Browsing by Author "Uotila, Sarri"

Haemoglobin and globin from blood cells and albumin, fibrinogen and immunoglobulins from blood plasma are the most important proteins in slaughter blood. Different fractions of blood have slightly different technological properties. Adding blood proteins can have an effect on the gelling, foaming and emulsifying properties of foodstuffs. Blood protein hydrolysates have antioxidative and antigenotoxic effects that could be utilised as food preservatives or in functional foods to strengthen health. The nutritional value of food can be improved by adding blood proteins. Blood proteins can be utilized by replacing egg, fat and sodium caseinate in foods, to improve structure and shelf life of food. Blood proteins can also be utilised replacing egg white, milk or soy proteins or replacing fat in light products. Ultrafiltration is a common method in the food industry and it is also suitable for processing blood proteins. The aim of the study was to optimize an ultrafiltration method to concentrate porcine slaughter blood for use in the food industry and to determine the technological properties of plasma concentrate and its suitability for use in the food industry. Response surface methodology was used to create a mathematical model to calculate the optimal ultrafiltration parameters for plasma concentrations. Optimal conditions for the ultrafiltration were an Ultracel PLTK 30 membrane, temperature of 40 ºC and pressure of 2 bar. The technological properties of blood proteins were measured at pH 4.5, 5.5, 6.3 and 7.0. Volume and stability were measured from foams prepared by whipping from plasma concentrate diluted to protein concentration of 5.8 %. Foam volume and stability were greatest at pH 5.5 and weakest at pH 7.0. Emulsifying capacity was measured from plasma concentrate diluted to 0.01 % protein concentration. Emulsifying capacity was weakest at pH 5.5 and increased towards high and low pH. Rheological properties of gels made from 10 % plasma concentrate were measured. The gels were weakest near the isoelectric point of plasma proteins at pH 5.5. Plasma concentrate was used to prepare bologna sausage. The structure and sensory properties of the sausages were evaluated. The sausages containing plasma concentrate were evaluated as equal to control sausages in every category.