Fizičke i senzorske karakteristike funkcionalnih prehrambenih namaza na bazi celuloznih hidrokoloida i brašna pogače uljane tikve | Physical and sensory characteristics of functional food spreads based on cellulose hydrocolloids and flour of pumpkin seed cake

The main objective of this study was to determine the possibility of production the low-fat functional food spreads based on flour of pumpkin seed and carbohydrate hydrocolloids. That included complete characterization of components of the spreads, the flour of hull–less pumpkin seed and fiber based food hydrocolloids. Flour of pumpkin seed was analyzed in order to determine its physico–chemical characteristics, functional characteristics, microbiological safety and microstructural nature. These analyses of flour defined the physical, nutritional and microbiological characteristics and behavior of flour, with the aim of determine the possibilities of its application in further work. Also, two types of carbohydrate based hydrocolloids were examined by microstructural aspect, by particle size distribution, rheological determinations and textural characterization. The aim of these analysis was to define the type and concentration of fibers in the gel structure of hydrocolloids, which has the ability of to flour carrier and the role of continuous phase in the spread. This predicted the behavior of carbohydrate based hydrocolloids in the food system such as spreads. The determination of main components of the spreads was followed by determination of optimal properties of the spreads, which included analysis of spreads with different type and concentrations of fibers in the gel system and the different amount of the applied hydrocolloid. To determine the significance of the influence of variable factors on the properties of the obtained spreads, the method of design of experiment (DOE) was used, with applied full factorial design. Also, correlation between certain sensory and instrumentally determined parameters was defined. The aim of all analysis was to define the composition of the spread with optimal properties and to formulate the low–fat food spread based on flour of pumpkin seed Based on the results obtained within this doctoral thesis, it was concluded that the flour of pumpkin seed cake is nutritionally and biologically very valuable raw material with good sustainability, without pathogenic microorganisms, thus it is a suitable raw material for the production of spread. Also, Vivapur MCG 611F was characterized as hydrocolloid with better rheological and textural properties than the hydrocolloid Vitacel WFG HS73, because of its thixotropic flow properties, higher degree of networking and pronounced elastic nature of structure that provides lower susceptibility to deformation and makes it suitable for the production of spread. Based on the influence of variable factors, related to the composition of spreads, it was concluded that the observed spreads were real rheological systems and that the composition of spreads signifficantly influenced on their rheological, textural and sensory characteristics. Obtained resultes of this research suggested that the production of low–fat food spread based on flour of pumpkin seed is possible. This spread contains 80% of MCG 611F fiber based hydrocolloid ( on the mass of the spread) with gel concentration of 7% and 20% of flour of pumpkin seed cake ( on the mass of the spread). The spread with optimal properties is poydisperse system with compact structure in which the flour particles are incorporated into continious network of hydrated MCG fibers and completly coated with avaliable amount of fat relacer. Due to this organization and structure of the system, optimal spread exhibits good properties for manipulation during production and application, such as good rheological characteristics, optimal spreadability and good adhesion to the surface. Obtained spread is nutritionaly valuable food product which can be classified into functional food product based on the composition and health inffluance.