Electronic Theses and Dissertation

Bunga cempaka putih (Michelia alba D.C) berpotensi sebagai bahan baku pembuatan cuka dengan aktivitas antioksidan. Penelitian ini bertujuan menentukan karakteristik kimia, kondisi optimum fermentasi, kandungan fitokimia, serta aktivitas antioksidan cuka bunga cempaka putih. Fermentasi dilakukan dua tahap, yaitu fermentasi alkohol oleh Saccharomyces cerevisiae dan fermentasi asam asetat dengan Acetobacter aceti pada variasi konsentrasi tertentu. Karakterisasi kimia menunjukkan bunga cempaka putih mengandung kadar abu 5,54%, lipid 3,70%, protein 9,40%, dan karbohidrat 81,34%. Fermentasi alkohol menghasilkan kadar alkohol tertinggi (9,3%) pada gula 15% dan Saccharomyces cerevisiae 5%. Fermentasi asam asetat menghasilkan kadar asam asetat tertinggi (5,62%) pada kombinasi gula 15%, Saccharomyces cerevisiae 5%, dan Acetobacter aceti 15% melalui titrasi NaOH. Kadar alkohol sisa yang dihasilkan masih melebihi 1% menunjukkan fermentasi belum optimal, sehingga diperlukan waktu lebih lama untuk hasil terbaik. Analisis HPLC mendeteksi asam asetat 0,0037% dan asam suksinat 0,0014%, lebih rendah dibanding titrasi karena hanya mengukur asam spesifik. Uji fitokimia mengidentifikasi alkaloid, flavonoid, terpenoid, dan fenolik. Kandungan total fenolik dan flavonoid berturut-turut sebesar 57,14 mg GAE/g dan 6,92 mg QE/g. Aktivitas antioksidan berdasarkan uji DPPH menunjukkan nilai IC50 94,59 ppm yang tergolong aktivitas kuat. Dengan demikian, cuka bunga cempaka putih berpotensi dikembangkan sebagai sumber antioksidan alami.

White champaca (Michelia alba D.C.) flowers have potential as raw materials for vinegar production with antioxidant activity. This study aimed to determine the chemical characteristics, optimum fermentation conditions, phytochemical contents, and antioxidant activity of white champaca flower vinegar. The fermentation process was carried out in two stages: alcoholic fermentation using Saccharomyces cerevisiae and acetic acid fermentation using Acetobacter aceti at varying concentrations. Chemical characterization showed that white champaca flowers contained 5.54% ash, 3.70% lipids, 9.40% proteins, and 81.34% carbohydrates. The alcoholic fermentation produced the highest alcohol content (9.3%) at 15% sugar and 5% S. cerevisiae, while the acetic acid fermentation produced the highest acetic acid content (5.62%) at the combination of 15% sugar, 5% S. cerevisiae, and 15% A. aceti, as determined through NaOH titration. The residual alcohol content, which remained above 1%, indicated that fermentation was not yet optimal and required a longer duration to achieve better results. HPLC analysis detected acetic acid (0.0037%) and succinic acid (0.0014%), which were lower than the titration results because HPLC measures only specific acids. Phytochemical tests confirmed the presence of alkaloids, flavonoids, terpenoids, and phenolic compounds. The total phenolic and flavonoid contents were 57.14 mg GAE/g and 6.92 mg QE/g, respectively. Antioxidant activity, based on the DPPH assay, showed an IC₅₀ value of 94.59 ppm, indicating strong antioxidant activity. Therefore, white champaca flower vinegar has potential to be developed as a natural source of antioxidants.