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This study was based on the production of an alcoholic beverage from apple using laboratory pervaporation equipment. Hungarian fruit brandy is called pálinka, which can be made by pot distiller or multistage distiller made of copper. In case of traditional pot still distillation the final product is gained from two separate distillations. Pervaporation is an energy efficient membrane process for separating liquid mixtures. Application of pervaporation to separate the product of the initial distillation leads to lower energy consumption than using double-distillation process. The aim of our work was to develop an alternative technology for the production of pálinka that integrates distillation and pervaporation.

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Two novel proteins with apparent molecular weight of 38 (Manduca sexta midgut MsM38) and 46kDa (MsM46) were isolated from midgut homogenates in wandering stage Manduca sexta larvae and both of them were found to be present exclusively in this tissue on Western blots. Immunocytochemical studies revealed that both proteins are expressed in the regenerative cells however, their distribution pattern is clearly different. MsM38 is localized in the cytoplasm of resting regenerative cells during the feeding period, and is accumulated in the calcospherits at the beginning of the wandering period. Along with the delamination of the larval epithelium, this protein is released apically from these vesicles. The antiserum labels an additional 76 kDa protein in the wandering larval midgut homogenates. The appearance of this 76 kDa protein coincides with the accumulation of the immunopositive material in the calcospherits. MsM46 is similarly distributed during the feeding period in the cytoplasm of regenerative cells. At the beginning of the wandering period it accumulates around the newly forming large apical vacuoles, that are released at the time of complete delamination of the larval epithelium. In parallel with this process MsM46, and another 40 kDa protein, that becomes labeled from this period on Western blots appeares on the apical microvillar projections. Thus both isolated proteins are directed apically from different compartments, that raises the possibility of a dual apical routing pathway in regenerative cells.

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The pattern of cuticle protein synthesis by the epidermis of insects changes during the last larval, pupal and adult development, leading to an alteration in cuticular stucture and feature. We have isolated a pro- tein that had an apparent molecular mass of 33.1 kD from larval cuticle of Manduca sexta. Synthesis, transport and accumulation of MsCP33.1 were followed during metamorphosis by immunoblots and immunocytochemical methods using the antibody developed against this protein. Our data prove that the presence of MsCP33.1 in the larval cuticle is general while its appearance in the pupal or adult integu- ment is restricted only in the cuticle of wings and apodemes. We established that the synthesis of 33.1 kD protein is negatively regulated by moulting hormone (20-hydroxyecdysone). Possible roles for this cuticular protein are discussed.

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Scolexin is one of the bacterial induced hemolymph proteins of tobacco hornworm (Manduca sexta) lar- vae, that has hemocyte coagulation-provoking activity. The 72 kDa scolexin complex is composed of two 36 kDa subunits. To examine the protein secretory pathways in insect epithelia a polyclonal antibody was raised against the 36 kDa hemolymph protein. This MsH36 antibody recognised a 36 and a 72 kDa pro- tein in tissue homogenates. On the basis of the characteristic labelling pattern observed on immunoblots and immunocytochemical sections we concluded that the 36 kDa protein in the hemolymph, in the midgut and in the epidermis was identical with the scolexin subunit. In present paper we report a labelling shift in the midgut epithelium between goblet and columnar cells that may be controlled by the hormonal system. A 72 kDa protein showed similar epitops and molecular weight to the scolexin com- plex and was detected in epidermis and in cuticle under both reducing and non-reducing conditions. Tissue localization of 36 kDa and 72 kDa MsH36 antibody labelling proteins indicated the possibility that the epidermal cells produce two kinds of scolexin-like proteins. The complex composed of 36 kDa subunits are transported basolaterally into the circulation and display hemocyte coagulation inducing activity while the 72 kDa form contains two subunits linked covalently secreted apically into the cuticle.

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Our experiments were based on a model solution containing five of the main pineapple aroma components. Both sweeping-gas pervaporation and vacuum-pervaporation methods were carried out. Measurements were performed at different temperatures and feed flow rates. The purposes of this study were to examine applicability of the two pervaporation methods in reference to the pineapple aroma recovery, the effects of the operating parameters on the process, and modelling the pervaporation process by resistance-in-series model. Higher enrichment could be reached with vacuum-pervaporation than the sweeping-gas method. The separation process is determined by the diffusion of compounds in the membrane, thus the resistance in the boundary layer at liquid side is negligible. Based on performed experiments, the pervaporation process can be applied in beverage industry for aroma recovery.

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In this study, pressed apricot (Prunus armeniaca L.) juice was concentrated using complex membrane technology with different module combinations: UF-RO-OD, UF-RO-MD, UF-NF-OD and UF-NF-MD. In case of the best combination a cross-flow polyethylene ultrafiltration membrane (UF) was applied for clarification, after which preconcentration was done using reverse osmosis (RO) with a polyamide membrane, and the final concentration was completed by osmotic distillation (OD) using a polypropylene module. The UF-RO-OD procedure resulted in a final concentrate with a 65-70 °Brix dry solid content and an excellent quality juice with high polyphenol content and high antioxidant capacity.Nanofiltration (NF) and membrane distillation (MD) were not proper economic solutions.The influence of certain operation parameters was examined experimentally. Temperatures of UF and RO were: 25, 30, and 35 °C, and of OD 25 °C. Recycle flow rates were: UF: 1, 1.5, and 2 m3 h−1; RO: 200, 400, and 600 l h−1; OD: 20, 30 and 40 l h−1. The flow rates in the module were expressed by the Reynolds number, as well. Based on preliminary experiments, the transmembrane pressures of UF and RO filtration were 4 bar and 50 bar, respectively. Each experimental run was performed three times. The following optimal operation parameters provided the lowest total cost: UF: 35 °C, 2 m3 h−1, 4 bar; RO: 35 °C, 600 l h−1, 50 bar; OD: 20, 30 and 40 l h−1; temperature 25 °C.In addition, experiments were performed for apricot juice concentration by evaporation, which technique is widely applied in the industry using vacuum and low temperature.For description the UF filtration, a dynamic model and regression by SPSS 14.0 statistics software were applied.

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Acta Alimentaria
Authors:
Zs. Molnár
,
Sz. Bánvölgyi
,
Á. Kozák
,
I. Kiss
,
E. Békássy-Molnár
, and
Gy. Vatai

Concentration of raspberry (Rubus idaeus L.) juice by combination of membrane processes was investigated. The pre-treatment steps were crushing, enzyme treatment, pressing and clarification by microfiltration (MF). Ceramic tube MF membrane was used at low pressure and temperature (3.9 bar and 30 °C).Nanofiltration (NF) and reverse osmosis (RO) process with flatsheet membranes was studied to pre-concentrate the clarified and sterilized raspberry juice. The NF experiments were carried out at different flow-rates (400 l h−1 and 600 l h−1). Any significant effect of flow-rate was not experienced. Both pre-concentration processes were used at low temperature (30 °C) for a mild concentration of raspberry juice. For further concentration osmotic distillation (OD) was applied. The initial total soluble solid content of the raspberry juice was 8–10 °Brix, the final concentrate of OD was 70–80 °Brix.The membrane-, fouling- and the polarization layer resistance were determined in case of micro-, nanofiltration and reverse osmosis.The soft drinks, made from RO and OD concentrates, were compared with well-known conventional raspberry juice from trade. During the sensory analysis (the colour, odour, flavour, acid taste and general impression was evaluated) our juices were preferred by customers.The antioxidant capacity, total phenol, anthocyanin and acid content, the total cell count and the number of yeasts and moulds were determined in the permeate and retentate samples of the different filtration steps.

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Acta Alimentaria
Authors:
Sz. Bánvölgyi
,
T. Vatai
,
Zs. Molnár
,
I. Kiss
,
Ž. Knez
,
Gy. Vatai
, and
M. Škerget

Two novel technologies were applied in order to investigate concentration and formulation of anthocyanins for potential use in food industry. Integrated membrane process technology was applied for concentrating elderberry juice. In the first step, the juice was clarified by microfiltration, followed by a pre-concentration step with reverse osmosis. Finally, the juice was concentrated to the end concentration of 56 °Brix by osmotic distillation. The elderberry juice concentrate was formulated in a powderous form by a high-pressure process — Particles from Gas Saturated Solution (PGSS™) — using supercritical CO2. The applied carrier material was palm fat. The products with different anthocyanin-carrier ratios were measured for their colour properties (lightness, hue angle, and saturation). Colour stability was monitored for prolonged storage at different conditions (light/dark and ambient temperature/ refrigerator). The obtained powderous anthocyanin-palm fat products showed good colour stability, which gives good bases for potential applications in the future.

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Acta Alimentaria
Authors:
L. Darnay
,
A. Dankovics
,
B. Molnár
,
L. Friedrich
,
Gy. Kenesei
, and
Cs. Balla

Several scientific papers suggest that microbial transglutaminase (mTG) is capable of reducing the salt content of cured and/or heat-treated meat products (ham, frankfurters, meat ball). These scientific results are not widely known in Hungary, and as a result of this, only little experience was gathered in our meat industry. According to this lack of knowledge, our aim was to lower the curing salt to a still microbiological safe level using mTG by frankfurters, one of the most well-known heat treated meat products in Hungary. The observed technofunctional properties suggest to use mTG enzyme preparation at 0.5% concentration. This enzyme dosage can reduce the average 1.8% salt content to 1.6% and it also may contribute to extended shelf life of popular frankfurters. Our sensorial analysis revealed that the panellists have not found a loss in quality between 1.4% and 1.6% salt.

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Enzyme-linked immunosorbent assays (ELISAs) are widely used to determine gluten contamination in gluten-free and low gluten food samples. ELISA assays developed using monoclonal antibodies against known toxic peptides have an advantage in the identification of toxic prolamin content in protein extracts of different food samples, as well as raw materials. R5 and G12 monoclonal antibodies specific for two known toxic peptides used in commercially available gluten ELISA assays were applied to test toxic peptide contents in wheat relatives and wild wheat species with different genome composition and complexity. Although the R5 peptide content showed some correlation with ploidy levels in Triticum species, there was a high variance among Aegilops species. Some of the analysed diploid Aegilops species showed extremely high R5 peptide contents. Based on the bioinformatics analyses, the R5 peptide was present in most of the sulphur rich prolamins in all the analysed species, whereas the G12 epitope was exclusively present in alpha gliadins. High variation was detected in the position and frequency of epitopes in sequences originating from the same species, thus highlighting the importance of genotypic variation within species. Identification of new prolamin alleles of wheat relatives and wild wheat species is of great importance in order to find germplasm for special end-use quality purposes as well as development of food with reduced toxicity.

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