Two novel cDNAs for two different genes, HDT1 and HDT2, are isolated from red clover and sequenced. Both HDT1 and HDT2 encode hydroxycinnamoyl-CoA:L-DOPA/tyrosine hydroxycinnamoyl transferase (HDT) which enzymatically produces clovamide and/or related hydroxycinnamoyl amides. Clovamide and related hydroxycinnamoyl amides reduce post-harvest protein degradation. Genetically altered alfalfa plants containing an expression cassette containing a cDNA encoding HDT1 or HDT2 are generated. These genetically altered alfalfa plants produce hydroxycinnamoyl-CoA:L-DOPA/tyrosine hydroxycinnamoyl transferase, which in turn produces clovamide and/or related hydroxycinnamoyl amides.