Judul: Super (a,d) edge antimagic total labeling pada graf petersen
Abstrak: Karya ilmiah ini membuktikan teorema-teorema untuk memperoleh super (a,d)-edge-antimagic total labeling pada graf petersen. Pada pelabelan, didefinisikan jumlah label sisi (edge) dan label dua simpul (vertex) yang menempel pada sisi (edge) disebut sebagai bobot sisi (edge-weights). Suatu graf yang memiliki bobot sisi yang berbeda untuk setiap sisi maka graf ini disebut graf dengan antimagic total labeling. Jika semua sisi mempunyai bobot sisi yang berbeda dan himpunan bobot sisi dari semua sisi membentuk barisan aritmatika dengan suku awal a dan beda (selisih) d maka pelabelan tersebut disebut (a,d)-edge-antimagic total labeling. Kemudian, (a,d)-edge-antimagic total labeling disebut super (a,d)-edge-antimagic total labeling jika f(v(g)) = {1, 2, …, v} dan f(e(g)) = {v+1, v+2, …, v+e}. Terdapat dua pembuktian teorema yang dibahas dalam karya ilmiah ini. Teorema pertama membuktikan bahwa graf petersen p(n,m) dengan n ≥ 3 bilangan bulat ganjil dan m = 1, memiliki super (5𝑛+52,2)-edge-antimagic total labeling. Teorema kedua membuktikan graf petersen p(n,m) dengan n ≥ 3, 1 ≤ m ˂ 𝑛2 , mempunyai sebuah super (4𝑛+2,1)-edge-antimagic total labeling
Keyword: edge-antimagic total labeling, antimagic total labeling, graf petersen, super (a,d)

Judul: Pelabelan Super Edge Magic Graceful pada Graf Petersen 𝑃��(𝑛��, 1) dan 𝑃�� (𝑛��, 𝑛��−1 2 ).
Abstrak: Pelabelan edge magic graceful pada suatu graf dengan banyaknya simpul ������ dan banyaknya sisi ������ adalah fungsi bijektif dari himpunan simpul digabung himpunan sisi yang dipasangkan ke himpunan bilangan bulat terurut dimulai dari 1 sampai ������ + ������, sedemikian sehingga untuk semua sisi, nilai mutlak dari penjumlahan label verteks yang saling adjacent dikurangi dengan label dari sisi yang incident dengan verteks tersebut akan sama dengan ������, ������ adalah konstanta magic. Pelabelan edge magic graceful yang memasangkan himpunan simpul ke himpunan bilangan bulat terurut {1,2, … , ������} disebut pelabelan super. Dalam karya ilmiah ini, ditunjukkan bahwa graf Petersen ������(������, 1) dan ������ (������, ������−1 2 ) keduanya memiliki pelabelan super edge magic graceful.
Keyword: graf Petersen, pelabelan super edge magic graceful

Judul: Xylooligosaccharide production of corncobs as prebiotic candidate by high temperature heating and enzymatic hydrolysis.
Abstrak: Corncob waste is a rich xylan source that can be utilized as raw material for xylooligosaccharides (XOS) production. XOS is a potential prebiotic and has high economic value. Two corn varieties i.e. Bisi and Pioneer were first analyzed for its hemicellulose, cellulose and lignin contents and xylan yield to choose the corn variety to be studied. Process technology for XOS production was studied using available equipment such as oven. Xylooligosaccharide (XOS) from corncob was produced in two stages i.e. xylan extraction by heating at high temperatures in oven or autoclave as comparison, followed by enzymatic hydrolysis. Analysis of two corncob varieties showed that Pioneer variety contained higher hemicellulose content (34.98%) and xylan yield (18.32%) than Bisi variety (12.28% and 10.22%, respectively), therefore Pioneer variety was chosen as raw material for XOS production. Corncob particles were soaked in dilute acid (1 g/l H2SO4) for 12 h at 60 oC, filtered and washed with tap water and then heated in oven or autoclave. Before oven heating, The corncobs were added with water at various ratios (1:1 – 1:5) and then heated in oven at various temperature (130 oC, 140 oC, 150 oC for 0.5 h) and autoclave at 121oC for 0.5, 1, 1.5 and 2 h with one and two heating cycles. During heating, the total sugar and reducing sugar were increase, while the degree of polymerization was decrease. The results showed that heating in oven to extract the xylan was affected by the ratios of corncobs and aquadest and heating temperatures. Oven heating (130-150 oC) with optimum ratio of corncobs and aquadest (1:3) successfully increased the xylan content from 3.98% up to 18.21 – 19.46% while repeated heating cycle (two cycles) did not affect the xylan content. Heating the corncobs with aquadest (at the ratio of 1:3) in oven at 130 oC for 0.5 h produced 18.98% xylan and enzymatic conversion of the xylan by xylanase significantly increased the XOS content from 19.60% up to 44.06%. Heating the corncobs in autoclave (121 oC, 0.5 h) followed by enzymatic conversion produced higher XOS content (65.67%). The corncob XOS could stimulate the growth of Lactobacillus plantarum kik and Bifidobacterium longum ATCC 15707 by 1.2 until 1.7 unit log, indicating the prebiotic properties. Cookies prebiotic produced by addition of 5% (based on wheat flour) had higher hardness texture (1256 gf) than control without XOS (1067 gf).
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