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- In vitro gastrointestinal digestion of pomegranate peel (Punica granatum) flour obtained from co-products: changes in the antioxidant potential and bioactive compounds stabilityPublication . Gullón, Beatriz; Pintado, Manuela E.; Fernández-López, Juana; Pérez-Álvarez, José A.; Viuda-Martos, ManuelThe effect of in vitro gastrointestinal digestion (GID) on the recovery, bioaccessibility and stability of polyphenolic compounds, the changes in antioxidant activity and the short chain fatty acids (SCFAs) production of pomegranate peel flour (PPF) were evaluated. The extracts obtained in each step of GID were used to determine the stability of polyphenolic profile using HPLC whilst the antioxidant properties were determined using five methodologies. The SCFAs production from PPF fermentation was also determined. At the end of GID process, the bioaccessibility of phenolic and flavonoid compounds was 35.90 and 64.02%, respectively. The polyphenolic compounds decreased after GID except that for ellagic acid which increased. GID increased the chelating activity and reducing power. However, the scavenging properties were reduced. Fermentation of PPF by colonic bacteria generated acetic, propionic and butyric acids. PPF could be used in the food industry as a potential ingredient to develop functional foods that promote health benefits.
- Chemical composition and in vitro antimicrobial, antifungal and antioxidant 1 propertiesPublication . Alves-Silva, Jorge M.; Dias dos Santos, Sandra M.; Pintado, Manuela E.; Pérez -Álvarez, José A.; Fernández-López, Juana; Viuda-Martos, ManuelThe aim of this study was determine (i) the chemical composition (ii) the antimicrobial activity (anti-bacterial and antifungal) and (iii) the antioxidant activity by means of four different antioxidant tests (DDPH, FIC, FRAP and TBARS) of the EOs of three aromatic herbs, Coriander (Coriandrum sativum), celery (Apium graveolens) and bush-basil (Ocimum minimum) widely used in Portugal. There is a great variability of the compounds presented in the three tested essential oils. Bush-basil EO had the highest total phenolic content (794.9 mg GAE/L) while coriander EO had the lower total phenolic content (52.3 mg GAE/L). Since bush-basil had the highest TPC it was expected to present a very high antioxidant profile, which was verified in 3 of the 4 assays (DPPH inhibition of 95.9%; FRAP values of 2.7 mmol Trolox/L; TEARS inhibition of 87.2%); coriander, despite the low TPC showed the highest inhibition in the FIC assay (94.1%). The bush-basil EO showed the highest antimicrobial activity, with MIC ranging between 0.6 and 5 mu L/mL against bacteria and 0.04-2.5 mu L/mL against yeasts. Both celery and coriander EO had a very similar antimicrobial activity against all the tested strains. The antifungal activity was higher in the bush-basil EO against Mucor racemosus and Penicillium chrysogenum since it was the only EO that showed growth inhibition on all the tested concentrations. Alternaria alternata showed great resistance against all the tested essential oils.
- Bioaccessibility, changes in the antioxidant potential and colonic fermentation of date pits and apple bagasse flours obtained from co-products during simulated in vitro gastrointestinal digestionPublication . Gullón, Beatriz; Pintado, Manuela E.; Barber, Xavier; Fernández-López, Juana; Pérez-Álvarez, José A.; Viuda-Martos, ManuelThe aims of this work were to evaluate the effect of in vitro gastrointestinal digestion (GID) on (i) the recovery and bioaccessibility indexes, (ii) the changes on antioxidant activity and (iii) the short chain fatty acid (SCFA) production of two DF rich extracts (date pits flour (DPF) and apple bagasse flour (ABF)) obtained from agroindustrial co-products. At the end of GID process, the bioaccessibility of phenolic compounds present in DPF and ABF was 78.54 and 91.58%, respectively. With regard to antioxidant activity, GID increased the chelating activity and reducing power. However, the scavenging properties were reduced. Fermentation of DPF and ABF by colonic bacteria generated SCFA such as formiate, succinate, acetate, propionate and butyrate. These findings suggest that DPF and ABF might be used as potential food ingredients due to GID produced that bioactive compounds released from the matrix which exerts antioxidant activity.
- In vitro evaluation of “horchata” co-products as carbon source for probiotic bacteria growthPublication . Sánchez-Zapata, Elena; Fernández-López, Juana; Pérez-Alvarez, José A.; Soares, José; Sousa, Sérgio; Gomes, Ana M. P.; Pintado, Manuela M. E.Tiger nut milk ("horchata") liquid co-products (TNLC) were evaluated as carbon source for probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium animalis) growth by screening via microplate assay and determination of viable cells and metabolic activity. Based on MRS five different basal media were prepared ((i) without carbon source, (ii) with 2% (w/v) glucose, (iii) with 2% (w/v) FOS, (iv) with 2% (v/v) TNLC and (v) 3% (v/v) TNLC). Additionally, reconstituted TNLC was also used as basal medium. For determination of viable cells and metabolic activity skim milk powder was used. Glucose was found to be the best substrate to L. acidophilus grows, followed by FOS and TNLC (2% and 3%, respectively). TNLC (3%) was found to be the best substrate followed by TNLC (2%), glucose and FOS, in the promotion of growth of B. animalis. The growth of L. acidophilus and B. animalis in skim milk reconstituted TNLC + water was higher than samples inoculated in skim milk reconstituted only with water (p < 0.05). This is supported by the pH effect and by the faster organic acid production (mainly lactic acid, acetic acid, and butyric acid), confirming the property of TNLC as a carbon source for probiotic bacteria growth.