Hot-melt extrusion-assisted Maillard-type modification of donkey-hide gelatin with mannose oligosaccharides improves aqueous dissolution and recovery of CTX-affected hematological and immune-related parameters.

BACKGROUND: Donkey-hide gelatin (DHG) is a collagen-derived macromolecule with reported hematopoietic and immunomodulatory activities, but its use is limited by slow aqueous dissolution. OBJECTIVE: To improve DHG dissolution through hot-melt extrusion (HME)-assisted Maillard-type modification with mannose oligosaccharides (MOS) and evaluate recovery of cyclophosphamide (CTX)-affected hematological and immune-related parameters. MATERIALS AND METHODS: DHG and MOS were processed by HME to obtain extrudates (EXT), with an unextruded physical mixture (PM) as comparison. Structural changes were characterized by OPA assay, UV absorbance, FTIR, PXRD, PLM, CD spectroscopy, GPC, and ^1H NMR. Dissolution was assessed photographically and by comparative UV analysis. Biological effects were evaluated in CTX-immunosuppressed mice. RESULTS: The optimized condition was a DHG:MOS mass ratio of 1:1, 148 °C, and 200 rpm, yielding an OPA-based apparent DG of 31.16%. HME promoted intermediate-stage Maillard-related changes while maintaining limited browning and induced MOS amorphization, DHG conformational rearrangement, altered proton environments, and apparent molecular-weight redistribution. EXT dissolved faster than PM. In CTX-treated mice, several hematological and immune-related parameters in the EXT group shifted toward values observed in the normal group. Because no MOS-alone group was included, the contribution of intrinsic MOS activity could not be separated from HME-associated modification. CONCLUSION: HME-treated DHG-MOS showed faster aqueous dissolution than PM and was associated with recovery of several CTX-affected hematological and immune-related parameters.