The alkaloid rich NP is combined with the citric acid solution and placed in the freezer.
The solution freezes and the NP is poured off.
The solution is thawed and evaporated at low heat.
As the solution evaporates the crystals form.
When a recoverable amount of crystals have formed, but before the water has all evaporated the remaining solution is removed. Then some tap water is used to cover the crystals and they are swirled around a bit, then this water is removed and added to the citric solution that was previously removed, so that it can be re-used.
The resulting crystals are transparent and barely tinted, so appear very close to white.
They have almost no sour taste, if there is a bit of sour just compare it to pure citric acid. If you can detect a sour flavor that is nothing compared to citric acid, which is extremely sour in small amounts. However the flavor of M-citrate is chalky and odd, not sour.
The M citrate is nearly insoluble in the tap water here (pH 8-8.5)
At no point in the extraction is any special water used, just tap.
also the major extraction proceeds as follows:
Fresh chopped cactus is boiled to make it soft, it takes less than 10 min of boiling.
Then the cactus is placed into a blender, being made soft already. It is blended and then added back to the boiling container. Then it is boiled until it is reduced to the appropriate volume. Then it is placed into a glass gallon jar and lye is added.
At no point is the cactus skin removed, or spines removed, nor is there a defatting step, all of those steps are completely unnecessary.
The caustic cactus solution is allowed to sit overnight.
Then xylene is added to it, the mix is shaken and allowed to separate. The NP now rich in cactus alkaloids is removed and salted out.