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agriTECH

agritech
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Published by Universitas Gadjah Mada

ISSN : 02160455 EISSN : 25273825 DOI : 10.22146/agritech

Core Subject : Agriculture,

Agriculture, Biological Sciences & Forestry

Agritech with registered number ISSN 0216-0455 (print) and ISSN 2527-3825 (online) is a scientific journal that publishes the results of research in the field of food and agricultural product technology, agricultural and bio-system engineering, and agroindustrial technology. This journal is published by Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta in colaboration with Indonesian Association of Food Technologies (PATPI).

Arjuna Subject : Ilmu Pertanian dan Biologi (Semua) - Ilmu Pertanian dan Biologi (Lain-Lain)

Articles 1,392 Documents

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Pemodelan Matematik Perubahan Parameter Mutu Selama Penyimpanan dan Sorpsi-Isotermi Kerupuk Goreng Pasir Siswantoro Siswantoro; Budi Rahardjo; Nursigit Bintoro; Pudji Hastuti
agriTECH Vol 32, No 3 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Shelf life of food is a time limit to which consumers can still accept its product quality. Chip fries are food product that has a hygroscopic property so that easy to absorb water vapor from environment. Hygroscopic property owned by chip is interesting phenomenon to be evaluated especially related to the change of quality product parameter during storage. At this research, samples were stored at room environment (T = 28 oC, RH = 80 %). The purpose of this research is to develop mathematical model of changing quality product parameter covering moisture content, stress, and strain during storage, and to get sorption-isotherm curve from chip fries. Research was done in laboratory by using research materials such as river sand, ferric sand, chip, and saturated salt solution. Diameter of river sand were 0.25 - 2.00 mm, and ferric sand were 0.10 - 0.40 mm. Frying process was conducted at temperature of 180 – 220 oC, and used a cylindrical fryer set at 5 – 36 rpm. Equipments used in this research consisted of stress-strain measuring instrument (universal of testing machine), oven, analytical balance, frying machine, tachometer, desiccators, hygrometer, thermocouple, data logger, interface, and personal computer. Result show that, the changing of product parameter during the storage reduced quality of chip especially related to the level of crispiness. This was caused by the value of water contain, stress, and strain which increased during storage. The error of prediction values and standard deviation of the developed model was less than 10% indicating that the mathematical model developed in this study was good.ABSTRAKUmur simpan suatu produk makanan adalah suatu batas waktu kualitas produk yang masih diterima oleh konsumen.Kerupuk goreng adalah produk yang bersifat higroskopis sehingga mudah menyerap uap air dari lingkungan. Sifathigroskopis yang dimiliki kerupuk merupakan fenomena menarik untuk diteliti, khususnya yang berhubungan denganperubahan parameter mutu produk selama penyimpanan. Pada penelitian ini penyimpanan dilakukan pada udaralingkungan (T = 28 oC, RH 80 %). Tujuan dari penelitian ini adalah untuk mengembangkan model matematika tentangperubahan parameter produk meliputi kadar air, tegangan, regangan selama penyimpanan, dan mendapatkan kurvasorpsi-isotermi dari kerupuk goreng pasir. Penelitian dilakukan dengan eksperimen laboratorium menggunakan bahanpasir kali, pasir besi, kerupuk mentah, dan larutan garam jenuh. Kisaran diameter pasir kali yang digunakan adalah0,25 – 2,00 mm, dan pasir besi adalah 0,10 – 0,40 mm. Penggorengan dilakukan pada suhu 180 – 220 oC, denganputaran slinder 5 – 36 rpm. Alat yang digunakan terdiri dari alat untuk mengukur tegangan dan regangan (universaltesting machine), oven, timbangan analitik, mesin penggoreng dengan pasir, tachometer, desicator, hygrometer,thermokopel, data logger, interface, dan komputer. Dari hasil penelitian diperoleh bahwa, perubahan parameter mutuproduk selama penyimpanan akan menurunkan mutu kerupuk khususnya yang berkaitan dengan tingkat kerenyahan,karena kadar air, tegangan, dan regangangan selama penyimpanan mengalami kenaikan. Kesalahan nilai prediksi dandeviasi standard pada penggunaan model matematik untuk perubahan parameter mutu kerupuk lebih kecil dari 10%.Hasil ini mengindikasikan bahwa model matematik yang dikembangkan mempunyai nilai prediksi dengan tingkatketelitian cukup baik.

Potensi Bakteri Asam Laktat yang Diisolasi Dari Bekasam sebagai Penghasil Angiotensin Converting Enzyme Inhibitor pada Fermentasi “Bekasam-Like” Product Prima Retno Wikandari; Suparmo Suparmo; Yustinus Marsono; Endang Sutriswati Rahayu
agriTECH Vol 32, No 3 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Bekasam, an traditional fermented fi sh is perceived to have antihypertensive activity, which was estimated to bethe activity of ACE inhibitory peptides, the product of proteolytic degradation of fi sh protein during the bekasamfermentation. Lactic acid bacteria was possibly to give a role on proteolytic degradation to produce ACE inhibitorpeptides in bekasam fermentation. Six strains of the selected strains of proteolytic lactid acid bacteria from bekasam,namely Lactobacillus plantarum B1765, L. plantarum T2565, L. plantarum N2352, L. plantarum B1465, Lactobacilluspentosus B2555, and Pediococcus pentosaseus B1661, were assessed for growth characteristics. The amount of peptidesas result of proteolitic degradation, and the inhibitory activities of ACE inhibitor which is released in fermentationof “bekasam-like” product. All selected strains grew well, exhibited proteolytic activity which was showed by theincreasing of peptides. The extent of proteolysis varied among strains and appeared to be time dependant. The highestpeptides (8.55 ± 0.05 mg/g sample) was found on L. plantarum B1765 and the smallest one (4.45±0.10 mg/g sample)on P. pentosaceus B1661. L. plantarum B1765 exhibited the highest ACE inhibitor activity (68.17±1.32%), followed by L. plantarum T2565 (62.54±2.11%), L. plantarum N2352 (61.56±1.32%), L. plantarum B1465 (59.85±1.58%), and L. pentosus B2555 (56.61±4.28%), whereas P. pentosaceus B1661 (18.66±3.91%) showed the smallest one.ABSTRAKBekasam adalah salah satu produk ikan fermentasi tradisional. Produk ini diduga mempunyai aktivitas antihipertensiyang disebabkan oleh aktivitas peptida Angiotensin Converting Enzyme (ACE) inhibitor yang dihasilkan dari degradasiproteolitik selama proses fermentasi bekasam. Bakteri asam laktat diduga berperan dalam degradasi proteolitikmenghasilkan peptida ACE inhibitor pada fermentasi bekasam. Sebanyak 6 strain bakteri asam laktat terpilih yangdiisolasi dari bekasam yaitu Lactobacillus plantarum B1765, L. plantarum T2565, L. plantarum N2352, L. plantarumB1465, Lactobacillus pentosus B2555, Pediococcus pentosaseus B1661 telah dikaji pertumbuhan, jumlah peptidayang terbentuk dari hasil degradasi proteolitik dan presentase penghambatannya terhadap aktivitas ACE selamafermentasi “bekasam-like” product. Semua strain dapat tumbuh dengan baik dan menunjukkan peningkatan jumlahpeptida dan peningkatan aktivitas penghambatan selama proses fermentasi yang bervariasi antar strain. Jumlah peptidatertinggi pada akhir proses fermentasi (8,55 ± 0,05 mg/g) dihasilkan L. plantarum B1765 dan terkecil (4,45±0,10mg/g) dihasilkan oleh P. pentosaceus B1661. L. plantarum B1765 juga menghasilkan aktivitas penghambatantertinggi (68,17±1,32%), diikuti oleh L. plantarum T2565 (62,54±2,11%), L. plantarum N2352 (61,56±1,32%), L.plantarum B1465 (59,85±1,58%), L. pentosus B2555 (56,61±4,28%), aktivitas penghambatan terkecil dihasilkan olehP. pentosaceus B1661 (18,66±3,91%).

Formulasi dan Stabilitas Mikroemulsi O/W sebagai Pembawa Fucoxanthin Lutfi Suhendra; Sri Rahardjo; Pudji Hastuti; Chusnul Hidayat
agriTECH Vol 32, No 3 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

The objective of this study was to obtain a clear and stable oil-in-water (o/w) microemulsion containing fucoxanthinwhich is intended for aqueous food system application. Virgin coconut oil (VCO) was used as the oil phase andcombination of Tween 80, Tween 20 and Span 80 were selected as nonionic surfactant having high, medium, and lowHLB (Hydrophilic-Lipophilic Balance) values, respectively. The o/w microemulsions were formulated to have the Þ nalHLB values of 13.5, 14.0, and 14.5. For each HLB value, three different microemulsion formulas were determined. Allof the formulated microemulsions were then subjected to oven heating at 105 oC for 5 hour, centrifugation at 4500 rpmfor 30 min, incubation at different pH (3.5, 4.5, and 6.5), water dilution, and photooxidation to evaluate its stability.The most stable microemulsion was then selected and used to deliver fucoxanthin as a hydrophobic antioxidant inaqueous system. Photo-oxidation was performed by exposing the microemulsions under ß uorescent light at 4,000 luxfor up to 4 hours at room temperature. Peroxide values were measured every hour using ferric thiocyanate method.Stable o/w microemulsions were obtained when its HLB value was 14.5, the ratio of oil:surfactants was 3:17, andthe ratio of (oil + surfactants) : water was 35 : 65. The ratio of Tween 80 : Tween 20 : Span 80 was 92.0 : 2.5: 5.5. Fucoxanthin microemulsion was remained stable at pH range from 3.5 to 6.5 even after heating treatment,centrifugation, and water dilution. However, there were increased peroxide values of these microemulsions after being subjected to photooxidation. The presence of fucoxanthin (over 12 ppm) in the microemulsion could not effectively inhibit photooxidation of the o/w microemulsion.ABSTRAKTujuan penelitian ini adalah untuk memperoleh mikroemulsi minyak dalam air (o/w) yang mengandung fucoxanthinyang stabil dan jernih untuk diaplikasikan dalam sistem makanan aqueous. Virgin coconut oil (VCO) digunakansebagai fase minyak dan kombinasi Tween 80, Tween 20 dan Span 80 sebagai surfaktan non ionik yang masingmasingmempunyai nilai HLB (Hydrophilic-Lipophilic Balance) tinggi, medium dan rendah. Formulasi mikroemulsio/w ditentukan nilai HLB akhir masing-masing 13,5; 14, dan 14,5. Masing-masing nilai HLB tersebut ditentukan tigaformula yang berbeda. Semua formulasi mikroemulsi kemudian dipanaskan dalam oven pada suhu 105 oC selama 5jam, disentrifugasi pada kecepatan 4500 rpm selama 30 menit, diinkubasi pada pH yang berbeda (3,5; 4,5 dan 6,5),diencerkan dengan akuades dan stabilitas diuji secara fotooksidasi. Mikroemulsi paling stabil selanjutnya dipilih dandigunakan untuk pembawa fucoxanthin sebagai antioksidan hidrofobik dalam sistem aqueous. Fotooksidasi ditentukandengan menempatkan mikroemulasi di bawah sinar ß ouresensi 4000 lux selama 4 jam pada suhu ruang. Angkaperoksida diukur setiap jam menggunakan metode feri thiosianat. Mikroemulsi o/w yang stabil diperoleh pada HLB14,5 dengan rasio minyak : surfaktan = 3 : 17 dan rasio minyak + surfaktan : air = 35 : 65. Rasio Tween 80 : Tween 20: Span 80 adalah 92.0 : 2.5 : 5.5. Mikroemulsi fucoxanthin yang diperoleh stabil pada pH 3,5 sampai 6,5 dan bahkansetelah perlakuan pemanasan, sentrifugasi dan pengenceran. Namun angka peroksida meningkat selama fotooksidasi.Fucoxanthin dalam mikroemulasi lebih dari 12 ppm tidak efektif untuk menghambat fotooksidasi dalam mikroemulsio/w.

Aktivitas Antioksidan Berbagai Fraksi dan Ekstrak Metanolik Daun Beluntas (Pluchea indica Less) Paini Sri Widyati; Hanny Wijaya; Peni Harjosworo; Dondin Sajuthi
agriTECH Vol 32, No 3 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

This study has been done to investigate the antioxidant activity of various fractions and methanolic extract of beluntasleaves by using several test system, such as DPPH, superoxide and hydroxyl radical-scavenging activities, hydrogenperoxide scavenging activity, ferric reducing power, iron and haemoglobin chelating capacities and b-carotene–linoleicbleaching assay. The results showed that methanolic extract of beluntas leaves (EMB) and its fractions (ethyl acetatefraction (FEA), water fraction (FA) and n-butanol fraction (FNB)) had scavenging activity of DPPH radical. EMBwhich had highest phenolic content and the strongest ferric reducing power, exhibited b-carotene–linoleic bleachinginhibition and the highest superoxide scavenging activity, while FEA showed antioxidant activity based on superoxideradical-scavenging activity, iron and haemoglobin chelating capacities and ferric reducing power.ABSTRAKPenelitian ini dilakukan untuk mengetahui aktivitas antioksidan berbagai fraksi dan ekstrak metanolik daun beluntasdengan berbagai sistem uji, seperti aktivitas menangkap radikal DPPH, superoksida, hidroksil dan hidrogen peroksida,mereduksi ion besi, mengkelat ion besi dan hemoglobin (Hb) dan menghambat pemucatan asam linoleat-b-karoten.Hasil menunjukkan bahwa ekstrak metanolik daun beluntas (EMB) dan fraksi-fraksinya (etil asetat (FEA), air (FA)dan n-butanol (FNB)) berpotensi menangkap radikal bebas DPPH. EMB mempunyai kadar fenolik total dan kekuatanreduksi tertinggi lebih berpotensi menangkap radikal superoksida, mereduksi ion besi dan menghambat pemucatanasam linoleat-b-karoten, sedangkan fraksi etil asetat (FEA) mempunyai aktivitas antioksidan berdasarkan kemampuanmenangkap radikal superoksida, mereduksi ion besi, mengkelat ion besi dan hemoglobin.

Pengembangan Metode Deteksi Minyak Kedelai dalam Campuran Minyak Kelapa Murni dengan Spektroskopi Infra Merah dan Kemometrika Abdul Rohman; Yakoob B. Che Man
agriTECH Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Fourier Transform Infrared (FTIR) spectroscopy combined with the chemometrics techniques of Discriminant Analysis (DA) as well as multivariate analysis of Partial Least Square (PLS) and Principal Component Regression (PCR) has been developed for analysis of soybean oil (SO) in virgin coconut oil (VCO). The spectral bands correlated with VCO, soybean oil (SO), and their blends were scanned, interpreted, and identifi ed. The combined wavenumber regions of 1200 – 1000 and 3025 – 2995 cm-1 were used during analysis either in classifi cation using DA or in quantifi cation using PLS and PCR. DA can be successfully used for the classifi cation of VCO and that added with SO with the accuracy level of 100 %. Furthermore, PLS using FTIR normal spectra was preferred to be used for the quantifi cation of SO in VCO over PCR and the spectral derivatives. The coeffi cient of determination (R2) value obtained for the relationship between actual and FTIR predicted value of SO is higher than 0.99 with acceptable errors, either in calibration or in validation models.ABSTRAKSpektroskopi Fourier Transform Infra Merah (FTIR) yang digabung dengan kemometrika analisis diskriminan serta analisis multivariat Partial Least Square (PLS) dan Principal Component Regression (PCR) telah digunakan untuk analisis adanya minyak kedelai dalam minyak kelapa murni (Virgin Coconut Oil, VCO). Spektra infra merah yang berhubungan dengan VCO, minyak kedelai, serta campuran keduanya direkam, diinterpretasi, dan diidentifi kasi. Kombinasi daerah bilangan gelombang 1200 – 1000 dan 3025 – 2995 cm-1 digunakan untuk tujuan ini. Analisis diskriminan menunjukkan bahwa VCO murni dapat dibedakan dengan VCO yang telah ditambah dengan minyak kedelai dengan tingkat akurasi 100 %. Sementara itu, model kalibrasi PLS menggunakan spektra normal lebih terpilih untuk kuantifi kasi minyak kedelai dalam VCO dibandingkan dengan PCR dan spektra turunannya. Nilai koefi sien determinasi (R2) yang diperoleh > 0,99 dengan tingkat kesalahan (baik kesalahan kalibrasi atau prediksi) yang dapat diterima.

Mekanisme dan Kinetika Quenching Oksigen Singlet dari Senyawa Fenolik Daun Cengkeh Terhadap Fotoksidasi yang Disensitasi oleh Eritrosin Edi Suryanto; Johnly A Rorong; Dewa Gede Katja
agriTECH Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

The objectives of this research were to isolate phenolic compound of clove leaves and to study the mechanism and kinetic of singlet oxygen quenching. Clove leaves was extracted by steam distillation using water for 6 hours. Crude clove leaves oil was purifi ed by distillation under reduced pressure. Isolated fractions were determined its structure by infrared (IR), nuclear magnetic resonance (1H-NMR), and mass spectrometry (MS) techniques. The effects of 0, 500, 1000 and 1500 ppm isolated compound on the photooxidation of linoleic acid (0,03M) containing 15 ppm erythrosine in ethanol were studied by measuring peroxide value of the oil. The quenching mechanism and kinetics of eugenol were studied by the steady-state kinetic method. Samples of 0; 0,06 x 10-4; 0,12 x 10-4; 0,24 x 10-4 dan 0,48x 10-4 mM eugenol prepared in water contained 0; 17,05 x10-4; 34,10 x 10-4; 68,19 x 10-4 and 136,39 x 10-4 mM of erythrosine stored under fl uorescent light (4000 lux) at room temperature for 15 hours. The result indicated that eugenol content of clove oil, F1, F2, F3 and F4 were 49.68; 54.32; 87.16 and 73.65%, respectively. The structure of F3 was identifi ed by IR spectrometry which shows strong absorption at 3448 cm-1 indicating hydroxyl group from the phenolic compound and the 1H NMR spectra showed that the number of proton ring was 3 hydrogen while the mass spectrometry showed the molecular ion peak at m/e = 164 as base peak and the absence of peak at (M-41)+ as the indicator of eugenol. The result showed that eugenol had antiphotooxidation activity on erythrosine sensitized photooxidation of oil. The mechanism of singlet oxygen quenching on erythrosine photodegradation showed that eugenol only quenched singlet oxygen. The total quenching rate constant of eugenol was 4,42 x 108/M/s.ABSTRAKPenelitian ini bertujuan untuk mengisolasi senyawa fenolik dalam daun cengkeh dan mempelajari mekanisme dan kinetika quenching oksigen singlet. Daun cengkeh diekstraksi dengan cara destilasi uap menggunakan air selama 6 jam. Minyak daun cengkeh kasar selanjutnya dimurnikan dengan destilasi pengurangan tekanan. Fraksi-fraksi yang terisolasi ditentukan strukturnya dengan metoda infra merah (IR), resonansi magnetik inti (1H NMR), dan spectrometer massa (MS). Efek 0, 500, 1000 dan 1500 ppm eugenol terhadap fotooksidasi asam linoleat (0,03M) yang mengandung 15 ppm eritrosin dalam etanol dipelajari dengan mengukur angka peroksida minyak. Mekanisme dan kinetika quenching oleh eugenol dipelajari dengan metode steady-state. Sampel 0; 0,06 x 10-4; 0,12 x 10-4; 0,24 x 10-4 dan 0,48x 10-4 mM eugenol dipersiapkan dalam pelarut air yang juga mengandung 0; 17,05 x10-4; 34,10 x 10-4; 68,19 x 10-4 dan 136,39 x 10-4 mM eritrosin yang disinari oleh cahaya fl uoresen (4000 lux) pada suhu kamar selama 15 jam. Hasil analisis kandungan eugenol dari minyak cengkeh, F1, F2, F3 dan F4 berturut-turut adalah 49,68; 54,32; 87,16 dan 73,65%. Kebenaran struktur F3 diidentifi kasi dengan spektrometer IR pada serapan kuat 3448 cm-1 yang menunjukkan adanya gugus hidroksil dari senyawa fenolik sedangkan pada 1H NMR menunjukkan jumlah proton pada cincin aromatic menjadi 3 atom H dan spektrometer massa menunjukkan m/e = 164 sebagai puncak tertinggi dan tidak muncul puncak (M-14)+ sebagai petunjuk adanya eugenol. Hasil ini menunjukkan bahwa eugenol memiliki aktivitas antifotooksidatif terhadap fotooksidasi asam linoleat yang disensitasi oleh eritrosin. Mekanisme quenching oksigen singlet terhadap fotodegrasi eritrosin oleh eugenol menunjukkan bahwa eugenol hanya menstabilkan oksigen singlet. Konstanta laju quenching oksigen singlet total oleh eugenol adalah 4,42 x 108/M/s.

Analisis Keberlanjutan Kawasan Usaha Perkebunan Kopi (KUPK) Rakyat di Desa Sidomulyo Kabupaten Jember Elida Novita; I B Suryaningrat; Idah Andriyani; Sukrisno Widyotomo
agriTECH Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Sidomulyo village, Silo region is one of main small holder coffee producer at Jember district. Unpredictable world production and price can cause unsustainability of small holder coffee production. The research objective was to evaluate sustainability of small holder coffee plantation in Sidomulyo, Jember district. Based on purposive and random sampling survey, questionnaire and discussion with key persons were implemented in this research in collecting data. Dimension of ecology, social institutional, economic and technology were analyzed using Rap-Coffee program modified from Rapfi sh software. The result reveals that from four dimensions implemented in this research, the sustainability index was 59,5 % means that activity of small holder coffee plantation at Sidomulyo still have sustainability as a coffee production unit. This index could be increased through factors improvement of each dimension. The improvement of high sensitivity attributes in each dimension is strongly needed to develop better regulation to support the continuity of small holder plantation of coffee production unit at Sidomulyo.ABSTRAKDesa Sidomulyo, Kecamatan Silo merupakan salah satu sentra produksi kopi rakyat utama di Kabupaten Jember. Perkembangan produksi dan harga kopi dunia yang tidak pasti dapat berimplikasi terhadap keberlanjutan usaha pertanian kopi rakyat. Tujuan penelitian ini adalah untuk mengevaluasi keberlanjutan usaha kopi rakyat di Desa Sidomulyo, Kabupaten Jember. Berdasarkan purposive and random sampling survey, penelitian ini menggunakan kuesioner dan diskusi dengan pihak terkait dalam pengambilan data. Dimensi ekologi, sosial kelembagaan, ekonomi dan teknologi dianalisis dengan menggunakan program Rap-Coffee hasil modifi kasi dari program Rapfi sh. Berdasarkan simulasi program Rap-Coffee untuk keempat dimensi keberlanjutan, maka Indeks Keberlanjutan KUPK Desa Sidomulyo adalah 59,5 % yang berarti berlanjut. Indeks keberlanjutan ini dapat ditingkatkan melalui perbaikan terhadap faktor pengungkit (indikator sensitif). Oleh karena itu di dalam perencanaan kebijakan untuk pengembangan KUPK Desa Sidomulyo sebaiknya memprioritaskan pada peningkatan indikator yang memiliki sensitivitas tinggi di masing-masing dimensi.

Mitigasi Pelindian Nitrat pada Tanah Inceptisol melalui Pemanfaatan Bahan Nitrat Inhibitor Alami Joko Pramono; Djoko Prajitno; Tohari Tohari; Dja'far Shiddieq
agriTECH Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

NO3 - leaching is one mechanism of N reduction in agricultural activity, which may contribute to environmental pollution. The purpose of this research is to investigate the use of natural products as nitrate inhibitors toward nitrate leaching in Inceptisol soil. In this study, three types of natural nitrate inhibitors (NI) derived from neem seed powder (NSP), mangrove bark powder (MBP), and coffee leaf powder (CLP) were tested combined with the three doses of NI, i.e. 20 %, 30 %, and 40 % of urea used were given. Moreover, a treatment without NI was used as a control. Material was supplied with urea nitrate inhibitor on the surface of the soil in the pot experiment that had been moistened with distilled water. Results showed that the nitrate inhibitors materials had different response to different nitrifi cation inhibition. Nitrate inhibitors material derived from neem seed powder (NSP) had the highest inhibition rate of 25.6 %, while mangrove bark powder (MBP) and coffee leaf powder (CLP) had the rate of 9.1 % and 11.8 %, respectively. NI ingredients naturally capable of inhibiting nitrifi cation through the inhibition of nitrifi er growth (ammonium oxidizing) which was temporary in the range of 7-14 days after NI materials application. Treatment of different materials and NI doses suppressed the leaching of nitrate from 56.6 % to 62.8 % during 14 day after application. Treatment using different materials had signifi cant effect compare to the control treatment without NI. Optimal dose of two selected NI materials showed the best performance of nitrifi cation inhibition (NSP and MBP), i.e. 18.3% (R2 = 0.69) and 21.67% (R2 = 0.69) from a given dose of urea, respectively, 7 day after application.ABSTRAKPelindian NO3- merupakan salah satu mekanisme kehilangan N dalam aktivitas pertanian, yang dapat berdampak terhadap pencemaran lingkungan. Tujuan dari penelitian adalah untuk mengetahui penggunaan bahan alami sebagai nitrat inhibitor terhadap pelindian nitrat pada tanah Inceptisol. Pada penelitian ini diuji tiga jenis bahan nitrat inhibitor (NI) alami yang berasal dari; serbuk biji Mimba (SBM), serbuk kulit kayu bakau (SKKB), dan serbuk daun kopi (SDK),yang dikombinasikan dengan tiga taraf dosis NI, yaitu: 20 %, 30 % dan 40 % dari urea yang diberikan, dan ditambah satu perlakuan kontrol tanpa NI. Bahan nitrat inhibitor diberikan bersama urea pada permukaan tanah dalam pot percobaan yang telah dibasahi dengan air suling. Hasil penelitian menunjukkan bahwa bahan NI yang berbeda memberikan respon terhadap penghambatan nitrifi kasi yang berbeda. Bahan NI yang berasal dari serbuk biji mimba memberikan tingkat penghambatan tertinggi sebesar (25,6 %), serbuk kulit kayu bakau sebesar (19,1 %), dan serbuk daun kopi sebesar 11,8 %. Bahan NI alami mampu menghambat nitrifi kasi melalui penghambatan pertumbuhan bakteri nitrifi kasi (pengoksida ammonium) yang bersifat sementara pada kisaran 7-14 hari setelah aplikasi. Perlakuan berbagai bahan dan dosis NI mampu menekan pelindian nitrat rata-rata pada kisaran antara 56,6 sampai 62,8 % dan berbeda sangat nyata terhadap perlakuan kontrol tanpa NI. Bahan NI yang mampu menurunkan rata-rata pelindian nitrat pada pengamatan 14 hari setelah aplikasi tertinggi adalah SBM sebesar 74,15 %. Dosis optimal dua bahan NI terpilih yang menunjukkan kinerja penghambatan nitrifi kasi terbaik (SBM dan SKKB) pada 7 hsa, masing-masing 18,30 % (R2 = 0,694) dan 21,67 % (R2=0.691) dari dosis urea yang diberikan.

Application of Neuro-Fuzzy Controller to Autonomous Agricultural Vehicle Operating on Unstructured Changing Terrain -Control Software Development- Lilik Sutiarso; Tomohiro Takigawa
agriTECH Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

The control of an autonomous agricultural vehicle operating on unstructured changing terrain includes many objective diffi culties. One major diffi culty concerns the characteristics of the terrain condition that the vehicle should operate in. Problems ranged from the effects of varying terrain conditions on the autonomous vehicle sensors and traction performance through to the need to deal with the presence of unexpected situations. On unstructured changing terrain, many factors infl uence vehicle behavior such as terrain slope, lateral slippage, and so on. Therefore, it is necessary to develop a more suitable model for vehicle motion on these terrain conditions. In order to control the vehicle along a course on unstructured changing terrain, it was developed control software to enable more accurate control. The developed method to control the vehicle when operating on these conditions was Neuro-Fuzzy Controller. Result of the trained model could be described as follows; number of nodes was 193, number of fuzzy rules was 81, average testing error between simulation and ANFIS output was 0.76, while for experimental and ANFIS output was 1.61. It was concluded that the developed control system had a good accuracy to steer the vehicle.

Hidrolisis Minyak Kelapa oleh Enzim Lipase dari Kentos Kelapa Moh. Su'i
agriTECH Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

This research learned the kind and amount of fatty acid that was produced from coconut oil hydrolyzed by lipase enzyme from coconut houstorium. Coconut oil was hydrolyzed by lipase enzyme from coconut houstorium for 30, 60, 90, and 120 minutes. The kind and amount of fatty acid obtained from hidrolization were measured. The result showed that hidrolization for 90 minutes produced the highest fatty acid 40,20 %. The highest fatty acid was lauric acid with 21,229 %, furthermore miristic acid 7,615 %, and capric acid 3,062 %.ABSTRAKPenelitian ini mempelajari jenis dan jumlah asam lemak yang dihasilkan dari hidrolisis minyak kelapa menggunakan enzim lipase dari kentos kelapa. Minyak kelapa dihidrolisis oleh enzim lipase kentos selama 30, 60, 9, dan 120 menit. Selanjutnya jenis asam lemak yang dihasilkan dan jumlahnya dianalisa. Hasil penelitian menunjukkan bahwa, hidrolisis selama 90 menit menghasilkan asam lemak paling tinggi yaitu sebesar 40,20 %. Jenis asam lemak yang paling banyak dihidrolisis adalah asam laurat sebesar 21,23 %, kemudian asam miristat 7,62 %, dan asam kaprat 3,06 % dari total asam lemak dalam minyak kelapa.

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Home Page

OAI Link

Editorial Team

Contact

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Contact Name Fiametta Ayu Purwandari

Contact Email fiametta@ugm.ac.id

Phone +6285712601130

Journal Mail Official agritech@ugm.ac.id

Editorial Address Faculty of Agricultural Technology, Universitas Gadjah Mada, Jl. Flora No. 1, Bulaksumur, Yogyakarta 55281, Indonesia

Location Kab. sleman, Daerah istimewa yogyakarta INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
Fiametta Ayu Purwandari

Contact Email
fiametta@ugm.ac.id

Phone
+6285712601130

Journal Mail Official
agritech@ugm.ac.id

Editorial Address
Faculty of Agricultural Technology, Universitas Gadjah Mada, Jl. Flora No. 1, Bulaksumur, Yogyakarta 55281, Indonesia

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA