The serum given to Blonsky was an attempt to recreate Erskine's original formula, the last sample of which had been stolen by Hans Kruger and then subsequently destroyed during his capture by Steve Rogers in 1943. Various people had been attempting to recreate it since then, but were largely unsuccessful due to the fact that Erskine was the only person who knew exactly what went into the serum. The only truly successful attempt was HYDRA's experiments on Bucky, as evidenced by the feats he performs in Captain America: The Winter Soldier . The other part of the serum, Vita-Rays, were necessary to the original formula working as it was designed to. However, if one was to attempt to replicate the effects of the serum and not necessarily the serum itself, one would not necessarily need Vita-Rays for it to work,as evidenced, again, by the fact that Arnim Zola, working without knowledge of Vita-Rays or their existence, managed to turn Bucky into a super soldier. Based on that, I believe that the reason the serum used on Blonsky turned him into a monster is not because they didn't have Vita-Rays or because the serum was imperfect(if you recall, Blonksy was able to do things after receiving it that we'd previously only seen Cap do), but rather because he was a nasty person inside, which, in The First Avenger, is why it turned Johann Schmidt into the Red Skull.