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Darnay L.,Corvinus University of Budapest | Koncz A.,Corvinus University of Budapest | Gelencser E.,Food Science Research Institute | Pasztor-Huszar K.,Corvinus University of Budapest | Friedrich L.,Corvinus University of Budapest

Our aim was to determine how 0.5-2 U/g non-inactivated mTG affects the pH development and apparent viscosity during fermentation. Furthermore we wished to examine how the enzyme addition could change protein structure, gel strength and sensory characteristics by healthy low-fat set-type yoghurt product. Therefore commercial mTG enzyme preparation was added in different concentrations (0.5-2.0 U/g, in 0.5 U/g steps) to 1.5 % bovine milk simultaneously with DVS starter culture. Our study revealed that enzyme dosage (0.5-2 U/g protein) had no impact on pH development and apparent viscosity during fermentation when manufacturing low-fat (1.5 %) set-type yoghurt. The addition of mTG contributed to 38 % more whey retention with incorporation of β-casein, and caused 44 % higher gel strength up to a level of 1 U/g protein. © 2016, Hrvatska Mljekarska Udruga. All rights reserved. Source

Szaloki-Dorko L.,Corvinus University of Budapest | Szaloki-Dorko L.,Food Science Research Institute | Steger-Mate M.,Corvinus University of Budapest | Abranko L.,Corvinus University of Budapest
International Journal of Food Science and Technology

Elderberry concentrate is widely used for food colouring. Its production includes several processing steps, which influence pigment composition, thus affecting the quality of final product. In this study, qualitative and quantitative changes in anthocyanin components were followed during the production of elderberry juice concentrate using Haschberg and Samocco varieties. Juice concentration resulted in more than five-fold concentration increase in anthocyanins; however, clarification, filtration and evaporation steps caused slight but continuous decrease in anthocyanins relative to the dry matter of the product. Pectolytic enzymatic treatment was found to be one of the most critical processing steps that affects anthocyanin yield during production, and this effect on yield can be variety-dependent. Additionally, two condensed dimeric anthocyanin species generated after heat treatment are reported for the first time to be present in elderberry juice concentrate. Our results suggest that cyanidin-based anthocyanin conjugates with more complex saccharide moieties are more robust during production. © 2016 Institute of Food Science and Technology. Source

Eva C.,Hungarian Academy of Sciences | Eva C.,Eotvos Lorand University | Zelenyanszk H.,Eotvos Lorand University | Tomoskozi-Farkas R.,Food Science Research Institute | Tamas L.,Eotvos Lorand University
South African Journal of Botany

Aldo-keto reductase (AKR) enzymes contribute to reactive aldehyde detoxifying capacity and to osmotic stress protection of various plant species. The protective effects of these enzymes have already been well characterised but only limited information has been gained on the role of AKRs in frost tolerance. The approach to study frost tolerance was based on transgenic barley ( Hordeum vulgare L.) carrying and expressing the Arabidopsis thaliana At2g37770.2 gene (coding AKR4C9) under constitutive regulation. We demonstrated that the osmoprotective sugar alcohol sorbitol was present in both non-transgenic (WT) and transgenic barley plants. The increase of the sorbitol concentration was around 2- and 4-fold higher in the low (line C2) and in the high (line C1) AKR4C9-expressing transgenic line, respectively, compared to WT. Furthermore by applying three subsequent, identical - 20. °C treatments 94.7% of all the leaves of WT plants had died, but only 80% in the case of transgenic line C1. The average electrolyte leakage of the transgenic plants (line C1) was lower than that of WT plants. Line C1 plant also had significantly higher fresh weight than the WT after 6. days of recovery following frost-treatment. Transgenic line C2 had an intermediate freezing tolerance based on the same physiological parameters. The results indicate that AKR-overexpression may lead to higher frost tolerance and higher post-frost regenerative capacity. © 2014 South African Association of Botanists. Source

Boka B.,Eszterhazy Karoly College | Korozs M.,Eszterhazy Karoly College | Nanasi M.,Eszterhazy Karoly College | Adanyi N.,Food Science Research Institute

An enzyme-based amperometric biosensor was developed for the determination of the lysine content of pharmaceutical products, food and feed samples. Lysine decarboxylase (EC from Bacterium cadaveris was coupled with diamine oxidase (EC from Pisum sativum and horseradish peroxidase (EC The enzymes were co-immobilized on a graphite electrode with an Os polymer. The biosensor worked in flow injection analysis system (FIA). Optimal working conditions were pH7.0 and -50mV potential vs. Ag/AgCl. The linear measuring range was 0.005-0.500mM. Different pharmaceutical products and feed samples were analysed by the lysine biosensor and by HPLC method for validation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Szucs V.,Food Science Research Institute | Szabo E.,Food Science Research Institute | Banati D.,International Life science Institute
Elelmiszervizsgalati Kozlemenyek

Partly because of consumer demand, and partly because of manufacturing and commercial aspects, our foods contain different additives, which is worrisome to some of the consumers. The goal of the present work was to study the level of knowledge related to additives, and the effect of the information provided in order to reduce the perceived risk. Results of our questionnaire survey showed that information has a beneficial effect on the consumer acceptance of food additives, and so credible and easy to understand information is extremely important for domestic consumers when making conscious decisions by. © 2015, Hungarian National Commiteee of the European Organization for quality. All rights reserved. Source

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