Abstract Composition and functionality of five waxy wheat (Triticum aestivum L.) genotypes were elaborately investigated and related to end-product attributes of extrudates. As such, the interaction between starch biopolymers and protein in extrusion processing could be studied. Furthermore, the effect of an increasing amylose-concentration was studied by the use of blends. Waxy genotypes absorbed more water, gave rise to stiffer doughs and had higher onset and peak gelatinization temperature. In contrast, a lower pasting temperature and final viscosity and higher peak viscosity and breakdown could be observed. The volume percentage of small starch granules showed to be negatively correlated with peak temperature and positively with final viscosity and holding strength as well as with extrudate hardness. This was also positively correlated with amylose concentration. Expansion index was highest at a slightly decreased amylose concentration of 16.6%. Markedly higher moisture content for all amylose-free extrudates was attributed to a combination of increased solubility of amylopectin and reduced water evaporation at die emergence. It was hypothesized that an interplay with protein content and composition was laying at the basis of the observed differences. Moreover, the altered pasting behavior of waxy wheat may enhance the extrudability of gluten containing wheat flour. Starch granule size distribution is related to extrudate texture. Amylose content affects expansion index, water absorption and texture of extrudates. Interaction between starch content and protein composition and quality was observed. Waxy genotypes are strongly varying in their protein composition and functionality. Maximum expansion was obtained for blends containing 25% waxy flour.

中文翻译：

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改变直链淀粉浓度以提高小麦粉的可挤出性

摘要 精心研究了五种糯小麦 (Triticum aestivum L.) 基因型的组成和功能，并与挤出物的最终产品属性相关。因此，可以研究淀粉生物聚合物和蛋白质在挤压加工中的相互作用。此外，通过使用共混物研究了增加直链淀粉浓度的影响。蜡质基因型吸收更多的水，产生更硬的面团，并具有更高的起始和峰值糊化温度。相反，可以观察到较低的糊化温度和最终粘度以及较高的峰值粘度和分解。小淀粉颗粒的体积百分比与峰值温度呈负相关，与最终粘度和保持强度以及挤出物硬度呈正相关。这也与直链淀粉浓度呈正相关。直链淀粉浓度略微下降时，膨胀指数最高，为 16.6%。所有不含直链淀粉的挤出物的含水量显着更高归因于支链淀粉溶解度增加和模具出现时水分蒸发减少的组合。据推测，蛋白质含量和组成之间的相互作用是观察到的差异的基础。此外，蜡质小麦改变的糊化行为可能会提高含麸质小麦粉的可挤出性。淀粉颗粒大小分布与挤出物质地有关。直链淀粉含量影响挤出物的膨胀指数、吸水率和质地。观察到淀粉含量与蛋白质组成和质量之间的相互作用。蜡质基因型在其蛋白质组成和功能方面存在很大差异。含有 25% 蜡质面粉的混合物获得了最大的膨胀。