New strategy for targeting beta-glucan activity and breeding of malting barley

大麦（Hordeum vulgare）是酿造麦芽和啤酒的关键原料。麦芽是由发芽的大麦生产的，用来制作酒精饮料。酿酒公司是大麦芽的主要消费者。加拿大是全球29亿美元麦芽贸易行业的主要参与者之一。大麦的麦芽品质是一种重要的经济表型，它是一个复杂的、多组分的性状。-葡聚糖（BG）是决定麦芽潜力和酿造产量的主要因素。在酿造过程中，BG会影响麦汁的胚乳修饰和粘度，造成很大的过滤困难。人们一直在努力鉴定具有葡聚糖酶活性的酶/蛋白质，目的是尽量减少麦汁中的-葡聚糖分子。我们成功地鉴定了一种新的大麦蛋白TLP8 (thaumatin like protein)，它与β -葡聚糖结合，并在酿酒过程中显著降低其含量。我们的研究结果表明，高含量的HvTLP8蛋白可以最大限度地减少啤酒在清洗和过滤过程中遇到的问题。HvTLP8的葡聚糖酶型活性在缓解麦芽和酿造过程中β -葡聚糖分子的问题和帮助改良麦芽品种的发展方面具有很大的潜力。这可作为下一代麦芽品种选育的功能和生化标记。

Barley (Hordeum vulgare) is a key ingredient in malting and brewing. Malt, produced from germinating barley is used for making alcoholic beverages. Brewing companies are the main consumers for barley malt. Canada is one of the major players in 2.9 billion USD global malt trading industry. Malting quality of barley, an economically important phenotype, represents a complex, multi-component trait. Beta-glucan (BG) is a major factor determining malting potential and brewing yield. BG affects the endosperm modifications and the viscosity of wort during brewing which cause great lautering and filtration difficulties. Continuous efforts are being made to identify enzyme/proteins with glucanase activity with the aim to minimise beta -glucan molecules in wort. We have successfully identified a novel barley protein, TLP8 (thaumatin like protein), which binds to beta-glucan and significantly lowers its amount during malting process. Our findings suggest that higher amounts of HvTLP8 protein can minimize problems encountered during the beer lautering and filtration processes. Glucanase type activity of HvTLP8 has great potential to mitigate problems of beta-glucan molecules during malting and brewing process and assist the development of improved malting barley varieties. This could be used as functional and biochemical marker for the breeding of future generation of malting varieties.