No abstract

Analyses of antioxidant and in vitro antimicrobial and anti-proliferative activities of anthocyanin-rich extracts from purple potatoes, Solanum tuberosum L. cv Vitelotte noire (Solanaceae), were performed by simulating both a domestic cooking process and human digestion. Extracts of crude and cooked purple potato did not exhibit antimicrobial activity against the tester strains: Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. The behaviour changed after the simulated gastrointestinal transit, when an inhibition halo was observed against all tester strains used, ranging from 0.53 cm against B. cereus to 0.82 cm against E. coli. In addition antioxidant activity exhibited, before and after the simulated gastrointestinal digestion (5.96 mg/mL ± 0.92; 28 mg/mL ± 0 .13, respectively) and the persistence of anti-proliferative activity against the colon cancer cells Caco-2, SW48 and MCF7, MDA-MB-231 breast cancer cells, after the simulated digestion, (EC50 = 0.21; 1.13 μg/mL), suggest that vitelotte consumption might bring tangible benefits for human health.

The probiotic yeast, Saccharomyces cerevisiae boulardii, was microencapsulated in a mixture of alginate-inulin-xanthan gum, and its ability to grow in berry juice and survive 4 weeks of storage at 4 °C was determined. Exposure of the yeast in these forms to artificial gastrointestinal conditions was also assessed. Encapsulation significantly enhanced cell viability after fermentation and storage compared with the free yeast (7.59 log10 colony forming units/ml versus 6.98 log10 colony forming units/ml, respectively) and protected it from exposure to a simulated gastrointestinal transit after 4 weeks of storage. Conversely, a dramatic loss of viability was exhibited by free yeast after 4 weeks of storage, and viability values closer to zero (0.23 log10 cfu/ml) were found after the simulated gastrointestinal treatment. Microcapsules were capable of absorbing a certain amount of polyphenols and anthocyanins. This work, based on use of microencapsulated probiotic yeasts, might represent the starting point for the development of new functional foods or functional ingredients. Microcapsules were capable to absorb, from berry juice, a certain amount of anthocyanins which, maintaining their native form after the in vitro gastrointestinal transit, might in vivo therein be transformed into other, simpler molecules, with beneficial effect on microflora and human health too.

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 (EC 50 1.53 mg and EC 50 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.

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.