Usman Ahmad
Departemen Teknik Mesin dan Biosistem, Fakultas Teknologi Pertanian, Institut Pertanian Bogor

Published : 55 Documents
Articles

Aplikasi film edibel dan kemasan atmosfir termodifikasi untuk meningkatkan umur simpan buah salak terolah minimal Ahmad, Usman; ., Yulianingsih; Lintang, Meivie
Jurnal Ilmu Pertanian Indonesia Vol 15, No 3 (2010): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

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Snake fruit is an exotic fruit from Indonesia, and nowadays has increasing in demand. There is opportunity to market minimally processed snake fruit, but this product becomes very highly perishable because of increasing in respiration rate. The objective of this research was to determine edible coating formulation in combination with modified atmosphere packaging, in order to maintain quality and to prolong shelflife of minimally processed snakefruit. The research was started by preparation of salak fruit, edible coating, measurement of respiration rate, determination of optimum atmosphere composition and critical parameter, and storage in modified atmosphere packaging. First, best atmosphere composition for minimally prcessed snakefruit was determined, then storage of minimally processed snakefruit was conducted after selection of the appropriate plastic film. Analysis was conducted on quality and organoleptic characteristics. Optimum gas composition storage for minimally processed snake fruit is 4±1%0[2] and 14±2% C0[2]. Minimally processed snake fruit with edible coatings made from pectin and chitozan combined with modified atmosphere packaging can extend shelflife and maintained quality until eight days, while without edible coating the minimally-processed snake fruit in with modified atmosphere packaging can extend until 6 days only.Keywords : Snake fruit, edible coating, modified atmosphere packaging, shelf life.
Development of Image Processing Algoritm for Determining the Maturity of Fresh Mangosteen Suhandy, Diding; Ahmad, Usman
Jurnal Keteknikan Pertanian Vol 17, No 2 (2003): Buletin Keteknikan Pertanian
Publisher : PERTETA

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One of important factor in post harvest handling is cropping at correct maturity level. Fruit maturity relates to age pluck vegetable or fruit to be harvested have old enough or not yet. Grading represent dissociation of product becomes some group quality of pursuant to maturity level, size measure, color, form, heavy, texture, aroma and freedom from foreign object or dirt.The objective of this research is to predict the maturity of fresh mangosteen by means of an image processing algorithm. In this study, four stages maturity (120, 126, 132 and 138 days after flowering) were used as objects with 33,37,40,40 samples for each stages of maturity. The image processing program to analyze the relationship between the maturity and the color, size, and shape of fruits.
Image Processing for Quality Inspection of Mango Fruit Ahmad, Usman
Jurnal Keteknikan Pertanian Vol 16, No 1 (2002): Buletin Keteknikan Pertanian
Publisher : PERTETA

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Indonesia has many kinds of tropical fruits, including mango, that can be exported besides to suplly the demand on the fruits in the country. To ensure the quality of mango, it is important to do sortation and grading on them, especially those for export, based on the quality requirement. In this case, the use of high technology such as image processing in necesary to put into practise with the aim to increase the consistance of sortation and grading processes as compare to the result of manual work.
Penentuan Pola Peningkatan Kekerasan Kulit Buah Manggis Selama Penyimpanan Dingin Dengan Metode NIR Spectroscopy Novita, Dwi Dian; Ahmad, Usman; ., Sutrisno; Budiastra, I Wayan
Jurnal Keteknikan Pertanian Vol 25, No 1 (2011): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract Pericarp hardening of mangosteen fruit has correlation with the decrease in moisture content due to transpiration and respiration during storage.  The change of pericarp moisture content during storage may be determined nondestructively using near infrared (NIR) spectroscopy. The objectives of this study were to build calibration model of NIR reflectance to predict the moisture content of the pericarp, and to determine the pattern of pericarp hardening based on change of moisture content during storage using NIR reflectance. NIR reflectance spectra were obtained from fruits stored at 8ºC, 13ºC, and room temperature.  Calibrations were built using partial least squares (PLS) and artificial neural network (ANN) models.  Results of analysis indicated that pericarp moisture content could be predicted well by NIR reflectance using the calibration model of PLS for mangosteen stored at 8ºC, 13ºC, and room temperature. The pattern of pericarp hardening based on change of moisture content also could be determined using NIR reflectance for mangosteen stored at 13ºC and room temperature. Keywords : mangosteen fruit, pericarp hardening, moisture content NIR spectroscopy, PLS, ANN Abstrak Pengerasan kulit buah manggis memiliki korelasi dengan penurunan kadar air kulit buah akibat dari proses transpirasi dan respirasi buah selama penyimpanan. Perubahan kadar air kulit buah selama penyimpanan bisa ditentukan secara non-destutive dengan menggunakan near infrared (NIR) spectroscopy. Tujuan penelitian ini adalah menyusun model kalibrasi reflektan NIR untuk memprediksi kadar air kulit buah manggis, serta untuk menentukan model pengerasan kulit buah berdasarkan perubahan kadar air selama penyimpanan menggunakan reflektan NIR. Spektra reflektan NIR diambil dari buah manggis yang disimpan pada suhu 8oC, 13oC dan suhu ruang. Kalibrasi dibangun dengan menggunakan model partial least squares (PLS) dan artificial neural network (ANN). Hasil analisis mengindikasikan bahwa kadar air kulit buah dapat diprediksi secara baik dengan reflektan NIR menggunakan model kalibrasi PLS untuk buah manggis yang disimpan pada suhu 8oC, 13oC dan suhu ruang. Model pengerasan kulit buah berdasarkan perubahan kadar airnya juga dapat ditentukan dengan reflektan NIR untuk buah manggis yang disimpan pada suhu 13oC dan suhu ruang. Kata kunci : buah manggis, pengerasan kulit, NIR spectroscopy, PLS, ANNDiterima: 19 Oktober 2010; Disetujui: 10 Maret 2011  
Pengembangan Algoritma Pengolahan Citra untuk Menghindari Rintangan pada Traktor Tanpa Awak Ahmad, Usman; ., Desrial; Subrata, I Dewa Made; Annas, Sjahrul
Jurnal Keteknikan Pertanian Vol 24, No 2 (2010): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract Unmanned tractors, even though it uses global positioning system (GPS) technology to identify the working path, still require an ability to recognize the environment in front of it in order to avoid obstacles thatmay exist. A device that can be used to recognize the environment in front of the tractor and avoid obstacles that may exist, is the camera. However, images captured by the camera need to be processed to detect possible obstacles at the front of the tractor. This study aimed to develop image processing algorithms to detect the possible presence of obstacles on the path to be traversed by an unmanned tractor, and directed the tractor to a safe path by giving the new coordinates when there are obstacles in front of it. Several mage processing techniques such as edge detection, opening and closing, marking free area, and the determination of the coordinates were used for the purpose of directing the path in front of the tractor when there are obstacles that must be avoided. Keywords: image processing, obstacles, unmanned tractor, algorithms Diterima: 19 April 2010; Disetujui: 18 Oktober 2010
Pengembangan Metoda Deteksi Rintangan untuk Traktor Tanpa Awak Menggunakan Kamera CCD Ahmad, Usman; Desrial, .; Saksono, Mudho
Jurnal Keteknikan Pertanian Vol 26, No 1 (2012): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstrak Kemampuan menghindari rintangan pada lahan kerja berupa pohon, batu, lubang, pematang, manusia, dan benda-benda lainnya yang tidak mungkin dilewati diperlukan oleh traktor yang dioperasikan  tanpa awak berbasis GPS.  Sistem pengindera lingkungan sekitar menggunakan kamera CCD memungkinkan untuk mendeteksi rintangan yang berada di depan traktor secaral realtime. Namun dengan kemungkinan beragamnya obyek yang ditangkap oleh kamera, pengolahan citra menjadi kompleks dan membutuhkan waktu yang relatif lama sehingga tidak cocok untuk diaplikasikan. Penelitian ini mencoba mengembangkan metoda deteksi rintangan pada lahan kerja traktor tanpa awak yang lebih sederhana dengan penambahan sinar laser merah pada kamera CCD yang digunakan. Sinar laser merah yang tertahan pada rintangan memberikan informasi pada sistem pengindera bahwa di depan ada rintangan, dan jaraknya dari traktor dihitung berdasarkan prinsip phitagoras. Hasil penelitian menunjukkan bahwa semua rintangan berjarak 1 m, 80% rintangan berjarak 2 m, dan 40% rintangan berjarak 3 m dapat dideteksi. Rintangan yang berjarak lebih dari 3 m dari traktor belum dapat dideteksi karena kekuatan sinar laser yang menurun dengan bertambahnya jarak. Akurasi  dalam pendugaan jarak secara keseluruhan untuk rintangan yang terdeteksi juga masih rendah, yaitu 67.5%. Kata Kunci: traktor tanpa awak, sistem deteksi, rintangan, pengolahan citra Abstract For unmanned tractor guided by global positioning system, ability for eluding obstacles such as trees, big stone, cavity, bund, people, and other objects in the work area is very important in order not to stop the operation.Surrounding detection system using CCD camera makes it possible for unmanned tractor to detect obstacles in front of it realtime. However, with so many different objects that may captured by the camera, it will need a lot of image processing steps that takes a lot of time so it is no longer suitable for realtime detection in application. The proposed research is aimed to develop a simpler obstacle detection method by adding a red laser pointer to the CCD camera used to capture scene in front of the tractor. The red laser light that reflected by an obstacle gives an important information in the image, and the distance of the obstacle could be calculated based on phytagoras theory. The results showed that all obstacles with 1 m distance, 80% obstacles with 2 m distance, and 40% obstacles with 3 m distance could be detected. Obstacles with more than 3 m distances could not be detected due to weak laser light for the distances. The accuracy of distance prediction for all situation is 67.5%, which is still need improvements. Key Words: unmanned tractor, detection system, obstacle, image processing Diterima: 01 November 2011; Disetujui: 04 Maret 2012  
Rancang Bangun Sistem Sortasi Cerdas Berbasis Pengolahan Citra untuk Kopi Beras W. Soedibyo, Dedy; Ahmad, Usman; Seminar, Kudang Boro; Subrata, I Dewa Made
Jurnal Keteknikan Pertanian Vol 24, No 2 (2010): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstrack Coffee has good prospects as a motor of development in Indonesia agribusiness  and agroindustry, therefore needs to be handled properly and professionally. Grading process in commercial green coffee asgrain commodity is still done manually. This process has the disadvantage of low efficiency, objectivity and the level of consistency. Therefore weneed a machine that can workautomatically to classify the quality of the green coffee by visual inspection. Theobjective of this study was to design the  green coffee sorting machine controlled by a computer based on image processing program consisted of conveyor belt, the image capture station used twodigital cameras, and the parallelsimulator divider. The design of sorting machine was used for the development of the green coffee sorting system that will categorizeinto four quality classes based on the qualifications according to the standard of SCAA ( Specialty Coffee Association of America). Keyword: Sorting Machine, green coffee, image procesing, computer programDiterima: 14 Juli 2010; Disetujui: 11 Oktober  2010
Karakteristik Edible Film dari Pektin Hasil Ekstraksi Kulit Pisang Akili, Muhammad Sudirman; Ahmad, Usman; Suyatma, Nugraha Edhi
Jurnal Keteknikan Pertanian Vol 26, No 1 (2012): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract Banana peel is a waste of banana processing industries which is obviously uneconomy and unfriendly to the environment.  However, this material could be used as a source of important natural compounds, such as pectin. Owing to the fact that pectin has good gelling properties, it can be used to make edible film. The objectives of this research were to extract and characterize pectin from banana peel and to make edible film from the obtained pectin by using glycerol as plasticizer. Characterization of edible films were conducted in terms of color, thickness, elongation, tensile strength and water vapor transmission. The research used factorial completely randomized design. The results showed that yield of pectin made from ambon banana peel ripeness level one was 8.42% with the characteristics werewater content : 11.27% (<12%), ash content : 1.70%, low methoxil content : 4.15% (<7%) and galacturonat content : 25.86% (65%). The addition of glycerol significantly increased elongation and decreased tensile strength of edible film. Based on edible film result, the recomended treatment is the addition with glycerol 20% as plasticizer of pectin based edible film. Keywords : banana peel,pectin,edible film. Abstrak Kulit pisang adalah limbah hasil industri pengolahan yang  tidak bernilai ekonomi dan ramah lingkungan. Meskipun limbah kulit pisang dapat digunakan sebagai sumber pektin yang merupakan senyawa alami. Kenyataannya bahwa pektin memiliki sifat gel yang baik sehingga dapat digunakan untuk membuat kemasan yang dapat dimakan (edible film. Tujuan dari penelitian ini adalah mengekstrak dan mengkarakterisasi pektin dari kulit pisang untuk membuat edibe film dengan penambahan gliserol untuk memberikan sifat plastis dan elastis. Karakteristik edible film pada penelitian ini adalah warna, ketebalan, elongasi, kuat tarik dan laju transmisi uap air.  Penelitian ini menggunakan rancangan acak lengkap. Hasil penelitian ini menunjukkan bahwa rendeman tertinggi terdapat pada pektin dari kulit pisang tingkat kematangan 1 dengan karakteristik kadar air: 11.27% (<12%), kadar abu : 1.70%, kandungan metoksil rendah : 4.15% (<7%) dan kandungan asam galkturonat  : 25.86% (65%). Penambahan gliserol secara signifikan meningkatkan elongasi dan menurunkan kuat tarik edibe film. Edible film dengan perlakuan penambahan gliserol 20% direkomendasikan sebagai perlakuan terbaik karena memiliki sifat plastis yang baik dan mampu mengemas bahan pangan. Kata Kunci : kulit pisang, pektin, edibe film Diterima; 27 Januari 2012; Disetujui: 30 Maret 2012  
Deteksi Chilling Injury pada Buah Mangga Gedong Gincu dengan Menggunakan Near Infrared Spectroscopy Zainal, Putri Wulandari; Ahmad, Usman; Purwanto, Yohanes Aris
Jurnal Keteknikan Pertanian Vol 26, No 1 (2012): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract Chilling Injury is a major problem in storing mango fruit in low temperature wich is unavoidable in order to extend the shelf life of fruit. symptoms of chilling injury during storage associated with the change in pH due to ion leakage. Chilling injury can be detected during storage destructively, but it will require time and a lot of samples. Alternatively, the detection can be performed non-destructively by using near infrared (NIR). The purpose of this research is to build the NIR calibration models for predicting ion leakage relating with change in pH and the detection of chilling injury symptoms can be done through ion leakage storage. Reflectant NIR measurements conducted on mango fruit stored at a temperature of 8 ° C and 13 ° C. Determination of chilling injury symptoms was predicted based on change in pH and the rate of ion leakage. The analysis showed that NIR spectroscopy was able to predict the change in pH during storage of mango fruit at a temperature of 8 °C based on reflectance and PLS method. Moreover ion leakage could also be predicted properly through the pH of the NIR predictions. The developed method could detect the chilling injury on mangoes after three days storage at a temperature of 8 °C. Keywords : NIR, Mangoes fruit, chilling injury, ion leakage, pH. Abstrak Chilling injury merupakan salah satu masalah utama didalam penyimpanan dingin buah mangga, dimana penyimpanan dingin ini berfungsi untuk memperpanjang umur simpan buah. Gejala chilling injury selama penyimpanan berhubungan dengan perubahan pH yang disebabkan oleh ion leakage. Chilling injury selama penyimpanan dapat dideteksi secara destruktif, tetapi deteksi secara destruktif membutukan waktu yang lama dan sampel yang banyak. Oleh karena itu, deteksi secara non-destruktif dapat dilakukan dengan menggunakan NIR. Tujuan dari penelitian ini adalah untuk mengembangkan model kalibrasi NIR untuk dapat memprediksi ion leakage yang berhubungan dengan perubahan pH dan deteksi gejala chilling injury yang berhubungan dengan ion leakage selama penyimpanan. Pengukuran reflektan NIR dilakukan pada buah mangga yang disimpan pada suhu 8 ° C and 13 ° C. Pengukuran gejala chilling injury diprediksi berdasarkan pH dan rata-rata perubahan ion leakage. Dari hasil penelitian dapat dilihat bahwa NIR-spectroscopy mampu untuk memprediksi perubahan pH selama penyimpanan dingin buah mangga suhu 8 ° C berdasarkan data reflektan dan metode PLS. Selain itu, ion leakage dapat diprediksi dengan menggunakan pH prediksi NIR. Pengembangan metode ini, dapat mendeteksi chilling injury pada buah mangga dimana pada pendeteksian chilling injury terjadi pada hari ketiga penyimpanan suhu 8 ° C. Kata Kunci : NIR, Buah mangga, chilling injury, ion leakage, pH. Diterima: 09 November 2011.; Disetuji: 13 Maret 2012  
Kajian Penanganan Bahan dan Metode Pengeringan terhadap Mutu Biji dan Minyak Jarak Pagar (Jatropha curcas L.) Mellyana, Verra; Ahmad, Usman; Widowati, Sri
Jurnal Keteknikan Pertanian Vol 26, No 2 (2012): Jurnal Keteknikan Pertanian
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ABSTRACT Energy is consumed in many sectors such as industry, transportation, and household. Most of the source of energy nowadays are obtained from fosil, which is predicted available for less than 10-15 upcoming years, and should be replaced by renewable energy. One of potential renewable energy to considered is Jatropha, a plant with seeds containing oil that can be processed into biodiesel. As a part of plant, fruit of Jatropha should be treated properly after harvest to maintain its oil in the seeds, so that good physical and chemical properties of  the oil extracted from the seed can be obtained. This research is aim to develop method of handling of the harvested Jatropha fruits, including its drying, to maintain quality of the seeds and oil resulted from extraction. Different combinations of preparation (fresh, seed and steamed seed) and drying (temperature of 50, 60, 70 oC and natural sun drying), have been investigated. The results showed that the best treatment was seed drying at 70 oC with the drying time of 4.83 hour, oil rate of 40.06%, and oil yield of 28.59%. Quality of the seeds which fulfilled Standard National Indonesia (SNI) 01-1677-1989 were broken seed (0.57%), cracked seed (0.20 %), foreign object (0%), moisture content (6.08%). However, the highest oil extraction (40.06%) was not satisfy SNI 01-1677-1989. This case, quality of castor oil which qualified SNI 01-1904-1990 were oil moisture content (0.23%) and acid value (0.33 mg KOH/g), but refractive index (1.6209), iod number (54.31) and saponification number (67.30) were unqualified. Keywords : Jatropha, drying, seed, castor oil  ABSTRAK Energi digunakan pada berbagai sektor seperti industri, transportasi dan rumah tangga. Sebagian besar sumber energi saat ini diperoleh darifosil, yang diperkirakan tersedia untuk kurang dari 10-15 tahun mendatang, dan harus digantikan oleh energi terbarukan. Salah satu energi terbarukan yang potensial untuk dipertimbangkan adalah jarak pagar, tanaman dengan biji yang mengandung minyak yang dapat diolah menjadi biodiesel. Sebagai bagian dari tanaman, buah Jatropha harus diperlakukan dengan baik setelah panen untuk mempertahankan minyakdalam biji, sehingga diperoleh hasil ekstraksi minyak dengan mutu fisik dan kimia yang baik. Penelitian ini bertujuan untuk mengembangkan metode penanganan panen dari buah Jatropha, termasuk pengeringan, untuk mempertahankan kualitas biji dan minyak hasil ekstraksi. Kombinasi yang berbeda mulai dari penanganan bahan (buah segar, biji dan biji hasil pengukusan) dan proses pengeringan (suhu 50, 60, 70oC dan pengeringan matahari alami), telah diteliti. Hasil penelitian menunjukkan bahwa perlakuan terbaik adalah biji yang dikeringkan pada suhu 70oC dengan waktu pengeringan tercepat (4.83jam), kadar minyak 40.06%, serta rendemen minyak tertinggi (28.59%). Mutu biji telah memenuhi Standar Nasional Indonesia (SNI) 01-1677-1989 diantaranya biji rusak (0.57%), bijipecah(0.20%), benda asing(0%), kadar air(6.08%). Akan tetapi kadar minyak (40.06%) yang merupakan kadar minyak tertinggi dari semua perlakuan ini masih belum memenuhi SNI01-1677-1989. Sedangkan mutu minyak yang memenuhi SNI01-1904-1990adalah kadar air minyak(0.23%) dan bilangan asam(0.33 mgKOH/g) dan yang tidak memenuhi adalah rata-rata indeks bias(1.6209), bilangan iod(54.31) dan bilangan penyabunan(67.30). Kata kunci: Jatropha, pengeringan, biji, minyak jarak