Simultaneous Evaluation of Intact Glucosinolates and Phenolic Compounds by UPLC-DAD-MS/MS in Brassica oleracea L. var. botrytis

A method for the simultaneous determination of intact glucosinolates and main phenolic compounds (flavonoids and sinapic acid derivatives) in Brassica oleracea L. var. botrytis was proposed. A simplified sample extraction procedure and a UPLC separation were carried out to reduce the total time of analysis. Brassica oleracea samples were added with internal standards (glucotropaeolin and rutin), and extracted with boiling methanol. Crude extracts were evaporated under nitrogen, redissolved in mobile phase and analyzed by UPLC with double detection (ESI--MRM for glucosinolates and flavonoids, and DAD for main sinapic acid derivatives). The proposed method allowed a satisfactory quantification of main native sinapic acid derivatives, flavonoids and glucosinolates with a reduced time of analysis.

Assessing the impact of high-pressure processing on selected physical and biochemical attributes of white cabbage (Brassica oleracea L. var. capitata alba)

The aim of this study was to investigate the effect of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on key physical and chemical characteristics of white cabbage (Brassica oleracea L. var. capitata alba). Thermal treatment (blanching) was also investigated and compared with high-pressure processing (HPP). HPP at 400 MPa and 20–40 °C caused significantly larger colour changes compared to any other pressure or thermal treatment. All pressure treatments induced a softening effect, whereas blanching did not significantly alter texture. Both blanching and pressure treatments resulted in a reduction in the levels of ascorbic acid, effect that was less pronounced for blanching and HPP at 600 MPa and 20–40 °C. HPP at 600 MPa resulted in significantly higher total phenol content, total antioxidant capacity and total isothiocyanate content compared to blanching. In summary, the colour and texture of white cabbage were better preserved by blanching. However, HPP at 600 MPa resulted in significantly higher levels of phytochemical compounds. The results of this study suggest that HPP may represent an attractive technology to process vegetable-based food products that better maintains important aspects related to the content of health-promoting compounds. This may be of particular relevance to the food industry sector involved in the development of convenient novel food products with excellent functional properties

High pressure processing of swede (Brassica napus): Impact on quality properties

The effects of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on the physical and nutritional properties of swede roots (Brassica napus var. napobrassica) were assessed. Changes induced by high pressure processing (HPP) on the original properties of swede samples were compared with those produced by thermal treatment (blanching). All studied treatments altered the physical properties of swede, resulting in a loss of hardness and water binding capacity. The strongest alteration of texture was observed after HPP at 400 MPa, while 600 MPa was the treatment that better preserved the texture properties of swede. Blanching caused less total colour changes (ΔE) than HPP. Antioxidant properties of swede were measured as total antioxidant capacity, ascorbic acid and total phenol content. All treatments caused a loss of antioxidant capacity, which was less pronounced after HPP at 600 MPa and 20 °C and blanching. Four glucosinolates were detected in swede roots, glucoraphanin, progoitrin, glucobrassicanapin and glucobrassicin. Glucobrassicanapin and glucobrassicin contents were reduced with all studied treatments. Progoitrin content was not affected by blanching and HPP at 200 MPa. HPP at higher pressure levels (400 and 600 MPa), though, induced an increase of progoitrin levels. The results indicated that blanching and HPP at 600 MPa and 20 °C were the treatments that better preserved the original quality properties of swede.

Metabolic origin of δ15N values in nitrogenous compounds from Brassica napus L. leaves

Nitrogen isotope composition (δ15N) in plant organic matter is currently used as a natural tracer of nitrogen acquisition efficiency. However, the δ15N value of whole leaf material does not properly reflect the way in which N is assimilated because isotope fractionations along metabolic reactions may cause substantial differences among leaf compounds. In other words, any change in metabolic composition or allocation pattern may cause undesirable variability in leaf δ15N. Here, we investigated the δ15N in different leaf fractions and individual metabolites from rapeseed (Brassica napus) leaves. We show that there were substantial differences in δ15N between nitrogenous compounds (up to 30 ) and the content in (15N enriched) nitrate had a clear influence on leaf δ15N. Using a simple steady-state model of day metabolism, we suggest that the δ15N value in major amino acids was mostly explained by isotope fractionation associated with isotope effects on enzyme-catalysed reactions in primary nitrogen metabolism. δ15N values were further influenced by light versus dark conditions and the probable occurrence of alternative biosynthetic pathways. We conclude that both biochemical pathways (that fractionate between isotopes) and nitrogen sources (used for amino acid production) should be considered when interpreting the δ15N value of leaf nitrogenous compounds

Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi

This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora, Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibition of P. expansum infection in wounds of Golden Delicious apples. Four strains (TC97, AC318, TM319, and FF441) reduced the fungal rot diameter of the apples by 20%; only Weissella cibaria strain TM128 decreased infection levels by 50%. Cell-free supernatants of selected antagonistic bacteria were studied to determine the nature of the antimicrobial compounds produced. Organic acids were the preferred mediators of inhibition but hydrogen peroxide was also detected when strains BC48, TM128, PM141 and FF441 were tested against E. carotovora. While previous reports of antifungal activity by LAB are scarce, our results support the potential of LAB as biocontrol agents against postharvest rot. [Int Microbiol 2008; 11(4):231-236]

Aportacions a la Flora de les comarques transiberiques, II.

Presentem un recull de novetats corològiques i taxonòmiques per a les comarques catalanes situades al sud de l'Ebre. Es descriuen dos tàxons nous: Brassica repanda (Willd.) DC. subsp. dertosensis Molero i Rovira i Helianthemum pilosum (L.) Pers. var. pseudoasperum Molero i Rovira. S'estableix una nova combinació nomenclatural: Reseda lutea L. subsp. vivantii (P. Montserrat) A. Rovira. En l'aspecte corologie, Euphorbia lagascae Sprengel representa una novetat per a Catalunya. La majoria de les altres citacions representen novetats pel conjunt d'aquestes comarques catalanes meridio-occidentals.

Contribució a la flora dels macromicets de l'illa de Mallorca

Com a resultat de les prospeccions micològiques realitzades a Mallorca entre els anys 1983 i 1990, donem a conèixer un catàleg de 218 taxons (8 Ascomycetes i 210 Basidiomycetes), dels quals creiem que 74 corresponen a citacions noves per a l'illa. En destaquem, entre d'altres: Cordyceps militaris (L.) Link, Daldinia vernicosa (Schw.) Ces. et de Not., Dichomitus campestris (Quél.) Domanski et Ori., Agaricus lanipes (Moell. et Schaeff.) Sing., Amanita boudieri Barla, Clitocybe lituus (Fr.) Metr., Hygrocybe reai Mre., Inocybe tenebrosa Quél., Leucopaxillus tricolor (Peck) Kühn, i Russula seperina Dupain.

Dades floristiques per a l'Alt Bergueda

Se presenta una lista de 19 táxones con interés corológico, del Alt Berguedá (Pirineos orientales), con algunas observaciones acerca de su ecología, y en algunos casos con su distribución en Cataluña. La lista incluye nuevas localidades pirenaicas para orófitos (Brassica repanda subsp. turbonis, Alyssum cuneifolium), plantas mediterráneas (Asparagus acutifolius, Arenaria modesta), sinantrópicas (Impatiens balfourii), etc.