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: Characterization of the Physical, Chemical, and  Organoleptic of Lactose-Free Ice Cream with Butterfly Pea Flower (Clitoria  ternatea) Addition.
Abstrak: Es krim bebas laktosa dapat dijadikan pangan alternatif yang aman bagi penderita intoleransi laktosa. Penambahan ekstrak bunga telang dalam pembuatan es krim dapat dimanfaatkan sebagai pewarna alami lokal dan sebagai antioksidan alami. Penelitian ini bertujuan menganalisis sifat fisik, kimia, dan organoleptik es krim bebas laktosa dengan bunga telang (Clitoria ternatea) pada konsentrasi 0% (kontrol), 5%, dan 10%. Analisis meliputi sifat fisik, sifat kimia, dan sifat organoleptik. Penelitian ini akan menggunakan rancangan acak lengkap (RAL) dengan tiga ulangan. Hasil penelitian menunjukkan bahwa penambahan ekstrak bunga telang pada es krim bebas laktosa berpengaruh nyata (p<0,05) terhadap overrun, nilai pH, dan tingkat kemanisan, serta hasil uji hedonik terhadap warna dan mutu hedonik terhadap warna, aroma, rasa manis, dan rasa susu berpengaruh nyata (P<0,05) terhadap parameter es krim yang dihasilkan., Lactose-free ice cream can be used as a safe alternative foods for people with lactose intolerance. The addition of butterfly pea flower extract in making ice cream can be used as a natural local dye and as a natural antioxidants. This study aims to analyze the physical, chemical, and organoleptic of lactose-free ice cream with butterfly pea flower (Clitoria ternatea) at 0% (control), 5%, and 10%. The analysis includes physics characteristics, chemical characteristics, and organoleptic characteristics. This study used completely randomzed design (CRD) with three repetitions. The results showed that the addition of butterfly pea flower extract to lactose-free ice cream had significant effect (p<0,05) on overrun, pH value, and sweetness rate, as well as hedonic test results on colour and hedonic quality on colour, aroma, sweet taste, and milk taste, had significant effect (p<0,05) on the resulting ice cream parameter.
Keyword: butterfly pea flower, ice cream, lactose, 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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