HPLC-DAD-MS/MS ESI characterization of unusual highly glycosylated acylated flavonoids from cauliflower (Brassica oleracea L. var. botrytis) agroindustrial byproducts

In a recent program to investigate the possible use of vegetable handling and commercialization wastes and residues as a source of potentially bioactive extracts, we have studied cauliflower byproducts. A total of twenty-eight compounds were characterized by HPLC-DAD-MS, of these, twenty-two are produced naturally by the plant. The main compounds found were kaempferol 3-diglucoside-7-glucoside and its combinations with different hydroxycinnamic acids. Moreover, some flavonoids with an unusual high grade of glycosylation have been isolated and tentatively identified for the first time. To our knowledge, the characterization of flavonoids with more than four sugars has not been previously reported. The new products isolated were tentatively identified as kaempferol 3-diglucoside-7-diglucoside, kaempferol 3-triglucoside-7-diglucoside, kaempferol 3-feruloyldiglucoside-7-diglucoside, kaempferol 3-sinapoyltriglucoside-7-glucoside, kaempferol 3-disinapoyltriglucoside-7-glucoside, kaempferol 3-sinapoyltriglucoside-7-diglucoside and kaempferol 3-disinapoyltriglucoside-7-diglucoside.     

Effect of combining urea fertilizer with P and K fertilizers on the efficacy of urease inhibitors under different storage conditions

Journal of Soils and Sediments - Urease inhibitors provide a simple solution to mitigate ammonia loss from fertilized soil. Consumption of bulk blend fertilizers and compound fertilizers were...     

Reflectance and Transmittance Spectroscopy Applied to Detecting Fumonisin in Single Corn Kernels Infected with Fusarium verticillioides

Reflectance and transmittance visible and near‐infrared spectroscopy were used to detect fumonisin in single corn kernels infected with Fusarium verticillioides. Kernels with >100 ppm and <10 ppm could be classed accurately as fumonisin positive or negative, respectively. Classification results were generally better for oriented kernels than for kernels that were randomly placed in the spectrometer viewing area. Generally, models based on reflectance spectra have higher correct classification than models based on transmittance spectra. Statistical analyses indicated that including near‐infrared wavelengths in calibrations improved classifications, and some calibrations were improved by including visible wavelengths. Thus, the color and chemical constituents of the infected kernel contribute to classification models. These results show that this technology can be used to rapidly and nondestructively screen single corn kernels for the presence of fumonisin, and may be adaptable to on‐line detection and sorting.     

Comparing three indices of catch per unit effort using Bayesian geostatistics

In assessing a fish stock, indices based on catch per unit effort (CPUE) are frequently used. Estimates of three indices of catch per unit effort were compared here (CPUE₁, CPUE₂ and CPUE₃), considering the fitting of two models: (i) a bivariate geostatistical model for catch and effort; (ii) a bivariate model where catch and effort were considered spatially independent. For comparing the estimates of the three indices after the fitting of the two models, catch and effort data were simulated in different scenarios. The simulation study showed that, in general, the estimates of CPUE₁ expressed by the ratio of the means of catch and effort, present better results for different scenarios and that the estimates from (i) are better than (ii), mainly when there is a correlation between catch and effort and an additional spatial correlation.     

Considerations on endopolygalacturonase activity and determination of comparison ratios with emphasis on the influence of the degree of substrate esterification

A study on the determination and standardization of endopolygalacturonase (EPG) activity is reported, with emphasis on the influence of the degree of substrate esterification using pure yeast EPG. Differences in the results, depending on how the EPG activity unit was defined, are described and discussed. From a theoretical analysis of the expressions established, a general equation for expressing EPG activity in standard international units was obtained, together with the proportional coefficient for each of the substrates studied. It was observed that for a wide range of enzyme concentrations good linear correlations were obtained. Analysis of the comparison ratio (CR) values calculated revealed that these do not differ significantly, except for low-methoxyl apple pectin, confirming the validity of the general expression obtained for pectins with different degrees of esterification. The anomalous CR value found for low-methoxyl (LM) apple pectin is discussed.     

HPLC-DAD-ESIMS analysis of phenolic compounds in nectarines, peaches, and plums

The phenolic compounds of 25 peach, nectarine, and plum cultivars were studied and quantified by HPLC-DAD-ESIMS. Hydroxycinnamates, procyanidins, flavonols, and anthocyanins were detected and quantified. White and yellow flesh nectarines and peaches, and yellow and red plums, were analyzed at two different maturity stages with consideration of both peel and flesh tissues. HPLC-MS analyses allowed the identification of procyanidin dimers of the B- and A-types, as well as the presence of procyanidin trimers in plums. As a general rule, the peel tissues contained higher amounts of phenolics, and anthocyanins and flavonols were almost exclusively located in this tissue. No clear differences in the phenolic content of nectarines and peaches were detected or between white flesh and yellow flesh cultivars. There was no clear trend in phenolic content with ripening of the different cultivars. Some cultivars, however, had a very high phenolic content. For example, the white flesh nectarine cultivar Brite Pearl (350-460 mg/kg hydroxycinnamates and 430-550 mg/kg procyanidins in flesh) and the yellow flesh cv. Red Jim (180-190 mg/kg hydroxycinnamates and 210-330 mg/kg procyanidins in flesh), contained 10 times more phenolics than cultivars such as Fire Pearl (38-50 mg/kg hydroxycinnamates and 23-30 mg/kg procyanidins in flesh). Among white flesh peaches, cultivars Snow King (300-320 mg/kg hydroxycinnamates and 660-695 mg/kg procyanidins in flesh) and Snow Giant (125-130 mg/kg hydroxycinnamates and 520-540 mg/kg procyanidins in flesh) showed the highest content. The plum cultivars Black Beaut and Angeleno were especially rich in phenolics.     

Mercury Distribution and Speciation in Soils Affected by Historic Mercury Mining

In this paper a novel methodology for estimating the parameters for an extended biokinetic model (Peev, Schönerklee, and De Wever, Water Science and Technology, 2004) of micropollutant removal in wastewater treatment is presented. In particular, the work concentrates on parameter estimation of the micropollutant degradation sub-model by specialised microorganisms in the case when only substrate measurement data are available. We have proven the structural identifiability of the model and have developed a new approach allowing practical identifiability on the basis of multiple substrate degradation curves with different initial concentrations. Experimental and related numerical methods for unambiguous parameter estimation have been developed. Finally, by means of simulated pseudo-experiments we have found convincing indications that the proposed algorithm is stable and yields appropriate parameter estimates even in unfavourable regimes.     

Nectar Flavonol rhamnosides are floral markers of acacia (Robinia pseudacacia) honey

With the objective of finding floral markers for the determination of the botanical origin of acacia (robinia) honey, the phytochemicals present in nectar collected from Robinia pseudacacia flowers were analyzed by high-performance liquid chromatography-tandem mass spectrometry. Eight flavonoid glycosides were detected and characterized as kaempferol combinations with rhamnose and hexose. Acacia honey produced in the same location where the nectar was collected contained nectar-derived kaempferol rhamnosides. This is the first time that flavonoid glycosides have been found as honey constituents. Differences in the stability of nectar flavonoids during honey elaboration and ripening in the hive were shown to be due to hydrolytic enzymatic activity and to oxidation probably related to hydrogen peroxide (glucose-oxidase) activity. Acacia honeys contained propolis-derived flavonoid aglycones (468-4348 microg/100 g) and hydroxycinnamic acid derivatives (281-3249 microg/100 g). In addition, nectar-derived kaempferol glycosides were detected in all of the acacia honey samples analyzed (100-800 microg/100 g). These flavonoids were not detected in any of the different honey samples analyzed previously from different floral origins other than acacia. Finding flavonoid glycosides in honey related to floral origin is particularly relevant as it considerably enlarges the number of possible suitable markers to be used for the determination of the floral origin of honeys.     

Ecological Considerations in Pesticide Risk Assessment for Aquatic Ecosystems

Risk assessment of pesticides for aquatic ecosystems is typically based on comparisons of exposure and effect concentrations at a variety of levels (tiers). At the highest tier, effects assessment can involve generating data under field conditions, typically in mesocosm experiments. However, interpreting the ecological significance of effects measured in these studies can be difficult because ecological factors can influence the outcome of perturbations in the real world. The influence of ecological factors is not readily addressed experimentally and so a strategic modelling approach is proposed which may aid in defining acceptability of effects. © 1997 SCI.