Filters
Impact of Bird Cherry (Prunus padus) Extracts on the Oxidative Stability of a Model O/W Linoleic Acid Emulsion
The delivery and uptake of adequate doses of a number of active compounds, including selected saturated and unsaturated fatty acids (frequently in the form of emulsion systems), is crucial to maintaining a healthy diet. The susceptibility of acids to oxidation and the time stability of emulsions are factors limiting their shelf life and storage time. Those parameters could be improved using selected additives, including antioxidants. In this study, we examined the influence of different bird cherry extracts (varying in the content amounts of bioactive compounds) on the oxidative stability of a model O/W linoleic acid emulsion, using C11-BODIPY581/591 as a fluorescent indicator. We also examined the effect of these extracts on the physicochemical properties of the emulsions and the time stability of the produced emulsion using the dynamic laser scattering technique. The antioxidative efficacy of extracts differed significantly, depending on the extraction method and conditions. The observed differences in the results could be attributed to variations in the specific compositions of the extracts used, which were more or less rich in terms of antioxidants or their synergistic effects. Our results indicated that acetone extract was the most effective with regard to both the oxidation stability and time degradation tests of the emulsions produced. Moreover, the addition of gallic acid did not always have a positive effect on the abovementioned properties.
Protein fractions from flaxseed: the effect of subsequent extractions on composition and antioxidant capacity
Flaxseed proteins exhibit functionalities interesting for the food industry, including antioxidant capacity. Antioxidant activity depends on the protein composition and the presence of phenolic compounds extracted with them from the matrix. The research focused on the effect of subsequent protein extractions (water, salt and alkaline) of flaxseed meals (of three cultivars) on the protein fraction composition and its relations to antioxidant capacity. The protein and phenolic profiles and antioxidant functionalities (in antiradical ORAC and emulsion assays) were analysed. Spectroscopic characteristics of the fractions (fluorometric and FT-IR analysis) were also included. Our study has shown the effect of fractionation on the share of proteins at MW from 56–38 kDa (globulin-like) and <15 kDa (albumin-like) in the protein profiles. The highest globulin share was in the alkaline-extracted fractions (AEF) and albumin in the salt-extracted (SEF) ones. SDG (secoisolariciresinol diglucosides) and phenolic acids (p-coumaric and ferulic) were extracted with flaxseed proteins. Their contents were fraction-dependent and the highest in AEF. The concentration of phenolics in AEF corresponded with the highest antiradical capacity (ORAC) compared with the other fractions. However, the SEF showed a higher ability to inhibit oxidation in emulsions than AEF, which could be associated with the higher content of the low MW proteins.