Projects / Programmes
Biokemijska in biofizikalno-kemijska karakterizacija naravnih snovi (Slovene)
January 1, 2009
- December 31, 2013
| Code |
Science |
Field |
Subfield |
| 4.03.00 |
Biotechnical sciences |
Plant production |
|
| 1.05.00 |
Natural sciences and mathematics |
Biochemistry and molecular biology |
|
| 1.04.00 |
Natural sciences and mathematics |
Chemistry |
|
| Code |
Science |
Field |
| T430 |
Technological sciences |
Food and drink technology |
| Code |
Science |
Field |
| 4.01 |
Agricultural and Veterinary Sciences |
Agriculture, Forestry and Fisheries |
natural substances, phenolic compounds, transport and volumetric phenomena, colligative properties, arhea, halocins, enzymes, additives, antimicrobials, antioxidants
Researchers (24)
Organisations (2)
Abstract
One part of the research will deal with phenolic compounds. This group of secondary metabolites comprises many compounds and it looks that a plant has a characteristic profile of them. A content of phenolic compounds can increase after a plant has been exposed to changes in the environment. The induced biosynthesis of phenolic compounds can be followed by increased activity of certain enzymes involved either in the biosynthesis of phenolic compounds and/or their degradation. Considering the phenolic compounds two oxidoreductases, polyphenol oxidases and peroxidases, are important. In an intact plant cell phenolic compounds are locally separated from the two enzymes and only after a cell has been damaged they come into contact and some reactions get started. Both enzymes catalyze oxidation of phenolic compounds to very reactive quinones and their further polymerisation to products of characteristically brown colour. Different elicitors can induce biosynthesis of certain phenolic compounds and some of them can have an antimicrobial effect. Due to this, plants can become more resistant to different microorganisms. Some phenolic compounds will be isolated, identified and possibly studied for their role in chosen plants. The selected plants could be considered as an interesting agricultural residue of antimicrobial compounds and antioxidants. As for other plants there is a possibility that phenolic compounds and/or their oxidative enzymes could be used as biochemical markers of their quality. This would be a base to develop biosensors which are becoming more and more interesting because of their great selectivity and speed of reaction. The biosensors developed so far, work on a base of immobilized polyphenol oxidase that catalyses oxidation of polyphenols. Our intention is to develop an optical biosensor for the detection of phenolic compounds in different sources and to compare this new method with the already established routine methods in our lab. Phenolic compounds can be used as additives in food industry. The use of additives gives numerous technological and economical advantages to food producers e.g. development of new products, better quality of the existing ones, extended shelf-life, favourable change in the structure, texture and taste as well as in visual perception of foods. Physico-chemical characteristics of these technologically and biologically important compounds are important in designing industrial processes regarding quality, control and storage parameters. Among the additives, which are categorized regarding their use, we will focus mainly on those responsible for the stabilization of products (like antioxidants, synergists and complexants, emulgators and thickeners) and on those influencing taste, especially on non-caloric sweeteners. The obtained thermodynamic parameters will be correlated to basic tastes (sweetness, astringency). The results will be useful also for testing systems in electronic recognition of basic tastes (electronical language)
The other part of the research will deal with archea, mainly with thermophilic and halophilic representatives of these organisms. Archea are interesting because they have adapted to life in the extreme conditions like extreme temperature and salinity. They are known to possess, among others, different structure of the membranes, cell walls, as well as specific rRNA motif. Adaptivity to extreme temperatures will be studied on Aeropyrum pernix (a strictly aerobic hyperthermophilic archea). We intend to characterize the organism as a whole as well as some of its cell components by the diffential scanning calorimetry. Some enzymes, which could be interesting due to their extreme thermal stability for biotechnological processes, will be isolated from this archea. We propose to use extracellular proteinases from A. pernix to degradate aggregates of the prion type. Additionally, we intend to search for possible substances with antimicrobial activity in A. pernix.
Significance for science
Extracts with antioxidant and antimicrobial activity originating from various secondary raw materials could provide sources of biologically active substances, and this can be of economic value for producers and for growers. Extracts from secondary sources as well non-volatile wine residues which contain a lot of antioxidants can be used in preparation of different foods or as a food additive. It was established that some extracts and phenolic compounds can replace artificial additives in foods as they show pronounced antioxidant as well as antimicrobial activity. Our investigations indicate that some phenolic substances are capable of protective activity at induced oxidative stress on primary cell cultures of neurons. This could lead to prevention of early occurrence of some neurodegenerative diseases with appropriate food and food additives. Research on the methodology of antioxidative tests gave an insight into the mechanism of the reactions of antioxidants with free radicals. The results are important on the field of analytics of antioxidants as well as for understanding the reactions in real biological systems. Optimizing the luminescent method for determination of antioxidant effectiveness we contributed to new alternative ways in determination of antioxidants in various samples. Basic research on hydration and association in water solutions of model solutes with numerous functional groups contributed to understanding of intermolecular interactions. The work on qualitative and quantitative composition on secondary plant metabolites was used for interpretation of some biotic properties (antimicrobial activity, antioxidative potential, sensory properties). The development of rapid, sometimes only screening analytical methods for determining the authenticity and quality of food is an important for the consumer as well as for the food industry. This group of analytical methods includes also the determination of electrical properties of food. The dielectric constant, which is widely used for determining the deterioration of frying oils, can also be applied for analyzing oil type (high oleic, polyunsaturated) and determination of adulteration. From initial experiments it can also be assumed that it is possible to determine the authenticity and adulteration of unrefined, more expensive oils with cheaper and refined ones using the electrical conductivity. Namely, the difference in electrical conductivity between these oils was measured to be several orders of magnitude. Stabilization of ascorbic acid is a great challenge in food industry and including it in liposomes which has been performed increases its stability (especially in foods) Lipids of archaea are unique and enable preparation of archaeosomes which are very stable, chemically as well as physically and present no health risk. Their stability, suitable tissue distribution as well as their immunomodulatory effect open new possibilities for the use of archaeosomes in medicine (drug, protein, peptide and gene carriers, carriers of diagnostically (cancer) important substances). They do not have a GRAS status in food industry, but they could assure a prolonged chemical stability of additives, prolonged taste, flavor and enzyme release and protect non-stable vitamins, preservatives and colorants from oxidation. The understanding of the mechanism of thermal stabilization of enzymes is one of the most challenging problems in biochemistry and biotechnology. It can be used as a model for preparation of proteins with new properties, potentially interesting for industry. Thermostable proteases were used in successful decomposition of protein aggregates (plaques). Thermostable enzymes are also widely used in molecular biology (thermostable DNA polymerase and restrictive enzymes).
Significance for the country
The results of this program are interesting in the field of improving the quality of food, for maintaining its quality and for improving its nutritional value and stability of some foods (juices, oils and honeys). Development of simple and non-destructive analytical methods is important from the point of the possibility of analyzing as many samples as possible as well as from the point of lowering costs of the analyses. Both are very important for food industry. Interesting plant species as well as different hop varieties (Styrian golding, Aurora) contribute to promotion of the Slovenian products. Various ways of organic growing of (bio-)food are important in Slovenia, since our land is still considered to have a good starting point in this economically interesting topics. Substances known to divert hop aphids could to diminish the use of insecticides and therefore the impact on the environment and finally the exposure of the insecticides. This could also increase the economy of hop growing. Plants with antioxidative and antimicrobial effect have a potential possibility for growing on farms with restricted possibilities. Hop sprouts are of special interest. There is no need of separate growing, they are an off-fall which could be turned into potential profit. There are also other secondary sources, like oil cakes and surpluses of wine, which could be sources of biologically active components, which could be used to enrich the foods and as food additives. Slovenia is a recognized producer of high quality olive and pumpkin seed oils. Developmnet of methodologies for the rapid assesment of adulteration of unrefined pumpkin seed oils measuring electrical conductivity and evaluation of antioxidant potential of unrefined vegetable oils contributes to the assurance of quality of products with high added value. We carried out the first systematic investigation of phenolic compounds in plant false flax (Camelina sativa), which grows in Slovenia in the region of Koroška. We have shown that the plant that may be grown organically, is a good source of phenolic compounds with antioxidant activity. Proteases of A. Pernix (recombinant – prepared in sufficient quantities) can be used in various medicinal procedures as well as in food processing. This can be used by Slovenian pharmaceutical companies and in food industry (removing of thermally stable toxins and potential alergenes). The results and findings have already been included in educational processes. Graduate and postgraduate students of the Biotechnical faculty get an opportunity to be involved in the research in preparing of their thesis. Work for Prešeren rewards, M. Sc. and Ph. D. degrees and other research work with young scientists are being organized. International collaboration (Erasmus, bilateral projects) are in progress. Members of the program group have taken part in the scientific and organizing committees of scientific and professional meetings. They are active as referees and editing committees in various journals. Collaboration with other scientific organizations in Slovenia was and remains vivid and fruitful (National Chemical Institute, Medical Faculty). Professional collaboration with Slovenian Industry took place (four major projects).
Most important scientific results
Annual report
2009,
2010,
2011,
2012,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2009,
2010,
2011,
2012,
final report,
complete report on dLib.si
