Paul, the point I am trying to make is that the act of freezing a bait will not make it a better bait. If you make a soya flour and semolina boilie then freeze it, it will still be made with soya flour and semolina.
I am a regular user of Mistral baits and I am NOT sponsored, I pay for my bait. The reason I believe their baits to contain excellent ingredients is that I have spoken to the company owner Alan at length and I trust him, completely. His baits have never let me down. If you are looking to try a high quality ready made, then I suggest you talk to him. He wont bullshit you, he knows his stuff. He'll explain more on bait than I, or, I suspect 99.9% of the people on this site, ever could, especially a lot about preservatives.
Some of their baits are designed to be long term food baits, some others are designed to be more short term. For instance last year I fished a French water (Vaumigny) which requires quite a bit of bait. After talking to Alan we took his Euro boilies as money was tight for this trip, these he said were more of a short / medium term bait. Result ? 75 carp caught by 2 anglers, including 7 thirties. Some Dutch guys fishing the lake could not believe our results, they managed about 10 between them, they were convince we must have spent a huge amount of money. In facr we spent far less than them. These baits proved excellent for a weeks fishing, but we were advised that they would not be suitable for a long term campaign. I appreciate that sort of honesty. For longer campaigns I would use one of Mistrals long term baits. Some of these do not even contain preservatives at all.