Excellent Saturday morning read.
"Releasing the air that had separated each berry from its neighbors" - the question, at least the way it's phrased here, doesn't say anything about any air. Made of blueberries means made of blueberries, period.
Nor does it mention water, but blueberries contain water. Likewise, the paper finds "the air content of the berries" to be "211 times the mass of Earth’s atmosphere" [1].
[1] https://arxiv.org/pdf/1807.10553.pdf page 3
I just don't think that "air that had separated each berry from its neighbors" should count.
(Picking up oxygen would be a high-confidence indicator of the presence of life, since oxygen reacts with everything and so can maintain a stable fraction of a planet's atmosphere only by continual replenishment, the only known mechanism for which is biological.)
Urp. Given "a roaring ocean of boiling jam", the surface doesn't sound likely to be very appetizing!
