The examples you bring are of food taste described badly, as @MarkBaker explains in great detail. Those descriptions fail to evoke what they're supposed to evoke, and instead take your mind to all kinds of unintended places.
But should food be described at all? Why shouldn't it? We describe sights, sounds, smells - why not taste then?
Of course, we do not describe everything our character sees, smells and hears. We describe only that which is important. And we avoid redundancies - if the character sees children playing, there's no need to also mention that the sound of their playing is heard (unless there's some additional information there, like the specific words of the children's song, if that happens to be important to the story).
That, I believe, is why you feel those descriptions are unnecessary: if the character eats a candy, we know what candies taste like. The same for pomegranates. The description of tastes is redundant. But imagine a scene where a character tries to identify by taste the ingredients of a dish. He might recognise for instance the heat of a pepper of some sort, the delicate citrus smell of kaffir lime, the particular sweetish tang of ginger... Or a character tasting some new fruit for the first time - they'd compare it to other tastes they are familiar with. Medjool dates, for instance, might be like a mouthful of honey, overwhelming in its sweetness.
But even that is not the key. Following a discussion with @MarkBaker in the comments, the specific taste is less important and less evocative than the emotions it connects to. If the taste evokes no emotion, if it doesn't connect to anything meaningful, why do we need that description there? Your examples, at least as you provide them, connect to nothing. They might try to evoke a taste, but the taste evokes nothing. Why is it there? Connected emotions might be quite varied: seduction, curiosity, home - think of Marcel Proust's madeleine, for instance. Describing the taste is not a goal, but a stepping stone to something else.
As an example, you might recall this scene from The Lion, the Witch and the Wardrobe:
The Queen took from somewhere among her wrappings a very small bottle which looked as if it were made of copper. Then, holding out her arm, she let one drop fall from it on the snow beside the sledge. Edmund saw the drop for a second in mid-air, shining like a diamond. But the moment it touched the snow there was a hissing sound and there stood a jewelled cup fill of something that steamed. The dwarf immediately took this and handed it to Edmund with a bow and a smile; not a very nice smile. Edmund felt much better as he began to sup the hot drink. It was something he had never tasted before, very sweet and foamy and creamy, and it warmed him right down to his toes.
"It is dull, Son of Adam, to drink without eating", said the Queen presently. "What would you like best to eat?"
"Turkish Delight, please, your Majesty," said Edmund.
The Queen let another drop fall from her bottle on the snow, and instantly there appeared a round box, tied with green silk ribbon, which, when opened, turned out to contain several pounds of the best Turkish Delight. Each piece was sweet and light to the very centre and Edmund had never tasted anything more delicious.
C.S. Lewis, The Lion, The Witch and the Wardrobe, chapter 4 - "Turkish Delight". My bold emphasis.
Here the descriptions of taste do not feel gross or unnecessary, do they? But they do not evoke the specific exact taste of Turkish Delight. Instead, they evoke the experience of Edmund eating Turkish Delight - the Queen seduces Edmund with something very enjoyable. And we are seduced right along with him, desiring to taste the magical treat for ourselves.