@unsynchronized – Your rant is certainly understandable – I’ve had a number of my own when it comes to tracking down good data on certain ingredients.
I will never, ever, take somebody’s ingredient posted on the DIY site at face value. As you’ve found, there is absolutely no guarantee as to the accuracy. I need to do the research and calculations myself to have any confidence in them.
Thus I have done my best to cobble together what I believe to be the best information available for each ingredient. Where possible, I always prioritize data from the USDA nutrient database – in many cases it is far more complete than any other source (product labels are inconsistent at best, omit certain nutrients entirely, and zero out or crudely round off others depending on the “serving size”).
In the case of soy lecithin granules, the USDA data is less than ideal. As you’ve pointed out, the data is for soy lecithin in its pure (liquid oil) form. Lecithin granules are produced through a combination of the lecithin oil with some kind of carbohydrate and/or protein binder (probably soy powder). This is likely to be a proprietary process that varies to some degree from one producer to the next.
What I did in the end was to combine the USDA entry for lecithin with the product label for the Bob’s Red Mill soy lecithin granules (basically I used the USDA data as the baseline but went with the Bob’s Red Mill values where they significantly differed). I believe this is sufficient to get values that are at least in the correct ballpark of reality.
As always, I invite you and others to point out any significant discrepancies you may find, bearing in mind the above process. It would be great if we could annotate the ingredient profiles with details on our research and decision process, but until then I’ll continue to grit my teeth and smile when the “Where did you get [X value] for whey protein?” type questions come in each week.
At the end of the day, I think we need to accept a certain degree of agnosticism when it comes to the nutrient content of certain ingredients (as non-pharmaceutical grade food products are going to vary from batch to batch regardless).