Optimization of Butterfly Pea Flower (Clitoria ternatea L.) Kombucha Formulation in Liquid Soap Preparation Using Factorial design Method / Optimasi Formula Kombucha Bunga Telang (Clitoria ternatea L.) Dalam Sediaan Sabun Mandi Cair Dengan Metode Factorial design

Introduction: Natural-based liquid soap has gained increasing interest as a multifunctional skin cleanser with antibacterial properties. Butterfly pea flower (Clitoria ternatea L.) is rich in bioactive compounds such as flavonoids and anthocyanins that exhibit antibacterial potential, which can be enhanced through fermentation into kombucha. Objective: This study aimed to optimize the formulation of butterfly pea flower kombucha liquid soap using a factorial design method and to evaluate its physical stability and antibacterial activity against Staphylococcus aureus. Methods: Optimization was performed using a 2² factorial design with a center point assisted by Design-Expert® software, with variations in kombucha fermentation time (7, 10.5, and 14 days) and kombucha concentration (20%, 30%, and 40%). The response parameters optimized included pH, viscosity, and foam stability. The optimum formula was evaluated for physical stability using a freeze-thaw cycling method for 6 cycles and tested for antibacterial activity against S. aureus using the well diffusion method. Results: The optimum formula was obtained at a fermentation time of 10.5 days and a kombucha concentration of 20%, yielding a desirability value of 0.874. The optimized formulation exhibited a pH of 5.23 ± 0.15, viscosity of 1674.0 ± 8.76 cP, and foam stability of 73.67 ± 1.53%. Verification experiments confirmed that the observed values fell within the 95% prediction interval, validating the model. Physical stability testing demonstrated no significant changes in organoleptic properties, homogeneity, pH, viscosity, or foam stability after 6 freeze-thaw cycles. The optimum formula showed strong antibacterial activity against S. aureus with an average inhibition zone diameter of 13.67 ± 0.29 mm. Conclusion: The optimized butterfly pea kombucha liquid soap formulation possesses excellent physical characteristics, good stability, and promising potential as a natural antibacterial cleanser.

Pendahuluan: Sabun mandi cair berbasis bahan alami semakin diminati sebagai pembersih kulit multifungsi sekaligus memiliki aktivitas antibakteri. Bunga telang (Clitoria ternatea L.) kaya akan senyawa bioaktif seperti flavonoid dan antosianin yang berpotensi sebagai agen antibakteri, yang dapat ditingkatkan melalui proses fermentasi menjadi kombucha. Tujuan: Penelitian ini bertujuan untuk mengoptimasi formula sabun mandi cair kombucha bunga telang menggunakan metode factorial design serta mengevaluasi stabilitas fisik dan aktivitas antibakterinya terhadap Staphylococcus aureus.Metode: Optimasi dilakukan dengan rancangan faktorial 2² dilengkapi titik pusat menggunakan perangkat lunak Design-Expert®, dengan variasi waktu fermentasi kombucha (7, 10,5, dan 14 hari) dan konsentrasi kombucha (20%, 30%, dan 40%). Parameter respon yang dioptimasi meliputi pH, viskositas, dan stabilitas busa. Formula optimum dievaluasi stabilitas fisiknya menggunakan metode freeze-thaw cycling selama 6 siklus dan diuji aktivitas antibakterinya terhadap S. aureus menggunakan metode difusi sumuran. Hasil: Formula optimum diperoleh pada waktu fermentasi 10,5 hari dan konsentrasi kombucha 20% dengan nilai desirability 0,874. Formula optimum menunjukkan pH 5,23 ± 0,15, viskositas 1674,0 ± 8,76 cP, dan stabilitas busa 73,67 ± 1,53%. Hasil verifikasi menunjukkan nilai aktual berada dalam rentang prediction interval 95%, sehingga model optimasi dinyatakan valid. Uji stabilitas fisik menunjukkan tidak ada perubahan signifikan pada organoleptik, homogenitas, pH, viskositas, maupun stabilitas busa setelah 6 siklus freeze-thaw. Formula optimum menunjukkan aktivitas antibakteri kuat terhadap S. aureus dengan diameter zona hambat 13,67 ± 0,29 mm. Kesimpulan: Formula optimum sabun mandi cair kombucha bunga telang memiliki karakteristik fisik yang baik, stabil secara fisik, dan berpotensi dikembangkan sebagai sabun mandi cair antibakteri berbasis bahan alam.