Judul: Effect of Cooking Water Ratio with Rice Cooker on Physicochemical and Sensory Gracilaria sp. Analog Rice
Abstrak: Beras analog Gracilaria sp. merupakan produk diversifikasi pangan yang menggunakan rumput laut sebagai bahan fungsionalnya. Penggunaan rumput laut Gracilaria sp. yang tinggi serat diharapkan meningkatkan nilai tambah pada nasi. Pengaruh rasio beras dan air (b/v) pada karakteristik sensori nasi diteliti dalam kaitannya dengan sifat fisiokimia. Penelitian menggunakan rancangan acak lengkap (RAL) dengan perlakuan berupa rasio air. Data parametrik dianalisis dengan normalitas dan analisis sidik ragam dengan uji lanjut Duncan. Data non-parametrik dianalisis dengan uji Kruskal Wallis dengan uji lanjut Dunn. Sampel beras analog Gracilaria sp. dimasak dengan tiga rasio (b/v) dan disajikan kepada 35 panelis tidak terlatih untuk evaluasi sensori. Rasio antara beras analog : air (b/v) sebesar 1:1; 1:1,5 ; dan 1:2. Perbedaan rasio beras dan air pada proses pemasakan berpengaruh terhadap sifat fisik, kimia, dan sensori beras dan nasi analog Gracilaria sp.. Nasi analog terbaik yaitu perlakuan 1:1,5 (b/v) yang ditentukan berdasarkan metode Bayes. Berdasarkan pada analisis penalti CATA, atribut yang harus dimiliki oleh nasi analog Gracilaria sp. berupa moistness of grains, sticky, soft, glossy grain dan firm. Nasi analog terbaik mengandung serat pangan sebesar 5,17% dan tergolong makanan sumber serat., Gracilaria sp. analog rice is a food diversification product that uses seaweed as its functional ingredient. Gracilaria sp. seaweed which is high in fiber is expected to increase the added value of rice. The effect of the ratio of rice and water (w/v) on the sensory characteristics of the rice studied in relation to its physiochemical properties. The study used a completely randomized design (CRD) with a water ratio treatment. Parametric data were analyzed by normality and analysis of variance by Duncan's test. Non-parametric data were analyzed using the Kruskal Wallis test with the Dunn test. Gracilaria sp. analog rice samples cooked at three ratios (w/v) and presented to 35 untrained panelists for sensory evaluation. The ratio between analog rice : water (w/v) is 1:1; 1:1,5 ; and 1:2. The difference in the ratio of rice and water in the cooking process affected the physical, chemical, and sensory properties of Gracilaria sp. analog rice. The best analog rice was the 1:1.5 (w/v) treatment which was determined based on the Bayes method. Based on the CATA penalty analysis, the must-have attributes are moisture of grains, sticky, soft, glossy grains, and firm. The best analog rice contains dietary fiber of 5.17% and is classified as a food source of fiber.
Keyword: Gracilaria sp., nasi analog, pemasakan, rasio air, serat pangan, analog rice, cooking, dietary fiber, Gracilaria sp., water ratio

Judul: Pengaruh Pemasakan Beras Analog Rumput Laut Gracilaria sp. dengan Microwave terhadap Karakterisik Fisikokimia dan Sensori
Abstrak: Beras analog dari rumput laut Gracilaria sp. merupakan salah satu produk diversifikasi pangan dengan sifat fungsional. Penelitian bertujuan menentukan pengaruh pemasakan beras analog rumput laut Gracilaria sp. dengan microwave terhadap karakteristik fisikokimia dan sensori. Rancangan percobaan menggunakan rancangan acak lengkap faktorial dengan tiga ulangan, jika hasil uji menunjukkan pengaruh nyata dilakukan uji lanjut Duncan pada taraf kepercayaan 95%. Perlakuan dengan daya 270 W selama 7 menit merupakan yang terbaik dan lebih efisien dalam penggunaan energi serta memiliki specific energy consumption yang lebih rendah dibandingkan dengan cara pemasakan konvensional menggunakan rice cooker. Karakteristik nasi analog dari perlakuan terbaik memiliki penyerapan air mencapai 94%, nilai L*, a*, dan b* berturut-turut 51,99; -0,75; dan 8,09. Profil tekstur menunjukkan hardness sebesar 10,52 N; springiness 0,69 mm; cohesiveness 0,60; adhesiveness 71,30 gs; dan chewiness 4,29 mJ. Preferensi panelis terhadap nasi analog di antaranya tekstur pulen, kenampakan nasi yang mengkilap, rasa yang diasosiasikan dengan bunga, dan aroma serta rasa manis., Analogue rice made from Gracilaria sp. seaweed is one of the food diversification products with functional properties. This study aimed to determine the effects of microwave cooking on its physicochemical and sensory characteristics. The experimental design employs a factorial completely randomized design with three replications. If the test results indicate a significant effect, Duncan’s post hoc test are conducted at a 95% confidence level. The treatment with a microwave power of 270 W for 7 minutes is considered the optimal choice and demonstrated greater energy efficiency with lower specific energy consumption compared to the conventional cooking method using a rice cooker. The characteristics of the selected treatment for analogue rice include a water absorption of 94%, L*, a*, b* values of 51.99; -0.75; and 8.09, respectively. Texture profile analysis indicates a hardness value of 10.52 N; springiness value of 0,69 mm; cohesiveness of 0.60; adhesiveness of 71.30 gs; and chewiness of 4.29 mJ. Sensory attributes preferred by panelists were moistness of grains, glossy grains, floral taste, sweet taste, and sweet aroma.
Keyword: beras analog, daya microwave, Gracilaria sp., waktu pemanasan

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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