Evaluation of a hybrid microwave process to replace malt kilning: feasibility and impacts on malt quality

麦芽干燥是一种传统的热空气干燥工艺，是一种能源密集型工艺，约占麦芽生产过程中一次能源使用量的78%，仅在英国，该行业每年就产生30万吨二氧化碳。该行业需要找到这一过程的节能替代品，以减少其碳足迹。该项目将使世界上最大的麦芽公司Boortmalt与专门从事麦芽和酿造科学（Cook）和微波工艺工程（Dodds）的学术合作伙伴聚集在一起。Boortmalt是世界上最大的麦芽制造公司，在地球仪拥有27家麦芽制造厂，可持续发展和创新是其两大战略支柱。合作伙伴已经在Boortmalt资助的项目上进行合作，使用混合微波/热风干燥技术开发新型烘焙麦芽和休闲食品。这种流化床技术正在诺丁汉的微波工艺工程团队的专业知识下进行商业开发。在干燥过程中，它可对单个颗粒内的温度梯度进行独特的控制。本项目针对酶的存活并不重要的应用，目的是生产新产品，而不是符合现有的规格。博士研究生将评估将该技术应用于生产淡麦芽的可行性，淡麦芽在全球范围内用作基础麦芽，全球年产量为2400万吨。这是一个要求更高的应用，因为必须调整空气和微波干燥的组合，以便在连续操作中实现现实的生产量，同时确保关键的酿造酶（例如淀粉酶、β-葡聚糖酶）不被热变性。此外，颜色和风味等其他关键规格必须与传统的煅烧产品密切匹配。该项目将评估这一方法的环境影响、技术和经济可行性，并与现有技术密切合作，对拟议技术进行基准测试。

Malt kilning is a traditional hot-air drying process that is energy intensive, accounting for around 78% of primary energy usage in the malting process, a sector which is responsible for 300,000 t of CO2 annually in the UK alone. The sector needs to find energy efficient alternatives to this process, to reduce its carbon footprint. This project will bring together Boortmalt, the world's largest malting company, with academic partners specialising in malting and brewing science (Cook) and microwave process engineering (Dodds). Boortmalt is the largest malting company in the world with 27 malting plants across the globe and sustainability and innovation are two of its strategic pillars. The partners are already collaborating on a Boortmalt funded project to develop novel roasted malts and snack foods using hybrid microwave/ hot-air drying technology. This fluidised bed technology is being developed commercially with the expertise of the Microwave Process Engineering Team at Nottingham. It offers unique levels of control over temperature gradients within individual particles during drying. The present project targets applications where the survival of enzymes is of no importance and the aim is to produce novel products rather than to match existing specifications. The PhD studentship will evaluate the feasibility of applying the technology to the production of pale malts, which are used as base malts in brewing worldwide, with a global annual production of 24 million tonnes. This is a much more demanding application because the combination of air and microwave drying must be tuned in order to achieve a realistic throughput in continuous operation, whilst ensuring that key brewing enzymes (e.g. amylases, -glucanases) are not thermally denatured. Furthermore, other key specifications such as colour and flavour must be closely matched to conventional kilned products. The project will evaluate both the environmental impact, technical and economic feasibility of this approach working closely and benchmarking the proposed technology against the current state of the art.