Abstract In this work, the evaluation of the antioxidant activity of natural phenolic compounds is performed and compared to that of a conventional antioxidative agent. Phenolic molecules, extracted from industrial processing coffee residues, are added to a matrix of poly(1,4‐butylene succinate) (PBS). The apparent activation energy ( E a ) of the thermo‐oxidative degradation is calculated by employing different methods like Kissinger‐Akahira‐Sunose, Flynn‐Wall‐Ozawa and Friedman. The results are compared with the antioxidant activity evaluation obtained through the ABTS radical scavenging assay. From the average activation energies, it is observed that the addition of the natural antioxidants led to an increase in the activation energy of the degradation process as a function of the phenolic compound content. This trend is confirmed by the results of the ABTS assay. Hence, this study proves that the active molecules extracted from agri‐food waste could be employed to improve the antioxidant capacity of the biopolymer, even if the composition of the extract must be evaluated in order to mitigate the effects of other components.
The present work reports the enzymatic valorisation of the protein fraction of scotta, a dairy by-product representing the exhausted liquid residue of ricotta production. Scotta was subjected to ultra-filtration with membrane cut-offs from 500 to 4 kDa and the obtained protein-enriched fractions were used for the optimization of enzyme-based digestions aimed at producing potentially bioactive peptides. Nine different commercial proteases were tested and the best digestion conditions were selected based on protein yield, fraction bioactivity and foreseen scale up processing costs. Scale up of the 3% Pancreatin or 5% Papain processes was performed up to 2 L (37°C or 60°C respectively, 1 h incubation), and the digestion efficiency increased with the reaction volume as well as antioxidant activity (up to 60 gBSA eq/L and to 1.7 gAA eq/L). Retentate 1 digested fractions also showed, for the first time in dairy-based peptides, anti-tyrosinase activity, up to 0.14 gKA eq/L. Digested proteins were sub-fractionated by means of physical membrane separations and 30–10 kDa fraction from Papain treatment showed the highest antioxidant and anti-tyrosinase activities. The peptide sequence of the most bioactive fractions was achieved.
Wild food plants are widely consumed all over the world and many have both nutritional and therapeutic value due to the presence of biologically active compounds. The present research, for the first time, aims to compare primary and secondary metabolite levels among different plant organs (flower, leaf, stem, root, bark) of seven species (Borago officinalis L., Cynodon dactylon (L.) Pers., Foeniculum vulgare Mill., Hypericum perforatum L., Malva sylvestris L., Sambucus nigra L., Urtica dioica L.) collected in three different Italian regions (Liguria, Tuscany, Apulia). Plant organ samples were extracted with water or 95% (v/v) methanol and liquid fractions were analyzed using spectrophotometric assays. The best results were obtained for Hypericum perforatum L. samples, followed by Sambucus nigra L. and Borago officinalis L. As also confirmed via PCA analysis on normalized data, flower and leaf extracts of all species exhibited higher levels of polyphenols (up to 105.7 mg GA eq/gDW), reducing sugars (up to 389.2 mg GLUC eq/gDW), proteins (up to 675.7 mg BSA eq/gDW) and of antioxidant capacity (up to 263.5 mg AA eq/gDW). No differences among the regions of gathering were detected after spectrophotometric assays, which was confirmed via PCA analysis. These data contribute to further validate the traditionally reported healing effects of these species on human health.
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