A method of preparing a non-wood fiber paper strengthening product is disclosed. The method comprises placing an additive in an aqueous alkaline medium, wherein the additive comprises a hydroxycarboxylic acid, and mixing a non-wood fiber material with the placed additive in the aqueous alkaline medium to form a mixture, wherein the non-wood fiber material comprises starch, protein and fiber, wherein the additive, starch, protein, and fiber of the non-wood fiber material, and metal ions of the alkaline medium become physically crosslinked resulting in a non-wood fiber paper strengthening product. In an aspect, the non-wood fiber paper strengthening product is used in making a paper product wherein the paper product has greater strength than the same paper product made with native starch or chemically modified starch instead of the non-wood fiber paper strengthening product.