Judul: Application of Honey Process for  “Coastal Arabica” Coffee at Yuam Roasted Coffee Kebumen Jawa Tengah
Abstrak: Kopi memiliki peran yang cukup penting dalam kegiatan perekonomian Indonesia. Yuam Roasted Coffee menjual kopi yang area tanamnya tergolong dataran rendah baik kopi jenis robusta maupun arabika. Produktivitas kopi arabika pesisir di kawasan ini tergolong rendah sehingga perlu dilakukan variasi pengolahan baru, seperti honey process. Tujuan penelitan ini adalah mengetahui perbedaan kandungan kopi, penerimaan konsumen, serta mengnalisis nilai finansialnya jika diolah menggunakan honey process dan dibandingkan dengan fullwashed process yang lebih umum digunakan. Pengujian kandungan yang dilakukan meliputi kadar air, kadar abu, kadar lemak, kadar sari yang menggunakan analisis proksimat gravimetri, serta pengujian kadar kafein yang menggunakan alat spektrofotometer. Pengujian penerimaan dilakukan menggunakan uji organoleptik hedonik. Analisa finansial menggunakan parameter net present value dan benefit/cost ratio. Hasil penelitian menunjukkan penerapan honey process pada kopi arabika pesisir mengubah secara nyata kadar air, kadar sari, kadar gula dan kadar kafein. Cita rasa secara keseluruhan dari honey process memiliki penerimaan lebih baik (nilai penerimaan rata-rata 3,77). Analisa finansial honey process memiliki nilai lebih tinggi (awalnya memiliki nilai NPV sebesar Rp 243.081.500 dan b/c ratio 1,42 untuk fullwashed process. Kemudian nilai proyeksinya bertambah menjadi sebesar Rp 326.245.222 dan 1,64 untuk honey process), Coffee has an important role in Indonesia's economic activities. Yuam Roasted Coffee sell coffee where planted in lowlands both robusta and arabica coffee. Arabica coffee productivity here is relatively low so it is necessay to carry out a new processing such as honey processing. The purpose of this research is to find out the differences in coffee content, consumer preferences, and to see the financial analysis when coffee is processed using the honey processing, compared with the fullwashed processing which is more commonly used. The method tests that carried out includes water content, ash content, fat content, extract content using the gravimetric proximate analysis, as well as caffeine content test using a spectrophotometer. Preferred testing is done using hedonic organoleptic tests. While the financial analysis uses by net present value and benefit/cost ratio parametric. The research showed that application of honey process for “coastal arabica” coffee changes moisture content, extract content, sugar content and caffein content significanly. The overall taste of honey process have higher value (average preference is 3,77) and the finance analysis is higher (NPV and b/c ratio were Rp135.048.284 and 1,24 for fullwashed process and then increase to Rp 326.245.222 and 1,64 for honey process).
Keyword: Kopi Arabika Pesisir, honey process, kandungan kopi, preferensi, analisis finansial

Judul: Effect of Drying Method on Organoleptic Properties of Arabica Coffee Beans
Abstrak: Sektor pertanian menjadi aspek penting dalam kehidupan manusia dan menjadi penunjang kehidupan seluruh masyarakat Indonesia, salah satunya adalah kopi. Kopi tidak hanya berperan sebagai sumber devisa melainkan juga merupakan sumber penghasilan bagi kurang lebih dari satu setengah juta jiwa petani kopi di Indonesia. Salah satu yang menjadi daya tarik terhadap kopi adalah dari segi citarasa kopi. Salah satu tahapan yang menentukan mutu dan kualitas kopi adalah pengeringan, dimana kadar air maksimal pada biji kopi kering menurut SNI yaitu 12.5% dan kualitas kopi akan menentukan citarasa kopi itu sendiri. Tujuan dilakukan penelitian ini adalah untuk mengetahui pengaruh metode pengeringan terhadap citarasa biji kopi arabika. Penelitian ini dilakukan pada bulan Juni hingga Oktober 2020 di Laboratorium Teknik Pengolahan Pangan dan Hasil Pertanian (TPPHP), Laboratorium Leuwikopo, Greenhouse Seafast, dan Balai Penelitian Tanaman Industri dan Penyegar (BALITTRI) Sukabumi. Sampel yang digunakan adalah buah kopi arabika varietas sigarar utang petik merah yang diolah dengan proses basah (full washed). Metode pengeringan yang digunakan adalah metode pengeringan Sun Drying, Efek Rumah Kaca (ERK), Mechanical Drying, dan pengeringan dengan angin (kering angin). Hasil penelitian menunjukkan perbedaan metode pengeringan tidak memberikan perbedaan yang signifikan terhadap citarasa biji kopi arabika. Metode pengeringan Mechanical Drying menunjukkan waktu pengeringan dengan efektifitas waktu tertinggi selama 18 jam dengan besar drying rate 2,324 %/jam untuk mengeringkan biji kopi dari kadar air 54% sampai 11% dengan hasil cupping skor didapat sebesar 76,1 dan masuk kedalam kategori fine commercial menurut SCAA (Specialty Coffee Association of America)., The agricultural sector is an important aspect of human life and supports the lives of all Indonesians, one of which is coffee. Coffee not only acts as a source of foreign exchange but is also a source of income for approximately one and a half million coffee farmers in Indonesia. One of the main attractions of coffee is the taste of coffee. One of the step that determines the quality of coffee is drying, where the maximum moisture content in drying coffee beans according to SNI is 12.5% and the quality of the coffee will determine the taste of the coffee itself. The purpose of this research was to investigate the effect of the different drying methods to the organoleptics of arabica coffee beans. This research was conducted from June to October 2020 at the Food and Agricultural Products Processing Engineering Laboratory (TPPHP), Leuwikopo Laboratory, Greenhouse Seafast, and Research Institute of Industrial Plant and Refreshments (BALITTRI). The samples used were arabica coffee cherries, varieties of sigarar utang that were processed using a wet process (full washed). The drying method used were Sun Drying, Greenhouse Effect (ERK), Mechanical Drying, and wind Drying. The results of research showed that the different drying methods did not give a significant difference to the taste of Arabica coffee beans. Mechanical Drying methode was found as a methode which have a highest time efficiency compared with another methods with drying time of 18 hours with amount of drying rate 2,324 %/hour to drying a cofffee beans moisture content from 54% to 11% with a cupping score 76,1 and it is categorized fine commercial according to SCAA (Specialty Coffee
Keyword: Cupping, Arabica coffee, Drying method, Organoleptic

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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