Judul: Coating Application of Aloe vera L. Powder to Preserve the Quality of Kenikir Flower (Cosmos sulphureus)
Abstrak: Peluang pasar edible flower di dunia kuliner semakin meningkat. Bunga Kenikir (Cosmos sulphureus) termasuk sebagai salah satu bunga yang dapat dikonsumsi secara aman. Bunga ini digunakan dalam keadaan segar sebagai garnish atau penghias makanan. Namun dalam kondisi segar, bunga mudah rusak sehingga masa gunanya terbatas. Permasalahan yang sering terjadi pada bunga potong adalah lama kesegaran bunga yang sangat singkat. Pelapisan kulit terluar bahan pangan menggunakan coating merupakan salah satu cara untuk memperpanjang masa simpan bahan pangan dengan memperlambat laju respirasi dan evaporasi bunga kenikir. Penelitian ini bertujuan mengkaji pengaruh aplikasi coating berbahan tepung Aloe vera L. sebagai edible coating untuk mempertahankan mutu bunga kenikir (Cosmos sulphureus). Tahapan penelitian terdiri dari persiapan sampel, pembuatan larutan coating, pengaplikasian coating, dan pengamatan selama 5 hari masa simpan. Konsentrasi yang dipilih untuk membuat larutan coating adalah lidah buaya (L) 0,5% dan 1%, serta jumlah penyemprotan (S) dari masing-masing konsentrasi yaitu sebanyak 1 kali dan 2 kali. Formulasi coating terbaik dipilih berdasarkan hasil analisis parameter mutu yaitu susut bobot, kadar air, warna, dan laju respirasi. Hasil penelitian menunjukkan bahwa coating dengan formulasi L2S2 (konsentrasi larutan 1% dengan aplikasi penyemprotan 2 kali) merupakan perlakuan terbaik dengan nilai susut bobot 7,3%, kadar air 82,57%, dan laju respirasi 898,99 ml kg-1 jam-1, serta nilai kecerahan tertinggi. Berdasarkan parameter mutu tersebut bunga kenikir dengan perlakuan L2S2 dapat dipertahankan sampai dengan 5 hari penyimpanan di suhu 10 oC, dibandingkan dengan kontrol yang bertahan selama 3 hari., The edible flowers market opportunity in the culinary world is increasing. Kenikir Flower (Cosmos Sulphureus) is considered an edible flower. This flower can be used fresh as a garnish or food decor. However, in fresh conditions, the flower can be damaged easily, which limits its lifespan. The problem that often occurs to fresh flowers is that their freshness doesn’t last long. Coating the outermost layer of the edible flower is an effort to prolong shelf life by slowing down the respiration and evaporation of the kenikir flower. This research aims to study the impact of the application of coating made from Aloe vera L. powder as an edible coating to maintain kenikir flower (Cosmos sulphureus) quality. The research stage is consists of sample preparation, coating solution production, coating application, and observation for five days shelf life. The chosen concentration to produce coating solution is Aloe vera (L) 0.5% and 1%, and the spraying of each concentration is one time and two times. The best coating formulation is chosen based on quality parameter analysis results: weight loss, water content, colour, and respiration rate. Research results show that coating with L2S2 (1% Aloe vera L. concentration with 2 spraying) formulation is the best treatment with a value of weight loss 7.3%, water content 82.57%, and respiration rate 898.99 ml kg-1 hour-1, also the highest in brightness value. Based on these quality parameters, kenikir flower with L2S2 treatment can be maintained for 5 days of storage at 10 oC, compared with the control treatment it can only lasts for 3 days.
Keyword: edible coating, edible flower, spraying, storage

Judul: Aplikasi Coating Kitosan dan Asam Sitrat untuk Meningkatkan Daya Simpan Bunga Marigold (Tagetes patula L.)
Abstrak: Bunga marigold memiliki nilai komersial yang tinggi, sehingga budidaya bunga marigold mulai berkembang. Marigold termasuk edible flower yang umumnya dimakan dalam keadaan segar atau pangan olahan. Namun, edible flower marigold memiliki sifat mudah rusak dan mempunyai daya simpan yang pendek. Mikroorganisme dan respirasi yang tinggi adalah penyebab utama penurunan mutu bunga marigold selama penyimpanan. Coating dan perlakuan asam sitrat menjadi salah satu solusi untuk mempertahankan mutu dan meningkatkan daya simpan bunga marigold. Penelitian ini bertujuan untuk mengkaji pengaruh aplikasi coating berbahan kitosan dan perlakuan asam sitrat terhadap perubahan mutu bunga marigold selama masa simpan. Tahapan penelitian terdiri dari persiapan sampel, pembuatan larutan coating, pengaplikasian coating, dan pengamatan selama 6 hari masa simpan. Konsentrasi yang dipilih untuk membuat larutan coating yaitu asam sitrat (A) 1% dan 2%, serta kitosan (K) 0,05% dan 0,1%. Hasil penelitian menunjukkan bahwa perlakuan terbaik adalah coating A2K2 yang mampu mempertahankan kadar air pada 83,04%, susut bobot 21,05%, dan nilai °hue sebesar 79,70° pada hari ke 6 penyimpanan, dengan penerimaan panelis pada skor 3 (dari 0-5) berdasarkan kenampakan dan warna. Sementara pada akhir penyimpanan untuk bunga marigold tanpa perlakuan coating (kontrol), susut bobot mencapai 28,43%, dengan kadar air 78,86%, °hue 75,90º, dan memiliki skor dibawah penerimaan panelis, Marigold flowers have a high commercial value, so marigold cultivation began to develop. Marigold is an edible flower that is generally eaten fresh or processed food. However, marigold flowers are easily damaged and have a short shelf life. Microorganisms and high respiration are the main causes of decreased quality of marigold flowers during storage. Coating and citric acid treatment are one of the solutions to maintain the quality and increase the shelf life of marigold flowers. This research aims to study the impact of the application of coating made from chitosan and citric acid treatment on changes in the quality of marigold flowers during the shelf life. The research stages consisted of sample preparation, coating solution preparation, coating application, and observation for 6 days of shelf life. The concentrations chosen to make the coating solution were citric acid (A) at 1% and 2%, and chitosan (K) at 0,05% and 0,1%. The results showed that the best treatment was A2K2 coating which was able to maintain water content at 83,04%, weight loss at 21,05%, and the °hue value of 79,70° on the 6 days of storage. The panelist acceptance is at a score of 3 (from 0-5) based on appearance and color. Meanwhile, at the end of storage for marigold flowers without coating treatment (control), the weight loss reached 28,43%, with a moisture content of 78,86%, °hue 75,90º and had a score below the panelist acceptance.
Keyword: citric acid, edible coating, edible flower, marigold flower

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
Keyword: