Luana Fernandes

Espresso coffee residues: a valuable source of unextracted compounds.

Espresso spent coffee grounds were chemically characterized to predict their potential, as a source of bioactive compounds, by comparison with the ones from the soluble coffee industry. Sampling included a total of 50 samples from 14 trademarks, collected in several coffee shops and prepared with distinct coffee machines. A high compositional variability was verified, particularly with regard to such water-soluble components as caffeine, total chlorogenic acids (CGA), and minerals, supported by strong positive correlations with total soluble solids retained. This is a direct consequence of the reduced extraction efficiency during espresso coffee preparation, leaving a significant pool of bioactivity retained in the extracted grounds. Besides the lipid (12.5%) and nitrogen (2.3%) contents, similar to those of industrial coffee residues, the CGA content (478.9 mg/100 g), for its antioxidant capacity, and its caffeine content (452.6 mg/100 g), due to its extensive use in the food and pharmaceutical industries, justify the selective assembly of this residue for subsequent use.

Effect of High Hydrostatic Pressure (HHP) Treatment on Edible Flowers’ Properties

Edible flowers are increasing worldwide because they can improve the appearance, taste, and aesthetic value of food, aspects that the consumer appreciates. However, some of these are highly perishable and have a short shelf-life. To overcome these problems, high hydrostatic pressure (HHP) food processing might be applied, allowing producing high-quality food with enhanced safety and increased shelf-life. The application of HHP to vegetables has been extensively discussed and is already an industrial reality, but information on edible flowers is scarce and incomplete. Thus, in order to summarize the current knowledge on potential applications of HHP treatment in edible flowers and to determine the effect of this treatment on physical (e.g., color and texture) and nutritional characteristics as well as on microbial and enzymatic inactivation, a literature review was performed. It was stated that broccoli and cauliflower (inflorescences, usually not considered by consumers as flowers) have been the most studied, existing few information for other edible flowers. Thus, much more works are needed to better understand the effect and mechanisms behind HHP, and to define the adequate technological conditions for each flower.

Physicochemical composition and antioxidant activity of several pomegranate (Punica granatum L.) cultivars grown in Spain

Abstract Nine pomegranate cultivars grown in Spain were selected, and their physicochemical (total soluble solids, pH, titratable acidity, maturity index, monomeric anthocyanin pigment, flavonoids, hydrolyzable tannins, and vitamin C) and antioxidant properties and polyphenolic composition of the juices were compared. A total of 53 polyphenols were identified, showing cultivars different profiles. Of all nine cultivars, Katirbasi had the highest contents of flavonoids, hydrolyzable tannins and vitamin C, as well as gallic acid and ellagic acid contents, explaining its high total reducing capacity. Principal component analysis allowed Katirbasi to be differentiated clearly from the others. Other cultivars presented also interesting characteristics such as high monomeric anthocyanin pigment content (CG8 cultivar) and interesting antioxidant activity (Wonderful 2 and CG8 cultivars). CG8 was the cultivar with the highest value of cyanidin-3,5-di-O-glucoside. Thus, this study will assist pomegranate producers in choosing the most suitable cultivar according to its ultimate use.

Optimization of high pressure bioactive compounds extraction from pansies (Viola × wittrockiana) by response surface methodology

ABSTRACT Response surface methodology (RSM) was employed for the first time to optimize high pressure extraction (HPE) conditions of bioactive compounds from pansies, namely: pressure (X1: 0–500 MPa), time (X2: 5–15 min) and ethanol concentration (X3: 0–100%). Consistent fittings using second-order polynomial models were obtained for flavonoids, tannins, anthocyanins, total reducing capacity (TRC) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The optimum extraction conditions based on combination responses for TRC, tannins and anthocyanins were: X1 = 384 MPa, X2 = 15 min and X3 = 35% (v/v) ethanol, shortening the extraction time when compared to the classic method of stirring (approx. 24 h). When the optimum extraction conditions were applied, 65.1 mg of TRC, 42.8 mg of tannins and 56.15 mg of anthocyanins/g dried flower were obtained. Thus, HPE has shown to be a promising technique to extract bioactive compounds from pansies, by reducing the extraction time and by using green solvents (ethanol and water), for application in diverse industrial fields.

Temperature Effect on Rheological Behavior of Portuguese Honeys

Abstract In the present work the temperature effect on rheological properties of Portuguese honeys was studied for the first time. Two unifloral honeys – heather and rosemary – and a polyflower honey were analyzed. All honeys showed flow independence over time and behaved as Newtonian fluids at the studied temperature and shear rate ranges. For all honeys it was found that the viscosity decreased with temperature and the rosemary honey was the one that always presented the lowest viscosity at 30°C (6120 mPa·s), 50°C (603 mPa·s) and 70°C (145 mPa·s). The temperature dependence of viscosity was well described by the K0×eAT-B

Effect of application of edible coating and packaging on the quality of pansies (Viola × wittrockiana) of different colors and sizes:

K_0 \times e^{{A \over {T - B}}}

Post-harvest technologies applied to edible flowers: a review: Edible flowers preservation

equation. Nevertheless, good regression coefficients were also obtained when fitting the experimental data to the Arrhenius model, showing the rosemary honey to be less temperature sensitive. The results obtained in this study are of great interest to beekeepers and industrials that handle and prepare eatable honey-based products because they will be better informed about the best type of honey to use.

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

The effects of alginate edible coating on the quality of pansies (visual appearance, weight loss, water activity, color, and dimensions change) were studied during refrigerated storage (4 ℃). The role of pansies’ color and size, as well as packaging, was also studied. Alginate treatments resulted in a beneficial effect on the visual appearance of pansies under refrigerated storage when compared to the uncoated, delaying their degradation from 3–4 days up to 14 days, depending on the pansies’ color, probably derived from their different petal thicknesses (83 to 183 µm for yellow and red pansies). The unpackaged coated pansies had different behaviors during storage, associated with their dimensions (the larger coated pansies maintained good visual appearance during longer storage times than the smaller ones). However, the packaged pansies treated with edible coating showed to have lower weight loss and shrinkage than the unpackaged, irrespective of the color and size, with physical stability up to 14 days. In summary, the cumulative use of alginate coating with packaging under refrigerated storage may contribute to extend pansies’ shelf life.

Seed oils of ten traditional Portuguese grape varieties with interesting chemical and antioxidant properties

ABSTRACT 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.

Fatty acid, vitamin E and sterols composition of seed oils from nine different pomegranate (Punica granatum L.) cultivars grown in Spain

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.