Biodegradable materials are used in the manufacture of packaging and compostable films and various types of medical products. They have demonstrated a large number of potential practical applications in medicine and particularly in the treatment of various cardiac, vascular, and orthopedic conditions in adults as well in children. In our research, the extrusion-cooking technique was applied to prepare thermoplastic starch (TPS), which was then utilized to obtain environmentally friendly starch-based films. Potato starch was the basic raw material exploited. Polyvinyl alcohol and keratin were used as functional additives in amounts from 0.5 to 3%, while 20% of glycerol was harnessed as a plasticizer. The processing of the thermoplastic starch employed a single screw extruder-cooker with an L/D ratio of 16. The film blowing process was carried out using a film-blowing laboratory line with L/D = 36. FTIR Spectroscopy was applied for the assignment of the prominent functional groups. The results showed that the processing efficiency of thermoplastic starch with functional additives varied depending on the level of polyvinyl alcohol and keratin addition. Moreover, the FTIR data correlated with the changes in the physical properties of the tested films. The analysis of FTIR spectra revealed several changes in the intensity of bands originating from stretching vibrations characteristic of the –OH substituent. The changes observed depended on the presence/lack of the hydrogen bonding occurring upon interactions between the starch molecules and the various additives used. In addition, notable changes were observed in bands assigned to glycoside bonds in the starch.

Directly expanded breakfast cereals were processed with a single screw extrusion-cooker TS-45 with L:D=16:1 at screw speed 120rpm, shaped on the circular open die 2mm in diameter. Wholegrain wheat flour in amount of 50, 60 and 70% of total mass was the basic raw material, additionally corn grit, rice flour, cocoa and sugar were used. The initial moisture content of raw materials was set to 17, 20 and 23%. Processing conditions, like process efficiency and energy consumption, as well as selected physical properties, like the expansion ratio, bulk density, water absorption and solubility indexes were tested. Texture profile with Ottawa cell for hardness, adhesiveness and chewiness, and sensory characteristics of breakfast cereals were evaluated. Higher wholegrain wheat flour content in the recipe and higher moisture of raw materials lowered energy consumption during extrusion-cooking of breakfast cereals. The expansion ratio, water absorption and solubility index values lowered with higher initial moisture content of raw materials. Increased moisture level before the extrusion-cooking increased bulk density and textural parameters, like hardness and chewiness of prepared for consumption breakfast cereals. Process management of extruded breakfast cereals according to various recipes and processing conditions allows creating desirable quality of final products