Protein is and will continue to be the most expensive component of any basic soylent recipe. I’ve been doing some research and would like to present a little question:
Whey protein (concentrate or isolate) is generally accepted as the most common and cost effective base protein, but cost effective is relative. Currently, it’s difficult to find a bulk whey protein that costs less than ~$7-8/lb. Not bad for a waste product that’s courting the body builder community.
Wheat protein (gluten), on the other hand, has been used extensively for decades by bakers. As a result, it’s phenomenally cheap - you can easily find bulk wheat protein isolate for under $3/lb ([here], for instance, it’s $2.50).
The predominant complaint against wheat protein (aside from the minority of sensitive individuals), is that it is incomplete. Significantly, wheat protein is lacking in lysine, an essential amino acid. In order to compensate for the lysine reduction, you would need to consume twice the amount of wheat as whey, which puts you at risk for all sorts things (particularly kidney stress) once you’re consuming that much protein in your diet.
[I found a study] comparing the relative prevalence of amino acids in wheat vs. cow milk proteins. Pay particular attention to the table on on the bottom left on page 9. As mentioned, the major impediment to wheat having a TAA status would be the relative lack of lysine (and possibly threonine), both of which are overly prevelant in whey.
Blending whey isolate or concentrate with wheat isolate in a 50:50 ratio will solve all problems of amino acid deficiency in unmixed wheat isolate, supply enough of all AAs for all age ranges, and significantly reduce/dilute the price concerns of whey protein and associated price shocks.
This has the potential (after some serious up front investment) to provide blended protein at a cost of ~$5/lb or perhaps even less, significantly reducing the daily cost of soylent. Blending in soy protein isolate ([~$3.7/lb here])as 1:1:1 would lower it further without negatively effecting overall AA ratios. People are averse to bulk consumption of soy protein, but diluted consumption should be fine for most everyone.
Using either or both of these, you can easily get protein costs for soylent near or below $1.50/day (depending on calorie targets) for low carb and keto recipes and below that ($1-.50?) for people following more standard dietary splits.
If someone was interested in taking on the blending and reselling, this could open the door to a lot more people finding soylent an affordable generic food choice.
Edit: to correct aggregate daily protein costs.