Genetic improvement of wheat to reduce the potential for acrylamide formation during processing.

据2002年的报道，在小麦、黑麦、马铃薯和其他主要植物源原料的高温烹饪和加工过程中，化学污染物丙烯酰胺的形成，食品中丙烯酰胺的存在现在被认为是农业和食品工业的一个难题。丙烯酰胺在实验动物中致癌，因此被认为可能对人类致癌。它还会影响神经系统和生殖。谷类食品（其中最重要的是小麦）产生了欧洲饮食中一半的丙烯酰胺，其中饼干、零食和早餐谷物尤其令人担忧。粮农组织/世卫组织食品添加剂专家委员会建议，应减少从饮食中摄入丙烯酰胺，欧盟委员会预计将在2010年底前发布食品中丙烯酰胺含量的指导值。目前的指导值草案提出的水平对于许多产品来说并不是始终可以实现的。例如，早餐谷物的建议指导水平是十亿分之400 (ppb)，而一些以小麦为基础的早餐谷物的水平超过1000 ppb。此外，许多会员国支持这些指导值成为管制限度。因此，食品工业既需要短期解决方案，也需要长期计划，以减少小麦丙烯酰胺形成的可能性，以符合这种不断发展的监管情况。在加工过程中减少丙烯酰胺形成的方法已被证明难以应用于小麦产品，要么无效，要么对产品质量产生不可接受的不利影响。开发具有商业可行性的小麦品种，这些品种的丙烯酰胺形成潜力低，但保留了对最终产品质量很重要的谷物特性，将有助于从源头上解决食品制造、餐饮和家庭烹饪中丙烯酰胺形成的问题，而不需要添加添加剂或对工艺进行可能代价高昂的改变。在糖（葡萄糖、果糖和麦芽糖）存在的情况下，氨基酸天冬酰胺的高温降解已被证明是丙烯酰胺形成的主要途径，小麦产品中的限制因素是游离天冬酰胺。小麦的天冬酰胺含量明显高于其他谷物。此外，全麦谷物和麦麸具有重要的促进健康的特性，它们也往往比精制小麦粉含有更高的天冬酰胺水平。该项目旨在确定目前可用的天冬酰胺含量低的小麦品种和基因型，并为小麦育种者提供进一步降低天冬酰胺浓度的遗传工具。此申请是通过BBSRC的独立LINK计划提交的。该项目将受益于一家主要的欧洲/英国小麦育种商和一个小麦供应链企业联盟的参与，允许工业合作伙伴确定和审查关键目标。行业支持的水平表明丙烯酰胺问题对小麦供应链企业的重要性以及该项目的潜在影响。食品标准局也提供了一封支持信。该项目将使用最先进的技术来分析小麦粉中的氨基酸浓度，利用洛桑研究所和约翰英纳斯中心开发的小麦遗传资源，包括绘制群体图谱、小麦基因改造（作为研究工具）和突变群体的高通量筛选，并利用最新的DNA测序技术来研究高和低天冬酰胺基因型之间基因表达的差异。粮食工业合作伙伴将评估减少粮食丙烯酰胺形成潜力对工业过程性能的影响。

The formation of the chemical contaminant, acrylamide, during high-temperature cooking and processing of wheat, rye, potato and other mainly plant-derived raw materials was reported in 2002, and the presence of acrylamide in foods is now recognized as a difficult problem for the agricultural and food industries. Acrylamide causes cancer in laboratory animals and is therefore considered to be probably cancer-causing in humans. It also affects the nervous system and reproduction. Cereals, of which wheat is the most important, generate half of the acrylamide in the European diet, with biscuits, snacks and breakfast cereals being of particular concern. The FAO/WHO Expert Committee on Food Additives has recommended that dietary exposure to acrylamide should be reduced and the European Commission is expected to issue guidance values on acrylamide levels in food before the end of 2010. The current draft of the guidance values proposes levels that will not be consistently achievable for many products. The proposed guidance level for breakfast cereals, for example, is 400 parts per billion (ppb), while levels in some wheat-based breakfast cereals are over 1000 ppb. Furthermore, many Member States support these guidance values becoming regulatory limits. The food industry therefore requires both short-term solutions and a long-term programme of reduction in the acrylamide forming potential of wheat in order to comply with this regulatory situation as it evolves. Methods for reducing acrylamide formation during processing have proven to be difficult to apply to wheat products, either being ineffective or having an unacceptably adverse effect on product quality. The development of commercially viable wheat varieties that are low in acrylamide-forming potential but retain grain characteristics that are important for end product quality would help to address, at source, the problem of acrylamide formation in food manufacture, catering and home cooking, without the need for additives or potentially costly changes to processes. The high-temperature degradation of an amino acid, asparagine, in the presence of sugars (glucose, fructose and maltose) has been shown to be the major route for acrylamide formation and the limiting factor in wheat products is free asparagine. Wheat contains significantly higher levels of asparagine than most other grains. Furthermore, whole wheat grain and wheat bran, which have important health promoting properties, tend also to have higher asparagine levels than refined wheat flour. This project seeks to identify currently available varieties and genotypes of wheat that are low in asparagine and provide wheat breeders with the genetic tools to reduce the concentration of asparagine further. This application is being submitted through the BBSRC's stand-alone LINK scheme. The project will benefit from the involvement of a major European/GB wheat breeder and a consortium of wheat supply chain businesses, allowing for the identification and review of key targets by the industrial partners. The level of industry support is indicative of the importance of the acrylamide issue to wheat supply chain businesses and the potential impact of the project. A letter of support has also been provided by the Food Standards Agency. The project will use state-of-the-art techniques for analysing amino acid concentrations in wheat flour, exploit the genetic resources in wheat that have been developed at Rothamsted and the John Innes Centre, including mapping populations, wheat genetic modification (as a research tool) and high-throughput screening of mutant populations, and utilise the latest DNA sequencing techniques to study differences in gene expression between high and low asparagine genotypes. The impact of reductions in acrylamide-forming potential of grain on performance in industrial processes will be assessed by food industry partners.