Soil Drenching with Wood Distillate Modifies the Nutritional Properties of Chickpea ( L.) Seeds by Increasing the Protein Content and Inducing Targeted Changes in the Proteomic Profile.

The production of food with a naturally enriched protein content is a strategic response to the growing global demand for sustainable protein sources. Wood distillate (WD), a by-product of the pyrolysis of woody biomass, has previously been shown to increase the protein concentration and bioavailability in chickpea seeds. Here, we evaluated the effect of 0.5% () WD soil drenching on chickpea productivity, nutritional profile, and proteomic pattern. WD treatment significantly improved the yield by increasing plant biomass (+144%), number of pods and seeds (+148% and +147%), and seed size (diameter: +6%; weight: +25%). Nutritional analyses revealed elevated levels of soluble proteins (+15%), starch (+11%), fructose (+135%), and polyphenols (+14%) and a greater antioxidant capacity (25%), alongside a reduction in glucose content, albeit not statistically significant, suggesting an unchanged or even lowered glycemic index. Although their concentration decreased, Ca (-31%), K (-12%), P (-5%), and Zn (-14%) in WD-treated plants remained within normal ranges. To preliminary assess the quality and safety of the protein enrichment, a differential proteomic analysis was performed on coarse flours from individual seeds. Despite the higher protein content, the overall protein profiles of the WD-treated seeds showed limited variation, with only a few storage proteins, identified as legumin and vicilin-like isoforms, being differentially abundant. These findings indicate a general protein concentration increase without a major alteration in the proteoform composition or differential protein synthesis. Overall, WD emerged as a promising and sustainable biostimulant for chickpea cultivation, capable of enhancing both yield and nutritional value, while maintaining the proteomic integrity and, bona fide, food safety.