Electronic Theses and Dissertation

Kulit buah kopi (kaskara) merupakan limbah hasil pengolahan kopi yang masih mengandung senyawa bioaktif, terutama polifenol, sehingga berpotensi dimanfaatkan sebagai bahan baku minuman fermentasi kombucha yang memiliki aktivitas antioksidan. Penelitian ini bertujuan untuk mengetahui pengaruh interaksi antara variasi konsentrasi kaskara dan lama fermentasi terhadap pH serta aktivitas antioksidan kombucha kaskara. Penelitian menggunakan Rancangan Acak Lengkap (RAL) faktorial dengan dua faktor, yaitu konsentrasi kaskara (1% dan 2%) serta lama fermentasi (0, 4, 8, 12, dan 16 hari). Parameter yang diamati meliputi nilai pH dan aktivitas antioksidan menggunakan metode DPPH yang dinyatakan sebagai persen inhibisi. Data dianalisis menggunakan analisis sidik ragam (ANOVA) pada taraf kepercayaan 95% dan dilanjutkan dengan uji Duncan apabila perlakuan berpengaruh terhadap nilai pH dan persen inhibisi. Hasil penelitian menunjukkan bahwa interaksi antara konsentrasi kaskara dan lama fermentasi berpengaruh nyata (α0,05) terhadap aktivitas antioksidan, namun lama fermentasi secara tunggal berpengaruh nyata (α

Coffee fruit husks (cascara) is a byproduct of coffee processing that still contains bioactive compounds, particularly polyphenols, and thus has the potential to be used as a raw material for kombucha—a fermented beverage with antioxidant activity. This study aimed to determine the effect of the interaction between variations in cascara concentration and fermentation duration on the pH and antioxidant activity of cascara kombucha. The study used a factorial Complete Randomized Design (CRD) with two factors: cascara concentration (1% and 2%) and fermentation duration (0, 4, 8, 12, and 16 days). The parameters observed included pH values measured using a pH meter and antioxidant activity determined using the DPPH method, expressed as the percentage of inhibition. The data were analyzed using analysis of variance (ANOVA) at a 95% confidence level, followed by Duncan’s multiple range test when significant differences were found. The results of the study showed that the interaction between cascara concentration and fermentation duration had a significant effect (α < 0.05) on pH, with the lowest pH value obtained from the combination of a 2% cascara concentration and a fermentation duration of 16 days (2.81 ± 0.01), while the highest pH value was obtained with a 1% cascara concentration and a fermentation duration of 0 days (3.34 ± 0.01). Conversely, the interaction between the two factors had no significant effect (α > 0.05) on antioxidant activity; however, fermentation duration alone had a significant effect (α < 0.05), with the percentage inhibition increasing with fermentation duration, namely from 79.60% to 85.40% at a 1% concentration and from 78.67% to 88.11% at a 2% concentration. It can be concluded that the longer the fermentation and the higher the cascara concentration, the lower the pH value and the higher the antioxidant activity of cascara kombucha. Keywords : antioxidants activity, cascara, fermentation, kombucha, pH