CHANGES IN SAPONIN CONTENT AND COMPOSITION DURING THE ENSILAGE OF ALFALFA (MEDICAGO-SATIVA L)

Two varieties of alfalfa (Medicago sativa L.) were ensiled under labor atory conditions after being treated with formic acid or after wilting for different times. Intact saponins, using an HPLC method, were dete rmined in the starting material and after ensiling. The presence of tw o saponins were detected and measured in the experiment using the vari ety Hodoninka and three saponins in the second experiment using the va riety Palava. Soyasaponin I was present in both varieties, whilst the two other saponins, designated as saponin A and saponin B, had chromat ographic properties consistent with glycosides, of medicagenic acid. S ignificant decreases in saponin concentrations were observed after ens iling varying from 12% to 100%. Soyasaponin I was found to be relative ly stable, while saponin A was not detected after the first week of en siling. Treatment with formic acid stabilised saponin B and soyasaponi n I for the variety Palava in contrast to the other treatments. Copyri ght (C) 1996 Elsevier Science Ltd