Yesterday I made my first Linden leaf curd. I liquified a large colander heaped with leaves in a blender with added water, strained it through a cheesecloth, and put the resulting liquid on to boil. It smelled like cutting grass.
When it had boiled, I strained it through cheesecloth again and squeezed it.
I ended up with about three tablespoons of bright green slime!
With some salt, it tasted a bit grassy.
Mixed into rice with olive oil and spices, it just added a pleasant green taste, and looked like a spinach dish.
I could produce a lot of my food from a line of Linden trees!
But before I can do that, I need to figure out what the nutritional value of this concoction is, and if I could be concentrating any toxins or anti-nutrients.
Most data on leaf curd is talking about tropic species. I can't even find nutritional values for plain linden leaves, or if they have any anti-nutrients.
I may have to mix up a batch and send it to a food testing lab.
Also, I need a better way to prepare it. The process I used was slow, inefficient, used a lot of energy, and made a big mess. I'm thinking that I will get a large juicer, and some large pillow cases for squeezing the stuff at the various stages. This would allow me to add less water, speeding up boiling and getting more final product per batch, and feeding leaves into a juicer can be continuous, unlike the batch process of blending. The pillow cases should be reusable, unlike the cheese cloth.
Once I get it tested and perfected, I can set up a linden coppice plot and go to town!
A food processor, rather than a blender, will help you to scale up. Blenders work all right when there is a lot of liquid and they can draw small chunks of food down into the blades. The blades of a food processor sweep out more area and do not rely as much on vortex action to bring the food into contact with the blades. I think you will find that if you stuff the leaves into the food processor, you will need to use less water to grind them into the consistency you want. You might even try leaving the water out and using oil as your liquifying agent -- like in making pesto.
Food processors come in different sizes, small ones that only have one set of blades and are most useful for making salsa, to larger ones that are top fed and have shredding and slicing blades. You might even blanch the leaves first, a little cooking before blending will break down the fibers and make them easier to process.
Sounds like a good experiment, so don't just tinker with your linden leaves, see what you can do with different pieces of equipment.
Gilbert Fritz wrote:
Would cooking the leaves ahead of time coagulate the proteins before they can be extracted?
It might. If you were to just denature the protein, then it would probably be less soluble. But cooking also starts breaking down the proteins, and generally increases the digestibility of foods. You would have to do some experimenting to see which effect dominates.
If I used oil as the liquid, how would that affect the subsequent straining and boiling steps?
I mentioned pesto, because that is processed leaves without the straining, i.e., all the natural (and beneficial) fiber left in. Generally, pestos aren't cooked, just stirred into some hot pasta. I mention it as an alternate method of preparing "leaves" for consumption. The use of nuts and olive oil in making pesto (maybe some Parmesan cheese too) results in a dish that is nutritionally complete, much more so than plain old boiled pasta.
Is it your intention to store the curd for later use? Are you trying to obtain a high protein liquid without all the fiber filler? Are you aiming for something on the order of spirulina?
I'm trying to concentrate the protein so that it can be a staple protein source; there is too much fiber and water in leaves to be a staple without processing. Also, yes, I would like to store it. And Linden and other tree leaves are a bit tough to be eaten in large amounts without processing in any case.
Now, as far as making pesto, I'm sure that would be a great way to eat them, but not necessarily a great way to provide one's protein.
The easiest way to get rid of the water is to dry it. If leaves are dried quickly, before the protein has a chance to degrade, you have a form of the protein you can store. Think of file powder -- dried and ground up sassafras leaves. Yes, there is the matter of that non-nutritious cellulose filler, but some plant leaves are over 20% protein on a dry matter basis. If you thoroughly homogenize your plant material with water, and strain out the large remaining bits, then you have your protein extracted, but then as the next step have you thought about not curdling it, but drying it? That would leave you with a protein powder, which you could add in to various recipes.
I take it you are going to use this as a base in recipes; something to add to flours and bake into cakes or loaves, or to put into stews. If that is the case, a dried powder would have advantages over a wet curd.