[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to monitor the changes in isoflavone content in different plant organs (leaves, stems, roots) during the crop growth stage of three cultivars of Lupinus albus (white lupin) under field conditions, taking into account sowing time effects (autumn and early spring) and cultivar effects. Three sampling dates (from late vegetative to late grain growth stages) were evaluated. Seven isoflavones and four flavonoids were identified by LC-ESI-MS analysis. The isoflavone content was higher in leaves than in stems, and it was highest before flowering, whereas it decreased during maturity. Autumn-sown plants showed higher isoflavone content than early spring-sown plants, especially in late vegetative and early reproductive stages. Genistein 7- O-glucoside was the main isoflavone of leaves and stems in the late vegetative stages of early spring sowing, whereas genistein was the main isoflavone under autumn sowing. Variation among cultivars affected only marginally the total isoflavone content. No isoflavones were detected in seeds.
Full-text · Article · Jul 2008 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The intake of lupin-based foods could imply the exposure of consumers to quinolizidine alkaloids. The objectives of this study were to assess the genetic variation among and within 11 geographic regions of Lupinus albus ecotypes, verify the quinolizidine alkaloids amount of alkaloid-poor L. albus and Lupinus angustifolius varieties, and assess the effect of two climatically contrasting Italian environments on the alkaloid content. The quantitation was performed by GC-MS, and in all samples lupanine was the most abundant quinolizidine alkaloid, followed by albine and 13alpha-hydroxylupanine for L. albus and by 13alpha-hydroxylupanine and angustifoline for L. angustifolius. Some regions tended to have a high (Azores) or low (Egypt, Near East, Maghreb) total alkaloids content, but the variation among ecotypes within regions was larger than that among regions following the estimation of variance components. Alkaloid-poor varieties tended to have higher total alkaloid contents when grown in the subcontinental climate site, exceeding in some cases the limit of 0.200 mg/g.
Full-text · Article · Jun 2008 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Lupin proteins are gaining attention to replace animal proteins and other plants ingredients in several foods such as bakery products, imitation dairy and meat products, and beverages. One of the major safety issues of lupin-based foods is the presence of quinolizidine alkaloids (QAs), bitter compounds produced by lupin plants as a defense mechanism against predators. In mammals, QA intoxication is characterized by trembling, shaking, excitation, and convulsion. Lupanine and sparteine, the most common QAs, show acute oral toxicity due to neurological effects leading to the loss of motor co-ordination and muscular control. In this paper, 27 samples of lupin-based products, i. e., flours, protein isolates, and food (either model or commercially available ones), were analyzed for evaluating the QA content using a method based on GC/MS. All the analyzed samples were safe since they respect the maximum limit of 200 mg/kg fixed by the Health Authorities of Australia, New Zealand, Great Britain, and France, that have regulated this topic. The QA contents were particularly low in protein isolates and in foods containing these ingredients, indicating that their use is a very effective tool for keeping low the daily intake of QAs.
[Show abstract][Hide abstract] ABSTRACT: The chemical degradation of the herbicide azimsulfuron was investigated in aqueous solutions at different pH values. The hydrolysis rate, determined by HPLC analyses, was pH dependent and was much faster in acidic than in neutral or weakly basic conditions. The metabolites formed at different pH values were compared with standards when possible or isolated and identified using ESI-LC-MS/MS, (1)H NMR and (13)C NMR. The two main products of hydrolysis in mild acidic solution were identified as 2-amino-4,6-dimethoxy-pyrimidine and 2-methyl-4-(2-methyl-2H-tetrazol-5-yl)-2H-pyrazole-3-sulfonamide, both produced as a result of the sulfonylurea bridge cleavage. Under basic conditions, a new product, a substituted 2-pyrimidinamine, deriving from the contraction of the sulfonylurea bridge, was isolated and completely characterized for the first time.
[Show abstract][Hide abstract] ABSTRACT: Foods based on sweet lupin proteins are gaining attention from industry and consumers because of their possible role in the prevention of cardiovascular disease. When promoting lupin-based foods for inclusion in a daily diet, the thermal damage suffered during processing is of relevance to the bioactive and nutritional quality of the food product. N-(2-furoylmethyl)-L-lysine (furosine) quantification demonstrates that currently available sweet lupin protein isolates have a thermal damage comparable to or lower than other traditional food ingredients, and are a good source of lysine in non-dairy products. In lupin-based foods claiming to have cholesterol-lowering potential, shotgun proteomics offers itself as a fast and effective screening method for assessing the biological availability of active peptides. Such a method is readily applicable to other legume-enriched food products.
[Show abstract][Hide abstract] ABSTRACT: Azimsulfuron is a recently introduced sulfonylurea herbicide useful in controlling weeds in paddy fields. To date very little information is available on the biodegradation of this pesticide and on its effect on the soil microbial community. The aim of this work was to study its biodegradation both in slurry soil microcosms and in batch tests with mixed and pure cultures.
Azimsulfuron was applied to forest bulk soil in order to study its effect on the structure of the bacterial soil community, as detectable by denaturant gradient gel electrophoresis (DGGE) analyses. Biodegradation and abiotic processes were investigated by HPLC analyses. In addition, a microbial consortium was selected, that was able to use azimsulfuron as the sole energy and carbon source. One of the metabolites produced by the consortium was isolated and identified through LC-MS analyses. Cultivable bacteria of the consortium were isolated and identified by 16S rDNA sequencing (1400 bp).
Azimsulfuron treatment seems to have the ability to cause changes in the bacterial community structure that are detectable by DGGE analyses. It is easily biodegraded both in microcosms and in batch tests, with the formation of an intermediate that was identified as 2-methyl-4-(2-methyl-2H-tetrazol-5-yl)-2H-pyrazole-3-sulfonamide.
The study increases the knowledge on the biodegradation of azimsulfuron and its effects on the soil microbiota.
[Show abstract][Hide abstract] ABSTRACT: This paper describes a pilot process for obtaining protein isolates from white lupin seed with improved water solubility and technofunctional properties as well as reduced thermal damage. After a careful optimization of the process parameters, two valuable food ingredients were prepared: lupin protein isolate type E, with a useful emulsifying capacity, and lupin protein isolate type F, with a high capability of foam formation and stabilization. The spray-drying process was particularly critical for inducing some thermal damage, but a careful selection of the conditions permitted ingredients having only marginally impaired lysine bioavailability to be obtained. The reproducibility of the protein extraction process was tested on two different lupin varieties.
Full-text · Article · Feb 2006 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The target of the present work was the chemical, technological, and sensorial characterization of the brown polymers (foaming fractions) of freshly prepared espresso coffee. The total foaming fraction (TFF) was precipitated with ammonium sulfate from the defatted freshly prepared beverage and then subfractionated by adding 2-propanol/water to give an insoluble fraction (foaming fraction A, FFA) and a soluble fraction (foaming fraction B, FFB). The former is almost colorless, has a higher molecular weight and a lower nitrogen content, and contains mostly polysaccharides, whereas the latter has a lower molecular weight and a higher protein/melanoidin content, which results in a darker color. FFB showed greater foaming capability, but FFA contributed to the stability of the foam. FFB was further fractionated with solid-phase extraction and characterized by different analytical methods (size exclusion chromatography, UV, HPLC-DAD, 1H NMR). All of the melanoidin-rich fractions showed antioxidant properties with the 2,2-diphenyl-1-picrylhydrazyl hydrate method.
Full-text · Article · Nov 2004 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: White lupin (Lupinus albus, L.), a widely cultivated crop that has been consumed for many years in Western Europe, may provide a useful alternative for individuals wishing to substitute animal with plant proteins for cardiovascular disease prevention. Lupin seeds have a very low content of isoflavones, and lupin protein isolates are essentially isoflavone free. In rats fed a casein-based cholesterol + cholic acid diet, a relatively low daily intake (50 mg/d by gavage for 2 wk) of total lupin protein extract reduced plasma total and VLDL + LDL cholesterol concentrations by 21 and 30%, respectively (both P<0.001). In an attempt to elucidate the lipid-lowering mechanism, LDL receptor activity was evaluated in a human hepatoma cell line (HepG2). In this model, the lupin total protein extract was essentially inactive, whereas one purified minor protein component, conglutin gamma, had a remarkable upregulatory effect, with maximal increases of 53 and 21% (both P<0.05) for LDL uptake and degradation, respectively. This initial study indicates that lupin, although isoflavone free, has hypocholesterolemic activity similar to that of other leguminous proteins in an established animal model. Further, the cholesterol reduction appears to be associated with stimulation of LDL receptors by a well-defined protein component of the lupin seeds as demonstrated by in vitro studies.
Full-text · Article · Jan 2004 · Journal of Nutrition
[Show abstract][Hide abstract] ABSTRACT: Two sulfonylurea herbicides, chlorsulfuron and metsulfuron-methyl, were studied under laboratory conditions, in order to elucidate the biodegradation pathway operated by Aspergillus niger, a common soil fungus, which is often involved in the degradation of xenobiotics. HPLC-UV was used to study the kinetic of degradation, whereas LC-MS was used to identify the metabolites structure. In order to avoid the chemical degradation induced by a decrease in pH, due to the production of citric acid by the fungus, the experiments were performed in a buffered neutral medium. No significant degradation for both compounds was observed in mineral medium with 0.2% sodium acetate. On the contrary, in a rich medium, after 28 days the degradations, chemical degradation excluded, were about 30% for chlorsulfuron and 33% for metsulfuron-methyl. The main microbial metabolites were obtained via cleavage of the sulfonylurea bridge. In addition the fungus seems to be able to hydroxylate the aromatic ring of chlorsulfuron. In the case of metsulfuron-methyl the only detected metabolite was the triazine derivative, while the aromatic portion was completely degraded. Finally, the demethylation of the methoxy group on the triazine ring, previously observed with a Pseudomonas fluorescens strain, was not observed with A. niger.
Full-text · Article · Dec 2003 · Journal of Environmental Science and Health Part B
[Show abstract][Hide abstract] ABSTRACT: Cercospora beticola strains with laboratory induced resistance to tetraconazole were compared with their parental WT sensitive strains to evaluate the effects of resistance on fitness and assess whether any change in the sterol biosynthetic pathway was associated to the reduced fungicide sensitivity. In vitro growth rate on agar media and pathogenicity were found to be negatively affected by resistance. The main functional sterols in C. beticola WT strains under investigation were ergosterol, brassicasterol and ergosta-7,22-dienol. Resistant strains showed the same qualitative sterol composition, ruling it out as, per se, a cause for resistance. On the basis of the sterols detected both in sensitive and resistant strains, a possible biosynthetic pathway to the three functional sterols is proposed. Tetraconazole treatment caused, in all sensitive strains, the immediate accumulation of 14alpha-methylated sterols, which, for inhibitor concentrations up to EC50 values, were, in order of abundance, 14alpha-methylergosta-8,24(28)-dien-3beta,6alpha-diol, eburicol and obtusifoliol. However the data do not support a critical role of the 14-methyl-3,6-diol derivative in the growth arrest of C. beticola. As main difference between sensitive and resistant strains, the formers were found to accumulate higher amounts of 14alpha-methylated sterols. Although the data do not allow to establish a specific mechanism for resistance, some molecular mechanisms such as target site alterations and sterol biosynthetic pathway can be ruled out as a possible cause for reduced sensitivity.
No preview · Article · Nov 2003 · Mycological Research
[Show abstract][Hide abstract] ABSTRACT: Casein and caseinates are the main ingredients of formulas for enteral nutrition. Their manufacturing procedure and the thermal treatments necessary to assure microbiological stabilization and satisfactory shelf-life of the end-products are particularly favorable for the formation of lysinoalanine (LAL), a cross-linked amino acid that is considered a useful marker of the thermal damage and reduced digestibility of proteins. The lysinoalanine content of 18 different kinds of formulas for enteral nutrition was determined by HPLC after derivatization. The liquid formulas have an average value of 528 microg/g protein LAL, ranging from 160 to 800 microg/g protein (average content of formulas for pediatric use 747 microg/g protein). These values are rather high considering that the average value detected in UHT-treated drinkable milk is 117 microg/g protein. In principle, the preparation of caseinates and the thermal stabilization of the end products are the two steps more favorable for the formation of LAL. The fact that the five samples stabilized by an UHT-treatment have an average value of 512 microg/g protein suggests that the LAL content depends more on the quality of the starting ingredients than on the sterilization process. A better selection of the starting ingredients should improve the quality of formulas for enteral nutrition, which is very desirable when formulating foods for consumers with very high nutritional demands.
Full-text · Article · Aug 2003 · Journal of Dairy Science
[Show abstract][Hide abstract] ABSTRACT: In this work, investigations were performed under laboratory conditions of the degradation ability by a common soil fungus, Aspergillus niger, toward chlorsulfuron and metsulfuron-methyl. The results were very encouraging (79% for chlorsulfuron and 61% for metsulfuron-methyl of total degradation), especially compared to those registered in our previous studies with a Pseudomonas fluorescens strain B2 (about 21 to 32%). Furthermore, the chemical degradation of the two compounds was studied and two products (1[2-methoxy-benzene-1-sulfonyl]-7-acetyltriuret and 1[2-chlorobenzene-1-sulfonyl]-7-acetyltriuret) were isolated and characterised by hydrolysis in acidic conditions. Our aim in the future will be the identification of intermediate metabolites by HPLC and LC-MS analyses in order to identify the degradative pathway by the fungal strain and to compare this to those obtained by chemical degradation and by P. fluorescens strain.
Full-text · Article · Jun 2002 · The Scientific World Journal
[Show abstract][Hide abstract] ABSTRACT: Sulfonylureas are a relatively new class of herbicides characterised by several aspects that make them particularly interesting in comparison with other products. Two microbial consortia able to grow on two sulfonylureas, chlorsulfuron and metsulfuron- methyl, were selected in laboratory conditions using as inocula soil samples previously treated with sulfonylurea herbicides and from a laboratory enrichment culture obtained with chlorsulfuron. From these mixed cultures, a Pseudomonas fluorescens strain called B2, was able to degrade in co-metabolic conditions with a rich medium in two weeks about 21% of metsulfuron-methyl and 32% of chlorsulfuron. For both herbicides, three microbial metabolites were detected and characterized, suggesting two different degradation path- ways in which the cleavage of sulfonylurea bridge takes place. Chemical hydrolysis, per- formed in acidic condition, in order to determine the chemical degradation pathways and to obtain pure standard for HPLC analyses, allowed to identify different compounds from those obtained with biodegradation; in fact the cleavage of triazinic ring happened. These results suggest that microbiological and chemical degradation can follow different path- ways.
Full-text · Article · Jan 2002 · Annals of Microbiology
[Show abstract][Hide abstract] ABSTRACT: Some important edible oils (extra virgin olive oil, canola oil, and sunflower oil) were added to aqueous glucose-lysine or xylose-lysine model systems to investigate their effect on the formation of volatiles from the Maillard reaction (MR). The volatile compounds were extracted by a Likens-Nickerson apparatus and quantified. Pyrazines, Maillard reaction products with an important impact on food flavor, appeared to be particularly sensitive to the presence of the oils in both the xylose-lysine and glucose-lysine model systems. The unsubstituted pyrazine was formed more with olive oil, less with canola oil, and even less with sunflower oil, whereas 2-methylpyrazine, 2,5-methylpyrazine, and 2,3-dimethylpyrazine were formed less with olive oil, more with canola oil, and even more with sunflower. The oxidative states of the oils and their fatty acid fingerprints were determined: the results indicated that the relative amounts of the pyrazines are sensitive to the degree of unsaturation of the oil. The autoxidation of the volatile compounds generated from the MR, investigated by the addition of free radical modulators (antioxidants alpha-tocopherol, 2,6-di-tert-butyl-4-methylphenol, and rosemary extract; or pro-oxidant alpha,alpha'-azobis-isobutyronitrile, a free radical initiator), was limited in respect to aqueous model systems.
No preview · Article · Feb 2001 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The volatiles produced in xylose/lysine model systems added with an antioxidant (alpha-tocopherol, 2,6-di-tert-butyl-4-methylphenol, or rosemary extract) or a free radical initiator (alpha, alpha'-azobis(isobutyronitrile), AIBN) were analyzed to investigate the effects of the presence of free radicals on the Maillard reaction. The pH was maintained constant at 4 or 6, by adding a base, and the data were compared by principal component analysis (PCA). The additives were more effective at pH 4 than pH 6. At pH 4, the model system added with AIBN is very well-discriminated by PCA from the models with the antioxidants and the reference model system, indicating that the volatiles are sensitive to compounds that can interfere in an opposite way with free radical formation.
No preview · Article · Mar 2000 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The aim of this report was to study the involvement of free radicals on the formation of volatiles from the Maillard reaction. An aqueous model system of glucose/lysine was heated in the presence of different amounts of antioxidants, such as α-tocopherol, 2,6-di-tert-butyl-4-methylphenol (BHT), and rosemary extract, or of α,α'-azobis-isobutyronitrile (AIBN) which is a pro-oxidant (free radical initiator). The differences in volatile formation between the standard model system and those with additives are relatively small. BHT, at pH 4, decreases pyrazine, while it increases slightly 2-methylpyrazine and 2,5-dimethylpyrazine and much more 2-acetylpyrrole, at pH 6 it produces a decrease in furaneol. α-Tocopherol, at pH 4, decreases pyrazine, furaneol, 2,3-dihydroxy-6-methyl-4H-pyran-4-one, and 2-acetylpyrrole, while at pH 6 it decreases 2-furanmethanol, and furaneol. Rosemary extract, at pH 4, decreases all the pyrazines and 2-furanmethanol and 2-acetylpyrrole; at pH 6 it produces a decrease of furaneol and 2,3-dihydroxy-6-methyl-4H-pyran-4-one. AIBN at both pH's decreases the pyrazines and increases 2-acetylpyrrole.
No preview · Article · Dec 1998 · Developments in Food Science
[Show abstract][Hide abstract] ABSTRACT: The formation of volatile compounds from an aqueous glucose−lysine model system heated in the presence of either a free radical initiator (pro-oxidant) or an antioxidant was investigated. α-Tocopherol, 2,6-di-tert-butyl-4-methylphenol (BHT), and rosemary extract were used as antioxidants, and α,α‘-azobis(isobutyronitrile) (AIBN) was used as a free radical initiator. The experiments were performed at pH 4 and 6, which were constantly maintained during the heating time by the addition of diluted NaOH. Principal component analysis was used to find similarities and differences among the model systems. Especially at pH 6 AIBN produces a depletion of pyrazine, 2-methylpyrazine, and 2,3-dimethylpyrazine, whereas the three antioxidants enhance the same compounds. This could be due to an autoxidation of the already formed pyrazines or of some intermediate: in particular, the sensitive material could be the C2 fragment necessary for the formation of pyrazine, 2-methylpyrazine, and 2,3-dimethylpyrazine, but not of 2,5-dimethylpyrazine. Keywords: Maillard reaction; antioxidants; autoxidation; glucose−lysine; rosemary extract; BHT; tocopherol; AIBN
No preview · Article · Jun 1998 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The aim of this paper was to monitor the variation of the isoflavone content in different plant organs (leaves, stems and roots) during the crop growth cycle of three cultivars of Lupinus albus (white lupin) under field conditions, taking account of environmental effects due to sowing time (autumn and winter) and genetic effects. Three sampling dates were evaluated, considering different growth stages of the plants. Seven isoflavones and four flavonoids were identified. The isoflavone contents were higher in leaves than in stems and before flowering than during maturity. Autumn-sown plants contained more isoflavones than late winter- sown plants, especially at the first sampling date. Genetic features appeared to affect only marginally the isoflavones production.