Judul: Pengaruh penambahan konsentrasi ekstrak Bunga Rosella terhadap aktivitas antioksidan minuman fungsional Pisang-Rosella
Abstrak: Bunga rosella dan buah pisang memiliki potensi sebagai bahan dasar minuman fungsional. Tujuan dari penelitian ini adalah untuk mempelajari penambahan berbagai konsentrasi ekstrak bunga rosella terhadap aktivitas antioksidan minuman fungsional pisang-rosella. Penelitian ini merupakan penelitian eksperimental, yang terdiri dari 2 tahap. Tahap pertama merupakan penelitian pendahuluan untuk mempelajari konsistensi minuman dengan berbagai rasio pisang dan ekstrak rosella secara kualitatif. Tahap kedua merupakan penelitian utama untuk mempelajari pengaruh konsentrasi ekstrak rosella terhadap sifat fisik, kimia, dan organoleptik minuman fungsional. Pembuatan minuman pisang ini dicampur dengan ekstrak rosella yang terdiri dari 3 taraf, yaitu 15%, 20%, dan 25%. Hasil penelitian menunjukkan kisaran kandungan kalium dan natrium dari ketiga perlakuan sebesar 85.85-99.66 mg/100 g dan 20.18-28.85 mg/100 g. Aktivitas antioksidan pada ketiga perlakuan sebesar 604.47-790.92 mg vit C/100 g (AEAC). Kandungan total fenol pada ketiga perlakuan sebesar 685.17-927.52 mg TAE/100 g. Pemilihan formula terpilih berdasarkan beberapa kriteria penilaian. Kriteria penilaian tersebut adalah nilai keseluruhan hedonik, aktivitas antioksidan, dan total fenol pada produk. Formula terpilih dalam penelitian ini adalah produk dengan konsentrasi ekstrak rosella sebesar 20%., Rosella flower and banana are highly potential as major component in functional drink making process.The aim of this research was to study the additional effects of rosella flower extract in various concentration toward antioxidant activity in banana-rosella functional drink. This research was experimental research, consisted of two stages. The first stage was preliminary research to learn about liquid consistency various banana and rosella extract ratio qualitatively. The second stage was main research to study the influence of extract rosella concentration on physical, chemical and organoleptic properties. There are three standards used in banana-rosella drink making process, 15%, 20% and 25%. The result showed a range of potassium and sodium content of the three treatments were 85.85-99.66 mg/100 g and 20.18-28.85 mg/100 g. Antioxidant activity in the third treatment was 604.47-790.92 mg vit C/100 g (AEAC) and the content of a total of phenol on third treatment was 685.17-927.52 mg TAE/100 g. The determination of the selected formula was based on some criteria, those are total value of hedonic levels, antioxidant activity, and total phenol content on product. The selected formula in this research is a product with 20% concentration of the rosella extract.
Keyword: antioksidan, bunga rosella, kalium, minuman fungsional, pisang

Judul: Hibiscus sabdariffa Linn
Abstrak: Es krim adalah makanan beku semi padat hasil olahan susu yang dibuat dengan melewati berbagai proses, yaitu pasteurisasi, homogenisasi, pematangan es krim, pengadukan untuk membentuk rongga udara pada adonan es krim, serta pembekuan dalam lemari es. Bunga rosella memiliki kandungan antioksidan yang tinggi. Kandungan antosianin pada bunga rosella mencapai 96 mg dan vitamin C mencapai 280 mg setiap 100 g. Antosianin pada bunga rosella mampu memberikan efek perlindungan terhadap penyakit kardiovaskuler, termasuk penyakit hipertensi. Penelitian ini bertujuan untuk menganalisis sifat fisikokimia, organoleptik dan aktivitas antioksidan es krim yang diberi penambahan bubuk bunga rosella. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan perlakuan persentase penambahan bubuk bunga rosella berbeda beda yaitu 0%, 5%, 10% dan 15%. Hasil penelitian menunjukkan bahwa penambahan bubuk bunga rosella pada es krim berpengaruh nyata (P<0.05) terhadap nilai pH, kadar air, aktivitas antioksidan, kapasitas antioksidan, daya leleh dan karakteristik organoleptik. Penambahan bunga rosella tidak berpengaruh nyata (P>0.05) pada nilai aw dan overrun. Persentase terbaik ditemukan pada penambahan rosella perlakuan 5%., Ice cream is a semi-solid frozen food processed by milk which is made by going through various processes, namely pasteurization, homogenization, ripening of ice cream, stirring to form air cavities in the ice cream dough, and freezing in the refrigerator. Rosella flowers have high nutritional content and antioxidant compounds. The anthocyanin content in rosella flowers reaches 96 mg and vitamin C reaches 280 mg for every 100 g. Anthocyanins in rosella flowers are able to provide a protective effect against cardiovascular disease, including hypertension. This study aims to analyze the physicochemical, organoleptic and antioxidant activity of ice cream which was added with rosella flower. This study used a completely randomized design (CRD) with different percentages, namely 0%, 5%, 10% and 15%. The results showed that the addition of rosella flowers to ice cream had a significant effect (P<0.05) on the pH value, water content, antioxidant activity, antioxidant capacity, melting power and organoleptic characteristics. The addition of rosella flowers had no significant effect (P>0.05) on the aw and overrun values. The best percentage was found in the addition of 5% rosella treatment.
Keyword: antioxidant, ice cream, rosella flower, milk

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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