RESUMO
Synthetic vitamin E is commonly used in aquafeeds to prevent oxidative stress in fish and delay feed and flesh oxidation during storage, but consumers' preferences tend towards natural antioxidant sources. The potential of vegetable antioxidants-rich coproducts, dried tomato (TO), carrot (CA) and coriander (CO) was compared to that of synthetic vitamin E included in diets at either a regular (CTRL; 100 mg kg-1) or reinforced dose (VITE; 500 mg kg-1). Natural antioxidants were added at 2% to the CTRL. Mixes were then extruded and dried, generating five experimental diets that were fed to European sea bass juveniles (114 g) over 12 weeks. Vitamin E and carotenoid content of extruded diets showed signs of degradation. The experimental diets had very limited effects on fish growth or body composition, immunomodulatory response, muscle and liver antioxidant potential, organoleptic properties or consumer acceptance. Altogether, experimental findings suggest that neither a heightened inclusion dose of 500 mg kg-1 of vitamin E, nor a 2% inclusion of natural antioxidants provided additional antioxidant protection, compared to fish fed diets including the regular dose of 100 mg kg-1 of vitamin E.
RESUMO
The single-dose coffee capsule is the most successful technology used to prepare espresso coffee (EC). However, the characterization of ECs extracted using this technology, regarding chlorogenic acids (CGAs) composition, antioxidant activity and stability during gastrointestinal digestion (GID), are still limited. The aim of this research work was: (i) to characterize the phenolic profile and antioxidant activity of 11 commercial ECs from single-dose capsule system and (ii) to evaluate the impact of the in vitro GID on the stability of CGAs. Within all the ECs analysed it was detected the presence of 4 caffeoylquinic acids (CQAs), 1 feruloylquinic acids, 2 caffeoylshikimic acids and 3 diCaffeoylquinic acids (di-CQAs). The major compound in all ECs was 5-CQA, followed by 4-CQA and 3-CQA. The di-CQAs were found in lower concentration than CQAs (4,5-diCQA > 3,4-diCQA > 3,5-diCQA). The total CQAs and diCQAs content of the ECs analyzed ranged from 1.86 ± 0.19 to 2.42 ± 0.28 and 0.26 ± 0.02 to 0.42 ± 0.06 mg/mL of EC, respectively. The high antioxidant activity of the ECs is related with the high CGAs concentration, which ranged from 4.92 ± 0.29 to 7.28 ± 0.25 mg AAE/mL of EC and from 6.13 ± 0.37 to 10.07 ± 0.17 mg TE/mL of EC for ABTS° and DPPH° methods, respectively. The principal component analysis showed that the coffee variety used in ECs preparation explained 74.8% of the results' variation and that 6 of the total number of ECs were related with high CGAs contents and antioxidant activity. The GID induced a decrease in most CGAs, which had a direct impact on the antioxidant activity, therefore concerning EC ingestion the CGAs bioaccessible concentration decreased in comparison with a non-digested EC. Nevertheless, the CGAs concentration available after GID is still sufficiently high to exert antioxidant activity (measured in vitro) that may exert a potential beneficial effect on humans health.
