Development of Vaccines

In this thesis the vaccine types, adverse events and the development of vaccines were discussed. Traditional vaccine types manufactured are live-attenuated, inactivated, subunit and toxoid vaccines. Also, combinations of these vaccine types are common. New vaccines that are manufactured include DNA technology. There are DNA vaccines and recombinant protein subunit vaccines. Adverse events are the possible side effects that immunization can cause. They do happen in a certain frequency and can range from mild reaction to severe. Adverse events are monitored from the beginning of the development of vaccines. Development of a vaccine is challenging and difficult. It includes many phases, high costs and can take several years, with no guarantee of success. Development starts with finding the suitable antibodies and antigens that provide the immunity against wanted disease. Then a prototype of vaccine is made and tested with animals. If the tests are showing good results, the vaccine is going to clinical trial phases, where it is tested with humans. If everything goes well, it is possible to apply marketing license. When the vaccine is in the market, it is still under surveillance for the adverse events.Tässä opinnäytetyössä käsitellään rokote tyyppejä, haittavaikutuksia ja rokotteiden kehittämistä. Perinteiset rokotetyypit, joita valmistetaan, ovat elävät heikennetyt, inaktivoidut, subunit ja toksoidi rokotteet. Näiden rokote tyyppien kombinaatiot ovat myös yleisiä. Uusien rokotteiden valmistuksessa käytetään DNA-teknologiaa. On olemassa DNA- ja rekombinantti proteiini subunit rokotteita. Haittavaikutukset ovat mahdollisia sivuvaikutuksia, joita immunisaatio voi aiheuttaa. Näitä tapahtuu tietyllä frekvenssillä ja ne voivat vaihdella miedoista reaktioista vaarallisiin. Haittavaikutuksia seurataan rokotteiden kehittämisen alkamisesta asti. Rokotteen kehittäminen on haastavaa ja vaikeaa. Se sisältää monia vaiheita, se on kallista ja voi viedä useita vuosia, ilman mitään varmuutta onnistumisesta. Kehittäminen alkaa sopivien vasta-aineiden ja antigeenien löytämisestä, jotka tarjoavat immuniteetin haluttua tautia vastaan. Sen jälkeen valmistetaan rokotteelle prototyyppi ja sitä testataan eläimillä. Jos testit näyttävät hyviä tuloksia, voi rokote edetä kliinisiin kokeisiin, missä sitä testataan ihmisillä. Jos kaikki menee hyvin, on mahdollista hakea markkinointi lupaa. Kun rokote on markkinoilla, sen mahdollisia haittavaikutuksia seurataan vielä

Enzymatic modification of oat protein concentrate for increased fibrillation during high-moisture extrusion cooking

This thesis was done at VTT Technical Research Centre of Finland Ltd as a part of the OatHow project funded by Business Finland. The aim of this thesis was to increase fibrillation between oat proteins during high-moisture extrusion cooking by enzymatic modification of oat protein concentrate (OPC). Protein concentrates do not typically fibrillate well due to their low protein content and the presence of other components e.g. starch. Enzymatic modification of oat proteins and hydrolysis of starch may lead to improved fibrillation due to the creation of a stronger protein network. Three commercial enzymes were used to modify the OPC. Transglutaminase (WM enzyme) was used to cross-link oat proteins, a mix of transglutaminase and protein-glutaminase (SYG enzyme) was used to cross-link as well as deamidate oat proteins, and α-amylase (BAN enzyme) was used to hydrolyse the starch from the OPC. Different treatment conditions were tested e.g. preheating, temperature, enzyme dosage, and incubation time. Protein solubility, viscosity, particle size distribution, and SDS-PAGE were analysed from the modified OPC. The modified OPC samples were extruded in a high-moisture extrusion cooker and tensile strength as well as free thiol groups were analysed from the extrudates. The results showed that both protein-modifying enzymes (WM and SYG) were able to induce the cross-linking reaction in the oat proteins. The highest cross-linking reaction was observed in the BAN+WM sample, where the starch had been hydrolysed. The samples treated with SYG had increased protein solubility, and decreased particle sizes. Viscosity was increased in the preheated SYG 5 U and the preheated BAN+SYG 5 U samples. The WM modified samples had a slight decrease in protein solubility and decreased particle sizes, although less than in the SYG treated samples. In addition, WM had no effect on the viscosity when compared to the control. When the samples were studied in the extrusion, two extrudates (SYG 0.5 U and WM 0.5 U) showed indications of fibrillation when compared to the extruded reference sample. All the non-preheated extrudates showed a rigid structure probably due to the formation of more disulphide bonds during the extrusion, while fewer disulphide bonds were formed in the preheated extrudates. The preheated SYG 5 U sample had the strongest structure according to the tensile strength results, probably since the proteins gelatinized in the elevated temperatures and formed a strong protein network. The viscosity result also supported this hypothesis. The BAN treated extrudates had a brittle structure, probably due to the strong hydrolysis of starch. Overall, this thesis provided new information about the functional properties of the modified oat proteins and the high-moisture extrusion cooking of the oat proteins. It was observed that a stronger protein network can be formed by enzymatic modification, however, a clear fibrillated structure was not observed. In the future, higher protein content OPC, partial hydrolysis of starch, and larger variety of the extrusion parameters could be tested to increase the fibrillation of the OPC

Masking off-flavors of faba bean protein concentrate and extrudate: The role of in situ and in vitro produced dextran

This study produced dextran both in situ by fermentation with Weissella confusa A16 and in vitro by isolated W. confusa A16 dextransucrase enzyme, and investigated its effects on the flavor properties of faba bean protein concentrate (FPC) and the corresponding extrudates prepared by high moisture extrusion. Descriptive sensory profiling revealed that the FPC and extrudates had an intense pea odor and flavor, bitter taste, and astringency. Partial least squares regression analysis suggested that the pea flavor was related to the presence of lipid-oxidation products such as hexanal, heptanal, and nonanal, whereas the bitterness and astringency were likely linked to vicine, convicine, condensed tannins, and arginine. Fermentation under optimized conditions resulted in low acid formation and sufficient dextran production (1.2% end-product basis), which was effective in masking pea and bitter off-notes and enhancing pleasant flavors in FPC (sweet and fruity) and extrudates (sweet and umami). The sweetness was related to fructose produced during fermentation, and the fruity odor was linked to the generated isoamyl isovalerate and ethyl acetate. The masking effect on pea and bitter off-notes was further confirmed by adding enzymatically synthesized dextran in FPC (1.2% dextran) and extrudates (1% dextran). Overall, fermentation with W. confusa A16 or addition of the enzymatically produced dextran showed potential for masking off-flavors of faba bean-based ingredients and extruded meat alternatives. Furthermore, the fermentation method was associated with nutritional benefits (reduction of anti-nutritional factors, e.g., condensed tannins and verbascose) and the generation of flavor compounds/precursors (e.g., esters and free amino acids)