Edible films based on potato starch, chitosan and Aloe vera gel (AV) as modifiers were evaluated towards their potential application in food or cosmetics industry. The films, with different AV gel concentration were prepared by casting method. The influence of UV radiation on samples chemical structure was analyzed. The surface morphology was observed with AFM method. The chemical structure and molecular arrangement of mixture components were analyzed with ATR–FTIR spectroscopy and X-ray diffraction. Hydrogen bond interactions among the film components, conformational rearrangements as well as changes in crystallinity degree were confirmed. A study of thermal resistance showed the delay of degradation observed together with an increase AV gel amount and after UV-irradiation. The hydrophilic character of the samples was proved. Water solubility slightly depends on the AV concentration in films, and it decrease after UV-irradiation. All the samples with AV gain the increase resistance to microbial action.

Biodegradable films based on starch modified with ascorbic acid or caffeine and dialdehyde starch (DS) were evaluated towards their applications in the food packaging industry. The morphology of the films surface was observed with SEM and AFM. The chemical structure was examined with ATR-FTIR spectroscopy and X-ray diffraction. The mechanical, thermal and barrier properties of the films were examined. The cross-linking and hydrophobic effect of dialdehyde starch on starch-based films was proven. Vitamin C addition prompts the crystalline structure formation and improves the hydrophilicity and antioxidant activity of the starch blends. Caffeine addition results in higher starch film hydrophobicity, whereas caffeine combined with DS reduces crystalline order in starch. Both caffeine and ascorbic acid incorporation influence the film stiffness, and dialdehyde starch causes an increase in brittleness. The high susceptibility to biodegradation and good antioxidant activity confirms the potential application of examined systems in the packaging industry.

In the present work, corn (CS) and waxy corn starch (WCS) with different amylose content (determined with the UV-vis spectroscopy) were subjected to acid hydrolysis, ultrasound, and a combination of both, performed at a raised temperature and short period, to obtain nanoparticles (nano-WCS and nano-CS). Scanning transmission electron microscopy (TEM-STEM) proved the effectiveness of the proposed method for nanoparticle synthesis with a size below 5 nm. FTIR spectroscopy and X-ray diffraction (XRD) delivered information on their molecular structure (i.e., reduction in nano-CS crystallinity degree (X_c) arising from higher amylose content and more stable X_c for nano-WCS). Thermogravimetric analysis (TGA) combined with FTIR analysis of gaseous products of thermal decomposition was also performed. The thermal stability decreased in varying degrees for nano-WCS and nano-CS. Less susceptibility of waxy corn starch for modification was proven.Nanoparticles are expected to be effective for functional food, and biomedical applications.

Due to the extensive application of petroleum-based plastics as packaging materials and problems related to their degradation/recycling, developing new solutions in the field of novel biopolymer-based materials has become imperative. Natural substitutes for synthetic polymers (starch, cellulose, chitosan) require modifications that enable their processing and provide them with additional properties (i.e., mechanical strength, controlled biodeterioration, antimicrobial and antioxidative activity). The antioxidant activity of natural packaging materials still requires further investigation. In this research paper, novel materials used for packaging perishable food susceptible to oxidizing agents were designed from potato starch (NS) reinforced with antioxidants such as dialdehyde starch (DS) and caffeic acid (CA)/quinic acid (QA). The use of spectroscopic techniques (ATR-FTIR, Raman) and X-ray diffraction allowed the examination of the chemical structure and arrangement of the blend and confirmed the component interactions. The film surface was examined by AFM. DS, functioning as a cross-linker, enhanced the film barrier as well as the mechanical and thermal properties, and it promoted starch amorphization when blended with other antioxidants. The antioxidant activity of caffeic acid was greater than that of quinic acid. Dialdehyde starch improves elasticity, whereas acids (particularly caffeic acid) influence film stiffness. A high susceptibility to biodegradation is valuable for potential eco-friendly packaging applications.

Fluorescent biopolymer derivatives are increasingly used in biology and medicine, but their resistance to heat and UV radiation, which are sterilizing agents, is relatively unknown. In this work, chitosan (CS) modified by three different heterocyclic aromatic dyes based on benzimidazole, benzothiazole, and benzoxazole (assigned as IBm, BTh, and BOx) has been studied. The thermal properties of these CS derivatives have been determined using the Thermogravimetric Analysis coupled with the Fourier Transform Infrared spectroscopy of volatile degradation products. The influence of UV radiation on the thermal resistance of modified, fluorescent chitosan samples was also investigated. Based on the temperature onset as well as the decomposition temperatures at a maximal rate, IBm was found to be more thermally stable than BOx and BTh. However, this dye gave off the most volatile products (mainly water, ammonia, carbon oxides, and carbonyl/ether compounds). The substitution of dyes for chitosan changes its thermal stability slightly. Characteristic decomposition temperatures in modified CS vary by a few degrees (<10 °C) from the virgin sample. Considering the temperatures of the main decomposition stage, CS-BOx turned out to be the most stable. The UV irradiation of chitosan derivatives leads to minor changes in the thermal parameters and a decrease in the number of volatile degradation products. It was concluded that the obtained CS derivatives are characterized by good resistance to heat and UV irradiation, which extends the possibilities of using these innovative materials.

The growing industrial demand for valuable biomaterials contributes to modifying readily available starch to give it the desired functional properties. The advantage of the reported studies was the modification of starch with succinic acid via sodium hypophosphite as a cross-linker. The cross-linked structure was confirmed with Raman, ATR-FTIR, ¹³C and ³¹P CP-MAS NMR spectroscopies. In the next step, the phosphonated starch succinate/chitosan materials were prepared for application in food packaging and coatings. The most desirable features for such employment were achieved, such as a low water vapour permeability through the membranes (~2 %) and accelerated biodegradability compared to starch film attributes. Significant differences in these properties resulting from the time of synthesis and the quantitative composition of the films were verified. The longer synthesis time of composites affected the better mechanical properties (Elongation at break, ε_b =~91-94 %, and Young's Modulus, E = 140-160 MPa). Thermal parameters (including FTIR analysis of gaseous products evolved during the thermal decomposition) were confirmed. The changes in ordering behaviour (crystallinity degree, X_c) determined with XRD varied from 23 % (for the starch film) to 10-21 % (starch in composites). Obtained biodegradable starch-based materials may constitute an attractive ecological alternative for plastics.