粉含有丰富的直链淀粉（55%以上），属于抗性淀粉2型（RS2），具有抗消化的特殊结构。本研究的目的是改性 HA 玉米淀粉，减小其粒径。使用机械处理，在 140、200 和 250 MPa 的不同压力条件下应用高压均质 (HPH)，处理周期为 1 到 4。HPH 对淀粉结构的影响，包括尺寸、形态和结晶度对直链淀粉含量进行了研究。通过动态光散射 (DLS) 测量颗粒粒径，使用扫描电子显微镜 (SEM) 测量它们的形态，并通过 X 射线衍射 (XRD) 测量结晶度。根据结果​​，最小粒径为 540 nm，在 250 MPa 下进行 4 次均质化循环后达到。发现施加的压力比处理时间更能显着减小颗粒的尺寸。在高压下，颗粒结构发生变化，观察到孔隙、深槽和聚集体。支链淀粉结构被破坏，导致直链淀粉：支链淀粉比例增加。然而，尺寸减小并没有伴随任何结构转化，HA 玉米淀粉仍然是 B 型淀粉。根据发现的信息，进一步了解了HPH对HA淀粉改性的影响。物理改性的 RS 可能导致不同的食品应用。在高压下，颗粒结构发生变化，观察到孔隙、深槽和聚集体。支链淀粉结构被破坏，导致直链淀粉：支链淀粉比例增加。然而，尺寸减小并没有伴随任何结构转化，HA 玉米淀粉仍然是 B 型淀粉。根据发现的信息，进一步了解了HPH对HA淀粉改性的影响。物理改性的 RS 可能导致不同的食品应用。在高压下，颗粒结构发生变化，观察到孔隙、深槽和聚集体。支链淀粉结构被破坏，导致直链淀粉：支链淀粉比例增加。然而，尺寸减小并没有伴随任何结构转化，HA 玉米淀粉仍然是 B 型淀粉。根据发现的信息，进一步了解了HPH对HA淀粉改性的影响。物理改性的 RS 可能导致不同的食品应用。根据发现的信息，进一步了解了HPH对HA淀粉改性的影响。物理改性的 RS 可能导致不同的食品应用。根据发现的信息，进一步了解了HPH对HA淀粉改性的影响。物理改性的 RS 可能导致不同的食品应用。