Zita Šereš

Separation of non-sucrose compounds from the syrup of sugar-beet processing by ultra- and nanofiltration using polymer membranes

Abstract Sugar, as the final product of the technology of sugar production, has to satisfy rigorous quality demands. Among others, it means low content of non-sucrose compounds, as well as the smallest possible share of coloured matters. Ultrafiltration and nanofiltration can be one of the solutions for a more effective separation of non-sucrose compounds from the intermediate products from which sucrose can directly be crystallized. Applying this procedure energy can be saved and the environment protected. Syrup solution from sugar-beet processing which contains 39.2% d.m. is being ultra- and nanofiltered.Polymer membranes with different MWCO (15–20 kDa, 6–8 kDa and 0.5 kDa) are used. Effects of UF are carried at 30°C and 60°C, with flow rates at 200 and 400 L/h and in the range of transmembrane pressure between 1–4 bar. NF is carried at 30°C and 50°C, with flow rates at 300 and 400 L/h and in the range of pressure between 1–30 bar. The separation of non-sucrose compounds is the most effective on a membrane with MWCO of 0.5 kDa, if the transmembrane pressure is kept at 30 bar and at a flow rate range between 300–400 L/h. Under these conditions colour and turbidity became lower for 76% and 80% respectively, if related to feed.

Flux Improvement during Cross-flow Microfiltration of Wheat Starch Suspension using Turbulence Promoter

The objective of this study was to investigate the effects of the process variables (transmembrane pressure, flow rate, and concentration) on the permeate flux during the microfiltration of model starch suspensions, and to determine the conditions under which the use of Kenics statics mixer as a turbulence promoter is justified. A response surface methodology was used to examine the influence of the selected operating conditions on starch suspension microfiltration using a single channel ceramic membrane with 200 nm pore size. The experimental results clearly show that the improved performance of starch suspension cross-flow microfiltration can be obtained by using a Kenics static mixer, especially at lower flow rates. Compared to the operation without the turbulence promoter, the average permeate flux improvement during the filtration period ranged from 30% to 230%. As a result of the statistical analysis, the optimal conditions for starch suspension microfiltration were determined and applied to microfiltration of starch industry wastewater.

Influence of low‐melting milk fat fraction on crystallization and physical properties of chocolate

Purpose – Investigated milk fat fraction differs in physical attributes, first of all in melting point and solid fat content and its influence on crystallization process of cocoa butter i.e. chocolate mass. It means that this fraction slows down crystallization rate, decreases melting point of mixture with cocoa butter and causes chocolate softness. It is very important for quality of chocolate especially chocolate with nuts or sunflower kernel. The aim of this paper was to investigate the influence of low‐melting (26°C) milk fat fraction on crystallization processes in chocolate mass and define the optimal concentration of this fraction with suitable precrystallization temperature time regime. Solid fat content of chocolate which designates the influence of precrystallization changes in chocolate mass with addition of milk fat fractions was investigated.Design/methodology/approach – The precrystallization was performed in a laboratory crystallizer that is in a modified Brabender pharinograph, which measu...

The Application of Membrane Separation Processes as Environmental Friendly Methods in the Beet Sugar Production

The sugar industry is one of the key segments of the food industry. This industry is also well known as one of the most energy-intensive in the field of food and chemical industry. In 1999, the total quantity of produced sugar was summarized. It was reported that the production reached 16 700 000 tones, while the total value of the produced sugar was 8924 million EUR. A significant quantity of thermal energy was consumed for the evaporation and beet pulp drying, as well as electrical energy needed for the pumps and for driving the centrifuges. According to CEFS, specific energy consumption was 31.49 kWh/100 kg beet in 1998 (IPPC, 2003). In a Greek study, a figure of 280 kWh/t is given for the electrical part of the energy consumption in sugar manufacturing (IPPC, 2003). While the overall water used is about 15 m3/t sugar beet processed, the consumption of fresh water is 0.25 – 0.4 m3/t sugar beet processed, or even less in modern sugar factories. Water consumption depends on the activities of each installation, e.g. more water is consumed in an installation that extracts and refines sugar beet compared to the one that does only one of these activities (IPPC, 2003). For example, the consumption of water in Austria was reported at a level of 1.5 m3/t of sugar beet processed, which is equivalent to 9 m3/t of produced sugar (IPPC, 2003). The transport water has high organic contamination due to the soil and sugar from damaged beets. Its COD is 5000 – 20000 mg/L. Waste water with high BOD levels is produced in large volumes (IPPC, 2003). Despite the fact that the sugar industry is one of the causes of the environmental pollution, not enough has been done on its improvement. The technology applied in almost all European sugar factories is based on the traditional principles and methods. The major steps in the traditional sugar beet processing are (Poel Van der et al., 1998): i) Pre treatment – Washing and slicing of the sugar-beets into cosettes are the initial operations;

Effects of quantity and layers number of low trans margarines on puff pastry quality

The aim of this study was to investigate the effect of puff pastry margarine with reduced content of trans isomers in production of puff pastry with enhanced nutritional value. Experiments were carried out on the basis of 3 factorial design, wherein the independent variables were the amount of puff pastry margarines (30, 40 and 50%, on flour weight) and number of margarine layers formed during the dough processing (108, 144, and 256). In order to determine the optimum values of independent parameters, the study was focused on defining of relevant qualitative indicators of the final product. By investigation of influence of the type of puff pastry margarine (ML1 and ML2) on the quality of puff pastry, it was determined that physico-chemical properties of margarine ML1 were not optimal for puff pastry production. Margarine ML1 had lower hardness by 50-60%, lower SFC by 20-35% and worse thermal characteristics compared to margarine ML2. Only by application of the maximum amount of margarine ML1 and 144 margarine layers a satisfactory quality of puff pastry was obtained: the lift of 2.89, hardness of 17.7 kgs, volume 83.6 cm and the total number of points of 14.8. Because of its better technological characteristics, margarine ML2 is favorable for making puff pastry. Significantly better physical properties and excellent pastry quality was obtained in samples with margarine ML2 in an amount of 50% of margarine and 256 layers: higher lift by 45%, volume by 25% and the total number of points by about 20% compared to sample ML1 with the best quality.

The Effect of Soy Flour on Cookie Quality

Cookies are a popular confectionery product with a unique texture and taste, long shelf life and a relatively cheap price ; therefore, it is a widespread snack among people of all generations. Nevertheless, cookies are usually made of wheat flour and most formulations are highly caloric and have a low fiber content. Soy flour is an excellent source of proteins, fibers, vitamins and minerals and it is being considered as a great supplement to wheat flour because it increases nutritive characteristics of the final product. By their digestibility and amino acid content, soy proteins are very similar to proteins derived from animals. They also contain many essential amino acids, which are deficient in most of the cereals. The purpose of this work was to determine the effect of soy flour on quality of cookies. Wheat flour was supplemented with 35% of soy flour (full-fat toasted, low-fat toasted, defatted lightly toasted, toasted and soy protein concentrate). The supplementation of wheat flour with soy flour had affected nutritive value and sensory characteristics of cookies.

Primena višekanalne keramičke membrane u mikrofiltraciji suspenzija skroba

This work investigates influence of different process parameters such as transmembrane pressure, flow rate and concentration of wheat starch suspension on the average permeate flux and permeate flux decline. Used membrane in all experiments was 19 channels ceramic membrane with 0.2 μm pore size. Experimental results were analyzed using response surface methodology. It is observed that the significant average permeate flux enhancement of 200% was achieved by the increase of the transmembrane pressure, while the increase of flow rate and concentration affected the increase in average permeate flux in the range of 40-100%. Permeate flux decline was almost independent of the transmembrane pressure, but the increase of the flow rate, as well as the decrease of the concentration led to decrease of permeate flux decline in the range of 20-50%.