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COST 928 2nd Annual Meeting - VTT project pages server


Academic year: 2023

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To improve the reaction rate of the enzyme with galactose as a substrate, different mutational strategies were used. For example, site-directed mutagenesis and saturation mutagenesis in the active center were performed to affect substrate binding and enzyme conversion rates. Most of the studies were carried out on mesophilic fungi, but there is little information on the enzyme production of thermophilic fungi.

O1.6: Towards the structural basis of the enzymatic mechanism of p-coumaric acid decarboxylase from Lactobacillus plantarum. The interface between monomers (1166 Å2) is highly symmetrical and is formed by the outer side of one of the β-sheets. More than 80% of the proteinaceous material was solubilized after the combined action of carbohydrases and peptidases in the two-step reactions, of which approx. 11%.

In sequential processes, the order of treatment with carbohydrase and peptidase had little effect on outcome. The scientific objective of the research was to study the influence of limited hydrolysis of extruded soybean meal (ExSF) on the microstructure and rheological and emulsifying properties of the hydrolysates.


Starch and sucrose are renewable resources used to produce various polysaccharides with interesting functional properties. Starch is a mixture of amylose, which contains essentially only alpha-1,4 linked glucose residues, and amylopectin, which consists of an alpha-1,4 linked glucose polymer branched by alpha-1,6 linkages. Sucrose is a disaccharide of fructose and glucose that is abundant in sugar beet and sugar cane.

Starch and sucrose can be modified using bacterial glucanotransferase or sucrase-type enzymes, respectively. These enzymes break the glycosidic bond present in starch and sucrose and transfer part of the donor molecule to a new saccharide acceptor. With 4-alpha-glucanotransferase from the thermophilic bacterium Thermus thermophilus, a thermoreversible gel-forming starch derivative was produced. Sucrose can be converted to Reuteran, a glucan with both alpha,1-4 and alpha,1-6 glycosidic bonds, can be used as a bread improver or as a weight management ingredient that helps in the fight against obesity.

These examples of novel functional polysaccharide products illustrate that carbohydrates, starch and sucrose, can be converted into high value products by a biocatalytic or bioconversion process. This offers a more sustainable and sustainable alternative to the current use of starch and sucrose as a source for the production of fermentable sugars for the bioethanol industry. O3.5: Use of enzymatically hydrolyzed starch to improve the structure of low protein imitation cheese.


Buchert VTT Technical Research Center of Finland, Espoo Finland VTT Technical Research Center of Finland, Espoo Finland. Enzymes that stabilize protein systems by forming additional covalent bonds between or within proteins are potential tools to modify the structure of food products, especially when the amount of such technological factors as salt and fat content is low. Currently, transglutaminases (TG) are widely used in the meat, dairy and baking sectors to improve the texture of various food products.

The TG-induced increase in the firmness of protein gels is already well known, but the effects of TG on the water retention of food gels vary depending on the protein system. The effects of cross-linking enzymes on texture and water retention in food systems will be presented. The role of TG in stabilizing food protein foams and emulsions, especially casein systems, has been investigated.

Efforts to develop technological solutions to produce stable protein foam structures using enzymatic protein cross-linking to modify the continuous phase or interface of protein foams will be discussed.


O4.2: Production of potential prebiotic oligosaccharides by enzymatic conversion of insoluble dietary fiber of durum wheat into soluble dietary fiber. The conversion of highly polymerized insoluble dietary fibers into soluble feruloyl-oligosaccharides DWF was achieved by a tailored enzymatic treatment. The conversion of insoluble dietary fiber from cereals to soluble dietary fiber resulted in microbial fermentation in the gut that supported bifidobacteria and lactobacilli.

The composition of the finally obtained GalOS mixture was 33.5% di-, 60.5% tri- and 4.8% tetra- and 1.0% pentasaccharides with a negligible amount of monosaccharides, lactose and lactobionic acid. To compare the prebiotic effect of the newly produced GalOS with three known commercial prebiotics (Vivinal GOS, TOS and FOS), two different cultivation methods were used. Procedures commonly used for measuring total dietary fiber (AOAC Official Methods 985.29 and 991.43) involve incubation of the sample at 100oC with thermostable -amylase, followed by protease at 60oC and then amyloglucosidase at 60oC and pH.50-4.

However, this procedure results in an underestimation of resistant starch (RS), which is now recognized as an important component of the dietary fiber complex, and especially in manufactured foods where RS can be added without deleterious effects on the organoleptic properties of the dietary fiber complex. the food. This method involves the use of pancreatic alpha-amylase and amyloglucosidase, followed by protease, and provides an accurate measure of RS as part of the dietary fiber value. The kinetic constants, the limiting rates of the enzymes and the initial concentration of the redox mediator also determine the productivity of the reaction system.

Large-scale purification and characterization of barley limit dextrinase, a member of the α-amylase structural family. Oxidoreductases and transamidases (transglutaminase) can crosslink food proteins and thus improve the structural properties of the protein matrix. This was followed by a screening test where the solubility of reducing sugars and pentosans was measured to select some enzymes for further study.

The viscosity of the soluble fraction was higher for rye bran than for wheat bran.



Arnous* & Meyer*

The functionality of the arabinoxylan, xylanase, and xylanase inhibitory system has already been extensively studied over the past decade. The phytic acid and myo-inositol phosphates generated during the reaction were separated by high performance anion exchange chromatography on a CarboPac PA-100 column (250x4) with post-column derivatization using 0.1%. In the experiment, an acoustic spectrometer was used that works at a range of kHz frequencies and measures the amplitude of the acoustic signal penetrated through the tested sample.

This means the possible application of the acoustic method to determine the changes that have occurred in the bread during storage. The non-destructive character of the acoustic method enables the testing of bread hardening in the same sample during storage and increases the effectiveness of the analysis. By using different modified caseinates, it was possible to create emulsions that were stable in the acidic, neutral and alkaline regions of the pH spectrum.

The stability behavior of the emulsions correlated well with the theoretical and experimentally determined pI values ​​of the caseinates. Tyrosinase is an oxidative enzyme known to catalyze the oxidation of the phenolic ring of tyrosine residues to the corresponding quinones. In this work, we studied the cross-linking of β-casein by Trichoderma reesei fungal tyrosinase (TrTyr) and microbial transglutaminase (TGase) by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-Page) and size exclusion chromatography (SEC) equipped with UV / Vis and multi-angle light scattering (MALLS) detectors for determining the molecular weights of cross-linked products.

Cross-linking with TrTyr led to the formation of colored products and thus the progress of the enzymatic reaction was also followed visually as a function of time. It was determined that the addition of xylanase and its combination with Raftifeed®OPS had no significant effect (p>0.05) on the majority of the chicken breast and thigh meat sensory attributes. An essential part of the polysaccharide was not utilized, and it was converted to a series of arabinoxyloyl oligosaccharides that differ in the degree of polymerization.

The structure of the shorter arabinoxyoligosaccharides remaining in the spent medium from wheat arabinoxylan was established using mass spectrometry and digestion with three glycosidases, one β-xylosidase and two distinct α-L-arabinofuranosidases.

Bayram & Özçelik

However, consuming a small amount of the right kind of tannins can be beneficial to human health. It was found that the higher the molar mass of the tannin molecules, the stronger the antinutritional effects and the lower the biological activities. Microbial degradation is one effective way to degrade large molecular tannins into smaller molecular tannins with valuable bioactivity.

By HPLC analysis, almost complete degradation of tannic acid was observed in the three commercial tannic acid samples analyzed. Using HPLC-DAD/ESI-MS, we partially determined the composition of tannic acid from Quercus infectoria galls. These four agricultural residues contained different amounts of xylan, cellulose and lignin, and the xylan obtained from these sources contained different amounts of sugar and uronic acid.

Regardless of the structural differences between the xylan types presented in this article, all xylans generated XO with different degrees of polymerization (DP), but the DP of XO depended on the enzyme specificity and the structure of the substrate. Institute of Food Research, Norwich Research Park, Colney, Norwich, UK email: Marta.Sujka@bbsrc.ac.uk. The requirement to encapsulate an active ingredient/therapeutic agent under one set of environmental conditions, and obtain release under a different set of conditions, is well established in the pharmaceutical sector.

In terms of food delivery, this approach could improve food quality through the controlled release of aroma, flavor and nutrients. In this study, we investigated the composition and responsiveness of polygalacturonic acid (PGA)-based multilayers to changes in salt concentration and pH. The limited growth of lysozyme/PGA systems was attributed to the globular structure of lysozyme.

The partial dissolution of PGA-based multilayers was in contrast to the complete dissolution previously observed for PLL/pectin multilayers1.



Genetic and Molecular Epidemiology Unit, Lund University Diabetes Centre, Department of Clinical Sciences, Skåne University Hospital, Lund University, SE-214 28, Malmö,