High-Limonene Orange Peel Essential Oil as a Natural Antibacterial Agent in Hand Sanitizer Gels

Orange peel waste has potential to be valorized from agro-industrial and food sectors to formulate products for personal hygiene and public health. This study presents the formulation of alcohol-based antibacterial gels incorporating essential oils extracted from Citrus sinensis orange peel waste and its sensory evaluation among 770 participants in a holistic approach. The orange essential oil, obtained via hydrodistillation, demonstrated a high limonene content of 96.5% by GC-MS. Antibacterial activity assessed by agar diffusion assays showed orange essential oil efficacy against Escherichia coli and Staphylococcus aureus, with inhibition zones of 25.9 mm and 23.62 mm, respectively. Two gel prototypes, GSA and GSB, were developed and sensorily evaluated. GSA was preferred for its superior appearance, spreadability, absorption, and smell, with 99% acceptability. Appearance and spread sensory parameters were the differentiators between both formulations according to user preferences. Thus, 93% of respondents are willing to use either GSA or GSB as a daily hygiene product over commercial ones. Although the gels exhibited reduced antibacterial activity relative to essential oil, with inhibition zones measuring 8.3 mm for E. coli and 9.0 mm for S. aureus, they retained satisfactory user acceptability. These findings support the use of citrus biowaste-derived essential oils in sustainable personal hygiene products.