Spectroscopic and compositional analysis of banana peel flour as a gluten-free ingredient compared to conventional flours

• Banana peel flour shows high minerals and antioxidants vs rice, wheat, and cornstarch. • Raman confirms no gluten-related amide bands, supporting gluten-free suitability. • LIBS reveals higher K, Ca, and Mg levels in banana peel flour than control flours. • Gluten-free cookies using banana peel flour achieved high sensory screening. • Valorizing banana peel supports sustainable food innovation and circular economy. Banana peel is an underutilized agro-industrial by-product with potential for conversion into functional food ingredients. This study assessed the nutritional, spectroscopic, and functional properties of banana peel flour (BPF) to evaluate its suitability for gluten-free applications. Proximate analysis revealed that BPF contains substantially higher dietary fiber and ash content compared with conventional flours. Elemental profiling using Laser-Induced Breakdown Spectroscopy (LIBS) confirmed the presence of key minerals, including potassium, calcium, and magnesium, with no detectable heavy metals. Raman spectroscopy showed dominant carbohydrate and phenolic vibrational features and an absence of amide I and amide III bands, verifying that BPF is naturally gluten-free. The functional performance of BPF was examined through its incorporation into a gluten-free cookie prototype. Physical quality parameters, including baking loss, spread ratio, dimensional stability, and instrumental hardness, indicated acceptable structural integrity consistent with fiber-enriched formulations. Antioxidant evaluation demonstrated that BPF exhibited the highest total phenolic content (TPC) and total flavonoid content (TFC) among all samples. A brief sensory screening provided supportive evidence of consumer acceptability. Overall, the combined compositional and functional findings highlight BPF as a promising gluten-free ingredient with nutritional and antioxidant advantages, contributing to sustainable food system development.