Can Organic Farming Lower Acrylamide in Cereal Products by the Selection of Cultivars Low in Free Asparagine?
For cereals grown under organic conditions, information on levels of free asparagine (free Asn) as a precursor to acrylamide (AA) formation, is almost completely lacking. This study investigated the impact of organically grown cereal species and cultivars of winter wheat (Triticum aestivum), winter spelt (Triticum aestivum ssp. spelta), winter rye (Secale cereale), winter einkorn (Triticum monococcum) and winter emmer (Triticum dicoccum) on the level of free Asn with simultaneous consideration
... eous consideration of grain yields and flour qualities over three growing seasons (2005–2006, 2006–2007 and 2007–2008) in Southwest Germany. Additionally, the relation of free Asn and AA was investigated. Heritability revealed how strongly the level of free Asn was linked to the genotype. In this context free Asn of species and cultivars grown at a second location in Southern Germany were analysed. The level of free Asn was significantly influenced by species and within species by cultivars. Rye was found to exhibit the highest free Asn amount (52 mg 100 g−1), followed by einkorn (32 mg 100 g−1), emmer (16 mg 100 g−1) wheat (10 mg 100 g−1) and spelt (8 mg 100 g−1), which showed the overall lowest free Asn content. Hence, replacing rye with spelt in food products would lead to an 85% reduction of free Asn in raw material. Within species, cultivars differed in their levels of free Asn by up to 67% for wheat, 55% for spelt and 33% for rye. Year also had a significant impact as almost all samples were significantly higher in their level of free Asn in 2008 compared to 2006 and 2007. Rye was most significantly affected by year as the level of free Asn varied by up to 32% between years. In contrast, wheat and spelt were only affected minimally by year. A high heritability was found for wheat (0.79) and spelt (0.91) concerning locations in 2008, meaning that the level of free Asn is mainly determined by the genotype and less influenced by environmental conditions. In contrast, heritability was low for wheat (0.23) but high for spelt (0.71) and rye (0.67) regarding years. As for organically grown cereals the relation between free Asn and AA formation was never investigated before. Correlation of both parameters was calculated. There was also a close correlation between free Asn and AA. Across species and years, the amount of free Asn correlated with the AA content in heated flour with R2 = 0.69***. Thus, free Asn can serve as an indicator for AA formation during processing. In conclusion, the level of free Asn can be highly influenced by proper selection of species and cultivars under organic growing conditions.