Improving the mechanical strength of bio-based drinking straws derived from rice straw through coating with bael protein isolate and pectin for applications in the food and beverage industry

The widespread use of disposable plastic straws poses a serious environmental threat, endangering both human health and aquatic ecosystems. Paper straws have emerged as an alternative, yet they often fall short due to poor water resistance and mechanical strength. To address these limitations, the present study explores the development of bio-based drinking straws made from rice straw, coated with Bael Protein Isolate (BPI) and a BPI-pectin mixture. These coated variants, termed RS/BPI and RS/BPI/P, demonstrated improved performance compared to Uncoated straws (UC). Specifically, the liquid absorption of Uncoated (UC) straws was 63.09% higher than that of the coated straws, indicating that the BPI and BPI-pectin coatings substantially improved liquid resistance in water, coke, and orange juice. Mechanical testing showed that the tensile strength of coated straws was enhanced by approximately 13.8% for RS/BPI and 43.2% for RS/BPI/P compared to the UC samples, respectively. Coating increased the straw thickness by approximately 20±5 µm and created a more uniform surface. Migration tests confirmed values below the acceptable limit (<60 mg/kg), while FTIR analysis confirmed the presence of cellulose, protein, and pectin. Thermogravimetric analysis indicated improved thermal stability of coated straws up to 200^°C. These findings suggest that rice straw-based straws, particularly with BPI and pectin coatings, offer a sustainable, microplastic-free alternative to conventional plastic straws, contributing to environmental conservation efforts.

Keywords: Eco-friendly Coating, Rice Straw, Protein, Pectin, Coating