Variation of Polyphenols, Anthocyanins and Antioxidant Power in the Strawberry Grape (<i>Vitis labrusca</i>) after Simulated Gastro-Intestinal Transit and Evaluation of <i>in Vitro</i>Antimicrobial Activity

The influence of a simulated digestive process on some biochemical and biological aspects of strawberry grape (Vitis labrusca) was investigated. The amount of total polyphenols and anthocyanins as well as the antioxidant power were evaluated. Results evidenced that the simulated gastrointestinal transit caused a decrease of the polyphenols content and total anthocyanins;these last, however, were more resistant than polyphenols, decreasing only of 50% respect to the initial value (31.50 μg/ml of extract). The extract exhibited an excellent antioxidant power (EC50 3.8 mg/ml), which decreased of about four times after the simulated gastrointestinal transit. The antimicrobial activity of the extract, evaluated against three Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus pathogen strains was enhanced by the simulated digestion, with an increase of the inhibition halo.

Polyphenol Composition and Antioxidant Activity of Two Autochthonous Brassicaceae of the Campania Region, Southern Italy

Torzella (Brassica oleracea acephala) is one of the most ancient kinds of cauliflower developed in the Mediterranean area. Broccolo (Brassica oleracea botrytis cimosa), var. “San Pasquale” is a leafy vegetable cultivated in Campania too, mainly in the province of Naples. We evaluated the polyphenols content and the antioxidant activity of these two Brassicaceae, provided by the same experimental plant of the Campania region. Both vegetables showed high content of total polyphenols (6.37 mM GAE/g and 2.24 mM GAE/g of Torzella and Broccolo, respectively), and a remarkable antioxidant activity (EC50 1.53 mg and EC50 6.51 mg, in Torzella and Broccolo, respectively). Polyphenol composition, determined by ultra performance liquid chromatography (UPLC), allowed us to detect a certain number of compounds (gallic, ferulic, chlorogenic, p-coumaric and caffeic acids, catechin, luteolin, naringenin) common to both species. Therefore, epicatechin was found only in the extract of san Pasquale broccoli;on the contrary, rutin and apigenin were detected only in the extracts of torzella broccoli. Hence, such products can be considered therapeutic functional foods due to their extraordinary reserve of secondary metabolites and bioactive constituents that are beneficial for managing and preventing several chronic illnesses in humans.

Polyphenol Composition and Antioxidant Activity of Different Potentially Functional Kale-Based Snacks

Four types of kale-based snacks were investigated on the basis of polyphenol content and composition, glucosinolates amount, and antioxidant activity. The amount of polyphenols resulted to be higher than that of raw material, fresh kale (0.57 ± 0.03 mg GAE). The antioxidant activity turned out indeed very effective, resulting sufficient just from 0.72 mg to 2.1 mg to dishearten the activity of 1 ml DPPH to 50%. Glucosinolates present in kale-based snacks ranged from 1.17 mg/gr to 1.52 mg of sinigrin equivalent/gr. Polyphenol profile, obtained by UPLC-DAD analysis allowed us to identify gallic acid, chlorogenic acid, and catechin common in all samples. Other polyphenols, that is caffeic acid, p-coumaric acid, and ferulic acid, were found in almost all samples, almost all more abundant than fresh kale, representing a precious source of beneficial metabolites. Our results suggest that such snacks could represent an effective functional dietary supplement also if compared to fresh vegetable. Manufacturing of kale-based snacks does not negatively affect the beneficial effect of the raw material;indeed, such snacks could positively meet people’s expectation, mainly children and young, well known consumers of snacks, which, also in such manner, could be addressed towards a healthier dietary regime.