Sugarcane Juice Clarification Research Articles

Performance of ceramic micro- and ultrafiltration membranes treating limed and partially clarified sugar cane juice

The performance of ceramic membranes with pore sizes of 0.02, 0.05 and 0.10 μm in clarifying limed and partially clarified raw sugar cane juice was investigated under different operating conditions. For the 0.10 μm membrane, the increase in transmembrane pressure (TMP) from 1 to 3 bar increased the initial flux by 15.5% and increased the average flux over a period of 4 h by 11.9%. The initial flux of the 0.10 μm membrane increased dramatically at a TMP of 1 bar when the membrane underwent a chemical cleaning with 1% NaOH and NaOCl equivalent to 3000 ppm free chlorine for 1 h and the average flux over a period of 4 h was also increased. Among the three membranes tested 0.05 μm membrane performed better than the other two membranes and yielded higher initial and average fluxes. Out of the four fouling models used to fit the experimental data, the cake filtration model predicted the initial fluxes of 0.02 and 0.05 μm membrane more accurately. On the other hand, the combination of external and progressive internal fouling model predicted the performance of 0.10 μm membrane better compared to the others. Intermittent air back flushing improved the performance of 0.10 μm but did not have any effect on the performance of the other two membranes. However, all the membranes produced high quality filtered juice.

Effect of Different Parameters on Clarification Efficiency of Mechanical Clarifier

Effects of parameters namely, height of agitator from lid (15, 16, 17 cm.), centrifugation speed (2500, 3000, 3500 RPM) and time of centrifugation (5, 10, 15 min.) on mechanical clarification of sugarcane juice were studied. Filtration was incorporated as a pretreatment which reduced the amount of impurities in the juice. Soluble solids, total solids, sediment obtained, optical density and percent transmittance were measured and used for determining the efficacy of mechanical clarification of sugarcane juice. Full factorial design was used for selecting the levels of parameters in the experiment. Full second order polynomial and best fit equations were developed to predict various responses and to study individual, square and interactive effects of parameters on the responses. The clarification efficiency ranged between 11.3-42.2% and Optical density varied between 1.52 and 0.92 for mechanical clarification of sugarcane juice. Minimum percent transmittance was 3 and maximum was 13. Minimum sediment per 20 ml. of juice due to centrifugal force was 0.989 g. and maximum was 2.358 g. for mechanical clarification. Centrifugation time had highly significant effect on clarification efficiency followed by centrifugation speed, and height of agitator in that order. However, centrifugation speed had significant effect on optical density and percent transmittance.

Via surface functionalization by photograft copolymerization to low-fouling polyethersulfone-based ultrafiltration membranes

Low-fouling ultrafiltration membranes have been prepared by simultaneous photograft copolymerization of poly(ethylene glycol) methacrylate (PEGMA) onto a polyethersulfone (PES) membrane with a nominal cut-off of 50 kg/mol. A comprehensive characterization was performed by flux measurement and sieving curve analysis, FTIR-ATR spectroscopy, contact angle and zeta potential measurement. The effects of UV irradiation and monomer concentration on membrane characteristics as well as membrane performance were also described. Model solutions of sugarcane juice polysaccharides and the protein BSA were used to examine the membrane performance. The results showed that UV irradiation time was the most important parameter with monomer concentration as another parameter to adjust the degree of functionalization. All modified membranes showed more resistance to fouling and higher rejection than unmodified membrane for both model solutions. A reduction of permeability due to pore constriction or even blocking by grafted polyPEGMA was also observed. Surface functionalization of PES UF membranes using relatively high monomer concentration (40 g/L) at medium irradiation times (1.5–3 min) was recommended as the best condition with respect to flux, rejection and fouling. This study provides valuable information for the development of low-fouling ultrafiltration membranes especially for sugarcane juice clarification.

EFFECT OF USING FROM CERAMIC MICRO-FILTRATION ON PURITY, TURBIDITY AND COLOR OF SUGARCANE JUICE

In this study conditions of refinement of clarified sugarcane juice including temperature at 3 levels (50, 60 and 70 °C) and pressure at 4 levels (0, 0.5, 1 and 1.5 bars) by micro-filtration membrane technology was investigated. The raw sugarcane juice primarily was pre-filtrated with lime and then the obtained juice (clarified juice) processed by ceramic micro-filter membrane (0.2 micrometer). Investigated characteristics were included purity, turbidity and color. The results shows that the effects of different conditions of process with micro-filtration in studied temperatures and pressures on reduction of turbidity and color were significant at probably < 1% and probably < 5% respectively. Finally, 70 °C temperature and 1.5 bar pressure were determinate as optimum conditions for ceramic micro-filtration. Membrane process at 70 °C and 1.5 bars reduced turbidity and color of clarified juice 56.25% and 6.49% respectively and increased 0.87 units of purity. Keywords: Micro-filtration, Raw sugarcane juice, Clarified juice, Purity, Turbidity, Color.

Elaboração de bebida composta por mistura de garapa parcialmente clarificada-estabilizada e sucos de frutas ácidas

O Brasil é grande produtor e consumidor de sucos de frutas, além de ser o maior produtor mundial de cana-de-açúcar. O caldo de cana, também conhecido popularmente como garapa, é uma bebida de grande aceitação pelo consumidor brasileiro, e nos vendedores ambulantes, normalmente é comercializada em misturas com sucos de frutas ácidas. O trabalho teve como objetivo avaliar físico-química e sensorialmente as misturas de garapa parcialmente clarificada-estabilizada com sucos de limão, abacaxi e maracujá, e posteriormente eleger a bebida preferida do ponto de vista sensorial. Foram realizados Testes Sensoriais de Aceitação e de Intenção de Compra. As outras determinações foram pH, ºBrix, acidez, relação ºBrix/Acidez, teor de ácido ascórbico, cor e turbidez. Os resultados das análises sensoriais indicaram que a mistura preferida foi aquela elaborada com garapa clarificada e 5% de suco de maracujá, seguida da mistura que continha 10% de suco de abacaxi. No entanto, pelo Teste de Intenção de Compra a maioria dos consumidores afirmaram que "possivelmente compraria" todas as misturas avaliadas. Todos os produtos apresentaram boa retenção nos níveis de vitamina C após o tratamento térmico. Microbiologicamente todas as bebidas apresentaram-se adequadas para consumo.

Pilot demonstration of sugarcane juice ultrafiltration in an Indian sugar factory

A field demonstration on ultrafiltration of sugarcane juice was conducted in a plantation white sugar factory in northern India. Clarified sugarcane juice at 91–97 °C was processed using polymeric spiral wound membrane modules in a pilot plant with a design capacity of 10 m 3/h. The investigations focused on the feed characteristics, plant performance in terms of the permeate flux and quality and limitations experienced during operation. The trials indicated that the membrane modules were tolerant to elevated temperatures and displayed satisfactory separation with an average purity rise of 0.9 units, 31% lower turbidity and 47% lower color in the permeate. The average flux was, however, low (7 l/m 2 h). The feed quality needs to be controlled, particularly with respect to suspended solids content and additional foulants introduced in the processing scheme. Further, the water available for membrane washing and cleaning was below recommended standards and must be improved.

Membrane distillation for the concentration of raw cane-sugar syrup and membrane clarified sugarcane juice

Membrane Distillation (MD) is a process being investigated the world over as a low cost energy saving alternative to conventional separation processes such as distillation and reverse osmosis. MD has a wide range of benefits such as a 100% (theoretical) rejection of ionic species, macromolecules, colloids, cells and other non-volatiles, lower operating pressures, reduced chemical interaction between membrane and process solutions, less demanding membrane mechanical properties and reduced vapour spaces. This process is ideally suited for the concentration of aqueous streams such as fruit juice and sugar solutions. Clarified cane sugar solution (20°Brix) obtained from the sugar mill, immediately after the Dorr filtration was subjected to membrane distillation, whereby the sensible heat from this stream was used to remove water as vapour through a hydrophobic polypropylene membrane. The influence of cross-flow rate and continuous water addition on flux was evaluated.

Comparison of sugarcane juice based beverage optimisation using response surface methodology with Fuzzy method

Response Surface Methodology (RSM) and Fuzzy techniques are applied for the development of sugarcane juice based lime beverage. Both the techniques were compared for the adequacy of optimization and applicability in beverage industry. The vegetative clarified sugarcane juice (SCJ) was used as sugar replacer in the preparation of beverage. The specific proportions of sugarcane juice were utilized for beverage preparation using central composite rotatable design (CCRD) for the development of the process for utilization of sugarcane juice in the preparation of lime RTS beverages. It was found that sugarcane juice could replace sugar up to a level of 100% for lime beverage using RSM. The results of fuzzy technique in agreement with the RSM based experimentation results. Therefore, this technique could also be used for the optimization and development of beverage formulation. If the domain knowledge exists in the form of knowledge base, then first approximation using fuzzy modeling is suited, with the further possibility of design cycle for the development of the product using RSM.

Folhas verdes, folhas secas, fibra do colmo e a clarificação do caldo de cana-de-açúcar

A presença de impurezas vegetais, como folhas verdes e secas, nos carregamentos de cana-de-açúcar entregues nas usinas de açúcar, tem preocupado os técnicos não somente por se tratar de um material sem qualquer valor tecnológico para processamento, como ainda por poder causar aumento na cor do caldo clarificado e conseqüentemente na cor do açúcar produzido, com redução de sua qualidade para o mercado; outro problema é o volume do lodo decantado nos clarificadores, cujo aumento causa maior recirculação e maior volume do caldo filtrado, com maiores perdas de sacarose e maior utilização dos filtros rotativos a vácuo. O trabalho teve como objetivo avaliar a clarificação do caldo de cana-de-açúcar com a adição de folhas verdes e folhas secas, tendo como controle a adição de fibra do colmo. Os ensaios foram delineados tendo como base a adição de quantidades das fontes fibrosas - folha verde, folha seca e fibra do colmo - para formular amostras que correspondessem a acréscimos absolutos de 0,25 , 0,50 e 0,75 ponto percentual sobre o teor de fibra do colmo da cana. Os efeitos sobre a clarificação do caldo, conduzida em clarificador de bancada em laboratório, foram avaliados pela cor do caldo clarificado e o volume de lodo decantado. Na presença de folhas verdes ocorreu uma elevação da cor do caldo clarificado e do volume de lodo decantado. Da folha verde são extraídos água e compostos que são responsáveis por alterações na composição do caldo; devido à presença de componentes não-sacarose o extrato foliar interfere na clarificação do caldo. Da folha seca também foram extraídos compostos solúveis, todavia não detectados através das análises do caldo. A fibra do colmo não afetou a clarificação.

The kinetics of collective sedimentation

The rate of fall of an isolated solid particle through a fluid and under the influence of gravitational and frictional forces has been described by a number of empirical laws, each a valid approximation within a certain range of conditions. In all instances the rate of fall varies with the particle size and the difference between the particle density and the density of the fluid. Sedimentation of an inhomogeneous batch of particles accordingly results in the segregation of particles of different sizes and densities. The occurrence of such segregation in dilute suspensions has indeed been used for the grading of particles and in particle size analysis (see, for example, ref. i). However, there are many instances, particularly in the technical arts, where suspensions of an inhomogeneous nature settle with no segregation and indeed with a sharp line of separation between the supernatant liquid and the precipitate (2). Such settling is referred to as collective sedimentation. Typical examples occur in the process of clarification by sedimentation in the sugar industry. Figure 1 represents successive photographs of a test tube in which a clarified sugar cane juice has been allowed to settle. The photographs were taken, respectively, I/~, I, 2, 3, 5, and 20 minutes after the settling commenced. The precipitate, which appears black in the photographs, consists of particles of insoluble calcium salts of phosphoric, silicic, and aconitic acids and perhaps smaller amounts of other organic acids mixed with particles of wax, coagulated protein, and certain polysaccharide present in the juice. The particle sizes range from i0 ~ to 5 ~. In spite of this large range in sizes practically all the particles settle together and indeed the line of demarcation between supernatant liquid and precipitate becomes sharper as settling proceeds. It is obvious in this instance that we are dealing with a relatively concentrated suspension. In such concentrated suspensions it is to be expected that the rate of fall of any particular particle should be modified by the fall of other neighboring particles. Bikerman (ref. 3, page 315) has listed mechanisms whereby

Sugar-cane juice clarification for syrup manufacture

A continuous clarification of grape juice was undertaken in a packed bed reactor (PBR) using pectinase enzymes immobilized on glass beads. The enzyme immobilization process decreased the specific activity and the volumetric productivity from 3 ± 0.2 to 2.7 ± 0.1 units mg−1 and from ~0.085 to ~0.070 mg mL−1 min−1, respectively. Also, it increased the optimum pH from 5.0 to 5.5, but did not influence the optimum temperature (50 °C). The best conditions for clarification of the grape juice were obtained at a flow rate of 0.5 mL min−1 and a treatment time of 42 min. After clarification, pH, total soluble solids, turbidity, total phenolic content, antiradical activity and viscosity of grape juice were decreased, and on the other hand, total titratable acidity and the color parameter L were increased. Generally, this study showed that the continuous operation in a PBR including glass bead immobilized enzyme can be a potential alternative for the batch system used in juice industries.