INNOVATIVE STRATEGIES FOR THE ACRYLAMIDE MITIGATION IN THE CEREALS SUPPLY-CHAIN

The acrylamide (AA) is a food process-contaminant classified as probably carcinogenic to humans (Group 2A) by the International Agency for Research on Cancer and highly widespread in cereal-based food products. Mitigation strategies for reducing AA in cereal-based foods include practices applicable at the field and processing levels. The aim of this PhD project was to identify agronomic strategies capable of limiting the concentration of ASN in the cereal kernels, and to mitigate AA formation in cereal-based products. Furthermore, the impact of milling was assessed to understand the effect of first-stage transformation and milling fractions recombination on ASN concentration in wholemeal flour. The ASN concentration was quantified in seven two-row barley genotypes cultivated across two years and three sites, with a significant effect of genotype. The ASN concentration explained 68% and 63% of the variability in AA formation in popping and gun-puffing products obtained from barley kernel, respectively. Cultivation site, thousand kernel weight and stay-green were identified such as significant contributors to ASN variability. Despite the technological influences observed in popping and gun-puffing, genotype remained the primary determinant of AA levels. Grain ASN concentration was also quantified in 25 soft wheat genotypes grown across two years and five sites. Site was the main source of variation (36%), while genotype and year accounted for 12% and 4%, respectively. Some genotypes showed more limited variability in ASN concentration than others. The heritability of ASN (H² = 0.65) supports the feasibility of selecting low-ASN genotypes. The AA concentration in wafers was significantly correlated with ASN levels in both wholegrain (R2=0.88) and refined (R2=0.65) flours, confirming the relevance of ASN reduction for AA mitigation. The combined effects of soil tillage, minimum tillage (MT) vs conventional tillage (CT), and a chemical disease control fungicide application (F) vs an untreated control (NF) on the accumulation of ASN in wholegrain and refined flour were also evaluated. MT_NF resulted in the highest ASN levels in wholegrain flour, whereas on average an MT_F treatment reduced ASN by 37%, CT_NF by 22% and CT_F by 48%. The AA levels measured in the wholemeal biscuits mirrored the initial ASN concentrations. The severity of Fusarium head blight was reduced by both the CT and F treatments, leading to heavier kernels due to enhanced starch accumulation, and lowering the ASN concentration per unit weight. This dilution effect accounted for more than 50% of the observed variation of ASN concentration in the wholegrain flour. Overall, agronomic practices that ensure an appropriate grain filling can dilute ASN in whole kernels and reduce the AA content of wheat-based products. The distribution of ASN and DON in the milling fractions was studied on two commercial batches of wheat processed by means of roller milling (RM), stone milling (SM) and debranning (D). ASN was mainly concentrated in the RM-fractions, with the highest levels in the germ, followed by shorts, red dog and bran. Because of its high ash content, bran can be included at low percentages in recombined mixtures, thereby limiting ASN, AA and DON in biscuits. D-fractions had less ash and a significantly higher level of DON. The wholemeal SM and control flour exhibited the highest AA levels and AA/ASN ratio. A food design approach based on ash and ASN content can simultaneously mitigate the risk of AA and DON. Overall, this study provides scientific evidence for the identification of agronomic and first-stage processing practices capable of supplying cereal food chains with raw materials intrinsically less prone to AA formation, while maintaining agronomic performance and nutritional advantages