Phytochemical characterization of Borago officinalis L. and Centaurea cyanus L. during flower development

The present work details the nutritional and chemical compositions of borage and centaurea, at three flowering stages. Water was the main constituent, followed by total dietary fiber. Both flowers showed statistically different (p < 0.05) nutritional and chemical profiles, although in both, polyunsaturated fatty acids (PUFAs) (mainly linoleic and α-linolenic acids), free sugars (3.9–28.9% dw as fructose, glucose, and sucrose), tocopherols (with the major contribution of α-tocopherol from 1.24 to 2.75 mg/100 g dw), carotenoids (0.2–181.4 mg/100 g dw, mainly as lutein), and organic acids (6.1–14.4 g/100 g dw, mainly malic, succinic, and citric acids) were quantified. Concerning flowering, significant differences (p < 0.05) were found for some components, particularly carotenoids; however, no specific trend was observed in either of the two flower species. Thus, the present study shows that each floThe authors acknowledge the Portuguese Foundation for Science and Technology (FCT, Portugal) for the financial support provided by the research grant SFRH/BD/95853/2013 to Luana Fernandes and FCT/MEC for the financial support to QOPNA research Unit (FCT UID/ QUI/00062/2013) and LAQV Research Unit (UID/QUI/50006/2013 -POCI/01/0145/FEDER/007265) through national funds and co-financed by the FEDER, within the PT2020 Partnership Agreement. Furthermore, the authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013).info:eu-repo/semantics/publishedVersio

Enzymatic activity during frozen storage of Atlantic horse mackerel (Trachurus trachurus) pre-treated by high-pressure processing

The assessment of enzymatic activity on Atlantic horse mackerel (Trachurus trachurus) during frozen storage was carried out in samples pre-treated by high-pressure processing (HPP) combinations of 150, 300 and 450 MPa with 0-, 2.5- and 5-min holding time (untreated samples were used as controls). The activities of four enzymes (acid phosphatase, cathepsins B and D, and lipase) in fish muscle were quantified during accelerated storage conditions (up to 3 months at −10 °C). The experimental data were fitted to second-order polynomial models to determine the effect of pressure level, holding time and frozen storage time on these enzyme activities and to identify conditions of maximum/minimal enzyme inactivation. Acid phosphatase and cathepsin (B and D) activities were significantly (p<0.05) influenced by HPP, showing behaviours during frozen storage different from control samples. Acid phosphatase and cathepsin B activities decreased (p<0.05) with HPP treatments, being this effect more intense for cathepsin B, particularly at 450 MPa. Regarding cathepsin D, the activity increased (p<0.05) at intermediate pressure (300MPa) and decreased (p<0.05) at higher pressure (450 MPa). During frozen storage, cathepsin D enzymatic activity tended to increase over time indicating activity recovery of these enzymes. Although a predictive model for its activity was not acceptable, the increase in lipase activity during storage was the most pronounced trend observed

Effect of high-pressure processing of Atlantic mackerel (Scomber scombrus) on biochemical changes during commercial frozen storage

This research focuses on biochemical changes related to quality losses observed in Atlantic mackerel (Scomber scombrus) muscle stored under commercial frozen storage conditions (9 months, −18 °C) when subjected to highhydrostatic pressure (HHP) treatments (125, 150, 175, and 200 MPa for 0 min) before freezing. After freezing, free fatty acid (FFA) formation (lipid hydrolysis assessment) showed a marked inhibition in HHP-treated fish and during frozen storage of samples treated at 175 MPa. Fluorescence ratio (FR) assessment of tertiary lipid oxidation showed a partial inhibitory effect during the 0–9-month period for samples treated at 175 and 200 MPa. After a 3-month storage of samples treated at these pressure levels, one-dimensional SDS-PAGE analysis of the sarcoplasmic protein fraction revealed the disappearance of a band; additionally, samples treated at 150 MPa showed the same effect at month 9. After gel excision, trypsin digestion, tandem mass spectrometry (MS/MS), and sequence database analysis, the band was identified as phosphoglycerate mutase 2 (28.7 kDa). On the other hand, HHP processing did not show a significant effect on trimethylamine (TMA) values, primary and secondary lipid oxidation, PUFA levels, 1-D myofibril protein pattern, and the activity of acid phosphatase and cathepsins B and D. Biochemical quality indices such as FFA, TMA, and FR and the activity of acid phosphatase and cathepsin B showed a progressive increase throughout the frozen storage of all samples

Effect of solvent type and high pressure treatment on the extraction of Gomphrena globosa L. bioactive compounds

The present study aimed to compare the influence of different extraction solvents (water, methanol, water:acetone (6:4, v/v)), methods (heating (37 °C, 30 min) or high pressure (HP) (300 or 500 MPa) and extraction time (7.5 or 15 min)) on flavonoids, hydrolysable tannins and antioxidant activity (Total Reducing Capacity (TRC), DPPH Free Radical Scavenging Activity and Reducing Power) of Gomphrena globosa L. flower extracts. The water:acetone extracts obtained by heating had the highest values of flavonoids, hydrolysable tannins and antioxidant activity. When applying HP, variable results were obtained. Still, the application of HP to water allowed to extract more hydrolysable tannins, as well as to obtain extracts with higher antioxidant activity than with heating, but no significant alterations were observed with methanol. In conclusion, both solvent and extraction method influence the content of bioactive compounds, being HP treatment a promising method to obtain enriched aqueous extracts in line with the principles of green-chemistry.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT, Portugal) for the financial support provided by the research grant SFRH/BD/95853/2013 and FCT/MEC for the financial support to QOPNA research Unit (FCT UID/QUI/00062/2013) and REQUIMTE (UID/QUI/50006/2013) through national funds and when applicable cofinanced by the FEDER, within the PT2020 Partnership Agreement.info:eu-repo/semantics/publishedVersio

Edible flowers: a nutritional perspective

As flores comestíveis têm sido usadas na culinária de diversos países, tendo hoje em dia, o seu uso despertado a atenção com o intuito de melhorar a aparência, sabor e valor estético de pratos, aspetos que o consumidor aprecia e valoriza. No entanto, os consumidores também exigem alimentos com propriedades benéficas para a saúde, procurando produtos com qualidade nutricional interessante. Nesse sentido, o presente documento pretende abordar a composição nutricional de algumas flores comestíveis, incluindo os macro e micronutrientes, bem como alguns compostos bioativos que demonstram o valor e potencial das flores comestíveis.info:eu-repo/semantics/publishedVersio

Influence of solvent and high pressure treatment in the extraction of bioactive compounds in Gomphrena globosa L.

Gomphrena species are edible, commercial ornamental and medicinal plants commonly known as Globe Amaranth or Bachelor Button.1 The flowers of Gomphrena globosa L. have medicinal potential, once they are rich in bioactive compounds such as betacyanins, betalaines and flavonoids. Currently there is a very large and global interest in finding cheap and abundant sources of natural antioxidants. High pressure extraction has been recently applied to extract bioactive ingredients from plant materials, taking advantages of time saving, higher extraction yields, fewer impurities in the extraction solution, minimal heat and avoidance of thermal degradation on the activity and structure of bioactive components.2 The present study aimed to compare the influence of different extraction solvents (water, methanol, water:acetone (6:4; v:v)) and methods (heating under agitation (37 °C, 30 min) and high pressure (300 or 500 MPa) at different times (7.5 or 15 min)) on the content of flavonoids, hydrolysable tannins and antioxidant activity (Total Reducing Capacity, Scavenging of DPPH free radical and Reducing Power) in flower extracts. The water:acetone extracts obtained by heating under agitation had the highest values of flavonoids, hydrolysable tannins and Total Reducing Capacity, as well as the lowest EC50 values of DPPH free radical scavenging activity and Reducing Power, suggesting higher antioxidant activity than other solvents. When performing high pressure extraction it was found that different results were obtained with different time and pressure combinations, as well as solvents. The highest values of hydrolysable tannins and flavonoids were obtained with the binomial time/pressure of 15 min/300 MPa for all solvents, while the lowest EC50 value of DPPH was obtained at 15 min/500 MPa, for all solvents. The others parameters differed on the binomial time/pressure for the three solvents studied. For all parameters the values ranges were higher without high pressure than with high pressure application. Generally, for water and methanol extractions higher concentrations of flavonoids, hydrolysable tannins and Total Reducing Capacity were obtained after application of high pressure treatment in comparison to the traditional method, suggesting a higher extraction efficiency. On the other hand, with the water:acetone mixture, higher values of the former parameters were obtained without high pressure application. In conclusion, the solvent and method used in the extraction directly influence the content of bioactive compounds of Bachelor Button. The results showed that high pressure extraction can be a promising method to extract more natural antioxidants. However, in future more studies must be performed on the compounds to be extracted after application of different time/pressure binomials to better understand their extractability.info:eu-repo/semantics/publishedVersio

Lipid and protein changes related to quality loss in frozen sardine (Sardina pilchardus) previously processed under high-pressure conditions

This research focuses on biochemical changes related to quality loss in frozen (−18 °C for 9 months) sardine (Sardina pilchardus) previously subjected to high-pressure (HP) processing (125–200 MPa). The inhibition (p < 0.05) of lipid hydrolysis development (lower free fatty acid formation and lipase activity), observed in frozen sardine as a result of the previous HP treatment, increased with the pressure level applied. Several parameters including peroxide value, thiobarbituric acid index, fluorescent compounds, and polyenes showed that the applied HP conditions prior to sardine freezing did not increase lipid oxidation. Also, HP did not induce a substantial modification of acid phosphatase and cathepsins B and D activities, and the electrophoretic patterns of sarcoplasmic and myofibrillar protein fractions did not change. However, HP processing led to a decrease in myofibrillar protein content in frozen pressure-treated fish, an effect that was higher in 175- and 200-MPa treated samples. In conclusion, this research showed that pressure treatments in the 125–200- MPa range with holding time of 0 min cause only minor modifications in biochemical indicators of deterioration throughout the subsequent frozen storage of samples for up to 9 months. This study shows the need to optimize HP conditions, particularly in the case of applications combining HP treatments, frozen storage, and thawing to obtain products with high quality and commercial viability

Efeito de diferentes métodos de secagem nos compostos bioactivos e propriedades antioxidantes de pétalas de Centáurea (Centaurea cyanus)

The present study aimed to evaluate the effects of hot-air convective drying, shade drying and freeze-drying on the bioactive compounds and antioxidant activity of Centaurea (Centaurea cyanus L.) petals, as well as on several of their physicochemical properties. All the dried samples showed different appearances as compared to fresh petals, with lower titratable acidity, lower carotenoids and hydrolysable tannins contents, and greater antioxidant activity. Of the drying methods, shade drying presented the highest values for monomeric anthocyanins, flavonoids, hydrolysable tannins, total reducing capacity and antioxidant activity. By contrast, greater losses were observed as a result of hot-air convective drying. Thus shade drying is a highly promising process that should be considered as a suitable drying method for Centaurea petals.No presente trabalho pretendeu-se avaliar o efeito da secagem por convecção com ar quente, secagem à sombra e liofilização sobre compostos bioactivos e actividade antioxidante de pétalas de centáurea, bem como em algumas propriedades físico-químicas. Todas as amostras desidratadas apresentaram uma aparência diferente das frescas, menor acidez titulável e menores teores de carotenóides e taninos hidrolisáveis. Por outro lado, as amostras secas apresentaram uma maior actividade antioxidante. Entre os métodos de secagem, a secagem à sombra apresentou os maiores valores de antocianinas monoméricas, flavonóides, taninos hidrolisáveis, capacidade redutora total e actividade antioxidante. Pelo contrário, as maiores perdas foram observadas com ar quente. Assim, a secagem à sombra é um processo bastante promissor que deve ser considerado como um método adequado para desidratar pétalas de centáurea.info:eu-repo/semantics/publishedVersio

Post-harvest technologies applied to edible flowers: a review

This review intends to summarize the current knowledge on the post-harvest technologies applied to edible flowers, to help producers to increase their market share and to inform consumers on the technologies that are available to maintain edible flowers’ quality and safety. Emerging post-harvest technologies as High Hydrostatic Pressure (HHP) or irradiation have given good results. Freeze- or vacuum-drying has shown to be highly effective in the preservation of flowers’ bioactive compounds in comparison with classical drying approaches. While osmotic dehydration is already in use, the application of edible coatings and films can be a healthier alternative, without increasing solute contents.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT, Portugal) for the financial support provided by the research grant SFRH/BD/95853/2013 and FCT/MEC for the financial support to QOPNA research Unit [FCT UID/QUI/00062/2013], through national funds and when applicable co-financed by the FEDER, within the PT2020 Partnership Agreement, and to REQUIMTE through the Project PEst/UID/QUI/50006/2013. The authors are also grateful to FCT (Portugal) and FEDER under Program PT2020 for financial support to CIMO [UID/AGR/00690/2013].info:eu-repo/semantics/publishedVersio