Edris Arjeh; Mikhalil Piruzifard; Sajad Pirsa
Abstract
Introduction Raw sugar beet juice (RSBJ) is an intermediate of sugar beet processing obtaining by diffusion process. The RSBJ contains approximately 85% water, 13% sucrose, and 2% non-sugar compounds (impurities) and its purity ranges from 85 to 88%. Due to the low purity, the RSBJ should be subjected ...
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Introduction Raw sugar beet juice (RSBJ) is an intermediate of sugar beet processing obtaining by diffusion process. The RSBJ contains approximately 85% water, 13% sucrose, and 2% non-sugar compounds (impurities) and its purity ranges from 85 to 88%. Due to the low purity, the RSBJ should be subjected to purification process. The conventional purification occurs in a complex multistage process including pre-liming, main liming, first carbonation, and second carbonation. In liming step, lime milk (Ca(OH)2) is added to destabilize and precipitate the non-sugar compounds. Then the CO2 gas is added to precipitate the lime (as calcium carbonate). Although the application of lime is very well known but some impurities, including phenolic compounds, saponins, proteins and lipids pass through purification processing into the white sugar and cause serious difficulties. Due to the variety of compounds (dissolved or suspended) present in RSBJ and this fact that different processes may remove different types of compounds, various fining agents are required to clarification of raw juices. Bentonite, silica sol, gelatin and activated carbon are four types of natural adsorbents, which have been used in many applications, in different fields and processes, including the food industry. Differences in the nature of ionic charges of juice compounds and the fining agents induce neutralization, and flocculation and result in the removal of them from the juice. Therefore, the purpose of this study was to investigate the efficiency of bentonite, silica sol, gelatin and activated carbon in the removal of impurities (protein, saponin and phenolic compounds) causing floc in acidic beverage and improving the purification indexes of RSBJ (turbidity, color, ash and purity). Floc refers to the cloudy and turbid precipitate that forms in some sugar-sweetened carbonated soft drinks after standing for several days. While flocs are harmless, they are a visible defect and consumers don’t accept the soft drink product for aesthetic reasons. Currently, most researchers assume that saponins are primarily responsible for floc formation. However, there are some studies indicating that protein, phenolic compounds and lipids also play a role in floc formation.
Materials and methods: The RSBJ was regularly obtained from the sugar factory of Piranshahr, Iran. The RSBJ was sampled at the point just before the purification step and immediately transferred to the lab. Fining agents used for clarification including bentonite (Na–Ca Bentonite ERBSLÖH, Geisenheim, Germany), silica sol 15% (Baykisol 15%), Gelatin (type-A; 100 bloom, Erbigel, Germany) and activated carbon (CS-2000, Gostar Ghoumes CO. Iran) was provided by Azar kam Co. Urmia. Iran. For each experiment, 200 ml of the raw juice was subjected to various refining treatments. The RSBJ were refined at 75 °C for 100 min by fining agents. Fining agents were added to beet juice samples according to the preliminary experiments. After the completion of the clarifying process, juice samples were passed through a microfilter (45 µm) to removing formed floc. In order to compare the mentioned treatments (bentonite, silica sol, gelatin and activated carbon) with the conventional method, the RSBJ was also treated with lime-carbon dioxide in four stages (pre-liming (15 minutes at 85 ° C), main liming (15 min at 88 ° C), first carbonation (up to pH 11, 90 ° C) and second carbonation (up to pH 9, 92 ° C)). After applying the treatments, purity and ash content (by conductimetry method) was measured as the main purification indexes for assessing the quality of the juice samples. The total protein (by dye-binding method), total phenolic compound (by Folin-Ciocalteu reagent) and total saponin content (by vanillin-sulfuric acid method) was also determined as the compounds have a key role in formation of acid beverage floc.
Results and discussion: In this study, four refining agents of bentonite, silica sol, gelatin and activated carbon were used to improve the purification indexes of RSBJ and to remove non-sugar impurities causing floc in acidic beverage (such as carbonated beverages). Based on the ash and purity, it was showed that the applied adsorbents (bentonite, silica, gelatin and active charcoal) significantly improved the purification indexes of RSBJ. The results also showed that the ability of bentonite as a negative charged adsorbent was considerably higher than silica-sol in removing impurities (protein, saponin and phenolic compounds) causing floc, and improving the purification indexes (turbidity, color, ash and purity). So, the bentonite treatment reduced protein, phenolic compounds and saponin content of juice by 68, 61 and 40 %, respectively. The combination of gelatin and activated carbon as supplemental clarifiers with bentonite and silica also improved the parameters measured. In general, Bentonite-Activated carbon treatment had the best results, resulting in a reduction of 73, 87 and 85 % in protein, phenolic compounds and saponin, respectively. In this study, mentioned treatments were also compared with conventional treatment (lime-carbon dioxide) and it was observed that new treatments can be a good choice to combine or replace with conventional treatment.
Marzieh Mirzaaghaei; Amir Hossein Goli; Milad Fathi
Abstract
Introduction: Flavor, taste, odor and color of fresh apple juice is unstable during concentration process and storage. Pectic substances and phenolic compounds are responsible for these physicochemical changes. So, decreasing of these compounds is necessary to improve the appearance and marketability ...
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Introduction: Flavor, taste, odor and color of fresh apple juice is unstable during concentration process and storage. Pectic substances and phenolic compounds are responsible for these physicochemical changes. So, decreasing of these compounds is necessary to improve the appearance and marketability of apple juice. In fruit juice industry, clarification is one of the most important steps which removes pectin, polyphenols and other unfavorable components and prevents haze formation during storage. Enzymatic clarification (depectinization) can be applied for removal of pectic substances by using pectinase. This enzyme can hydrolyze pectin and produce pectin-protein complexes which would be settled easily. Also in depectinization step, some enzymes such as amylase and amyloglucosidase can be used to degrade starch. Fining agents such as gelatin, bentonite, activated carbon, silicasol or a combination of these compounds can be used in conventional clarification. Sepiolite is a natural fibrous phyllasillicate clay mineral with a formula Mg8Si12O30(OH)4(OH2)4. nH2O(n=6-8) which has specific physicochemical properties such as high porosity, surface area and adsorption capacity. This clay clay has been used in several important applications such as decolorization of sugar juice, removal of phosphorus from vegetable oil and enhancing decoloration of crude palm oil. In this research, efficiency of Sepiolite for apple juice clarification was evaluated. First, the response surface methodology (RSM) was used to optimize apple juice clarification conditions. Then, a comparison among Sepiolite and other commercial fining agents in respect to clarification efficiency was accomplished. Finally, three types of zero-, first- and second-order kinetic models were used for explanation of changes in turbidity, color, viscosity and total phenolic content (TPC) during clarification process of apple juice.
Materials and Methods: The pasteurized and unclarified apple juice, Bentonite, Gelatin (Bloom= 80-100), Amylase (Alphamyl MG) and Pectinase (Pectofruit XL) were gratefully obtained from Behnoosh Iran Co. (Shahrekord, Iran). Sepiolite (with specific surface area of 105 m2/g) was purchased from Farapooyan Isatis Yazd Co. (Yazd, Iran). The kieselgel and chemicals with analytical grade were purchased from Merck Co. (Germany). Sepiolite was activated with hydrochloric acid according to Balci’s method with slight modification. For evaluation of Sepiolite changes, some analysis like pH, acidity, density and the moisture content of Sepiolite clay were done before and after the activation by the method of Sabah and Çelik. Specific surface area was measured by using the BET method (Belsorp mini II, Japan). XRF method (PW148, Philips Co.) was used for determining of difference between Sepiolite elemental compositions before and after the activation. A pretreatment was conducted to improve the performance of fining agents according to Türkyilmaz et al.’s method with slight modification. The swelling capability of fining agents in water increases their clarification capacity. In the method of RSM, the independent factors at three levels were concentration of activated Sepiolite (0.05-0.1% w/v), temperature of clarification (50-60˚C) and process time (2-10 h). Juice turbidity was regarded as response. As the first step in clarification of apple juice, amylase and pectinase enzymes were applied (25 µl of each enzyme per 100 mL juice at 20˚C). The mixture was stirred and heated in an incubator at 55˚C for 1 h. Sepiolite was mixed with juice in certain concentrations, stirred and placed in definite temperature and time according to each run of RSM. Finally, the juice was centrifuged (12000 rpm for 5 min) to remove the clay from clarified juice. For kinetic studies, the above steps were done in the optimized conditions using 0.05% fining agents at 50˚C for 7 h. A portable turbidometer (MARTINI, Mi 415, Romania) and the capillary viscometer (Ubbelohde-Viscometer, Fisher, USA) were used for measuring the juice turbidity and viscosity at 20˚C and expressed as NTU (Nephelometeric Turbidity Unit) and centipoise (cp), respectively. Color was measured at 20˚C by using a color meter (ZE 6000, Nippon DENSHOKU). The parameters which used for color expression were L* and a* parameters based on CIE Lab system. The Folin-Ciocalteu reagent was used for measuring the total phenolic content of juice and expressed as mg gallic acid equivalent per 100 mL juice. To evaluate Sepiolite performance in juice clarification, following fining agents were applied at optimal conditions: sepiolite (S), commercial bentonite (B), and combination of these agents with gelatin (G) and kieselgel (K) (S+G, B+G, S+G+K, B+G+K). The used concentrations of bentonite, gelatin and kieselgel were 0.05%, 0.015% and 0.04% (w/v), respectively. Sampling was conducted at 1 h intervals to evaluate the changes in juice turbidity, viscosity, color and TPC during clarification process. The rates of changes were determined by three types of zero-, first- and second-order kinetic models.
Results and Discussion: Results showed that the activated Sepiolite had less amounts of weight loss, density and pH than the native sample. On the other hand, moisture content and acidity increased. Also, acid activated Sepiolite had higher amounts of SiO2 groups. The second-order polynomial (quadratic) model was suggested as the best for describing the optimum conditions of clarification with insignificant lack of fit and high R2 (0.9845). Based on the results, process time had a significant (p
Mehdi Jalali; Mohammad Hossein Hadad Khodaparast; Eisa Jahed
Abstract
In this study , response surface methodology and face central composite design in order to investigate decolorization and clarification extraction of Kaluteh date was used for the production of liquid sugar. The optimum amount of bentonite ( 1-3 g/l ) and gelatin ( 0/02-0/08 g/l ) was determined that ...
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In this study , response surface methodology and face central composite design in order to investigate decolorization and clarification extraction of Kaluteh date was used for the production of liquid sugar. The optimum amount of bentonite ( 1-3 g/l ) and gelatin ( 0/02-0/08 g/l ) was determined that the desired amount of bentonite and gelatin , 3 and 0/05 ( g/l ) , respectively. To determined the optimum conditions for maximum activity of these two compounds for clarification with regard to fixed amount of bentonite and gelatin , three factors determine the temperature ( 30-70 °C) , pH ( 4-6 ) and time ( 40-120 min ) was implemented. Parameters consists of the colors , ash and absorbance. Bentonite and gelatin at low temperature and pH with over time , more active and reduce the mount of impurities. The least amount of this responses for the color at 420( nm) , ash and absorbance at 660 (nm),4302 Icumsa ,0/421 % and 0/059 ,respectively. By comparing amounts in the optimum point the clear syrup by bentonite and gelatin ,the initial syrup ,it was found that this technique able to reduce the mount syrup color ,ash and absorbance ,68/25 % , 8/7 % and 89/46 % ,respectively.
Arash Koocheki; Seyed Ali Mortazavi
Abstract
In order to prevent the turbidity during storage of kiwifruit juice, clarification is necessary. Through proper clarification, flavor and taste of the product is also improved. Therefore, the purpose of the present study was to present a method to determine the optimum amount of clarifying agents (Pectinase ...
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In order to prevent the turbidity during storage of kiwifruit juice, clarification is necessary. Through proper clarification, flavor and taste of the product is also improved. Therefore, the purpose of the present study was to present a method to determine the optimum amount of clarifying agents (Pectinase enzyme, Bentonite and polyvinyl poly pyrolidone) for producing kiwifruit juice with stable clarity. For this purpose, effect of Pectinase enzyme (2-8 g/kg), Bentonite (200-350 g/Ton) and polyvinyl poly pyrolidone (70-110 g/100 lit) on viscosity, turbidity, clarity and total phenolics compound of kiwifruit juice was investigated. For each response a second order polynomial model was developed using a multiple linear regression analysis. Results showed that R2 for viscosity, turbidity, clarity and the total amount of phenolics were more than 0.90. The statistical analysis indicates that viscosity, turbidity and clarity (P
Eisa Jahed; Mohammad Hossein Hadad Khodaparast; Khalil Behzad; Mohammad Elahi; Arash Koocheki
Abstract
In this study, response surface methodology was used to determine the optimum raw sugar beet juice purification process conditions using bentonite to produce inverted liquid sugar. For this purpose, impact of factors on the purification process such as bentonite concentration (1-5 gr/li), pH (3.5-6) ...
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In this study, response surface methodology was used to determine the optimum raw sugar beet juice purification process conditions using bentonite to produce inverted liquid sugar. For this purpose, impact of factors on the purification process such as bentonite concentration (1-5 gr/li), pH (3.5-6) and temperature (35-95 ˚C) was investigated. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Correlation coefficients of fitted regression models of color, turbidity, ash, adjusted purity and invert sugar for juice purification process were determined as 0.95, 0.89, 0.90, 0.91 and 0.96 respectively. Results showed that while increasing the bentonite concentration increased the turbidity content but the adjusted purity decreased, and had no significant effect on other parameters. At lower pH levels, separation of color and turbidity causes by bentonite, but was in creased it decreased separation of ash and also increased invert sugar levels. With increasing temperature from 35˚C, to 95˚C, Separation of color and turbidity causes and invert sugar and adjusted purity content as well as increased, while this variable has no significant effect on syrup ash content. The optimum conditions of raw sugar beet juice purification process using bentonite was determined to obtain minimum color, turbidity and ash with maximum invert sugar and adjusted purity which were verified experimentals were found to be bentonite concentration of 1.70 gr/li, pH of 4.47 and temperature of 75˚C. At this optimum point, color, turbidity, ash, adjusted purity and invert sugar content were found to be 1664 ICU420, 6.3 NTU, 0.55 %, 93.9 % and 1.60 %, respectively.
