Biorefining Protein from UK Grasslands - Can We Combine Novel Protein with Surplus Bread Crusts to Sustainably Feed Healthier Food to More People?

英国的草地农业占已利用农业面积的72%（1260万公顷），分别饲养了970万头牛和3400万只羊。再加上2040年零碳排放的推动，从畜牧业生产和植物蛋白进口（如大豆和其他豆类）转向适合人类消费的岸上种植植物蛋白的多样化，可能会为英国农民提供长期的环保经济保障。在英国现有的农业水平上，植物蛋白生产的机会是存在的。英国大约70%的商业牧草（Loillium/Festuca spp. <10%粗蛋白质）和三叶草（Trifolium spp. <20%粗蛋白质）品种是在阿伯里斯特威斯大学（AU）培育的。先前的研究表明，在压榨草和/或三叶草后，这种蛋白质很容易作为液体流提取，而剩余的纤维可以用作动物饲料，显示与原始草的营养相当（羔羊试验- stars项目AU，牛肉试验-奥胡斯大学2,3）。此外，草含有可溶性果聚糖（-2,1和-2,6-果糖多糖，20% DM），一种有效的益生元（AU；英国和欧洲专利，美国专利申请）。红三叶草汁还含有次生代谢物（植物雌激素和蒎醇等），具有已知的营养/功能特性。这两种多年生作物都能固碳，而三叶草具有固氮的额外优势，从而减少肥料投入。将这种富含蛋白质的材料转化为富含蛋白质的食品成分和/或产品的方法是通过共发酵过程（例如豆豉生产）。然而，大多数使用的本地细菌是致病性的（如肺炎克雷伯菌）4，因此研究与GRAS状态生物的替代共培养不仅具有营养价值，而且具有监管和营销效益。素食主义者和弹性素食主义者的饮食是一个增长的长期趋势，后者每年增长9%。在这些挑剔的消费者的未来需求中，有一种强烈的偏好是非转基因的，道德来源的植物蛋白，由可追溯的供应链证书支持，确保对环境和社会负责的农场到餐桌制造。Samworth Brothers Ltd （SBL）是英国领先的三明治供应商；每周生产30-50吨多余的面包皮，其处理方式是作为动物饲料。使用来自英国种植作物的植物蛋白使这种面包留在人类食物链中是Samworth兄弟公司未来的愿望。开发新的富含蛋白质的成分对食品工业来说是一个挑战，因为产品必须具有高营养价值（氨基酸分布和消化率），无过敏性，适当的技术性能（如溶解度，起泡性等），可接受的风味和口感（涩味）。通过共发酵，可以降解抗营养因子，形成蛋白质结构，并产生其他代谢物（维生素B12）和风味（鲜味）；因此，控制底物、生物和过程可以帮助开发一种新的生物精制工艺，生产高质量的富含植物蛋白的食品。本研究要验证的假设是：从牧草/三叶草中提取的富含蛋白质的汁液，与剩余的面包皮结合，可以通过混合微生物群落进行生物转化，从草原中生产出安全、可持续、新颖的人类食品成分（图1）。本研究的目标是：1)优化富含蛋白质和营养成分（果聚糖、植物雌激素和蒎醇）的草/三叶草汁的提取、浓缩和纯化。2)以面包渣为原料，通过固态乳酸杆菌、无酸丙酸杆菌（GRAS）和根霉（Rhizopus）发酵制备富含蛋白质的果汁（实验室和中试）

British grassland farming covers 72% (12.6 million ha) of the utilised agricultural area, supporting 9.7 and 34 million cattle and sheep respectively1. Coupled with the drive towards zero-carbon 2040, diversification away from livestock production and plant-protein imports (e.g. Soya and other pulses) to alternative on-shore grown plant-protein fit for human consumption may provide longer-term environmentally beneficial economic security for UK farmers.The opportunity for plant-protein production on an existing agricultural level exists within the UK. Approximately 70% of the UK's commercial forage grass (Loillium/Festuca spp. <10% crude protein) and clover (Trifolium spp. <20% crude protein) varieties have been bred at Aberystwyth University (AU). Previous research has demonstrated that this protein is readily extractable as a liquid stream following pressing of grass and/or clover, while the remaining fibre can be used as an animal feed showing nutritional equivalence with the original grass (lamb trials-STARS project AU, beef trials-Aarhus University2,3). Furthermore, grass contains soluble fructan (-2,1 and -2,6-fructosylpolysaccharides, 20% DM), an effective pre-biotic (AU; UK & European Patent, US patent filed). Red clover juice, also contains secondary metabolites (phytoestrogens and pinitol etc.) with known nutraceutical/functional properties. Both of these perennial crops sequester carbon, while clovers have the added advantage of nitrogen fixation, thereby reducing fertiliser inputs. A method to convert this protein-rich material into a protein-rich food ingredient and/or product is through co-fermentation processes (e.g. tempeh production). However, most of the native bacteria used are pathogenic (i.e. Klebsiella pneumoniae)4, thus the investigation of alternative co-culture with a GRAS status organism, will not only be of nutritional value, but also regulatory and marketing benefit.Vegetarian and flexitarian diets are a growing, long-term trend, with the latter achieving 9% growth per annum. Among the future needs of these discerning consumers are a strong preference for non-GM, ethically sourced plant-protein supported by traceable supply chain credentials ensuring environmental and socially responsible farm to fork manufacture. Samworth Brothers Ltd (SBL) are a leading UK sandwich provider; producing 30-50 tonnes per week of excess bread crusts from their manufacturing operations whose disposal route is as animal feed. Using plant-protein from UK grown crops to keep this bread in the human food chain is a future aspiration of Samworth Brothers. The development of new protein-rich ingredients involves many challenges to the food industry as the product must have a high nutritional value (amino acid profile and digestibility), no allergenicity, adequate technological properties (e.g. solubility, foamability etc.), acceptable flavour and mouthfeel (astringency). Through co-fermentation anti-nutritional factors can be degraded, protein structures are developed, and other metabolites (vit B12) and flavours (umami) are produced; thus, controlling the substrate, organism and process could help develop a novel biorefining process producing high quality vegetable protein-rich food product(s).The hypothesis to be tested in this studentship is: Protein-rich juice extracted from forage grass/clover and combined with surplus bread crusts can undergo bioconversion by mixed microbial consortia producing a safe, sustainable, novel human food ingredient from grasslands (fig1).The objectives of this studentship are: 1) Optimisation of extraction, concentration and purification of grass/clover juice rich in protein and nutraceuticals (fructans, phytoeostrogens and pinitol).2) Development of a biorefining process for protein-rich juice through solid-state Lactobacillus spp., Propionibacterium freundenreichii (GRAS) and Rhizopus spp fermentation, using excess bread crusts as a scaffold (laboratory and pilot plant s