Processes and compositions are described for use in foodstuff flavors and as foodstuff article aroma and taste augmenting and enhancing materials of at least one alpha-substituted alkylidene methionals having the structure: ##STR1## wherein R.sub.1 or R.sub.2 is one of the moieties: ##STR2## and the other is hydrogen or methyl. Addition of one or more alpha-substituted alkylidene methionals to foodstuff flavorings or to foodstuffs is indicated to produce the following aroma and flavor characteristics, in the alternative taken together:AromaPotato;Methional-like;Green;Hydrolyzed vegetable protein-like;Chicken-like;Cabbage;Green potato;Green weedy;Broccoli-like; andGreen bean-like.FlavorPotato;Metallic;Sulfury-green;Cabbage-like;Chicken;Mushroom-like;Green-weedy;Broccoli-like; andGreen bean-like.The compounds of our invention are useful in augmenting or enhancing the flavor and aroma nuances of vegetable (including potato and cabbage) and chicken flavors.