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We have studied the kinetics of gas transport through films made of self-assembled cellulose nanofibrils (CNF) by a time-resolved mass spectroscopy technique. Few micrometers thick films deposited on polylactic acid (PLA) substrates act as impermeable barriers for CO2, O2, and N2 and reduce the 2H2 (deuterium) and He permeation flux by a factor of ∼103 with respect to the uncoated substrate. Penetrant transport is controlled by the solution-diffusion mechanism and the coating acts as a diffusive barrier. 2H2 and He diffusivity values are in the 10–10 and 10–9 cm2 s–1 range, respectively, and their migration occurs by thermally activated process with 39 ± 1 and 33 ± 2 kJ mol–1 activation energy. Positron annihilation lifetime spectroscopy analysis indicates that the diffusive path between the packed nanofibrils consists of elongated cavities with cross-sectional size ∼ 0.31 nm. Results evidence that the selective transport of the small size penetrants is due to sieving effects and that small penetrant tran...

Eight varieties of Cichorium genus vegetables (five heavily red colored, one red spotted, and two fully green) were investigated for their phenolic content (by HPLC and UV-vis spectrophotometry) and for their antioxidant activity. In particular, the capacity (that is, the amount of trapped peroxyl radicals) and the efficiency (that is, the amount of antioxidant necessary to halve the steady-state concentration of peroxyl radicals) were measured. All of the studied chicories are characterized by the presence of a large amount of hydroxybenzoic and hydroxycinnamic acids, whereas the red color is due to cyanidin glycosides. The presence of these phenolics in red chicories confers to them an exceptionally high peroxyl radical scavenging activity in terms of both capacity and efficiency, particularly in their early stage of growth, and makes this popular and low-cost foods comparable or superior to many foods having well-known antioxidant properties such as red wine, blueberry, and tomato.

Thirty-two experimental red wines, obtained from eight cultivars and aged in bottles for 2 and 7 years, were examined for the presence of stable free radicals (SFR), for the peroxyl radical trapping capacity (PRTC), and for the concentrations of some important polyphenol families. Aging significantly increases SFR, polyphenol polymers with n ≥ 5 (HMWP), and PRTC and is accompanied by a strong decrease of free anthocyanins. Multivariate regression analyses show that HMWP and SFR are independently associated with PRTC while HMWP and anthocyanins are independently associated with the formation of SFR. These results indicate that polymeric polyphenols generated from anthocyanins and proanthocyanidins during wine aging are able to convert highly reactive free radicals into nonreactive radicals through electron delocalization. The strict correlation between SFR and antioxidant activity that we found suggests that these characteristics are related to the functional properties of food. Keywords: Free radical; ant...

Highly reactive radicals, ROO(*), were generated from 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] and linoleic acid. The ROO(*) scavenging capacity of some Italian red wines was evaluated following the changes in oxygen consumption. Under the experimental conditions the time course of oxygen consumption shows two typical behaviors: trolox-like (class I) and gallic acid-like (class II). Usually the time course of wine was similar to that of gallic acid. The rate of oxygen consumption was found to decrease exponentially with the amount of wine or gallic acid added to the test solution. On this basis the capacity of red wines to scavenge peroxy radicals was expressed as content of gallic acid (S(GA)). The S(GA) values were found to be correlated to the amount of total proanthocyanidins and total polyphenols of some Italian red wines (p < 0.01). The proanthocyanidins extracted from seeds were shown to make a major contribution to the peroxy radical scavenging capacity of red wines, whereas, interestingly, the chemical class of the low molecular weight tannins reactive to vanillin did not correlate with the S(GA) values.

The kinetics of ascorbic acid oxidation by molecular oxygen, catalyzed by bis(histidine)copper(II) (CuL22+), was followed in 0.1 M phosphate buffer at pH 7.0. Saturation of the oxidation rate was o...