Development of a process scheme for the production of high value functional products from DDGS

DDGS是生物乙醇发酵的主要副产物，每年在世界范围内大量生产。目前，DDGS是由酿酒厂或生物乙醇工厂生产的低价值农工产品，主要用作富含蛋白质的动物饲料。与大豆和菜籽粕相比，这种应用的一个主要问题是其成分的可变性，从而影响其营养质量和消化率，从而降低了其利用率。这项工作的目的是开发一种新颖的、可扩展的、经济上可行的工艺，将DDGS转化为几种中高价值的产品，即益生元食品成分、用于薄膜包装的麸质蛋白、用作营养补充剂的甜菜碱和胆碱，以及粗膳食纤维。拟议的工艺是基于生物精炼厂的概念，其中农业原料被转化为几个增值流，这些流要么是最终产品，要么是二次加工的起始材料。开发这种以DDGS为原料的多流程工艺将是生物炼制行业的先驱，因为它将为DDGS增加相当大的价值。益生元是一种不可消化的食品成分，通过肠道细菌的选择性代谢对健康产生有益作用，在消化健康市场具有诱人的前景。目标将是转化阿拉伯木聚糖（AX），其中包含30-50%的DGGS，为阿拉伯低聚糖（AXOS）；这些已被证明具有益生元活性，并在过去五年中吸引了相当大的商业兴趣。一个具有商业吸引力的前景是针对生产具有相对高分子量（MW）的AXOS，以努力增加益生元在结肠中的持久性和目标递送到远端区域。这将增加益生元的有益作用，因为大多数结肠疾病，主要是溃疡性结肠炎和肠癌，主要起源于远端区域。另一方面，麸质占DDGS的30-40%，将用于生产可生物降解的薄膜包装材料。研究将集中在提取和表征面筋和评价薄膜的性质。这将为DDGS面筋开辟新的应用领域，具有很高的市场潜力和经济效益。最后，甜菜碱和胆碱对人体健康具有重要的生物学功能，因此它们作为营养补充剂获得了许多商业利益。它们存在于小麦中，因此在DDGS中的浓度远远高于其他天然食物来源，因此从DDGS中提取这些化合物具有相当大的经济和市场潜力。该工艺包括几个可扩展的单元操作，包括将DDGS分离为可溶性和不溶性流，将可溶性蒸汽分馏成谷蛋白、AX、甜菜碱和胆碱，控制AX水解成AXOS，以及AXOS的纯化。影响该工艺效率、可扩展性和经济可行性的关键因素是：(i)开发出高效的加工步骤，将原料分离成高产量和高纯度的目标化合物；（ii）利用高活性酶，控制合成具有特定分子量和益生元活性的AXOS； （iii）生产具有适当形态和功能特性的面筋膜，用于商业用途。这项工作将由雷丁大学和洛桑研究所的多学科研究人员组成的团队进行，并将汇集小麦生物化学、生物加工、蛋白质科学、食品成分功能和肠道微生物学方面的独特专业知识。

DDGS is the major co-product of bioethanol fermentation and is produced at very large quantities annually worldwide. Currently, DDGS is a low value agro-industrial product produced by distillers or bioethanol factories, and is primarily used as a protein-rich animal feed. A major issue with this application, which reduces its utilisation compared to soybean and canola meals, is its compositional variability, which consequently affects its nutritional quality and digestibility. The aim of the proposed work is to develop a novel, scalable and economically viable process that will transform DDGS into several medium to high value products, namely a prebiotic food ingredient, gluten protein for film packaging, betaine and choline for use as nutritional supplements, and crude dietary fibre. The proposed process is based on the biorefinery concept in which the agricultural raw material is transformed into several value-added streams, which are either end-products or starting materials for secondary processing. Developing such a multi-stream process using DDGS as the raw material would be pioneering for the biorefinery industry as it would add considerable value to DDGS.Prebiotics are non-digestible food ingredients that have a beneficial effect on health through their selective metabolism by bacteria in the intestinal tract, and are attractive prospects in the digestive health market. The objective will be to transform arabinoxylan (AX), which consists 30-50% of DGGS, into arabinooligosaccharides (AXOS); these have been shown to have prebiotic activities and over the last five years have attracted considerable commercial interest. A commercially attractive prospect is to target the production of AXOS with relatively high molecular weights (MW) in an effort to increase the persistence of the prebiotics in the colon and target delivery into the distal region. This would increase the beneficial effects of prebiotics as most of the colonic diseases, principally ulcerative colitis and bowel cancer, predominantly originate in the distal region. Gluten on the other hand consists 30-40% of DDGS and will be used to produce biodegradable film packaging material. The research will focus on extracting and characterising the gluten and evaluating the properties of the films. This will open up new applications for DDGS gluten with high market potential and economic benefits. Finally, betaine and choline have important biological functions for human health and as such they have received a lot of commercial interest as nutritional supplements. They are present in wheat and consequently in DDGS at much higher concentrations than in other natural food sources, and therefore extraction of these compounds from DDGS has considerable economic and market potential.The proposed process consists of several scalable unit operations including the separation of DDGS into a soluble and non soluble stream, the fractionation of the soluble steam into gluten, AX, betaine and choline, the controlled hydrolysis of AX to AXOS, and the purification of AXOS. Key factors influencing the efficiency, scalability and economic feasibility of the process are (i) the development of efficient processing steps for the separation of the raw material into the target compounds, with high yields and purities, (ii) the utilisation of highly active enzymes that lead to the controlled synthesis of AXOS with specific MW and prebiotic activities and (iii) the production of gluten films with suitable morphological and functional properties for commercial use. The work will be carried by a multidisciplinary team of researchers from the University of Reading and Rothamsted Research and will bring together unique expertise in wheat biochemistry, bioprocessing, protein science, food ingredient functionality and gut microbiology.