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 ...
Read More
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.
Maryam Naghipouzade Mahani; Mohammad Hosein Aghkhani; Khalil Behzad; Abbas Rohani
Abstract
Introduction: Conventional technology of sugar production from sugar beet roots consists of the next subsequent steps: sugar beet slicing, thermal denaturation of the sliced beet roots followed by diffusion in hot water at 70–75 _C, purification of extracted juice by lime, concentration of purified ...
Read More
Introduction: Conventional technology of sugar production from sugar beet roots consists of the next subsequent steps: sugar beet slicing, thermal denaturation of the sliced beet roots followed by diffusion in hot water at 70–75 _C, purification of extracted juice by lime, concentration of purified juice and crystallization. The diffusion process is one of the most important steps that effect on product yield. The quality of cossettes is too important that increase extraction yield. Therefore the main function of the beet-slicing operation is to improve the diffusion operation. The most important factors in producing quality cossettes are the type of knives. Most knives have a V shape that cause increase of the surface area of the beets. At slicing operation, Amount of the sucrose of beet extract directly. Considering the blade edge causes the rupture of beet cell so it effects on quality of juice and yield of extraction. Also the different blades edge causes different surface areas that effect on osmotic operation. In this work, the effect of two kinds of blades (serrate and flat edge) is studied on extraction process and the juice quality. Material and method: Fresh sugar beets (Beta vulgaris) were obtained from Ferdowsi university farm and storage at 5C°. For each test run, 300gr of cossette 4mm thickness and 8cm in length were cut by cutting device with ability of blade change. The sucrose content of cossetttes was measured in ICUMSA method. These tests were organized as follows 4 steps. The first step was washing. Considering amount of sucrose of sugar beet extract directly at slicing operation, the decrease of sucrose content of cossettes and the sucrose of washing juice should be measured. For this stage, 120gr of cossettes were washed with 320gr of distilled water. After washing the cossettes, the sucrose content of cossettes was measured again and the decrease of suocrose content of cossettes was calculated and sucrose of washing juice was measured. For the thermal-pretreatment step, 130gr of sugar beet cossettes were treated with 260gr of distilled water 70C° at 7min and the sucrose of thermal-pretreatment juice was measured. In the diffusion step, 130gr of these cossettes were immersed in 260gr of distilled water 73C°. The solute concentration (Brix, g solubles 100 g_1 juice) was measured by digital refractometre (PR-101, Atago, 50 Kyo, Japan) every 5 to 10 min up to equilibrium conditions. The final step was pulp pressing. The pulps were compressed by laboratory press (2 bar) at 15min. following by the pressed pulp was weight then the sucrose content of them was measured. In the following, purity and nonsucrose of juice were determined for washing, thermal-pretreatment and diffusion steps. These parameters were measure in ICUMSA unit which is based on polarimeter method. Also extraction yield of diffusion, mass of extraction sucrose and extraction sucrose at diffusion, pressed pulp yield, extraction degree and energy were calculated. The data were analyzed in 2-sample t-test at minitab17 and the graphs were drew in excel. Results and discussion The results showed that the edge of the baled had significant effect on the juice purity (washing and thermal-pretreatment steps), non-sucrose content and sucrose of juice, extracted sucrose at cutting operation, extracted sucrose at diffusion, degree of extraction, yield of pulp, time and energy (P<0.05). The most juice purity was obtained from flat blade with 78.33%, 84.86% and 85.52% at washing, pretreatment and diffusion steps respectively. Also the least of non-sucrose content was obtained from this blade with 0.1%, 0.55% and 0.51% at washing, pretreatment and diffusion steps respectively. The serrate blade increase the tearing (rupturing) of the beet cells at slicing operation. Torn cells allow more impurities (nonsugars) to be diffused into the surrounding juice, causing an increase in nonsugars and, consequently, a reduction in juice purity. For the serrated blade, The most extracted sucrose at cutting operation and diffusion step, mass of sucrose of diffusion juice and degree of extraction were obtained 14.5%, 94.4%, 7.22 gr and 0.19 respectively that compare to another blade is more. The edge of serrate blade increases the surface aria of cossettes compare to use of flat blade. The surface area is one of the most important parameter to improve osmotic operation. The more contact area between the beet cells and the water in the diffuser cause the more movement of sugar from the cells to the diffusion juice. Therefore the use of the serrate blade improves the osmotic operation and enhances the extracted sucrose. The least of pulp yield, extraction time and energy were obtained 27.97%, 40 min and 1.7 Kw/h respectively for this blade. The increase of sucrose extraction reduces the pulp yield. As regards osmotic operation improve whit the increase of surface area cossettes, therefor the sucrose extract at lees time and the total energy decrease. Regarding to the results, both of blades improve some of the extraction parameters.
