Judul: Extraction And Determination Of Antioxidant Activities Of Phenolic Compounds In Defatted Perilla Seed Meal
Abstrak: Perilla seed (Perilla frutescens) is an herb that usually used in cooking and traditional medicine. Defatted perilla seed meal (DPSM) is a by-product from extraction of perilla seed oil using screw press. This by-product might contain some bioactive compounds such as polyphenol that can be used as antioxidant. This research was conducted to study the extraction condition of polyphenol from DPSM which extracted using ethanol 70 % and 50 %, acetone 70 % and 50 %, nhexane, and mixture of hexane:ethanol (50:50 v/v). This study also determines the antioxidant activities of DPSM extracts. The proximate analysis showed that raw perilla seed contained 18.84 % crude protein and 28.63 % crude fat, while DPSM contained 27.11 % crude protein and 4.49 % crude fat. DPSM was extracted using solvents with different polarity at various extraction times. The total phenolic compounds of DPSM extracts were measured by Folin-Ciocalteu assays as well as antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). Longer extraction time yielded higher TPC and better antioxidant activity. Total phenolic content of DPSM extract which be extracted using acetone 70 % for 90 minutes (1031.99 ± 92.45 μmol GAE/100 ml) resulted in the highest yield. It was not significantly different (p<0.05) from extracting using ethanol 70 % for 90 minutes. While extraction using n- hexane for 30 minutes (58.92 ± 7.60) indicated the lowest yield but it was not significantly different from extracting using n- hexane for 60 and 90 minutes as well as hexane:ethanol for 30 minutes at p<0.05. Extraction using acetone 70 % for 90 minutes exhibited the high FRAP (1269.44 ± 134.45 μmol AAE/100 ml) and DPPH values (1029.52 ± 7.4 μM Trolox). While n- hexane extraction for 30 minutes showed the lowest FRAP (216.20 ± 33.13 μmol AAE/100 ml) and DPPH values (18.48 ± 1.65 μM Trolox). Another polar components and phenolic compounds that have high activity in DPSM extracts can influence the antioxidant capacities. Based on the results, it is likely that hexane or mixture of hexane:ethanol have low yield of phenolic compounds but the antioxidant activities were not always low. When the extraction processes using polar or nonpolar solvent, it is suggested to use another method other than FRAP and DPPH which more suitable to know the antioxidant capacity in DPSM extracts. To optimize the solubility of polar or non-polar compounds of DPSM, the continuous solvents can be used. This research is expected to explore more to know the application of this result into food products.
Keyword: antioxidant activity, defatted perilla seed meal, Perilla frutescens, total polyphenol

Judul: Optimization of Total Phenolic Extraction and Antioxidant Activity (DPPH method) of Amomum compactum Fruit with Simplex-centroid Design
Abstrak: Amomum compactum atau dikenal dengan kapulaga adalah suatu tanaman obat yang memiliki banyak potensi karena kandungan senyawa metabolitnya, salah satunya sebagai antioksidan. Penelitian ini bertujuan memberikan informasi kombinasi pelarut yang optimum dalam mengekstrak buah kapulaga menggunakan desain simplex-centroid dengan pelarut air, metanol, etanol, dan etil-asetat untuk mendapatkan ekstrak dengan total fenolik dan aktivitas antioksidan yang tinggi. Ekstraksi yang dilakukan menggunakan metode maserasi, uji kadar fenolik menggunakan metode Folin-Ciocalteau, dan uji aktivitas antioksidan menggunakan metode DPPH. Ekstrak air-metanol menghasilkan kadar total fenolik tertinggi sebesar 0.346 mg GAE/g bobot kering dan ekstrak air-etanol menghasilkan kadar aktivitas antioksidan tertinggi sebesar 0.197 µmol TE/g bobot kering dibandingkan ekstrak lainnya. Solusi optimasi desain simplex-centroid ditentukan oleh nilai desirability. Nilai desirability yang didapat dari optimasi simplex-centroid yaitu 0.933 pada campuran 0.472 air dan 0.528 metanol dengan prediksi nilai total fenolik sebesar 0.333 mg GAE/g bobot kering dan nilai prediksi aktivitas antioksidan sebesar 0.179 µmol TE/g bobot kering., Amomum compactum or known as cardamom is a medicinal plant that has a lot of potential due to its metabolite compounds, one of which is as an antioxidant. This study aims to provide information of the optimum solvent combination in extracting cardamom fruit using the simplex-centroid design with water, methanol, ethanol, and ethyl-acetate solvents to obtain extract with high total phenolic compounds and antioxidant activity. The extraction using the maceration method, the phenolic content test using the Folin-Ciocalteau method, and the antioxidant activity test using the DPPH method. The water-methanol extract produced the highest total phenolic content of 0.346 mg GAE/g dry weight and the water-ethanol extract produced the highest antioxidant activity level of 0.197 µmol TE/g dry weight compared to the other extracts. The simplex-centroid design optimization solution is determined by the desirability value. The desirability value obtained from simplex-centroid optimization is 0.933 in a mixture of 0.472 water and 0.528 methanol with a predicted total phenolic value of 0.333 mg GAE/g dry weight and a predicted value of antioxidant activity of 0.179 µmol TE/g dry weight.
Keyword: Antioxidant activity, Extract optimization, Simplex-centroid design, Total phenolic compounds

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular