Judul: Sanitary Application of Sodium Hypochlorite  (NaOCl) and Sodium Metabisulfite (Na2S2O5) in the Red Ginger Washing Process (Zingiber officinale var. rubrum)
Abstrak: Jahe merah (Zingiber officinale var. rubrum) merupakan jenis rempahrempah jahe yang banyak digunakan masyarakat Indonesia sebagai bahan obatobatan tradisional sebagai salah satu pangan olahan yang memiliki banyak mafaat untuk kesehatan dan sangat diminati oleh masyarakat, proses pengolahan jahe merah harus dilakukan dengan baik untuk menjamin keamanan pangan. Proses sanitasi pada pengolahan jahe merah dilakukan untuk menekan jumlah mikroorganisme selama proses produksi. Penggunakaan sanitasiser dari bahan kimia pada proses sanitasi banyak diaplikasikan pada industry pangan. Penggunakaan sanitaiser bertujuan untuk membunuh sejumlah besar mikroorganisme pathogen pada bahan pangan hingga pada tingkatan aman bagi kesehatan manusia. Batasan maksimum jumlah mikroorganisme yang ada pada pangan harus sesuai dengan Peraturan BPOM Nomor 13 Tahun 2019. Sanitaiser sodium hipoklorit (NaOCl) dengan konsentrasi 50 ppm, 100 ppm, dan 150 ppm ditambahkan pada proses pencucian jahe merah segar yang telah dikupas, dan direndam dalam waktu 10 menit. Sanitaiser natrium metabisulfit (Na2S2O5) 150 ppm, diujikan untuk melihat perbandingan efektifitas sodium hipoklorit (NaOCl). Pengujian mikrobiologi dilakukan untuk melihat mutu dari jahe merah segar. Hasil penelitian menunjukkan penambahan sanitaiser sodium hipoklorit (NaOCl) dengan konsentrasi 150 ppm pada proses sanitasi jahe merah dapat menekan pertumbuhan mikroorganisme secara efektif, yaitu mendapatkan hasil negatif dari adanya Escherichia coli dan negatif/25g pada Salmonella sp, 1,2 × 103 koloni/g untuk angka lempeng total (ALT) dan <1,0 koloni/g untuk total kapang dan kamir. Pada sanitaiser natrium metabisulfit (Na2S2O5) pertumbuhan kapang dan kamir masih melebihi batas maksimum SNI 7388: 2009 yaitu, 2 × 104 koloni/g.
Keyword: red ginger, microorganism, sanitizer, sodium hypochlorite (NaOCl)

Judul: Aktivitas antimikroba ekstrak jahe (Zingiber officinale Roscoe) terhadap beberapa bakteri patogen
Abstrak: hazards to the human health. Ginger (Zingiber officinale Roscoe) is commonly used as traditional medicine. It has a potential as antimicrobial agent by inhibit or kill microbes in dose dependent manner. The principle compounds of ginger are essential oils and non volatile compounds which maximum have antimicrobial activity. The objectives of this research are: (1) to study the yield of ginger extracts by multistage maceration with different polarity solvents, (2) to study antimicrobial activity of hexane, ethyl acetate and ethanol extract of ginger against foodborne pathogen such as Staphylococcus aureus, Bacillus cereus and Salmonella enterica serovar Typhimurium. Ginger extracts were prepared by multistage maceration method using solvent hexane, ethyl acetate and ethanol. The ginger extracts were assayed for antimicrobial activity by agar well diffusion method with Diameter Inhibition Zone (DIZ) and dillution broth method. The yield of hexane, ethyl acetate and ethanol ginger extracts from multistage maceration were respectively 3,57; 3,17; 3,02 g/100 g dry ginger. The DIZ value for Staphylococcus aureus were 5,0; 5,7; 1,3 mm with hexane, ethyl acetate and ethanol ginger extracts respectively 6,1; 6,6; 6,0 mm for Bacillus cereus and Salmonella Typhimurium were show no inhibitory zone. This results showed that the ginger extracts from multistage maceration have a weak antimicrobial activity (1,3 – 6,6 mm) against Gram-positive bacterial. The inhibition activity was determined for ethyl acetate ginger extract that showed the relatively highest inhibition zone. The minimum inhibition concentration did not reach in a range concentration between 5 – 20 mg/ml against Staphylococcus aureus and Bacillus cereus, therefore ginger extracts from multistage maceration with rotavapor temperature 50 o C and freeze dry process were not efficient to developed as natural antimicrobial.
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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