Judul: Aplikasi Coating Berbahan Lidah Buaya (Aloe vera L.) dan Karagenan untuk Memperpanjang Masa Simpan Ubi Jalar (Ipomea batatas (L). Lam) cv. Cilembu
Abstrak: Ubi jalar (Ipomoea batatas L.) menjadi salah satu komoditas ekspor yang sangat diminati karena rasanya yang khas. Rasa manis seperti madu dapat meningkatkan nilai ekonomi dan menjadikan ubi Cilembu diakui sebagai produk yang terdaftar dalam Indikasi Geografis (IG) dengan nomor IDIG000000019. Keistimewaan itulah yang membuat ubi Cilembu perlu dilakukan penanganan pascapanen agar kualitas dapat dipertahankan, sehingga ubi Cilembu dapat masuk pasar ekspor karena membutuhkan waktu distribusi yang lebih lama dibandingkan dengan pasar lokal. Pengaplikasian coating menjadi salah satu upaya penanganan pasacapanen yang dapat digunakan dalam memperlambat proses respirasi dan transpirasi ubi Cilembu. Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan coating kombinasi tepung lidah buaya dan karagenan terhadap perubahan mutu ubi Cilembu selama masa simpan. Tahapan penelitian terdiri dari persiapan sampel, pembuatan larutan coating, pengaplikasian coating, dan pengamatan selama 30 hari masa simpan. Konsentrasi yang dipilih untuk membuat larutan coating adalah lidah buaya (AL) 1% dan 2%, serta karagenan (K) 0,01% dan 0,02%. Formulasi coating terbaik dipilih berdasarkan hasil analisa parameter mutu mengunakan metode pembobotan. Hasil penelitian menunjukkan bahwa coating AL2K2 merupakan formulasi coating terbaik yang mampu meminimalisir terjadinya perubahan warna browning index 2,37%, spot coklat 5,00%, susut bobot 7,82%, kandungan air 65,72%, total padatan terlarut 15,2%, dan kekerasan 5,59 kgf., Sweet potato (Ipomoea batatas L.) is one of the most popular export commodities because of its characteristic taste. Sweetness like honey can increase economic value and make Cilembu sweet potato recognized as a product that is registered in a Indikasi Geografis (IG) with number IDIG000000019. This feature is what makes Cilembu yams need post-harvest handling so that the quality can be maintained so that Cilembu sweet potatoes can enter the export market because they require a longer distribution time than the local market. The application of the coating is one of the postharvest handling efforts that can be used to slow down the respiration and transpiration process of Cilembu sweet potato. This study aims to determine the effect of using a coating combination of aloe vera flour and carrageenan on changes in the quality of Cilembu sweet potato during the shelf life. The research stages consisted of sample preparation, coating solution manufacture, coating application, and observation for 30 days of shelf life. The concentrations chosen to make the coating solution were 1% and 2% aloe vera (AL), and 0.01% and 0.02% carrageenan (K). The best coating formulation is selected based on the analysis of quality parameters using a weighting method. The results showed that the AL2K2 coating was the best coating formulation that was able to minimize browning index discoloration of 2.37%, brown spot 5.00%, weight loss of 7.82%, water content 65.72%, total dissolved solids 15.2 %, and a hardness of 5.59 kgf
Keyword: aloe vera, carrageenan, coating, 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: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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