Bio-preservation using onion and lemon peel biomass: a cleaner leather processing alternative

This research investigated the efficacy of onion (Allium cepa) peels powder and lemon (Citrus limonum) peels powder for goatskin preservation. Various parameters like hydrothermal stability, moisture content, hydroxyproline content, total bacterial count, antibacterial activity test, and organoleptic properties were assessed against the outcomes attained with the traditional preservation technique. Shoe upper crust leathers were manufactured from the skins after being preserved for 30 days, and the quality was evaluated based on physical tests. The findings showed that raw goatskin could be successfully preserved for 30 days using 2.5% onion peel powder alone and 5% lemon peel powder + 5% NaCl. This method produced leather that met the minimum standards for a shoe upper leather, having characteristics similar to those obtained using the standard procedure, with tensile strengths surpassing the 200 kg/cm² requirement. Other parameters, such as grain crack strength (minimum requirement 20 kg) and stitch tear strength (requirement: 80–100 kg/cm), also met standards. Additionally, the new preservation methods resulted in reductions of TDS by 78.81% and 50.39%, chloride content by 98% and 95%, and COD by 66.66% and 54.44% respectively in the pre-soaking process during leather processing. These findings suggest that this approach could be a viable and environmentally friendly option for preserving goatskin, with the potential to reduce the ecological impact of leather production.