Judul: Analisis in vitro toleransi isolat bakteri asam laktat asal daging sapi terhadap pH lambung, pH usus dan garam empedu sebagai kandidat probiotik
Abstrak: Lactic acid bacteria have been reported to be useful as a health adjunct and are commonly added to food as delivery mechanism. As candidate for probiotic, lactic acid bacteria should have the ability to survive in the digestion process such as resistance towards gastrointestinal tract pH and bile salt concentrations. Lactic acid bacteria utilised in this research were isolated from meat. Twenty eight isolates of lactic acid bacteria selected for their resistancy towards gastric juice pH (pH 2,0) and small intestines pH (pH 7,2) with 0,3% bile salt under in vitro conditions. The result showed that all strains well grown in small intestines pH (pH 7,2), but only 10 isolates had good resistance to gastric juice pH. There were significant difference among theme (P<0,05). Bile salt 0,3% with pH 7,2 influenced significantly the growth of lactic acid bacteria selected at gastric juice condition showed that only three strains (1A5, 2B4, and 1B1) showed tolerance (P<0,05) could be used as probiotics candidate in further applications.
Keyword: 

Judul: Karakteristik Pertumbuhan Bakteri Asam Laktat Indigenous Susu Sapi Segar Sebagai Kandidat Bakteri Probiotik Dalam Saluran Pencernaan in vitro
Abstrak: Functional foods in the form of probiotic yogurt serves as a food that provides health effects, especially in the digestive tract. This probiotic yogurt can maintain the balance the intestinal microflora, especially between beneficial and pathogen bacterials. Terms of the probiotic bacteria concerned to lactic acid bacteria that were able to survive at the digestive tract. The purpose of this study was to investigate the characteristics of lactic acid bacteria indigenous cow’s milk as a candidate of probiotic bacteria. Resistancy of lactic acid bacteria through different pH conditions, in presence of bile salts or antibiotics, were tested in the media that was conditioned as human digestive tract (in vitro). Lactic acid bacteria resistance was seen through a comparison of the original population before the treatment and the population after treatment. The results of this study, bacteria L. acidophilus Y-01, B. longum Y-01 and L. bulgaricus S-01 can be used as candidates probiotic bacteria because it survived in a pH condition (pH 2, 2,5, 3,2 and 7,2), the condition of bile salts, and antibiotics. Although the population of S. thermophilus S-01 and L bulgaricus S-01 decreased after treatment, all four of these bacteria also produce antimicrobial evidenced by the clear zone that formed around the supernatant. This antimicrobial activity showed inhibition to the growth pathogenic bacteria (E. coli, S. Typhimurium, and S. aureus).
Keyword: 

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf