The plant does NOT absorb fruit juice, it will take what water it can but not the flavour nor the sugars..
Plants MAKE sugars, they don't suck them out of the ground.
Any sugars that you add are for the benefit of the micro-organisms that feed in the soil and release nutrients for the plant to use.
Too much fruit juice can raise the soil acidity and cause nute lock-out.
Also, too much juice will actually suck water molecules out of the plant - simple osmosis where the greater concentration of water molecules (in the plant) travel through the cell membranes to the lower concentration area (the fruit juice).
And if you taste pineapple flavour, it is either your imagination, the plants particular pheno being different from the others, or simply bullshit.