In the present study, γ-aminobutyric acid (GABA) and valine (Val) were used to simultaneously scavenge acrolein and dicarbonyl compounds (methylglyoxal and glyoxal), which are widely distributed in foods, and the underlying mechanisms were explored. We found that formaldehyde, instead of dicarbonyls, participated in the formation of the final product. Further investigation found that GABA and Val induced dicarbonyl compounds to generate formaldehyde, which then, along with acrolein, reacted with amino acids to generate methylene piperidinyl aldehyde. This study provides a new perspective for understanding the reaction mechanism of amino acids with acrolein and dicarbonyls, and offers a new mechanism for the formation of formaldehyde in foods.