Dariusz Kowalczyk

Characterization of films based on chitosan lactate and its blends with oxidized starch and gelatin.

Minimal inhibitory concentration (MIC) of chitosan lactate (CHL) was tested against bacteria and phytopathogenic fungi. Then, the structural, physicochemical and antimicrobial properties of films based on CHL, oxidized potato starch (OPS), and gelatin (GEL) were investigated. With the exception of Rhizopus nigricans, CHL was effective against the target organisms. Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) were more sensitive to CHL than Gram-negative bacteria (Pectobacterium carotovorum and Escherichia coli). Cryo-SEM images showed total miscibility between the polymers in the blends and the ATR-FTIR spectra revealed that there was an interaction among the polymeric components. Pure CHL films displayed the highest moisture content (25.51%), water vapor permeability (48.78gmmm(-2)d(-1)kPa(-1)), and the lowest tensile and puncture strength (2.00 and 1.45MPa, respectively) among the studied films. CHL50/GEL50 films had lower permeability, higher mechanical strength, and lower elongation compared to CHL50/OPS50 films. Films obtained from CHL and CHL50/GEL50 were completely water-soluble and did not show sorbitol recrystallization. The incorporation of CHL into OPS and GEL films did not affect their transparency and improved UV-blocking capacity. CHL films were the only ones that exhibited antibacterial efficiency. Antifungal activities against Alternaria alternata and Monilinia fructigena were detected for CHL and CHL50/GEL50 films.

Grinding and Nutritional Properties of Six Spelt (Triticum aestivum ssp. spelta L.) Cultivars

ABSTRACT Some physical, technological, nutritional, and nutraceutical determinants of six spelt varieties were evaluated. The grains were characterized by similar grain hardness and gave similar breakage patterns on a hammer mill and relatively low grinding energy requirements. The highest protein content was determined for Spelt I.N.Z. and Schwabenkorn (155 mg/g db), whereas the lowest was for Ceralio (98 mg/g db). The total starch content in tested cultivars averaged about 500 mg/g db; however, significant differences were observed for resistant and potentially bioavailable starch. The highest starch digestibility was observed for Ostro, Schwabenspelz, and Spelt I.N.Z. (about 45%), whereas the lowest was for Ceralio (about 33%). Chemically extractable total phenolic compounds content did not differ between cultivars. When flavonoids contents were compared, however, significant differences were observed; their contents ranged from 0.61 to 2.12 mg/g db (Spelt I.N.Z. and Schwabenkorn, respectively). The ab...

Ascorbic acid- and sodium ascorbate-loaded oxidized potato starch films: Comparative evaluation of physicochemical and antioxidant properties

The purpose of this study was to compare the effects of increasing concentrations of ascorbate ions (AIs, 0-100mM) in the form of ascorbic acid (AA) and sodium ascorbate (SA) on the properties of edible oxidized potato starch films. The browning reactions were faster in the SA-added films than in those of AA-added. In, turn, AA recrystallized faster than its sodium salt. The highest concentration of SA increased the water vapor permeability of the films. The mechanical strength and stiffness of the films gradually decreased with the increase of AI content. Fourier-transform infrared spectroscopy spectra suggested that addition of SA provoked a more intensive structural changes in the films than AA. X-ray diffraction showed that 25 and 50mM AI-added films exhibited higher crystanility than the control. The films with AA and SA did not differ in terms of dissolving behavior, ability to release AI, and consequently, antioxidant activity.

Antifungal resistance and physicochemical attributes of apricots coated with potassium sorbate-added carboxymethyl cellulose-based emulsion

Summary Antifungal effectiveness of potassium sorbate (KS) incorporated into edible coating composed of carboxymethyl cellulose and candelilla wax blend (CMC-CnW) was tested on apricots inoculated with fungi. The efficiency of KS-added coating was higher than KS-free formulation. The antifungal action of KS-free coating was likely associated with a reduced access of oxygen to the infection sites and, consequently, modification of the gaseous atmosphere within the fruit tissues. Rhizopus nigricans as the fastest growing fungus was the most resistant to the coating treatment. In turn, KS-loaded coating was very effective against Botrytis cinerea and Monilinia fructigena. Coating significantly delayed softening of apricots. The results of this study demonstrate that KS can be incorporated into coating to control common fungal diseases of apricots. Nevertheless, the CMC-CnW coating treatment inhibited the respiratory functions and caused deterioration in the fruit sensory quality.

Quality of wholemeal wheat bread enriched with green coffee beans

Scientific studies have revealed that bioactive components of coffee play a preventive role against various degenerative diseases. Green coffee, in particular, is characterized by its unique composition and properties. The objective of this work was to investigate the influence of green coffee (Coffea arabica) beans (GCB) addition on the quality and antioxidant properties (AA) of the wholemeal bread. For bread preparation, flour form GCB, and wholemeal wheat flour, type 2000 were used. Wholemeal wheat flour was replaced with GCB flour at 1 to 5% levels. Loaf volume, texture, color and sensory properties of bread were determined. Furthermore, total phenolic content and antioxidant activity were evaluated. The results showed that bread supplementation with GCB had little influence on the bread volume. The highest volume of bread was obtained with 3 and 4% of GCB flour. The texture properties of bread crumb (hardness, elasticity, cohesiveness and chewiness) were slightly changed as a result of the GCB addition. The lightness of bread crumb decreased with the GCB addition (average from 46.3 to 42.6). Besides, the addition of GCB significantly enriched wheat bread with hydrophilic phenolic compounds. The phenolic compounds were highly bioaccessible in vitro. Moreover, the GCB addition enhanced antiradical activity of bread.