What made these red lentils ‘brick’ together

I do not have any information on the change itself, but neither does that claim in Wikipedia.

However, I would refer you to the discussion page of lentil's and read over the community's discussion regarding the article's nutrition claims generally. They are not pleased with many of the claims, and have been active in moderating it. Also of note, the claim has no citation.

Upon my reading, I would not take for granted that the minor act of sprouting in water changes nutritional value substantially, especially as compared to deep-frying them or other processes.

That said, you might refer to the general sprouting article:

These nutrients are essential for human health. To clarify, the nutritional changes upon germination & sprouting have been summarized below. Chavan and Kadam (1989) concluded that - “The desirable nutritional changes that occur during sprouting are mainly due to the breakdown of complex compounds into a more simple form, transformation into essential constituents and breakdown of nutritionally undesirable constituents.”

It goes on to explain that, according to studies done by Chavan & Kadam (1989), Cuddeford (1989) and Shippard (2005), changes during the sprouting process result in:

• Increases in protein quality
• Increases in crude fiber content
• Increases in essential fatty acids
• Increases in vitamin content

The article cites a claim from the Shipard (2005) study: "“When seeds are sprouted, minerals chelate or merge with protein, in a way that increases their function.”

Soaking beans is a normal practice. While 36 to 48 hours is unusually long, they normally shouldn't spoil in this time.

Assuming that your beans did indeed spoil, there are different explanations possible.

• you misunderstood the recipe and used canned beans instead of dry beans. You can use canned beans for refried beans, but then you have to leave out the soaking and cooking steps.
• you added something to the beans which bacteria could feed on, for example sugar. While a recipe which recommends this would be an incredibly dumb recipe, there are all kinds of recipes out there, and maybe your paper just printed a bad recipe without testing it.
• you somehow created favorable conditions for bacterial growth. I am not sure if this can happen, but maybe leaving beans out for that long can lead to spoilage if other factors come into play, for example a very hot kitchen.

If the beans were really spoiled, but you didn't do any of the things above, it is very probable that it was a fluke. Try again, and you can reduce the soaking time. 12 to 24 hours is normal for beans.

It is also possible that your beans weren't spoiled. When beans are soaked, they can produce both slime and froth. This is a perfectly normal chemical reaction caused by complex molecules found in the beans, and it is not a sign of spoilage. A really strong stink will indeed mean that they were spoiled. But if you are not accustomed to soaking beans, maybe you assumed that something is wrong when you saw the slime, sniffed the beans and noticed their normal smell. It is faint, and to my nose it isn't offensive, but it is different from the smell of cooked beans, so maybe you associated it with "not normal" and therefore classified it as "nasty". I can't tell if that happened or not as I can't smell your beans, but if it happened, don't worry. There are lots of things in the kitchen which seem strange the first time. As for throwing out rotten-smelling food, I'd say better safe than sorry.