Modelowanie fizycznych cech nadziewanych produktów spożywczych w zmiennych warunkach wytłaczania

The aim of studies to develop the models enabling complex, multifactor formation of physical and sensory trails of the stuffed products produced by extrusion with the use of non-stress technologies (NST) to achieve the highest standards of stuffed food. The research included complex studies on the influence and modelling of factors forming physical and sensory parameters of co-extruded food products. The variables in research process included: the flours of differentiated technological usability (variable gluten content) as well as biologically, physically and chemically active additives to stabilize mass structure under variable operation conditions in forming apparatus. As all the above components significantly affect the final quality of product, they should be studied and analysed in complex. The literature review as well as preliminary own research works enabled to formulate the following hypotheses: - biologically active additives stabilize the rheological and textural properties of studied products more effective than the chemical additives, without any unfavorable changes in time; - chemical and physical additives negatively affect the textural changes in time and make impossible to achieve the seven days' period of shelf live; - building the quantitative models of changes in physical and sensory qualities of viscoelastic masses enable to find such a composition that makes possible to obtain the products free of mentioned faults. The object of studies included: - experimental determination of the scope for particular factor influence on the course of extrusion process and quality of the final product; - building the mathematical models which describe physical and sensory trails of the stuffed products; elaborating the method to measure the quality of rheological properties of viscoelastic masses and textural products on the basis of synthetic property indices (SWWR and SWWT); - optimization process that aims to obtain the composition of viscoelastic masses and ready products on the basis of assumed different criteria; - definition of the possibilities to forecast in time the physical and sensory qualities of products in order to creating the solutions applicable under production conditions. The models were built on the basis of own research results obtained with the use of up-to-date research equipment. Analysis of obtained results enabled to determine the effects of: - selected wheat flours type 500 of variable gluten content, on rheological mass properties, - the amount of liquid (milk) on rheological, textural and sensory properties, - selected modifying additives (dI, dII, dIII) as well as their quantities, on rheological, textural and sensory properties of the masses being used in co-extrusion process and on the quality of final products, - the forming process parameters on the content of stuff and quality of products, - the analysis enabled also to optimize the quality of products. Statistical analysis of the results showed significant relationships between the quantities of all supplied additives and studied rheological, textural and sensory parameters. Whereas the analysis of activity indices as well as synthetic rheological and textural indices, confirmed that the biologically active substance dI improved the quality of food obtained in such a way much stronger than in case when the chemical additives were applied. It may be assented that the application of biologically active additives, improving and stabilizing the quality of stuffed food produces, is a prospective trend in technological process because of achieving the longest of shelf life at the best valuation of profile texture. That is a positive verification of assumed hypothesis. Presented mathematical models enable to determine the mass consumption of required rheological parameters, which ensure the proper shaping and the highest quality of stuffed food products. Constructed models, considering the time dependent changes in stuffed products parameters (hardness, brittleness, elasticity), enable to determine maximum products shelf life. High quality of the stuffed food products achieved at production with variable stuffing contents may be obtained through determination of boundary ranges for phase angle δ[°] and deformation γ[-] (depending on the contents of liquid, gluten, as well as the kind and quantity of additive applied). On the basis of synthetic indices (SWWR) the rheological parameters of half-finished products may be determined; thus, the correct formation process is to be realized for them. Proposed way of creating the physical and sensory properties makes possible to achieve the products free of faults and acceptable by the consumers (results of sensory valuation). Formulated models of rheological features may be used to determine the critical points in production process (making it independent on fluctuations in components' parameters), considering physical properties of the raw materials, rheological properties of the masses and the parameters of structure creation and extrusion process. Optimization of the phase angle and deformation may be a basis to indicating the ranges of their permissible changes within the limits, where properly formed products are obtained. Developed models of physical and sensory quality features may be a basis to foresee the final quality of stuffed food products and the term of their shelf life. Realized optimization may be a proposal of an uniform system to evaluating the quality of ready stuffed food products.