Judul: Edible Coating Application From Sugar Palm Fruit To Extend Cucumber’s Shelf Life
Abstrak: Mentimun merupakan sayuran berbentuk buah yang memiliki umur simpan yang sangat pendek, yaitu 3-4 hari setelah dipanen. Pengaplikasian edible coating adalah salah satu upaya untuk memperpanjang umur simpan buah tersebut. Kolang-kaling mengandung galaktomanan yang mampu membentuk larutan dengan viskositas tinggi dalam konsentrasi yang rendah, sehingga diduga dapat menjadi bahan baku edible coating yang baik. Penelitian ini dilakukan untuk mengetahui pengaruh aplikasi edible coating dari kolang-kaling terhadap umur simpan buah mentimun. Penelitian dilakukan dengan cara mencelupkan buah mentimun ke dalam suspensi edible coating selama ±5 menit, buah kemudian dikeringanginkan selama ±2 jam dan disimpan di wadah PET berongga. Analisis yang dilakukan adalah perubahan susut bobot, total padatan terlarut, kekerasan, dan warna pada buah yang dilapisi oleh edible coating dengan konsentrasi 1 : 9, 1 : 12, dan 1 : 15 dan diamati setiap hari ke-3, 6, 9, 12, dan 15. Hasil penelitian menunjukkan penambahan edible coating dari kolang-kaling dengan konsentrasi 1 : 15 mampu memberi perbedaan yang signifikan terhadap laju perubahan warna buah selama 12 hari penyimpanan. Hasil penelitian tidak menunjukkan perbedaan yang signifikan terhadap laju perubahan susut bobot, total padatan terlarut, dan kekerasan pada penyimpanan buah mentimun selama 3, 6, 9, 12, dan 15 hari., Cucumber is a fruit-shaped vegetable that has a very short shelf life, which is 3-4 days after harvest. The application of edible coating is one of the efforts to extend the shelf life of the fruit. Sugar palm fruit contains galactomannan which is able to form solutions with high viscosity in low concentrations, so it is suspected that it can be a good raw material for edible coatings. This research was conducted to determine the effect of edible coating application from sugar palm fruit on the shelf life of cucumber. The research was conducted by dipping cucumbers into edible coating suspension for ± 5 minutes, then drying the fruit for ± 2 hours and storing in a hollow PET container. The analysis carried out was the change in weight loss, total soluble solids, hardness, and color of the fruit coated with edible coating with concentrations of 1 : 9, 1 : 12, and 1 : 15 and observed every 3rd, 6th, 9th, 12th, and 15th day. The results showed that the addition of edible coating from sugar palm fruit with a concentration of 1: 15 was able to give a significant difference to the rate of change in fruit color during 12 days of storage. However, the results did not show a significant difference in the rate of change in weight loss, total dissolved solids, and hardness on cucumber fruit storage for 3, 6, 9, 12, and 15 days.
Keyword: edible coating, sugar palm fruit, cucumber, shelf life

Judul: Application of Edible Coating from Corn Starch and Red Galangal to Maintain The Quality of The Cilembu Sweet Potatoes
Abstrak: Komoditas ubi jalar cilembu banyak diminati oleh konsumen domestik maupun mancanegara karena mengandung karbohidrat dan kalori yang cukup tinggi, serta rasa manis seperti madu yang menjadi ciri ubi jalar cilembu. Namun, karena umur simpan singkat dan kualitas hasil panen yang rendah, ubi jalar cilembu memerlukan penanganan pascapanen yang tepat. Edible coating merupakan cara efektif mempertahankan kualitas ubi jalar cilembu, karena berfungsi sebagai pelindung produk yang aman dikonsumsi dan dapat memperlambat transpirasi serta respirasi ubi jalar cilembu. Tujuan penelitian ini yaitu mengatahui pengaruh penggunaan edible coating dengan kombinasi pati jagung dan ekstrak lengkuas merah terhadap kualitas ubi jalar cilembu selama masa simpan. Prosedur penelitian meliputi persiapan sampel, pembuatan larutan edible coating, pengaplikasian edible coating, dan pengamatan selama 30 hari masa simpan. Larutan edible coating terbuat dari kombinasi pati jagung 2% serta lengkuas merah 1%, 3%, dan 5%. Pengaplikasian edible coating dilakukan menggunakan metode pencelupan sebanyak satu kali selama satu menit. Edible coating P1L3 merupakan perlakuan paling efektif untuk menjaga kualitas mutu dan memperpanjang masa simpan ubi jalar cilembu dengan meminimalisir susut bobot 8.91%, kadar air 66.02%, kekerasan 7.49 kgf, total padatan terlarut 17.3oBrix, dan spot coklat 12.33%., The cilembu sweet potatoes commodity is in great demand by domestic and foreign consumers because it contains fairly high carbohydrates and calories, as well as a sweet taste like honey which is a characteristic of cilembu sweet potatoes. However, due to the short shelf life and low yield quality, cilembu sweet potatoes require proper postharvest handling. Edible coating is an effective way to maintain the quality of cilembu sweet potatoes, because it functions as a protector of products that are safe for consumption and can slow down the transpiration and respiration of cilembu sweet potatoes.The purpose of this study is to determine the effect of edible coating with a combination of corn starch and red galangal extract on the quality of cilembu sweet potatoes during the shelf life. The research procedure includes sample preparation, making edible coating solution, applying edible coating, and observation for 30 days of shelf life. Edible coating solution is made from a combination of 2% corn starch and 1%, 3%, and 5% red galangal. The application of edible coating is carried out using the dipping methode once for one minute. Edible coating P1L3 is the most effective treatment to maintain quality and extend shelf life cilembu sweet potatoes by minimize weight loss 8.91%, moisture content 66.02%, hardness 7.49 kgf, total dissolved solids 17.3oBrix, and brown spots 12.33%.
Keyword: cilembu sweet potatoes, corn starch, edible coating, red galangal, quality

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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