DIRECT CANE FIBER DETERMINATION BY THE PRESS METHOD

Transcription

1 Ill ' PROCESSING DIRECT CANE FIBER DETERMINATION BY THE PRESS METHOD S.G. Gandana Indonesian Sugar Experiment Station Pasuruan (BP3G) i I l ABSTRACT A method for direct determination of fiber in cane has been developed using a HAFICO hydraulic press. The washing of the pressed residue is directly done in the container 'of the press. The results are compared with the figures of the fiber content calculated according to the Hawaiian method. A very significant correlation has been found between the weighed and the calculated fiber contents. The method is simple, rapid and accurate. The HAFICO hydraulic press is rather cheap in comparison with other hydraulic presses employed for direct cane analysis.. I I 1 i INTRODUCTION The determination of the fiber content of sugarcane is of great importance in evaluating the cane as a material or raw material. The determination of the fiber content by common extraction methods followed by drying is time consuming, and the results are only available some hours after sampling. In many cases this time delay can hardly be accepted so that methods which reduce the time of analyzing the fiber content have gained more and more attention. Among others, the combined press -quick drying method has gained attention and it is one subject (Nr. 10) within the ICUMSA program of research4. The recommendation is to standardize the quick method. During the last two decades, several research workers have tried todevelopthe press method up to optimization and now, as the official method for the determination of the available sucrose content of the cane, for the individual payment of the cane, it is used in Hawaii (~animoto*), Mauritius (saint ~ntoinefi), Reunion (Hugot3). Guadeloupe. A review ot tne press method For fiber and available sucrpse determinatio!i of cane was given by Saranin7. In principle, the methods use a predetermined mass of prepared cane which is squeezed under high pressure to gain most or all of the juice in cane which is supported by washing of the pressed residue. The sugarfree fibrous residue is dried, and the fiber content of the cane calculated. The press juice is analyzed according to the needs of the method for calculating the sucrose content. The presses used are mostly high pressure hydraulic presses which are

2 2352 PROCESSING rather expensive. The Indonesian Sugar Exgeriment :tation has for several years also been doing research on the direct analysis of cane'though the individual payment of cane deliveries is not a standaid practice in Indonesia. But the development of the sugar industry in Indonesia, shifting from cane cultivated by the mills to farmer's cane (Mubyartos), will require the introduction of an individual cane payment system in o,rder to stihulate thelfarmers to improve their techniques. BP3G has worked with the Pinette ~midecau'h~draulic pressy, but more recently a much simpler hydraulic press has come into hse and the results bf the operation of this press are dealt with in this paper. MATERIALS AND METHODS The press used was the HAFICO hydraulic press made in ~erman~l, schematically shown in Figure 1. The maximum permissible pressure is about 44 MPa. The pressure is applied to a perforated stainless steel piston of 16 cm diameter which moves upwards in a stainless steel cylinder with a capacity of about 2 dm3. The piston plate is covered by a strainer for holding back fine particles. The hydraulic pressure is applied by a manual pumping system, which makes the press independent from electrical power. The cane was prepared by means of a Jeffco cutter grinder for about 5 minutes. After thoroughly mixing the prepared cane, a 600 g subsample was pressed at 29.5 MPa for 2 minutes. The expressed juice was analyzed for refractometric dry matter content and Pol content. The pressed residue was weighed and thoroughly mixed. 50 g of the pressed residue was dried in a Dietert Moisture Teller till constant weight. Another 100 g of the pressed residue was mixed with 1 dm3 of water in a bin, thoroughly mixed and transferred back to the cylindrical container of the HAFICO press and distributed evenly by hand to form a uniform mat on the strainer. The first outflowing liquid was returned to the container to retain the fine bagasse particies. Then 10 dm3 of cold water was poured to the bagasse which nbrmally leaves the bagasse free from sugar. The liquid was discarded, the fiber pressed, then dried to constant weight at 105%. Fiber % cane was calculated from the measured figures. The fiber content so determ~ned was compared with the fiber content calculated according to the Hawaiian method.' RESULTS AND DISCUSSIONS The results of the cane fiber determination by the HAFICO press method and the Hawaiian method are shown in Table 1.

3 S. G. GANDANA I 1 TABLE 1. Corrlparison of results between the fiber content of cane determined by the Hawaiian method and HAFICO method Fiber content Fiber content Sample Pressed of cane according to of cane according to number residue the Hawaiian method the HAFICO method 9 % %

4 FIGURE 1. HAFICO Hydraulic Press. (H. Fischer & Co.). PROCESSING

5 s. G. GANDANA 2353 I I The Relationships between the calculated and the weighed fiber contents and between the weight of the pressed residue and the fiber contents were evaluated by linear regression analysis. correlation between the calculated (x) and the weigh'ed (y) fiber corltent is very significant (r = ) with regression line y = x. A very, significant correlation was also found between the weight of the pressed residue (x) and the calculated fiber content (y) (r = ) with regression line y = x and between the weight of the pressed residue (x) and the weighed fiber content (y) (r = ) with regression line y = The reproducibility of the HAFICO press method including subsampling and analysis was examined on 13 replicate subsamples of a prepared cane sample (by Jeffco cutter grinder), pressed at 29.5 MPa for 2 min~~tes and analyzed. The results are shown in Table 2. TABLE 2. Summary of the standard deviation and coefficient of variation of the weights of pressed residue and expressed juice and fiber content Pressed Expressed Fiber content I 11 residue juice of cane I I CONCLUSIONS The method for direct cane fiber determination making use of the HAFICO hydraulic press is fast, simple and accurate. The washing of the pressed residue in the container of the press take about 15 to 20 minutes. The results indicate that the method is highly reproducible. In comparison with other hydraulic presses for direct cane analysis, the HAFICO press shows advantages. The container is not perforated so thar the washing of the pressed residue can be done in the container. The shredded cane is

6 23% PROCESSING not pressedfrom the top to the bottom but from the bottom upwards. This results in an easy draining of the squeezed out juice and also an easy releasing of the press cake. Furthermore, the operation of the HAFICO press is very simple. Cleaning can be done conveniently as the press can be easily dismantled and afterwards reassembled. Weighipg only 16 kg, it can be transported easily so that the press can also be usd, e.g., for field tests. REFERENCES 1. Brosur. HAFICO TlNKTURENPRESSENt H. Fischer & Co., K.G Norfuber Neusz, lndustriestrasze 26/30 Postfach Germany. 2. Gandana, S.G,. (197'8). Cane analysis by the wet disintegratdr compared with the hydraulic press for the determination of the rendement factor. Mahalah Perusahaan Gula XIV (2) Hugot, E. (1974). Direct analysis and evaluation of sugarcane. Proc. ISSCT 1 5th Congress: lchlmsa Report of the Praceedings of the 17th session, 1978: Mubyarto (1977). The Sugar Industry: from estate to smallholder cane production. Bulletin of Indonesian Economic Studies X111,(2), Australian National University, Canberra. 6. Saint Antoine, J.D. de R. de (1968). Asimplified method for calculating pol of cane harvested from experimental plots. Mauritius Sugar Industry Research Institute, Annual fieport 1968, Saranin, A.P. (1975). Sugar cane payment systems. Sugar Technol. Rev Panimoto, T. (1964). The press method of cane analysis. The Hawaiian Planters' Record 57, DmEMINACION DIWCI'A DEL CONTENIDO DE FIBRA EN LA CARA BOR EL hletodo DE LA PRENSA S.G. Gandana RESUMEN Ka sido desarrollado un metodo para la deierminacion directa

7 i del contesido de fibra en la cab utilizando una prensa hidraulica HAFICO. El lavado del residuo prensado se hace directamente en el' recipiente de la prensa. Los resultados se comparan con 10s obiellidos a1 calcular la fibra por el metodo hawaiiano. Se ha encontrado una relacion may signifkativa entre el contenido de fibra por peso y por calculo. El metodo es sencillo, rapido y preciso. La prensa hidraulica