Electronic Theses and Dissertation

Penelitian ini bertujuan menganalisis karakteristik fitokimia, profil senyawa, aktivitas biologis, dan karakteristik mikrobiologis water kefir berbasis cascara pulp dan cascara husk dengan penambahan ekstrak buah jamblang (Syzygium cumini). Penelitian menggunakan Rancangan Acak Lengkap (RAL) faktorial dengan dua faktor, yaitu jenis cascara (pulp dan husk) serta konsentrasi ekstrak jamblang (0%, 5%, dan 10%) dengan tiga ulangan (18 satuan percobaan). Parameter yang diamati meliputi profil senyawa menggunakan GC-MS, asam organik menggunakan LC-MS/MS QTOF, total asam, aktivitas antioksidan (IC₅₀), total bakteri asam laktat (BAL), total bakteri asam asetat (BAA), aktivitas antibakteri terhadap Escherichia coli dan Staphylococcus aureus, serta identifikasi molekuler BAL. Hasil penelitian menunjukkan bahwa ekstrak jamblang didominasi oleh 5-Hydroxymethylfurfural (20,38%) dan 4H-Pyran-4-one (15,23%), sedangkan cascara pulp didominasi 6-Oxa-bicyclo[3.1.0]hexan-3-one dan cascara husk didominasi asam asetat serta kafein. Jenis cascara dan konsentrasi ekstrak jamblang berpengaruh nyata (p≤0,05) terhadap total asam (0,60–1,22%). Aktivitas antioksidan tergolong kuat dengan nilai IC₅₀ 71,43–91,89 ppm, dimana perlakuan cascara pulp dengan 10% ekstrak jamblang menghasilkan aktivitas antioksidan terbaik (IC₅₀ 71,43 ppm). Total BAL berkisar 5,14–5,67 Log CFU/mL dan tidak dipengaruhi perlakuan, sedangkan total BAA berkisar 3,60–4,40 Log CFU/mL dan dipengaruhi oleh jenis cascara. Penambahan ekstrak jamblang meningkatkan aktivitas antibakteri terhadap E. coli, tetapi tidak berpengaruh nyata terhadap S. aureus. Isolat BAL dari perlakuan terbaik teridentifikasi sebagai Lacticaseibacillus paracasei strain CG2 dan Lacticaseibacillus paracasei subsp. tolerans. Kombinasi cascara pulp dan 10% ekstrak jamblang menghasilkan water kefir dengan karakteristik fungsional terbaik.

This study aimed to evaluate the phytochemical characteristics, compound profile, biological activity, and microbiological characteristics of water kefir produced from cascara pulp and cascara husk supplemented with Syzygium cumini fruit extract. A completely randomized factorial design was applied using two factors: cascara type (pulp and husk) and S. cumini fruit extract concentration (0%, 5%, and 10%), with three replications (18 experimental units). The evaluated parameters included volatile compounds (GC-MS), organic acids (LC-MS/MS QTOF), total acidity, antioxidant activity (DPPH IC₅₀), total lactic acid bacteria (LAB), total acetic acid bacteria (AAB), antibacterial activity against Escherichia coli and Staphylococcus aureus, and molecular identification of LAB. The results showed that S. cumini fruit extract was dominated by 5-Hydroxymethylfurfural (20.38%) and 4H-Pyran-4-one (15.23%), while cascara pulp was characterized by 6-Oxa-bicyclo[3.1.0]hexan-3-one and cascara husk by acetic acid and caffeine. Cascara type and fruit extract concentration significantly affected total acidity (0.60–1.22%; p≤0.05). The antioxidant activity was classified as strong, with IC₅₀ values ranging from 71.43 to 91.89 ppm; the lowest IC₅₀ (71.43 ppm) was obtained from cascara pulp supplemented with 10% S. cumini extract. Total LAB ranged from 5.14 to 5.67 log CFU/mL and was not significantly affected by treatments, whereas total AAB ranged from 3.60 to 4.40 log CFU/mL and was significantly influenced by cascara type. S. cumini extract significantly enhanced antibacterial activity against E. coli but had no significant effect on S. aureus. The dominant LAB isolate from the best treatment was identified as Lacticaseibacillus paracasei strain CG2 and Lacticaseibacillus paracasei subsp. tolerans. The combination of cascara pulp and 10% S. cumini fruit extract produced water kefir with the best functional characteristics.