No abstract

In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies.

Antioxidant activity of grapeseed and 2 chestnut extract in dry-cured sausage "chorizo" 3

This study reports the optimised conditions (temperature, ethanol concentration and processing-time) for antioxidant extraction from potato peel (Agria variety) waste. At short extraction times (34 min), optimal yields of phenolic (TP) and flavonoid (Fv) compounds were reached at 89.9°C and ethanol concentrations of 71.2% and 38.6%, respectively. The main phenolic compounds identified in the extracts were chlorogenic (Cl) and ferulic (Fer) acids. A significant positive correlation was found between antioxidant activity and TP, Fv, Fer and Cl responses. Potato peel extracts were able to stabilize soybean oil under accelerated oxidation conditions, minimising peroxide, totox and p-anisidine indices. The production of hexanal and 2-hexenal in soybean oil samples was maximal for extracts obtained at intermediate temperatures and ethanol concentrations. Our results demonstrate potato peel waste is a good source of antioxidants able to effectively limit oil oxidation, while contributing to the revalorisation of these agrifood by-products.

The β-carotene bleaching assay, a common method for evaluating antioxidant activity, has been widely criticized due to its low reproducibility, problematic quantification, complex reagent preparation, and interference of different factors (temperature, pH, solvents, and metals). In this work we have examined the effects of these factors and developed a highly reproducible procedure for microplate assay, evaluated the critical points of the method, and proposed a kinetic model for quantifying both antioxidant and prooxidant activities. The application of these tools produced very consistent results, which provide robust and meaningful criteria to compare in detail the characteristics of several well-known commercial antioxidants, as well as several predictable prooxidants, and can be easily applied to natural extracts, food samples, and many other type of compounds. As an example, we have tested a set of commercial antioxidants and some typical lipophilic prooxidants. The activity of the tested antioxidants decreased in the following order: ethoxyquin ≫ α-tocopherol > butylhydroxyanisole > butylhydroxytoluene ≫ propyl gallate. On the other hand, hemoglobin and Fe(2+), Fe(3+), Co(2+), and Cu(2+) showed a strong prooxidant effect, and the activity was null in Cd(2+), Ni(2+), and Sr(2+), slightly antioxidant in Mg(2+), and strongly antioxidant in Zn(2+) and Mn(2+).