Phytochemistry of fruit and vegetables

AbstractsCentro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Synthesis of the antioxidant hydroxytyrosol using tyrosinase as biocatalyst

7 pages, 6 figures.Hydroxytyrosol (HTyr), a natural ortho-diphenolic antioxidant with health-beneficial properties that mainly occurs in virgin olive oil and olive oil mill waste waters (also known as vegetative waters), has been enzymatically synthesized using mushroom tyrosinase. This o-diphenol (not commercially available) was obtained from its monophenolic precursor tyrosol (commercially available) in the presence of both tyrosinase and ascorbic acid. The reaction synthesis is continuous, easy to perform, and adaptable to a bioreactor for industrial purposes. The HTyr concentration is time-predicted, and the yield of reaction can be 100%. The synthesis method reported here is an alternative approach to obtain this compound in an environmentally friendly way.J.C.E. is holder of Marie Curie Contract HPMF-CT-1999-00023 from the European Commission under the framework of the program “Improving the Human Research Potential and the Socio-Economic Knowledge Base. E.C. is holder of a grant from the Movilidad de Investigadores y Tecnólogos program under the action “Mit-Becas; Modalidad F2”. (This work has been partially supported by the project CICYT-AGL-2000-2014).Peer reviewe

Production of bioavailable flavonoid glucosides in fruit juices and green tea by use of fungal a-L-rhamnosidases

Flavonoid glucosides have been reported to be more bioavailable than their rutinoside counterparts. The aim of this study is to describe a first step in the use of alpha-L-rhamnosidases (RhaA and RhaB) from Aspergillus aculeatus as a way to produce functional beverages based on their potentially increased flavonoid bioavailability. Blackcurrant juice (BCJ), orange juice (OJ), and green tea infusion (GT) were incubated with either RhaA or RhaB at 30 degreesC for 10 h. Aliquots of controls and enzyme-treated samples were taken at different time points and analyzed by high-performance liquid chromatography-photodiode-array detector-mass spectrometry of daughter fragments (HPLC-DAD-MS-MS). Both RhaA and RhaB selectively catalyze in situ the removal of terminal rhamnosyl groups in the three beverages despite the heterogeneity of assay conditions such as different rutinosides and pH. Incubation of the three beverages with the two rhamnosidases resulted in a hyperbolic decrease in the flavonoid rutinosides (anthocyanins in BCJ, flavanones in OJ, and flavonols in GT) and a concomitant increase in their flavonoid glucoside counterparts. The time required for conversion of 50% of the rutinoside into the corresponding flavonoid glucoside ranged from 30 min (RhaB-rutin in GT) to 6 h (RhaB-delphinidin 3-rutinoside in BCJ). The results presented in this paper are a step forward in the use of enzyme-treated beverages as a source of bioavailable flavonoid glucosides

Effects of water stress and rootstocks on fruit phenolic composition and physical/chemical quality in Suncrest peach

The aim of the present work was to evaluate the effects of water stress and different rootstocks on the quality indices and nutritional characteristics of peach fruit, cv. Suncrest. The results show how pre-harvest factors, such as the type of rootstock and water stress, can influence the quality indices and nutritional properties of peach fruits. Rootstocks type influenced both quality indices such as flesh firmness (FF) and soluble solid content (SSC), but it is unclear how rootstock exerted its influence. Also water stress induced changes in quality indices of peach fruit grafted on GF 677 and Montclar whereas minor effects were recorded when water stress was applied on Penta. The content of hydroxycinnamic acids was similar in control fruits of GF677, Montclar and Penta and it increased significantly only in fruit of trees grafted on GF 677 following water stress. Anthocyanins content in fruit of control plants was higher in Montclar in comparison with the fruit grafted on the other two rootstocks while procyanidin content was higher in fruit of control plants grafted on Penta. Following the water stress an increase in total anthocyanins was observed in GF 677 and Penta whereas no significant differences were found for Montclar. Water stress induced a significant decrease in procyanidin content in Penta. In conclusion in fruits of trees grafted on Penta following water stress quality indices did not show changes but significant variations in some phytochemicals, i.e. anthocyanins and procyanindins were observed. The results suggest that the regulation of water management is an important factor to maintain a good quality of the fruits. In fact, if irrigation stress can induce a higher biosynthesis of phytochemical compounds and an increase of SSC, at the same time, it can change fruit quality traits, such as a lower FW in Montclar, a higher titratable acidity (TA) in GF 677 and Penta and a lower FF in Gf 677 and Montclar

Estudio sobre el contenido en flavonoides de las mieles de La Alcarria Su aplicacion a la caracterizacion geografico-botanica

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai