Processing ACTION OF SOME BACTERICIDES ON RAW SUGARCANE JUICE. Horacio G. Ayala, Dardo Bravo Limpias, Alejandro Delfini and Carlos A.

Transcription

1 Processing ACTION OF SOME BACTERICIDES ON RAW SUGARCANE JUICE Horacio G. Ayala, Dardo Bravo Limpias, Alejandro Delfini and Carlos A. Gargiulo TucumLn Agricultural Experiment Station, Tucumin, Argentine ABSTRACT An investigation has Been carried out lo determine the efficiency of some bactericides in raw sugarcane juice. The results indicate that chlorinated bactericides were the best, at doses of about 1000 PPm. INTRODUCTION AND RECORDS I I I Sugarcane juice is a favorable medium for the development of microorganisms. Once it has been extracted Prom its natural medium, the stalk, it is easily attacked by them. In infected sugarcane, microorganisms abound and other degradation processes take place, alfecting sucrose recovery. A large amount of work has been done in the microbiological field of raw and clarified sugar juice, to estimate more accurately the losses caused by microbiolocal factors in sugarcane milling, but the control of these losses has been as extremely complicated task up the present. The control of microorganisms in the sugar-mill crusher has always been a problem. It has been attempted by cleaning with cold water, hot water, by hand or by chemicals. Many operators think that chemicals are not necessary, perhaps on account of the difficulty in evaluating such products. Sugarcane is harvested in various ways: by' hand, mechanically, after burning it, by cutting it into pieces. It is harvested under different weather conditions, in cold, mild and warm periods, and from different kinds of soil. All these factors have great influence on microbial activity and, of course, on the quality of the raw material. The organism Leuconostoc mesenteroides plays an important role and is responsible for sugar losses due to the formation of gummy material, apart from causing other troubles in the normal factory operation, such as increased viscosity and resultant difficulties in the clarification, evaporation, decoction and crystalization. /I Sugar losses are caused by sucrose destruction an6$gum formation, especially dextrane, which might influence the polarj$hetric reading and, 2909

2 2910 PROCESSING thereby the factory balance, since the specific dextrane rotation is [a]% = + 195O a If this is compared with that of sucrose which has [a]g = + 66,53O, we can see that, if the juices to be analized contain dextrane, they will cause greater polarization than they should. It must not be forgotten that levane may also be present, due to the action of Bacillus subtilis. Its specific rotation is negative, the value being [a]%' = -40, and its levorotatory effect would equal the dextrorotatory effect of dextrane if the amount of levane were five times as high as the amount of dextrane. This is unlikely since the prevalence of dextrane is taken for granted. MATERIALS AND METHODS Cane juices fre6hly extracted in a laboratory crusher, were placed in erlenmeyers of 2,5 liters capacity, previously sterilized. Seven identical samples were pre$ared, to 6 of which predetermined bactericide doses were added, leaving one without treatment as a test. The treatments were as follows: 1) Test; 2) Chlorinated organic product; 3) Formaldehyde; 4) Disodic cyanodithioimidocarbonate product + N-Methyl potassium dithiocarbamate + Ethylendiamine; while treatments 5), 6) and 7) were compound products of quaternary ammonium. The samples, after being homogenized, were divided into five groups, with as many controls. The first analysis was made inmediately after homogenization of the samples, while the rest were made at regular intervals of from 2 to 3 hours. The incubation temperature was 30 C. ANALYSES The factors analysed were as follows: Brix, Pol, Purity, by the conventional methods, reducing sugar by using the Lane and Eynon method, ph by potentiometry and acidity by titration with NaOH 0,l N up to ph 8,3 in 50 ml. of sample. RESULTS With the result of each assay an analysis ol: variance was made and the purity records, ph, acidity, and glucose coefficient, which were the parameters taken to test the effectiveness of the products, were graphed. In order to analyse statistically the differences among the averages of the treatments, the Tukey test was used. From.the statistical and graphic point of view, the results were as follows.

3 H.G. AYALA ET ALII 2911 PURITY Assay No 1 : In general there was no decrease in purity. The variance analysis does not indicate any difference among the treatments. Graphicaly it is observed that the purity remained the same for the first four hours; while the test, at the eight hour, was below the treatments. Assay No 2: Graphically, until the fifth hour, a behavior similar to that of assay No 1 is observed, and statistically there are no significant differences among the treatments. Assay No 3: There are no major differences among the treatments either statistically or graphically. A considerable decrease in purity occurred, starting from the 3 hour, but this occurred in the same way in every treatment. There are very significant differences among the hours 0, 3 versus 5, 7 and 8, as shown below: Hours: DMS.05 = 0,96 Averages: 88,27 87,59 82,66 83,77 84,24 DMS.O1 = 1,19 Assay No 4: There were significant differences between the treatment with formaldehyde (3), which was the one with the highest purity, and the test. Treatments: DMS.05 = 0,708 Averages: 91,32 91,65 92,09 91,89 91,65 91,85 91,94 DMS.O1 = 0,864 FIGURE 1. ASSAY N." 1 Date : 12/11/75 85 ' Rates of Bactericides: Treatment 1 : Control Treatment 2 : 500 ppm Others : 80 ppm 4 6 h' Hours

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5 H.G. AYALA ET,ALII FIGURE 4. ASSAY No 4 Date / Rates of Bactenades. Treatment l Control Treatment Ppm Others 40 P P ~ 89 ' Hours ACIDITY Assay No 1: Despite the apparknt graphic effects, statistically there were no differences among the treatments, but the Tukey test showed that the eight hour, which had the highest average of acidity, was quite significantly different from; the rest. It can be observed that the average acidity increases as time goes by. Hours: DMS.05 = 1,803 Averages: 6,87 7,14 7,42 7,82 9,67 DMS.O1 = 2,248 Assay No 2: Treatment 2, with the chlorinated product, had a lower acidity average than the rest, the difference being significant with treatment 7 (quaternary ammonium). Every treatment behaves in a similar way except No. 2. The ninth hour shows a highly significant difference from the rest. Treatments: DMS.05 = 4,835 Averages: 9,98 5,62 7,35 8,07 10,O 9,92 10,25 DMS -01 = 5,90 Hours: DMS.05 = 3,75 Averages: 5,71 6, ,34 15,67 DMS.01 = 4,65

6 Assay No 3: Treatment No 2 with chlorinated product is in general the one with the lowest acidity, followed by treatment 3 (formaldehyde), 5 (quaternary ammonium) and 1 (test) ; treatment 6 (quaternary ammonium) is the one which shows the highest acidity. The acidity increases with time. Treatments: DMS.05 = 5,32 Averages: 10,36 7,72 9,70 10,96 9,66 15,84 10,76 DMS.01 = 6,50 Ilours : DMS.05 = 5,07 Averages: 6,09 7,46 8,83 12,46 17,88 DMS.O1 = 6,29 Assay No 4: There are no major differences am;ong the treatment, except No 2 which, being the one with the lowest acidity, shows marked.differences from the others. The first and second hours are significantly different' from the others. Treatments: DMS.05 = 0,455 Averages: 14,42 12,98 14,38 14,323 14,75 14,37 14,50 DMS.O1 = 0,555 Hours : DMS.05 = 0,353 Averages: 13,84 13,93 14,40 14,56 14,54 DMS.O1 = 0,438 FIGURE 5. ACIDITY ml ASSAY N.O 1 Date : 12/11/75 Rates of Bactericides: Treatment 1 : Control Treatment 2 : 500 ppm Others : 80 ppm 7 8 Hours

7 j H.G. AYALA ET ALII 1 ACIDITY ml Rates 5 FIGURE 6. of Bactericides: Treatment 1 : Control Treatment ppm Others : 40 ppm ASSAY N.O 2 Date : 13/11/ Hours - FIGURE 7. ACIDITY ASSAY N.O 3 Date : 14/11/75 6 I Rates of Bactericides: Treatment 1 : Control Treatment 2 : 250 ppm Others : 20 ppm -..'1?.: 2 3 "? Hours \ I'. -

8 PROCESSING FIGURE 8. t ACIDITY ASSAY N.O 4 Date : / 75 Rates of Bacter~c~des Treatmeht 1 Control Treatment 2 l 000 Ppm 5 Others 40 P P ~ Hours ph Assay No 1: Treatment 2 (chlorinated) is the one with the highest ph and presents a most significant difference from treatment 5, 7 (quaternary ammonium) and 1 (test) and a significant difference from treatment 6 (quaternary ammonium). On the average, the eight hour sampling gave a lower ph value than the others and the mean comparison test shows a great difference from the hours 0, 2 and 4 and a significant difference from the 6 hour sampling. Treatments: DMS,05 =-r 0,245 Averages: 4,79 5,16 4,96 4,96 4,79 4,89 4,86 DMS.01 = 0,299 Hours : DMS.05 = 0,190 Averages: 5,04 5,02 4,97 4,88 4,69 DMS.O1 = 0,236

9 ~,H.G. AYALA ET ALII 2917 Assay No 2: Again treatment 2 (chlorinated) has the highest ph, showing a quite significant difference from treatments 5, 6 and 7 (cpa;ernary ammonium) and the test, while there is a difference from treatments 3 and 4; samples tested at the sevedth and ninth hours Show a much lower ph than those at the 0, 3 and 5 hours. Treatments: DMS.O5 = 0,405 Averages: 4,64 5,31 4,87 4,83 4,63 4,64 4,62DMS.O1 =0,494 Hours : DMS.05 = 0,314 Averages: 5,15 5,11 5, ,11 DMS.O1 = 0,389 Assay No 3: Treatment 2 maintains a significant difference from 6, 7 and 4 and an outstanding difference irom 1 and 3. Treatment 6 has the lowest ph. Statistically the difference from the average and also from treatments 5 and 3, is remarkable. The seventh and eighth hours have the lowes ph. Treatments: DMS.05 = 0,354 Averages: 4,67 5,07 4,71 4,62 4,75 4,33 4,61 DMS.O1 = 0,432 Hours: DMS.05 = 0,275 Averages: 5,10 5,00 4,79 4,44 4,08 DMS.O1 = 0,341 ' Assay No 4 Treatment 2 has a much higher ph than the rest. Statistically the differences among the means is significant when compared with the other treatments. As in the previous 1 assays, the last hour gives the lowest ph.! Treatments: DMS.05 = 0,046 I Averages: 5,15 5,46 5,18 5,16 5,15 5,20 5,16DMS.01=0,056 Hours: Averages: 5,26 5,25 5,21 5,18 1, 5116 I ' DMS.05 = 0,035 DMS.O1 = 0,045 ti

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11 I1J F1.G. AYALA ET ALII ph 4 FIGURE 11. ASSAY N.O 3 Date : 14/11/75 Rates of Bactericides: Treatment 1 : Control Treatment 2 : 250 ppm Others : 20 Ppm 7 8 Hours ASSAY N.O 4 Date : Rates of Bacteric~des: Treatment 1 : Control... Treatment 2 : ppm Others : 40 ppm Hours

12 PROCESSING GLUCOSE COEFFICIENT Assay No 1: The variance analysis shows no significant differences among the treatments, but the last hour is notably different from the others. Assay No 2: The average difference between treatments 5 and 2 is to be noted. Treatment 2 has the lowest glucose coeficient, whereas treatment 5 has the highest. A glucose coeficient increase is noted between the seventh and ninth hours. Treatments: DMS.05 = 0,83 Averages: 3,06 2,33 2,65 2,79 3,26 2,94 2,92 DMS.O1 = 1,013 Hours: DMS.05 = 0,645 Averages: 2,06 2,25 2,49 3,37 4,07. DMS.O1 = 0,799 Assay No 3: Treatment 2 has the lowest glucose coeficient. The difference is most remarkable from treatment 6, and only significant from treatments 1 and 7. The glucose coeficient increases from hour to hour. Again the differences are significant. Treatments: DMS.05 = 0,580 Averages: 5,33 4,77 5,30 5,30 5,06 5,49 5,43 DMS.01 ~0,707 Hours: DMS.05 = 0,450 Averages: 3,64 4,24 5,45 6,18 6,68 DMS.O1 = 0,558 f Assay No 4: Treatment 5 and 7 (quaternary ammonium) have the highest glucose coeficient. The means comparison test at 1% gives marked differences from the others treatments. Treatment 6 (quaternary ammonium) follows 5 and 7 with marked contrast at 5 % with treatment 2 (chlorinated), which has the lowest glucose coeficient. Treatments: DMS.05 = 0,222 Averages: 1,40 1,36 1,39 1,49 2,05 1,57 1,82 DMS.O1 ~0,270 Hours: DMS.05 = 0,172 Averages: 1,31 1,34 1,57 1,79 1,91 DMS.O1 -- 0,213

13 H.G. AYALA ET ALII 2921 CONCLUSION Purity: There are -no differences among the treatments in any of the different assays, except with the 1000 pprn doses for treatment 2 (chlorinated), which is the only one that shows differences from the test. Purity is thus not a good parameter to judge the action of bactericides. Acidity: Treatment 2 has the lowest acidity values and the products with quaternary ammonium tend to raise the acidity values. There are no differences among the other treatments. ph: Treatment 2 (chlorinated) maintains a higher ph in all the replications. In general it differs sharply, at 1% probability from the test and from treatments 5, 6 and 7 (quaternary ammonium), and significantly at 5% from the others. The difference between treatincnt 2 and the others is emphasized in tests with the 1000 pprn doses, corresponding to assay No 4. Glucose Coeficient: Treatment 2 keeps the lowest glucose coeficient values except for the test (1) (with a 500 pprn dose for assay No 2, and an 80 pprn dose for the others). Treatments 5, 6 and 7 (quaternary ammonium) and 1 (Test) have the highest glucose coeficient. Treatments 3 and 4 are intermediate. Glucose % Brix: The previous statements are repeated for the glucose coeficient as can be seen in the corresponding graph. THE BEST DOSAGE To assess the best dosage from each assay and for each product studied, the average on the test sample was obtained in the original set of data. Then, in each assay, the corresponding average per parameter was obtained. Afterwards variance analysis was made on the seven treatments including the test and with four repetitions corresponding to the four assays, with the following results : 1st. Assay 4 with the 1000 pprn dose for treatment 2, and the 40 pprn doses for the rest. 2nd. Assay 2 with 500 pprn for treatment 2, and 40 pprn for the others. 3rd. Assay 1 with 500 pprn for assay 2, and 80 pprn for the rest. 4th. Assay 3 with 250 pprn for treatment 2, and 20 pprn for the rest. 'i 3., i

14 2922 PROCESSING To determine the best bactericides, the variance analysis in the seven treatments was made, using the different hours as repetitions, which gives seven treatments with five repetitions with the following results: 1st. 2nd. Bactericide 2 (chlorinated). Bactericide 3 (formaldehyde). 3rd. Bactericide 4 (Disodic cyanodithioimidocarbonate + N-Methylpotassium, dithiocarbamate + Ethylendiamine). REFERENCES 1. Appling, J.W. (1958). Nuevo bactericida inactiva invertasa. Sugar y Az6car. 53(6) : Bevan, D. and Bond, J. (1971). Microorganisms in field and mill. A preliminary survey, 38 Conf. Q.S.S.C.T. : De Almeida Lima, U. et al. (1974). Ocorrencias de microorganismo en caldo bruto, caldo misto e aaua de embebicfio em uma usina de acucar de cana. Brasil Acuaareiro 83(4):2i Hinocavle Silva. M. (1974). Control de la inversibn en el. iuao - del molido. Sugar - y ~ziiiar 69(8): Honing, F. (1969). Principios de Tecnologia Azucarera. CompaHia Editorial Continental. Tomo 3: D Imrie, F.K.E. and-~ilbur~, R.H. (1972). Polysaccharides in sugarcane and its products. Sugar Technology Reviews. 1(4): Obregon Luna, J. (1971). Sobre 10s indices para detectar infecciones'en 10s molinos. Boletin Azucarero Mexicano. Agosto: ACCION DE ALGUNOS BACTERICIDAS EN EL JUG0 CRUD0 DE LA CARA DE AZUCAR H.G. Ayala, D.B. Limpias, A. Delfini y C.A. Gargiulo RESUMEN Se ha efectuado un trabajo Zendiente a determinar la eficacia de diferentes bactericidas en el jug0 crudo de la catia de azljcar. Los resultados obtenidos sefialan que 10s bactericidas clorados fueron 10s de mejor comportamiento con dosis de alrededor de I