Microbial Activities in Cocoa (Theobroma Cacao L.) Pulp During Fermentation With Ragi Tape Addition

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Pusat Penelitian dan Pengembangan Perkebunan
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Microbial activities in cocoa pulp decomposition is key in cocoa beans fermentation. Ragi tape is widely used as a source of microbes (starters). The study aimed to investigate the pattern of changes in the number of microbes, substrate degradation activities and primary metabolites production during fermentation with the addition of ragi tape. The study was conducted at the laboratories within the Faculty of Agriculture Technology and Integrated Laboratory of Experiment and Research, UGM from March to October 2018 . Fermentation experiment used 2 kg of fresh cacao beans stored in a plastic box per batch, its temperature was set daily. The amount of microbes was enumerated using total plate count (TPC), whereas substrate degradation and primary metabolites were analyzed using high performance liquid chromatography (HPLC) and gas chromatography (GC). Temperature, pulp and seed pH, and fermentation index were observed. The results showed that adding ragi tape for fermentation generated a maximum amount of yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) of 9.03+0.85; 9.05+0.17; and 9.15+0.89 log cfu/g of cocoa pulp respectively, with substrate degradation in the form of sucrose reduced by 97%, glucose 98.6%, fructose 97%, and citric acid 71% on the third day. Maximum production of primary metabolites of ethanol is 27.84+21.85 mg/g of cocoa pulp, lactic acid 4.18+3.16 mg/g of cocoa pulp and acetic acid 3.38+5.43 mg/g of cocoa pulp. Fermentation with the addition of ragi tape accelerates the process to three days with a fermentation index value of 1.05+0.06 and seed pH of 5.97+0.20.
Aktivitas mikrob pada proses penguraian pulp biji kakao merupakan kunci pada proses fermentasi biji kakao. Ragi tape merupakan sumber mikrob (starter) yang banyak digunakan untuk fermentasi, mudah didapat dan disimpan. Tujuan penelitian adalah mempelajari pola perubahan jumlah mikrob, aktivitas degradasi substrat, dan produksi metabolit primer selama fermentasi biji kakao dengan penambahan ragi tape. Penelitian dilaksanakan di laboratorium-laboratorium Fakultas Teknologi Pertanian dan Laboratorium Pengujian dan Penelitian Terpadu (LPPT) Universitas Gadjah Mada (UGM), Yogyakarta, mulai bulan Maret sampai Oktober 2018. Fermentasi dilakukan skala laboratorium sebanyak 2 kg biji kakao basah dalam kotak plastik per batch yang diatur suhunya per hari. Jumlah mikrob dienumerasi menggunakan total plate count (TPC), degradasi substrat dan metabolit primer dianalisis menggunakan high performance liquid chromatography (HPLC) dan gas chromatography (GC). Suhu, pH pulp dan biji, serta indeks fermentasi diamati selama fermentasi. Hasil penelitian menunjukkan bahwa fermentasi biji kakao dengan penambahan ragi tape menghasilkan jumlah yeast, bakteri asam laktat (BAL), dan bakteri asam asetat (BAA) maksimal masing-masing 9,03+0,85; 9,05+0,17; dan 9,15+0,89  log cfu/g pulp kakao dengan degradasi substrat berupa sukrosa berkurang 97%, glukosa 98,6%, fruktosa 97%, dan asam sitrat 71% pada hari ketiga. Produksi maksimal metabolit primer etanol 27,84+21,85 mg/g pulp kakao, asam laktat 4,18+3,16 mg/g pulp kakao, dan asam asetat 3,38+5,43 mg/g pulp kakao. Proses fermentasi biji kakao dengan penambahan ragi tape dapat mempercepat proses fermentasi menjadi 3 hari dengan nilai indeks fermentasi 1,05+0,06 dan pH biji 5,97+0,20.
Keywords
Cocoa pulp; fermentation; primary metabolites; ragi tape; yeast, , Fermentasi; metabolit primer; pulp kakao; ragi tape; yeast,
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