I'm not a food scientist, but one could say something like:
Intact alliums have no pungency, since the volatile products are only released following the interaction of the enzyme, alliinase, with the S-alk(en)ylcysteine sulfoxide (alliin, I) which occurs when tissue is damaged or disrupted (Figure 1). The initial products of this enzymic hydrolysis are ammonia, pyruvate, and an alk(en)ylthiosulphinate (allicin, II). The latter, which possesses odor characteristics typical of the freshly cut tissue, can undergo further nonenzymic reactions to yield a variety of compounds, including thiosulfinate [III] and di- and trisulfides [IV]. These compounds have slightly differing flavors and odors, and may impart a cooked note to steam-distilled onion or leek oils.
Bingo, was about to post that but read the comments instead.
I got many herbs and spices in my kitchen, including little bottles of powdered, dried garlic & onion. I prefer fresh, but when I'm lazy I use that instead. There's also Tabasco for pungent/acidic taste (which also contains vinegar, like this onion juice product) whereas chili sauce here [according to my anecdata] is often 90+% sugar.
Now, the powdered, dried garlic is strong in flavour, but dried onion less so. You still miss out on the fried, caramelised taste of (stir) fried onions though or the sharper taste of fresh onion (especially the red ones). I do love either of these, but in e.g. a soup, if you don't require the bite, you're good to go with powder. Unless when you're making a French onion soup. Speaking of soup one could also check their bouillon powder ingredients. Some are just mostly salt (or, less salt + MSG), but some contain a complex mix of a variety of herbs and vegetables.
Onion itself (as well as garlic) is found and used in so many dishes in my country it is too much to mention. From herring to frikandel/frites special, gehaktbal, and even the vegetarian clone of the gehaktbal, "gehacktbal", contains it.
Onion (and its relatives) and horseradish (and its relatives) store the components of a sulfur-based binary chemical weapon to deter being eaten by animals. When the tissue is ruptured, the chemical deterrent is formed and released. However, the compound breaks down with time, oxygen, heat, etc.
Does tang yield the same flavor as fresh squeezed orange juice? On the one hand yeah they both taste like their source, on the other there is a quality difference that is noticeable.
