Judul: Lactobacillus plantarum SK(5) Asal Bekasam sebagai Starter dalam Fermentasi Yoghurt Spirulina
Abstrak: Lactobacillus plantarum SK(5) asal bekasam dapat dimanfaatkan sebagai kultur starter dalam pembuatan yoghurt. Bubuk spirulina dapat digunakan sebagai prebiotik yang mampu meningkatkan pertumbuhan dan daya tahan probiotik. Tujuan penelitian ini menentukan pengaruh penambahan spirulina terhadap karakteristik yoghurt yang difermentasi menggunakan starter L. plantarum SK(5) asal bekasam. Perlakuan yang digunakan pada penelitian ini yaitu penambahan spirulina 0%, 0.25%, 0.5%, dan 0.75% (b/v campuran). Penambahan spirulina mempengaruhi secara nyata kadar total asam tertitrasi (TAT), pH, kadar protein, dan viskositas yoghurt. Penambahan spirulina tidak mempengaruhi secara nyata total BAL, kadar lemak, dan total padatan yoghurt. Perlakuan terpilih yaitu perlakuan spirulina 0.5% berdasarkan kadar protein dan karakteristik lainnya yang telah memenuhi standar yoghurt. Perbedaan lama fermentasi mempengaruhi secara nyata total BAL, kadar TAT, dan pH yoghurt perlakuan spirulina terpilih.
Keyword: Lactobacillus plantarum SK(5), probiotic, spirulina, yoghurt

Judul: Characteristics of Spirulina Yoghurt by starter Lactobacillus plantarum SK(5) in Different Biomass Concentration and Incubate Term
Abstrak: Lactobacillus plantarum SK(5) merupakan bakteri probiotik asal bekasam dan dapat digunakan sebagai starter dalam pembuatan yoghurt. Spirulina platensis termasuk kedalam cyanobacteria yang memiliki banyak manfaat bagi tubuh. Penambahan spirulina dalam fermentasi yoghurt dengan starter L. plantarum SK(5) bertujuan menentukan suhu dan lama fermentasi yoghurt spirulina berdasarkan perubahan pH menentukan pengaruh perbedaan konsentrasi spirulina basah dan waktu inkubasi terhadap nilai pH, kadar asam tertitrasi, dan total BAL yoghurt spirulina; serta menentukan karakteristik yoghurt terpilih setelah fermentasi 24 jam. Penelitian terdiri dari empat tahap yaitu 1) penyegaran dan kultivasi spirulina; 2) penyiapan kultur starter L. plantarum SK(5); 3) penentuan waktu dan suhu inkubasi yoghurt spirulina; 4) Pembuatan yoghurt spirulina dengan waktu dan suhu inkubasi terpilih menggunakan starter L. plantarum SK(5). Suhu dan lama fermentasi terbaik pada yoghurt spirulina terpilih yaitu 37oC dan 24 jam. Penambahan spirulina dan waktu inkubasi mempengaruhi secara nyata terhadap nilai pH, kadar TAT, dan total BAL yoghurt spirulina. Penambahan spirulina 1.5% dengan lama fermentasi 24 jam merupakan perlakuan terpilih berdasarkan nilai pH dan kadar TAT. Karakteristik dari yoghurt spirulina terpilih memiliki nilai pH 3.9, kadar TAT 1.195%, Total BAL 9.11 log cfu/mL, viskositas 85.25 cPs, kadar protein 38.43%, kadar lemak 26.93%, dan nilai IC50 297.06 mg/L., Lactobacillus plantarum SK(5) is a probiotic bacteria which isolated from bekasam and that can be used as starter in yoghurt process. Spirulina platensis belong to cyanobacteria which hold many function for healthy. The addition spirulina in yoghurt with starter L. plantarum SK(5) expected to determined effect of temperature and time of fermentation yoghurt spirulina by based on pH, determined effect of spirulina wet biomass concentration and incubation time to pH, total acid content, with total L. plantarum SK(5), and the characteristics of selected product after fermentation for 24 hours. This research consist to four stage namely 1) refreshing and cultivation of spirulina; 2) the preparation culture starter L. plantaurm SK(5); 3) the determination time and temperature of incubation yoghurt spirulina; 4) the production yoghurt spirulina with the selected time and temperature using L. plantarum SK(5) as starter. The temperature and incubation time selected for spirulina yoghurt were 37oC and 24 hour. The addition spirulina and incubation time had a significant effect on the pH alue, the levels of TAT, and total LAB yoghurt spirulina.The best treatments in this research was the addition of 1.5% spirulina with incubation times of 24 hours. Characteristics of yoghurt spirulina 1.5% include pH 3.9, total acids contents 1.195%, total LAB 9.11 log cfu/mL, viscosity 85.25 cPs, protein contents 3.00%, fat contents 3.14%, and IC50 287.06 mg/L
Keyword: lactic acids, Lactobacillus plantarum SK(5), probiotic, spirulina, spirulina yoghurt

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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