Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) Determine the physico-chemical properties from sugarcane varieties subjected to new harvesting practices. Examine the use of innovative compounds, including polyaluminium compounds, to improve clarification of sugarcane and sugarbeet juices. Approach (from AD-416) Participate in sugarcane variety trash trials to characterize the physico- chemical quality and processing ability of different components of green sugarcane trash. Undertake industrial studies to find improvements in clarification processing problems. Significant Activities that Support Special Target Populations Progress concluded with the 2008 Annual Report, but was not terminated because of financial management reasons. See 2008 Annual Report for last reported progress.
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Progress 08/01/03 to 07/31/08
Outputs
Progress Report Objectives (from AD-416) Determine the physico-chemical properties from sugarcane varieties subjected to new harvesting practices. Examine the use of innovative compounds, including polyaluminium compounds, to improve clarification of sugarcane and sugarbeet juices. Approach (from AD-416) Participate in sugarcane variety trash trials to characterize the physico- chemical quality and processing ability of different components of green sugarcane trash. Undertake industrial studies to find improvements in clarification processing problems. Significant Activities that Support Special Target Populations Laboratory Studies on Polyaluminum Coagulants (PAC) in Sugarbeet and Sugarcane Processing Products. We have conducted numerous laboratory studies using these PACs in the clarification and/or decolorization of sugarbeet diffusion juice, beet thick juice, beet molasses, beet extract, cane mixed juice, cane molasses, and raw sugar. Samples following PAC addition were tested for removal of turbidity, color, total polysaccharides; aluminum carryover, and destruction of sucrose and invert and compared to control treatments. Effective removal of color, polysaccharides, and turbidity was demonstrated when compared to control samples with no PAC added. In addition to laboratory testing, three factory experiments were conducted to evaluate improvement to clarification through the addition of PACs. Hundreds of samples were taken at several collection points at each factory and these samples are currently being analyzed. Preliminary analysis shows increased reduction in color and turbidity as compared to conventional clarification procedures. Interaction of PAC with commercially used flocculants. As observed in factory tests, PAC and commercially used flocculants (chemical that causes flocs) can form insoluble polymers immediately upon contact. This was determined to be a chemical that causes flocs reaction between the positive charged PAC and the negative charged flocculants that are routinely used. Because of this reaction, separation of the materials is required. Point of addition of PAC in commercial applications. The point of addition in commercial applications was determined to be critical to the success of PAC in enhancing clarification. The PAC must have adequate exposure to the juice to improve the clarification scheme, but yet requires addition at some point away from the flocculants in order to avoid direct contact of the two materials. In one factory test the PAC was added downstream from the flocculant addition point, while in a second test it was added upstream. Samples are currently being analyzed to determine the effect of point of addition of PAC in the traditional clarification scheme used in sugar processing. The progress is monitored via periodic emails and phone conversations.
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Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) Determine the physico-chemical properties from sugarcane varieties subjected to new harvesting practices. Examine the use of innovative compounds, including polyaluminium compounds, to improve clarification of sugarcane and sugarbeet juices. Approach (from AD-416) Determine the influence of macromolecules on the color and turbidity of sugar, their nature and occurrence in processing and their transfer into the sugar crystal, as these constituents strongly impact the processing and quality of sugar. Examine the use of new enzymes to lower color and polysaccharide macromolecules in cane juice and beet juice and to prevent the transfer of macromolecules into the crystal, which causes a lowering of final product quality and loss of product. Examine the relationships of calcium, magnesium, and soda ash in processing to minimize use of lime, to minimize evaporator scaling and to improve heat transfer coefficients on evaporation. Examine the use of innovative compounds, including polyaluminum compounds, to mitigate the formation of evaporator scaling by macromolecules and inorganic components in cane and beet juice. Examine the use of bagasse fly ash, currently a waste product, as a new absorbent of pollutants in water, including heavy metals, pesticides, and textile dye waste. Significant Activities that Support Special Target Populations This report serves to document research conducted under Specific Cooperative Agreement between the Agricultural Research Service (ARS) and Sugar Processing Research Institute (SPRI). Additional details of research can be found in the report of the in-house project 6435-41000- 095-00D, "Characterization and Improvement of Sugar Industry Process Units Impacted by New Production Practices." Control of color, turbidity and polysaccharides are important in sugarbeet and sugarcane processing. Twenty-eight commercial enzymes with targeted functionalities were examined for their ability to reduce color, turbidity and/or polysaccharides in raw beet and raw cane juice. Juices were treated with each enzyme for 30 min at 50�C and monitored for reduction of color, turbidity and total polysaccharide content. Enzymes with specific activity were noted for beet juice and cane juice. There has been some interest in polyaluminum compounds (PACs) currently used in water treatment as processing aids in sugar products. Several PACs were tested with some composed of only aluminum compounds while others were composed of a blend of cationic aluminum polymers with a nitrogen-containing compound (aminc). Effective removal of color, polysaccharides, and turbidity was demonstrated when compared to control samples with no PAC added. Solutions of raw and refined sugar were sequentially filtered on millipore membranes with varying pore sizes. The material that coated the membrane surfaces was examined by electron microscopy. The microscopy images showed that membranes with the smaller pore sizes tested were completely coated with an amorphous, gel-like material. Filtration studies showed that most refined cane sugar solutions will clog with specific membrane pore sizes before a sugar solution can be completely filtered. Enzyme studies showed that treatment of raw sugar solutions could improve filtration. Five sugarcane varieties of varying genetic backgrounds were analyzed for total polysaccharide content. Total polysaccharide analysis included starch, dextran, indigenous sugarcane polysaccharide (ISP), and any other soluble polysaccharide in solution. Four regions of the sugarcane stalk were examined for each variety. The four regions were defined as the growing point, stalk, green leaves, and brown leaves. Four replicates of each region were studied giving a total of eighty samples included in the study. This subordinate project was monitored by periodic conversations between ARS and SPRI.
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 4d Progress report. This report serves to document research conducted under Specific Cooperative Agreement between ARS and Sugar Processing Research Institute. Additional details of research can be found in the report for the inhouse project 6435-41000-095-00D, Characterization and Improvement of Sugar Industry Process Units Impacted by New Production Practices. (1) Examination of aluminum compounds for clarification and decolorization of cane juice. Last year we reported on laboratory studies using several commercial polyaluminum coagulants (PAC) used in water purification to clarify cane juice. During this period, studies on improving clarification of cane juice were continued, with further laboratory tests confirming the efficacy of PAC. A mill study using PAC was conducted during the 2005 harvest season. Studies done this year showed that adding PAC alone, without addition of lime, resulted in improved removal of color, turbidity (sediment and
cloudiness in the juice) and polysaccharides (high molecular weight compounds made up of chains of sugar molecules). The removal of these components, however, was not as effective as when they are used in conjunction with lime. Lime is necessary to raise the pH of cane juice, which is naturally acidic, in order to stabilize it (prevent deterioration of sucrose), and to precipitate impurities. These studies indicate that the amount of lime used could be reduced if PAC were used during purification of cane juice. A reduction in the amount of lime used would be of benefit to the environment and could reduce the cost of processing. The comparison of using lime alone for clarification, lime plus PAC, and PAC only, is shown below for one of the commercial PAC products: Laboratory Results: % removal of:_______Lime only___Lime plus PAC___PAC only Color_______________34.2%_______73.0%___________52.3% Turbidity___________96.9%_______99.6%___________97.5%
Polysaccharides_____35.3%_______54.4%___________52.7% Mill studies were conducted at a Louisiana mill in November and December, 2005. In summary, the following was noted: 3% improvement in turbidity removal; 3-10% decrease of ash content in clarified juice compared to an increase of up to 18% ash in regularly clarified juice; approximately double the color removal from 16% to 35%; pH increased by 1.25 units compared to 0.79 units; no change in polysaccharides; no carry-over of aluminum into the clarified juice was noted. These studies show that PAC may help in color and pH control in cane factories. Mill personnel anecdotally reported that mill performance appeared improved. Further studies are needed to determine the optimal addition point of PAC in the mill. (2) Filter plugging material in raw sugar. Study on the material in raw and white sugars that plugs filters was continued. The filter-clogging material was isolated from raw sugar and from white sugar, hydrolyzed, and
the sugar composition determined by gas chromatography. This material is colloidal in nature that is, made up of small, semi-soluble particles that do not settle out of solution. The composition of filter- clogging material in raw sugar and refined sugar was partially characterized by using acid to decompose it into its component sugars. The composition was similar for both raw and white sugar. Component sugars included mannose at 6-9 percent, and glucose 88-91 percent. Minor sugars, rhamnose, arabinose and xylose, were present in the 1 percent range. This composition is different from the indigenous sugarcane polysaccharide (ISP) previously identified in cane juice and raw sugar because of the absence of the sugar galactose and the high proportion of mannose. Also, ISP is soluble, whereas this material is not. Use of the enzymes cellulase and hemicellulase prior to filtration of sugar solutions improved the filtration rate. This indicates that the filter- clogging material
could be a form of highly pulped or degraded bagasse cellulose, which could be caused by the conditions of high heat and high pH that occur during clarification of cane juice. (3) Turbidity in white sugar collaborative study. Turbidity in white sugar is a quality issue that impacts sugar users, such as manufacturers of clear beverages and carbonated beverages. A validated method for determining turbidity in white sugar solutions is needed. The method must be quick, easy and use low cost equipment that is routinely available in quality control laboratories. In order to validate a method for official use, it should be tested by a collaborative study, in which at least eight laboratories participate. A turbidity method was chosen that is based on the official color method of the International Commission for Uniform Methods of Analysis (ICUMSA), already routinely used around the world. The conduct of the test was delayed several months due to the closure of the Southern Regional
Research Center during which time samples deteriorated. The test has now been conducted, and results are coming in. Statistical analyses will be done on the results, to determine if this test meets the criteria for an official method of analysis under the auspices of ICUMSA. (4) Anthocyanins in cane juice, a potential new product. Anthocyanins are red pigments found in many flowers. Proanthocyanins are colorless plant compounds, that when treated with acid are converted to red anthocyanins. Both of these plant compounds have been shown to have strong antioxidant properties, which are considered beneficial in the diet. Cane juice from different cane varieties showed up to a six-fold difference in the content of proanthocyanin. In order to determine the content of colorless proanthocyanins in cane juice, they are first converted to red anthocyanins with heat and acid and determined spectrophotometrically. A method was devised to extract anthocyanin from cane juice. The
antioxidant strength of the juice from nine cane varieties, collected in October 2005 and November 2005, was examined using the Randox Test Kit for Total Antioxidant StatusRG. The results showed total antioxidant concentration of 1-2 mmol/l. The anthocyanins increased about 20% from October to November, but the antioxidant level did not change over the two months.
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Progress 10/01/04 to 09/30/05
Outputs
4d Progress report. This report serves to document research conducted under Specific Cooperative Agreement between ARS and Sugar Processing Research Institute. The title of the agreement is "Processing of Sugarcane and Sugarbeet: Product Quality, Process Innovation and New Product Development." Additional details of research can be found in the report for the parent project 6435-41000-095-00D, Characterization and Improvement of Sugar Industry Process Units Impacted by New Production Practices. (1) Examination of aluminum compounds for clarification and decolorization of cane juice. The first, and perhaps most important, step in making raw cane sugar is clarification of the cane juice. This traditionally involves the use of lime to adjust the pH of the juice and to cause precipitation of impurities. Last year we reported on the use of magnesium compounds in combination with lime to improve the process. In the current study, the objective was to evaluate
polyaluminum compounds, known as coagulants, for improved removal of turbidity (haze), color and polysaccharides (very high molecular weight molecules composed of long chains of sugar units) from cane juice during clarification. The aluminum compounds were to be used in conjunction with normal lime clarification. Polyaluminum compounds are routinely used for water purification. Removal of haze is important to achieve a clear solution; removal of color is important to achieve a sugar with low color; and removal of polysaccharides is important because they cause gummy syrups, impede filtration and slow down the crystallization of sugar. Results showed that the five commercial polyaluminum compounds investigated significantly improved the removal of color, turbidity and polysaccharide compared to the regular clarification process. The traditional clarification process using heat, lime and flocculent (a compound that helps solid particles to aggregate and settle), removed an average
of 34% color, 97% turbidity and 35% polysaccharides. Supplementation of clarification with aluminum coagulants resulted in 51. 2-75.5% color removal, 97.5-98.8% turbidity removal and 43.5-56.4% removal of polysaccharides. These results indicate that addition of polyaluminum coagulants in clarification has the potential for a doubling of color removal, 61% increase in polysaccharide removal and 2% improvement in turbidity removal. The reason for this enhanced performance is that when flocculents are combined with aluminum coagulants, the suspended material is aggregated into larger and heavier particles that settle better. A test for aluminum in the treated cane juice samples showed low levels of residual aluminum, to a concentration that was less than the natural aluminum concentration in the untreated cane juice. (2) Enzyme studies. A study was undertaken to determine the effect of various enzymes on the polysaccharides and colorants in cane and beet juice. Several enzymes were
found to reduce color and polysaccharide in cane juice by more than 10 percent. These included enzymes that attack specific polysaccharides and included cellulase (breaks down cellulose), xylanase (breaks down xylan, a component of sugarcane stems), hemicellulase (breaks down hemicellulose, polysaccharides found in cell walls) and ferulic acid esterase (removes ferulic acid from polysaccharide matrices). These results help to confirm the hypothesis that much of the plant-derived pigment in cane juice is a colorant- polysaccharide complex. The fact that a phenolic acid, such as ferulic acid, which is prominent in the cane plant, was also attacked, indicates that sugarcane colorant has a phenolic nature. The hydroxyl groups on the ferulic acid may be acting as the linking agent between colorant and polysaccharide molecules. Enzymes that reduced beet juice color by more than 10 percent were catalase, beta-glucanase, hemicellulase and xylanase. Cellulase, xylanase and pectinase
removed more than 10 percent polysaccharides. These ongoing studies are helping to determine the nature of the colorant in cane and beet, and their interactions with polysaccharides. (3) Filter plugging material in raw sugar. The discovery of colloidal material in raw sugar that plugs filters was reported in 2004. Further studies have shown that this material can also carry through the process to the refined sugar and cause filtration impedance in white sugar. Microscopy showed that this gel-like material can coat and "blind" resin beads used in refining raw sugar. Enzymatic studies showed that filtration was improved in slow-filtering raw sugars after treatment with several enzymes, including amylase (removes starch), dextranase (removes dextran), cellulase (breaks down cellulose), xylanase (breaks down xylan) and hemicellulase (breaks down hemicellulose). It is already known that dextran and starch will impede filtration, and the results with amylase and dextranase confirmed
that these will slow filtration in raw sugar and can be removed by enzymes, improving filtration performance. These results also indicate that the portion of the filter-plugging material that is not composed of starch and dextran is likely to be hemicellulose and degraded cellulose that arises from small bagasse particles (known as bagacillo) that are entrained in the cane juice and undergo degradation during clarification. Bagasse, the stalk material of sugarcane that remains after the cane is pressed out, is composed of celluose, xylan and hemicellulose. During sugarcane processing, the bagasse is finely chopped up and undergoes mechanical and heat damage and pH changes, which cause some of the bagasse to degrade into its components parts. (3) Dextran collaborative study. Dextran is a microbial polysaccharide that causes many problems in sugar processing, including, among others, sugar loss, high viscosity and poor sugar recovery. Dextran in refined sugar causes elongation of
the sugar crystal and distortion of hard candies. The levels of dextran in refined sugar are very low, and there are no validated analytical methods to determine dextran in refined sugar. We organized and carried out a collaborative study on two methods for dextran determination in white sugar an antibody method and a haze method, for dextran concentrations ranging from 15-240 ppm. In the antibody method, a commercial antibody that is specific for dextran is used; when dextran is present, the antibody and the dextran interact to form a hazy solution. The amount of haze formed is proportional to the amount of dextran in the solution. In the haze method, a solution containing dextran is made up to 50% alcohol, at which point, the dextran begins to precipitate out, forming a hazy solution, which is proportional to the amount of dextran present. A statistical analysis of the results from ten laboratories testing blind duplicates showed acceptable repeatability and reproducibility
values for the antibody method. Too few laboratories conducted the haze test for a statistical analysis, but the results obtained showed comparable results to the antibody method as well as to the standard comparison method, the Roberts copper method, in which dextran is reacted with copper and measured. These results will be presented at the next meeting of the International Commission for the Uniform Methods of Sugar Analysis (ICUMSA) to obtain a recognized status for the antibody method.
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Progress 10/01/03 to 09/30/04
Outputs
4. What were the most significant accomplishments this past year? This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the Sugar Processing Research Institute. Additional details of research can be found in the report for the parent CRIS 6435-41000-074-00D, "Characterization and Improvement of Sugar Industry Process Units Impacted by New Production Practices." (1) The nature of sugar colorants. As part of continuing studies to understand the nature of cane and beet sugar colorants, and ways to control and/or eliminate them, studies were done to determine the effect of ozone, hydrogen peroxide and sulfur dioxide on the high molecular weight (HMW) components. HMW consist of color molecules and polysaccharides. Sulfur dioxide is routinely used in some tropical countries to produce a sugar called plantation white sugar and is also used to produce beet white sugar, but it is not used to make cane raw or refined
sugar. Sulfur dioxide action seems to prevent color from going into the crystal: Thus a very highly colored syrup, if previously treated with SO2, will crystallize a sugar having about 0.01% of the original color. By contrast, when SO2 is not used, the transfer of color from syrup to crystal is about 10%. The goal of this research is to try to find a way to obtain the beneficial effects of SO2 by other means. Earlier studies by many researchers indicates that much of the color that transfers into sugar crystals is of the HMW type. Our work showed that sulfite destroyed from 1-12% of cane polysaccharides; ozone and hydrogen peroxide did not affect the polysaccharide concentration. Gel permeation chromatography showed that ozone had little effect on HMW in cane and beet, and that hydrogen peroxide almost eliminated a major colorant peak in cane. Sulfite removed color and polysaccharide in laboratory clarification experiments on cane juice and also had significant but complicated
effects on the GPC colorant profiles of both cane and beet sugar, diminishing some peaks and shifting some peaks to a lower molecular weight range. (2) Rapid starch test. A high starch concentration in cane juice causes processing problems in the cane mill, and starch carried into raw sugar can also cause problems in the refinery. A simple test is needed, but there is no uniform method for the sugar industry to use. A simple, rapid starch test that uses only equipment already available in a cane sugar mill was developed previously by Sugar Processing Research Institute (Final Report, Specific Cooperative Agreement No. 58-6435-8-109, July 31, 2003). Further studies this year showed that the test is suitable for clarified juice, syrup and raw sugar. It was not suitable for raw juice because it underestimates the starch content in raw juice. A collaborative study was conducted to validate the method for raw sugar in which 14 U.S. companies participated, including cane mills in
Louisiana, Florida, and Texas, refineries and laboratories. The statistics from the study showed that the test met the parameters for acceptable precision (repeatability and reproducibility). In April, 2004, the method was given tentative method status by the International Commission for Uniform Methods of Analysis (ICUMSA). At least three sugar companies have adopted this method as part of their routine testing. (3) Discovery of a filter plugging material in raw sugar. In the course of determining the nature of the sediment in raw sugar, we noted that material caught on a 0.45 mm membrane had a gelatinous appearance when examined by scanning electron microscopy. If a raw sugar is pre- filtered on 20 mm, 8 mm, and 1.2 mm membranes, the larger sediment particles are screened out, and the gelatinous material can easily be seen. This material plugs filters and slows down processing. The material is visibly colored, tan to brown, on the surface of the membrane. It was found in
all the raw sugars examined (5 samples from Louisiana (2), Brazil, Philippines, and Guatemala). This material is thought to be a complex of polysaccharide and colorant, possibly hemicellulose and possibly some degraded cellulose. Studies are ongoing to determine the composition of the material, with a view to finding control measures. (4) Clarification experiments. The first, and perhaps most important, step in making raw cane sugar is clarification of the raw cane juice. This traditionally involves the use of lime to adjust the pH of the juice and to cause precipitation of impurities. Magnesium compounds may have some advantages over lime, such as a more rapid settling rate, a smaller volume of settling, less evaporator scale formation and improved evaporator performance and crystallization, but are more expensive. Bench scale experiments were conducted with raw juice using, alone or in various combinations, lime, magnesium compounds (magnesium oxide, dolomitic limestone - a
mixture of calcium and magnesium hydroxides, and dolomitic quicklime - a mixture of calcium and magnesium oxides) and soda ash (sodium carbonate). The effect on settling rate, pH, color, turbidity, sucrose, glucose, fructose, polysaccharides, calcium, magnesium, oxalic acid, citric acid, and aconitic acid was determined. The results showed that there is an optimum mixture of lime, magnesium and soda ash for clarifying cane juice. (5) Studies on bagasse fly ash. Bagasse fly ash is the residue remaining after bagasse has been burned to produce electricity in the cane mill, and is considered a waste product that is difficult to dispose of. Fly ash samples from two harvest seasons were studied for their ability to absorb heavy metals, quaternary amines (benzalkonium chloride), and textile dye waste. Microscopy showed that the fly ash is a heterogeneous material, with particles ranging from a few micrometers to about 1 mm, with numerous pores in the particles. Compositional analyses
showed that fly ash consists of about 75% silica, 10% aluminum oxide, 2- 4% carbon, plus various amounts of calcium, magnesium, and iron oxides. The fly ash showed a very high affinity for mercury, lead, benzalkonium chloride, and textile dye wastes. It had less ability to absorb chromium, cadmium, and arsenic. Bagasse fly ash may have some promise in environmental remediation.
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