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

2002年报告了在小麦、黑麦、土豆和其他主要植物原料的高温蒸煮和加工过程中形成的化学污染物丙烯酰胺，食品中丙烯酰胺的存在现在被认为是农业和食品业的一个难题。丙烯酰胺会导致实验动物的癌症，因此被认为可能是人类的致癌物质。它还会影响神经系统和生殖系统。谷物，其中小麦是最重要的，产生了欧洲饮食中丙烯酰胺的一半，饼干、零食和早餐谷类食品尤其令人担忧。粮农组织/世卫组织食品添加剂专家委员会建议减少从饮食中接触丙烯酰胺，预计欧盟委员会将在2010年底之前发布关于食品中丙烯酰胺水平的指导值。目前的指导值草案提出了许多产品无法始终如一地实现的水平。例如，早餐谷类食品的建议指导水平是百万分之400(Ppb)，而一些以小麦为基础的早餐谷类食品的水平超过1000 ppb。此外，许多会员国支持将这些指导性价值观作为监管限制。因此，食品工业既需要短期的解决办法，也需要一个减少小麦丙烯酰胺形成潜力的长期方案，以便在其演变过程中遵守这一管制情况。减少加工过程中丙烯酰胺形成的方法已被证明很难应用于小麦产品，要么无效，要么对产品质量产生不可接受的不利影响。开发商业上可行的低丙烯酰胺形成潜力但保留对最终产品质量重要的籽粒特征的小麦品种，将有助于从根本上解决食品制造、餐饮和家庭烹饪中的丙烯酰胺形成问题，而不需要添加剂或潜在代价高昂的工艺改变。氨基酸天冬酰胺在糖(葡萄糖、果糖和麦芽糖)存在下的高温降解是丙烯酰胺形成的主要途径，而小麦制品中的限制因素是游离天冬酰胺。与大多数其他谷物相比，小麦中天冬酰胺的含量明显更高。此外，具有重要健康促进作用的全麦谷物和小麦麸皮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较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。这项申请是通过BBSRC的独立链接计划提交的。该项目将受益于一家主要的欧洲/GB小麦育种商和一个小麦供应链企业财团的参与，从而使工业合作伙伴能够确定和审查关键目标。行业支持程度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面粉中的氨基酸浓度，开发Rothamsted和John Innes中心开发的小麦遗传资源，包括绘制种群图、小麦遗传修改(作为研究工具)和高通量筛选突变种群，并利用最新的DNA测序技术研究高天冬酰胺和低天冬酰胺基因型之间的基因表达差异。食品工业合作伙伴将评估谷物中丙烯酰胺形成潜力的降低对工业过程中性能的影响。

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.