Effect of Beetroot Powder Incorporation on Functional Properties and Shelf Life of Biscuits.

The demand for ready-to-use functional foods is high, which encourages manufacturers to develop new, nutritionally valuable products. As an excellent source of biologically active compounds, beetroot (Beta vulgaris L.) is considered to have highly beneficial effects on health. This research aimed to evaluate the impact of replacing spelt flour (SF) with 15%, 20% and 25% beetroot powder (BP). The physicochemical and functional properties of biscuits baked at different temperatures (150 and 170 °C) were followed at the beginning, and after 3 and 6 months of storage as standard conditions. Moisture content and water activity (aw) gave insight into the biscuits' shelf life. The value of aw from 0.35 to 0.56 indicated appropriate storability. Dietary fiber content in fresh biscuits ranged from 6.1% to 7.6%, protein from 9.2% to 8.9% and sugar from 30.6% to 35.9%. The content of betalain, total polyphenols and flavonoids, and antioxidant activity (DPPH, FRAP) increased with beetroot powder content incorporated. A slight decrease of all the mentioned parameters during the storage indicated satisfied retention of bioactive molecules. The content of prevalent phenolic compounds gallic and protocatechuic acid, identified by HPLC, decreased from 22.2-32.0 and 21.1-24.9 in fresh biscuits to 18.3-23.4 and 17.3-20.3 mg/100 g upon six months of storage, respectively. An increase of the L* and a* and a decrease of the b* coordinate values, compared with the control sample without beetroot values, was noticed as well as the expected level of their change during the storage. The obtained results indicated that biscuits enriched with beetroot powder showed a significantly improved functional, nutritional and antioxidant potential during storage.

Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells.

Polyurethane copolymers based on α,ω-dihydroxypropyl poly(dimethylsiloxane) (PDMS) with a range of soft segment contents were prepared by two-stage polymerization, and their microstructures, thermal, thermomechanical, and surface properties, as well as in vitro hemo- and cytocompatibility were evaluated. All utilized characterization methods confirmed the existence of moderately microphase separated structures with the appearance of some microphase mixing between segments as the PDMS (i.e., soft segment) content increased. Copolymers showed higher crystallinity, storage moduli, surface roughness, and surface free energy, but less hydrophobicity with decreasing PDMS content. Biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact, an extraction method and after pretreatment of copolymers with multicomponent protein mixture, as well as by a competitive protein adsorption assay. Copolymers showed no toxic effect to endothelial cells and all copolymers, except that with the lowest PDMS content, exhibited resistance to endothelial cell adhesion, suggesting their unsuitability for long-term biomedical devices which particularly require re-endothelialization. All copolymers exhibited excellent resistance to fibrinogen adsorption and adsorbed more albumin than fibrinogen in the competitive adsorption assay, suggesting their good hemocompatibility. The noncytotoxic chemistry of these synthesized materials, combined with their nonadherent properties which are inhospitable to cell attachment and growth, underlie the need for further investigations to clarify their potential for use in short-term biomedical devices.

In vitro biocompatibility evaluation of novel urethane-siloxane co-polymers based on poly(ϵ-caprolactone)-block-poly(dimethylsiloxane)-block-poly(ϵ-caprolactone).

Novel polyurethane co-polymers (TPUs), based on poly(ϵ-caprolactone)-block-poly(dimethylsiloxane)-block-poly(ϵ-caprolactone) (PCL-PDMS-PCL) as soft segment and 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) as hard segment, were synthesized and evaluated for biomedical applications. The content of hard segments (HS) in the polymer chains was varied from 9 to 63 wt%. The influence of the content and length of the HS on the thermal, surface, mechanical properties and biocompatibility was investigated. The structure, composition and HS length were examined using (1)H- and quantitative (13)C-NMR spectroscopy. DSC results implied that the synthesized TPUs were semicrystalline polymers in which both the hard MDI/BD and soft PCL-PDMS-PCL segments participated. It was found that an increase in the average HS length (from 1.2 to 14.4 MDI/BD units) was accompanied by an increase in the crystallinity of the hard segments, storage moduli, hydrophilicity and degree of microphase separation of the co-polymers. Depending on the HS content, a gradual variation in surface properties of co-polymers was revealed by FT-IR, AFM and static water contact angle measurements. The in vitro biocompatibility of co-polymers was evaluated using the endothelial EA.hy926 cell line and protein adsorption on the polyurethane films. All synthesized TPUs adsorbed more albumin than fibrinogen from multicomponent protein mixture, which may indicate biocompatibility. The polyurethane films with high HS content and/or high roughness coefficient exhibit good surface properties and biocompatible behavior, which was confirmed by non-toxic effects to cells and good cell adhesion. Therefore, the non-cytotoxic chemistry of the co-polymers makes them good candidates for further development as biomedical implants.