Eco-Friendly Microcapsules of Clove Oil Using Collagen Hydrolysate and Chitosan Derived From Chrome Shavings

The leather industry, which utilizes by-products of the meat industry as raw materials, produces substantial waste, with chrome shavings being a major by-product. These shavings are primarily composed of collagenous Cr (III) complexes and are rich in protein. In this study, collagen hydrolysate (CH) was extracted from chrome shavings through enzymatic hydrolysis, and its chemical properties were analyzed. The CH was combined with chitosan (C) to develop microcapsules containing clove oil, known for its antifungal and antimicrobial properties, using the complex coacervation method with glutaraldehyde as a cross-linking agent. These microcapsules have potential applications in preventing biodeterioration by inhibiting microbial activity on susceptible surfaces. Encapsulation efficiency was assessed, and the effects of parameters such as the CH-to-C ratio, glutaraldehyde concentration, and clove oil release rate were examined. Results showed that encapsulation efficiency improved with a lower CH-to-C ratio and higher cross-linker concentration. Over a 60-h release study, it was observed that increasing C content and cross-linker concentration slowed clove oil release. SEM analysis revealed spherical microcapsules, whereas TGA thermograms confirmed their thermal stability up to 135 °C. The sustained release of clove oil offers promising potential for long-term protection against microbial biodeterioration.