Abstract

The malt criteria of viscosity and β-glucan are used as an integral part of routine laboratory control measures to classify the cytolytic malt modification level and to ensure good processability. To optimize separation processes in general, the main focus of barley breeding has been on intensifying the cytolytic modification level and reducing the β-glucan concentration. However, not all new malting barley varieties show good processability despite a low β-glucan content, since the effect of hemicellulose constituents such as arabinoxylan and their enzymatic hydrolysis are largely disregarded. For this reason, the aim of the present work was to investigate the individual cytolytic composition of different malting barley (malt) varieties and to point out differences in cytolytic malt parameters depending on their genetically determined modification level. Appropriate analytical possibilities for arabinoxylan determination and suitable extraction methods for cytolytic evaluation have been further shortcomings in breeding quality control. In addition, the most important cytolytic degrading enzymes have been characterized in this paper. Part one of this two-part study demonstrated that cytolytically highly modified varieties have a lower β-glucan but in consequence a higher arabinoxylan content. With regard to the activity of enzymes, the results suggested small differences in β-glucanase, but not in arabinofuranosidase and xylanase. Finally, a principal component analysis showed that most of the cytolytically highly modified barley varieties (52%) were affected by arabinoxylan. The first part of the paper confirms that while breeding progress has reduced β-glucan, arabinoxylan has become the more dominant impact factor on processability.

摘要

麦芽粘度和β-葡聚糖标准用作常规实验室控制措施的组成部分，以对细胞溶麦芽的修饰水平进行分类并确保良好的加工性能。通常，为了优化分离过程，大麦育种的主要重点一直在增强细胞溶解修饰水平和降低β-葡聚糖浓度。然而，尽管β-葡聚糖含量低，但并非所有新的麦芽大麦品种都具有良好的加工性能，因为很大程度上忽略了半纤维素成分（如阿拉伯木聚糖）的作用及其酶水解作用。为此原因，本工作的目的是研究不同麦芽大麦（麦芽）品种的细胞溶质组成，并根据其遗传确定的修饰水平指出细胞溶麦芽参数的差异。阿拉伯木聚糖测定的适当分析可能性和用于细胞溶解评估的合适提取方法已成为育种质量控制的进一步缺陷。此外，本文还对最重要的细胞溶解降解酶进行了表征。这项由两部分组成的研究的第一部分证明，经细胞溶解高度修饰的品种的β-葡聚糖含量较低，但阿拉伯木聚糖含量较高。关于酶的活性，结果表明β-葡聚糖酶的差异很小，而阿拉伯呋喃糖苷酶和木聚糖酶差异不大。最后，主成分分析表明，大多数溶胞度高修饰的大麦品种（52％）受到阿拉伯木聚糖的影响。本文的第一部分证实，尽管育种进程减少了β-葡聚糖，但阿拉伯木聚糖已成为影响加工性能的主要因素。