From Corn Gluten Meal to Bioactive Glutamine Peptides: Stepwise Enzymatic Release, Peptidomics Analysis, and Identification of a Novel Peptide QFSLP Alleviates LPS-Induced Inflammation

Glutamine peptides not only serve as delivery vehicles for supplemental glutamine but also frequently possess unique biological activities that surpass glutamine itself, playing a crucial role in maintaining intestinal health. Corn gluten meal, as a major byproduct of corn processing with substantial production volume, is rich in glutamine, making it an ideal raw material for preparing glutamine peptides. This study aims to establish an enzymatic hydrolysis process for the efficient release of glutamine peptides from corn gluten meal and to identify glutamine peptides with gut health-maintaining effects. The results indicate that stepwise enzymatic hydrolysis of corn gluten meal using Protamex and Trypsin yields a glutamine-rich corn protein hydrolysate (GRCH). A total of 175 glutamine peptides were further identified from the low-molecular-weight fraction of GRCH. Through physicochemical property analysis and molecular docking technology, five glutamine peptides with potential inhibitory activity against the JAK2/STAT3 signaling pathway were screened, among which QFSLP demonstrated outstanding performance. In vitro experiments demonstrate that QFSLP is fully absorbed by intestinal epithelial cells and effectively alleviates LPS-induced inflammatory responses in intestinal cells. Following QFSLP intervention, the levels of proinflammatory factors TNF-α, IL-1β, and IL-8 in cells were significantly reduced (p < 0.05), while the level of the anti-inflammatory factor IL-10 was significantly increased (p < 0.05). The findings of this study contribute to the industrial-scale production of glutamine peptides and provide experimental evidence for their development in gut health-related products.