Based on the other answers and comments reasonable people have room to disagree on how to handle this. So I'd like to work down the logic tree and see if we can come to a certain conclusion (or at least approximate one). God speed, adventurer!
The General Rule
As others quote from the Expanded Psionics Handbook and SRD, the rule is "no, Psionics doesn't use components", and from the otherwise quoted Wizards:
Psionic training, on the other hand, allows a psionicist to become the
source of his own power, rather than channeling external power through
himself. The game's rules reflect the subtle differences between
psionics and magic in various ways. Chief among these is a
psionicist's pool of power points. Other aspects of psionics are
less obvious; for example, psionic powers don't employ verbal,
somatic, or material components, and a psionic effect cannot be
recorded on a scroll.
And the ESH is said to say the same thing, and I have no reason to disbelieve that (not having a copy on hand myself).
So this should be a slam dunk, right? If only!
The Specific Case
As you noted, minor creation says "except as noted", and the spell version explicitly uses components. So what overrides what? Well, I find arguments on both sides convincing, so I don't know. Let's continue on to...
Comparable Cases
Does Psionics never ever require components explicitly? At first, I thought the answer was clear:
Psionic Power Overview
Metacreativity
A metacreativity power draws raw ectoplasm from the Astral Plane to
create an object or creature in the place the psionic character
designates (subject to the limits noted above). Objects created in
this fashion are as solid and durable as normal objects, despite their
originally diaphanous substance.
And if we look at the Shaper (Metacreativity) Discipline Powers, we see that with Psionics one can create an Astral Construct, mini-plane, crystals, quintessence, and more and yet none of these require any components in accordance with the general rule.
So far we note a lack of any explicit rule that Psionics ever uses any components or materials. That is, until we get to Creating Psionic Items, where every item requires all sorts of materials and this is unquestionably plainly written.
Now we know for a fact that some Psionic abilities require physical substances, and this allows a very real possibility that others might as well. This clearly contradicts the idea that Psionics doesn't require "material components", and it does so in a way that clearly must take precedent over the general rule.
As KRyan pointed out in an earlier comment, we now should compare Minor Creation to Major Creation, and we see that Major Creation specifies no components even though Minor Creation does. The same link is provided from Psionic Minor Creation to Minor Creation as the link between Major Creation and Minor Creation.
So we have two choices of interpretation: either Major Creation as a spell requires no material components and thus Psionic Major/Minor Creation certainly doesn't, or it does require components and Psionic Creation does (might?) too.
Worse, D&D Wiki quotes the SRD differently: Major Creation needs material and explicitly says the spell needs components but doesn't say the Psionic version does either. *[The validity/reliability of D&D Wiki is in question, and I do not know enough of the site to determine this - so caveat emptor and all that]
Conclusion
The decision that must be made, from a pure RAW standpoint, is whether or not Minor Creation should be treated like other Metacreation skills and so requires no material component, or if it should be treated like other material creation skills of that level and Psionic Items (of any level) and thus require at least a sample of the desired material.
In my mind, given the cited sources, one cannot make an iron-clad determination without some additional rule or source. It seems like it should be house-ruled to remove the ambiquity.
If I had to pick myself, I'd say that it makes little sense that a 1st level Shaper spell requires no sample material while a 4th level Wiz/Sorc/Arcanist spell does, given that when creating magic items every class in existence needs materials and components to create an item.
One final note: "psi-like" abilities are said to never ever require components or XP, though it does word it like this:
Psi-like abilities have no verbal, somatic, or material components,
nor do they require a focus or have an XP cost (even if the equivalent
power has an XP cost).
The wording goes out of its way to point out it has no XP cost even if the power would have one, in a way that indicates that it was taking for granted that it would have no material component and didn't even need to clarify that point - but did see a need to 0 the XP cost, as some Psionic abilities do have XP costs.
GAH!
I'm sorry, but I just can't see how one can say for sure precisely what the RAW rule should be, due to conflicting indications and implicit statements with no explicit clarification.
The PCs are testing the rumor—so make a choice!
Your campaign is a custom one, so while purify food and drink maybe should apply only to food and drink that's consumable by a creature of the race casting the spell or by the god that grants the spell or something, that doesn't mean the campaign's pixies aren't actually food for everybody.
In other words, the PCs have heard rumors of a creature that gains power via snacking on pixies, so when the PCs cast purify food and drink on a pixie corpse and they or their goat friend is about to dig in, you've to decide if those rumors of greatness through faerie feasting are true. (Fun Fact: PCs—and players!—will likely be disappointed if such rumors are untrue.)
If the rumors aren't true, the spell simply fails. No harm, no foul, no pixie picnic, no übergoat. All done.
If the rumors are true, then you've to decide how true. Can anyone partake of this pixie power-up? Need the pixie be alive? (Ew.) Some degree of fresh? (A day sounds good.) Must the entire pixie be consumed? ("Pixie wings taste like fruit roll-ups!") Is that healthy? (Likely not.) Must pixie be prepared a certain way? ("It must be served... on a stick!") Do a certain number need to be consumed to gain ultimate pixie power? And so on. Then the spell works, but, maybe, after consuming the pixie, the PCs are left wondering why their goat has a bellyache instead of awesome pixie powers.
This is your campaign, and—to challenge the frame a bit—this is less about how the spell purify food and drink works and more about the effects of pixie-eating in your campaign. That is, determine event's outcome and steps required to reach it first, and the question about the spell likely answers itself.
Best Answer
The game does not provide guidelines for this.
D&D 3.5 is not a "life simulator". It is a game whose mechanics largely involve abstracting combat against fantasy monsters. How a character handles the digestion of magical food is a detail the game simply does not address. In fact, the game doesn't seem to consider food an important topic in general, it often being handwaved away. Digestion is way below the simulation threshold - unless it has to do with fighting monsters.
Nevertheless, you are asking a question about a situation that can come up. People can and always will come up with questions the game can't not address, given the open-ended nature of RPGs.
In D&D, such questions are mostly answered by the DM. The DM makes some kind of ruling, and the game continues. If you are the DM in this situation, I suggest you go with whatever ruling that you think is...
most likely to enrich/improve the players' experience of the game world (does it being possible for any 1st level Psion to create food from nothing have an odd effect on the setting?)
... and so on. In any case, you're going to have to make a decision for yourself. The game doesn't help you.