Potential applicaton of β-galactosidase in food science and nutrition

β-galactosidase is an enzyme with hydrolytic and transgalactosylation activity. The origin of the enzyme dictates the balance between both activities. Industrially used β-galactosidases are obtained with recombinant production from filamentus funghi Aspergillus sp. and yeasts Kluyveromyces sp. Recently thermostabile β-galactosidases have been subject of many research. The enzyme can be industrially used in free or immobilized form. Immobilization often provides better stability, reusability and lower expenses. Application of β-galactosidase is most common in food processing and nutrition, it is also used in medicine and ecology. Hydrolytic activity of the enzyme has long been used for reducing lactose content in milk, while transgalactosylitic activity is used for synthesis of products such as galactooligosaccharides, lactosucrose and others. The latter have a great potential in food industry for obtaining products with reduced lactose content and increasing of nutritional value by adding dietetic fibers such as galactooligosaccharides. Despite the potential it is vital that reaction mechanisms become better understood and optimization is in place in order to reach the usability of this enzyme at industrial level

Proteomički pristup istraživanju pčelinjih proizvoda, tj. matične mliječi, propolisa i meda

Bee products such as royal jelly, honey and propolis have been reported to possess several biological activities. In order to better understand their mechanism of action and, consequently, their efficiency and safety, \u27omic\u27 approaches are used. Here cases with proteomic approach are indicated. In addition to studying biological activity at a proteome level, a proteomic approach for investigation of bee products has also been applied in analyzing proteins as their (bioactive) components.Pčelinji proizvodi, kao što su matična mliječ, med i propolis, imaju višestruku ulogu u biološkim procesima. U ovom su radu prikazane proteomičke metode koje se koriste za proučavanje mehanizma njihova djelovanja i sigurnosti hrane. Proteomički je pristup, osim za proučavanje biološke aktivnosti pčelinjih proizvoda na molekularnoj razini, primijenjen i pri analizi proteina, tj. bioaktivnih sastojaka tih proizvoda

Potential of bovine kappa - casein as biomarker for detection of adulteration of goat’s milk with cow’s milk

Korištenjem dvodimenzionalne elektroforeze dokazano je da kravlji kapa-kazein može biti odgovarajući biomarker za utvrđivanje patvorenja kozjeg mlijeka kravljim mlijekom, ne samo u sirovom mlijeku, već i za mlijeko koje se termički obrađuje pasterizacijom ili ultra-visokom temperaturom. Prisutnost kravljeg mlijeka u kozjem mlijeku moguće je detektirati na razini od 2 %. Nadalje, položaj proteinskih mrlja kapa-kazeina na 2-D gelovima ostao je nepromijenjen uspoređujući uzorke mlijeka različitog geografskog podrijetla, Belgije i Slovenije. Ovi rezultati pokazuju da ni toplinska obrada niti različito geografsko podrijetlo ne utječu na položaj kravljih proteinskih mrlja kapa-kazeina na 2-D gelovima.Using two-dimensional (2-D) electrophoresis it was shown that bovine kappa-casein could be an appropriate biomarker of adulteration of goat’s milk with cow’s milk not only in raw milk, but also for milk thermally processed by pasteurization or treated with ultra-high-temperature. The presence of cow’s milk in goat’s milk was detected at level of 2 %. Furthermore, position of bovine kappa-casein spots on 2-D gels remained unchanged even with samples from two different geographical origins, Belgium and Slovenia. These results show that neither thermal processing nor different geographical area seem to affect the position of bovine kappa-casein spots on 2-D gels

Bioactivity of Cod and Chicken Protein Hydrolysates before and after in vitro Gastrointestinal Digestion

Bioactivity of cod (Gadus morhua) and chicken (Gallus domesticus) protein hydrolysates before and aft er in vitro gastrointestinal (GI) digestion was investigated using yeast Saccharomyces cerevisiae as a model organism. Both hydrolysates were exposed to in vitro GI digestion prior to cellular exposure to simulate digestion conditions in the human body and therefore investigate the role of modulations in the GI tract on the cell response. The eff ect of digested and undigested hydrolysates on intracellular oxidation, cellular metabolic energy and proteome level was investigated. No diff erence in the eff ect on intracellular oxidation activity was obtained between cod and chicken hydrolysates, while higher aff ect on intracellular oxidation was provided by digested hydrolysates, with relative values of intracellular oxidation of cod of (70.2±0.8) and chicken of (74.5±1.4) % than by undigested ones, where values of cod and chicken were (95.5±1.2) and (90.5±0.7) %, respectively. Neither species nor digestion had any eff ect on cellular metabolic energy. At proteome level, digested hydrolysates gave again signifi cantly stronger responses than undigested counterparts; cod peptides here also gave somewhat stronger response than chicken peptides. The knowledge of the action of food protein hydrolysates and their digests within live cells, also at proteome level, is important for further validation of their activity in higher eukaryotes to develop new functional food ingredients, such as in this case chicken and cod muscle-derived peptides

Characterization of S-layer proteins of potential probiotic starter culture Lactobacillus brevis SF9B isolated from sauerkraut

Abstract S-layers represent the simplest biological membranes developed during the evolution and are one of the most abundant biopolymers on Earth. Current fundamental and applied research aim to reveal the chemical structure, morphogenesis and function of S-layer proteins (Slps). This is the first paper that describes the Slps of certain Lactobacillus brevis strain isolated from sauerkraut. The whole genome sequence (WGS) analysis of the L. brevis SF9B strain uncovered three genes encoding the putative Slps, but merely one, identified as similar to the SlpB of L. brevis ATCC 14869, was expressed. Slp-expressing SF9B cells exhibited increased survival in simulated gastrointestinal (GI) conditions and during freeze-drying. Their survival in stress conditions was additionally enhanced by microencapsulation, especially when using alginate with gelatine as a matrix. Thus prepared cells were subjected to simulated GI conditions and their mortality was only 0.28 ± 0.45 log CFU/mL. Furthermore, a correlation between the high surface hydrophobicity and the remarkable aggregative capacity of SF9B strain was established. The results indicate a prominent role of Slps in adhesion to mucin, extracellular matrix (ECM) proteins, and particularly to Caco-2 cells, where the removal of Slps utterly abolished the adhesiveness of SF9B cells for 7.78 ± 0.25 log CFU/mL.Peer reviewe

シンポジウム

Additional file 14. A table with description of strains and plasmids generated and used in this study and graphical representation of over-expressed operons/genes