Abstract
Sugarcane is a perishable commodity and must be processed into sugar quickly after it is harvested. Post harvest sucrose losses have been reported from many cane producing countries and linked with low sugar recovery and several problems during sugar processing. Bio deterioration is associated with the inordinate delays between harvest to milling of sugarcane and aggravated by many intrinsic and extrinsic factors causing enormous depreciation in cane tonnage as well as sugar recovery. Besides harvest-to-mill delays, other factors such as ambient temperature, humidity, cane variety, period of storage, activities of invertase, maturity status etc. are responsible for decline in sugar recovery. The activity of invertase and proliferation of acid, ethanol and polysaccharides (dextran) producing microbes play a crucial role in the loss of recoverable sugars in cane and milled juice. In addition to loss in sugar recovery, its adverse affects has been noticed in the sugar manufacturing process and sucrose quality. Efforts have been made to reduce loss in tonnage and sucrose using physico-chemical methods. These include spraying of water, bactericidal solution, use of anti-inversion and anti-bacterial formulations and pre-harvest foliar and soil
application of zinc and mangnous compounds. An integrated mill sanitation program and simultaneous use of dextranase could further improve sugar recovery and minimize problems caused by dextran. The possibility of electrolyzed water (EW) fogging to reduce post harvest deterioration in field and mill yard has also been explored. Some of these methods are useful and present larger options for the industry to minimize afterharvest quality losses in the field and milling tandem.
Keywords : Post-harvest deterioration, acid invertase, dextran,
commercial cane sugar, biocides, field control, dextranase
S. Solomon
Sugartech 2009 : 11 (2) : 109 - 123
Abstract
Dextranase only have a small market and low volume sales compared to many other industrial enzymes. Consequently, research and development efforts to engineer properties of dextranase to specific conditions of industrial processes have not occurred and are not expected soon. This book chapter highlights the difficulties associated with the practical application of dextranases, that are sometimes applied to hydrolyze dextran in sugar manufacture when bacterial deterioration of sugarcane or sugarbeet has occurred. Less than optimum application existed because of confusion about where to add the dextranase in the factory/refinery and which commercial dextranase to use. The wide variation in activity of commercially available dextranase in the U.S., and a standardized titration method to measure activities at the factory are discussed. Optimization by applying “concentrated” dextranase as a working solution to heated juice is described. Promising short-term technologies to further improve industrial dextranase applications are discussed, as well as the long-term outlook.
Gillian Eggleston · Adrian Monge · Belisario Montes · David Stewart
Sugar Tech (2009) 11(2) : 135-141
Abstrak
Nira jernih hasil proses pemurnian nira cara sulfitasi masih berkualitas rendah. Penyebabnya antara lain tebu yang diolah berkualitas rendah, ditengarai dengan kadar total CaO nira jernih tinggi, > 1000 ppm. Kadar CaO nira jernih yang tinggi menyebabkan deposit kerak pada dinding bejana penguapan, menurunnya koefisien perpindahan panas sehingga pemakaian energi dalam proses menjadi boros. Telah dilakukan percobaan pemurnian nira skala laboratorium dengan membubuhkan amonium oksalat ke dalam proses pemurnian nira tebu cara sulfitasi. Tujuan utama percobaan ini adalah untuk menurunkan kadar total CaO ke tingkat minimal, akan tetapi harus mempertimbangkan pula kualitas nira yang dihasilkan yaitu sesuai dengan kaidah-kaidah proses pemurnian nira dan kemungkinan terapannya di pabrik gula. Rancangan percobaan yang digunakan rancangan blok acak lengkap. Variabel yang diamati : 1. Letak pembubuhan oksalat (sebelum dan sesudah proses pengendapan); 2. pH nira tersulfitasi pada saat pembubuhan oksalat (pH 7, 8 dan 9); dan 3. Konsentrasi oksalat yang dibubuhkan (0, 2000, 4000 dan 6000 ppm amonium oksalat). Kualitas nira jernih yang diamati: kemurnian nira (HK pol), kadar total CaO, warna dan kekeruhan. Hasil percobaan menunjukkan : 1. Pengaruh letak pembubuhan oksalat terhadap kemurnian dan kadar total CaO nira jernih tidak signifikan, sedangkan terhadap warna dan kekeruhan nira jernih signifikan. Warna nira jernih pada pembubuhan oksalat sesudah proses pengendapan (12843 IU) lebih rendah dibanding sebelum proses pengendapan (13927 IU), akan tetapi kekeruhan sesudah proses pengendapan (216 ppm SiO2) lebih tinggi dibanding sebelum proses pengendapan (44 ppm SiO2). 2. Pengaruh pH nira tersulfitasi pada saat pembubuhan oksalat terhadap kemurnian dan kadar total CaO nira jernih tidak signifikan, sedangkan terhadap warna dan kekeruhan nira jernih signifikan. Warna nira jernih pada pH nira tersulfitasi 7 (13936 IU) tidak berbeda dengan warna nira jernih pada pH nira tersulfitasi 8 (13678 IU), akan tetapi keduanya berbeda lebih tinggi dibanding warna nira jernih pada pH nira tersulfitasi 9 (12541 IU). Kekeruhan nira jernih pada pH nira tersulfitasi 9 (175 ppm SiO2) lebih tinggi dibanding kekeruhan pada pH nira tersulfitasi 8 (120 ppm SiO2) dan keduanya lebih tinggi dibanding kekeruhan pada pH nira tersulfitasi 7 (96 ppm SiO2). 3. Read the rest of this entry »
Gula merupakan salah satu kebutuhan pokok dan paling banyak dikonsumsi oleh masyarakat. Sebagai produk makanan tentunya harus memenuhi standar mutu yang telah ditetapkan sehingga layak untuk dikonsumsi. Di Indonesia ada tiga jenis gula yang beredar di pasaran, yaitu gula kristal mentah (GKM) atau raw sugar yang digunakan sebagai bahan baku industri gula rafinasi, gula kristal putih (GKP) yang dikonsumsi secara langsung dan gula rafinasi sebagai bahan baku industri makanan dan minuman.
Gula yang kita konsumsi sehari-hari adalah gula kristal putih secara internasional disebut sebagai plantation white sugar. GKP dibuat dari tebu yang diolah melalui berbagai tahapan proses, untuk Indonesia kebanyakan menggunakan proses sulfitasi dalam pengolahan gula. Kriteria mutu gula yang berlaku di Indonesia ( SNI ) saat ini pada dasarnya mengacu pada kriteria lama yang dikenal dengan SHS (Superieure Hoofd Suiker), yang pada perkembangannya kemudian mengalami modfikasi dan terakhir SNI 01-3140-2001/Rev 2005, Tabel 1. Secara garis besar kriteria mutu gula (GKP) yang kita ikuti meliputi kadar air, polarisasi, warna larutan, warna kristal, kadar SO2, abu konduktivitas dan besar jenis butir.
Tabel 1. Syarat mutu gula kristal putih (SNI-3140-200/Rev 2005)
