Judul: Characterization of Kombucha Fermented Drink Microalgae Spirulina sp. with Different Extraction Methods
Abstrak: Spirulina sp. is a microalga with a protein content of 64-73 %. Kombucha is a fermented beverage that is beneficial for body health. This research aims to determine the effect of extraction methods on the characteristics of kombucha extract made from Spirulina sp. The methods used include cold temperature maceration extraction, freeze-thaw, and hot temperature extraction. The treatments applied are freezing, brewing, and cold processes. Sample extraction undergoes fermentation with SCOBY (Symbiotic Culture of Bacteria and Yeast). The research results indicate that the method influences the pigment content in Spirulina sp. extract. The freezing treatment using the freeze-thaw method yields the highest pigment content in allophycocyanin pigment and total chlorophyll. Kombucha extract from Spirulina sp. is successfully obtained with pH values ranging from 2.5 to 3.8, alcohol content <0 %, and a TPC value of 105-106 CFU/g. The favorability level of kombucha from Spirulina sp. extract is not significantly different.
Keyword: characterization, extraction, fermentation, kombucha, Spirulina sp.

Judul: Chemical Characterization of Fermented Spirulina and Screening of Metabolic Compounds Produced by it
Abstrak: Spirulina platensis dapat menstimulasi pertumbuhan mikroba non patogenik. Penelitian sebelumnya menunjukkan Spirulina fermentasi memiliki karakteristik kimiawi dan aktivitas antioksidan. Pengeringan beku (liofilisasi) dilakukan dan digunakan dalam penelitian ini. Penelitian bertujuan menentukan karakteristik kimiawi dan penapisan senyawa metabolit dari Spirulina fermentasi setelah liofilisasi. Spirulina fermentasi liofilisasi memiliki nilai pH 4,15 ± 0,00, total asam tertitrasi (TAT) 11,96 ± 0,00 %, dan total bakteri asam laktat (BAL) <2,5 × 101 ± 0,00. Spirulina fermentasi mengandung komponen aktif flavonoid, steroid, tanin, saponin dan fenol hidrokuinon, serta negatif alkaloid. Penapisan senyawa metabolit menggunakan LC-MS/MS menghasilkan 88 senyawa, terdiri dari golongan terpen atau terpenoid, fenolik, dan alkaloid, serta kelompok asam amino, asam lemak, asam organik, natural pigmen, gula dan kelompok lainnya. Senyawa dominan teridentifikasi diantaranya propenyl pyrazine, ribonic acid, pyroglutamic acid, phenyllactic acid, 1,2-cyclohexanedicarboxylic acid, didecyl ester, cis-caftaric acid, malic acid, 1,2-cyclohexanedicarboxylic acid, cyclohexylmethylnonyl ester, dan gallic acid., Spirulina platensis can stimulate the growth of non-pathogenic microbes. Previous studies have shown that lyophilized fermented Spirulina and Spirulina biomass have antioxidant activity. The study aims to determine the chemical characteristics and screening of metabolites produced by lyophilized fermented Spirulina and Spirulina biomass. Lyophilized fermented Spirulina had a pH value of 4,15 ± 0,00, total titrated acid (TAT) 11,96 ± 0,00%, and total lactic acid bacteria (LAB) < 2,5 × 101 ± 0,00. Fermented Spirulina contains active components of flavonoids, steroids, tannins, saponins and phenol hydroquinone, as well as negative alkaloids. Screening of metabolites using LC-MS/MS resulted in 88 compounds, consisting of terpenes or terpenoids, phenolics, and alkaloids, as well as groups of amino acids, fatty acids, organic acids, natural pigments, sugars and other groups. The dominant compounds identified were propenyl pyrazine, ribonic acid, pyroglutamic acid, phenyllactic acid, 1,2- cyclohexanedicarboxylic acid, didecyl ester, cis-caftaric acid, malic acid, 1,2- cyclohexanedicarboxylic acid, cyclohexylmethylnonyl ester, and gallic acid.
Keyword: Lactobacillus plantarum SK (5), Spirulina, metabolomic, metabolites

Judul: Rantai Markov Pada Bilangan Biner
Abstrak: Ranlai Markov {Xn} yang didefinisikan pada ruang peluang (n, P, P) dilllana n = (O,I],dan 'Fadalah cr-lapangan Borel, lllelllpunyai ekspansi biner X n = 0, dl(n) din).. n = I, 2, ... Mengkonstruksi rantai Markov ini diawali dengan memilih sembarang bilangan ..Y o di (0,1], nyatakan bilangan Xo dalam ekspansi biner Xo =0, diD) diD) ... d~O) ... dimana { d~O) ,n = 1,2, ... } adalah barisan nol dan satu. Peubah acak XI ditentukan oleh .Xo dan asumsi berikut.
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