Giovanna Boschin

Legumes are valuable sources of tocopherols

Grain legumes contain numerous phytochemicals useful for their nutritional or nutraceutical properties, such as tocopherols, involved in the prevention of cardiovascular disease and eye pathologies. In this work, tocopherols were quantified in soybean, chickpea, lentil, pea, common bean, broad bean, and three lupin species. In all samples, the gamma congener was the most abundant tocopherol, followed by minor quantities of alpha-tocopherol (with the exception of common bean lacking in this congener) and delta-tocopherol (with the exception of Lupinus angustifolius and Lupinus mutabilis). Beta-tocopherol and tocotrienols were never detected. Some samples of soybean, pea, white lupin and chickpea contained over 10mg/100g seeds of total tocopherols. In order to estimate the nutritional value, the vitamin E activity was calculated. Chickpea, soybean and, to a lesser extent, lupin, broad bean and pea may contribute in a relevant way to the daily intake of this vitamin.

ACE-inhibitory activity of enzymatic protein hydrolysates from lupin and other legumes.

The objective of this investigation was to compare the angiotensin converting enzyme (ACE)-inhibitory activity of the hydrolysates obtained by pepsin digestion of proteins of some legumes, such as chickpea, common bean, lentil, lupin, pea, and soybean, by using the same experimental procedure. The ACE-inhibitory activity was measured by using the tripeptide hippuryl-histidyl-leucine (HHL), as model peptide, and HPLC-DAD, as analytical method. The peptide mixtures of all legumes were active, with soybean and lupin the most efficient, with IC50 values of 224 and 226 μg/ml, respectively. Considering the promising results obtained with lupin, and aiming to identify the protein(s) that release(s) the peptides responsible for the activity, the peptides obtained from the pepsin digestion of some industrial lupin protein isolates and purified protein fractions were tested. The most active mixture, showing an IC50 value of 138 μg/ml, was obtained hydrolysing a mixture of lupin α+β conglutin.

Effect of genotype and environment on fatty acid composition of Lupinus albus L. seed.

Six cultivars of Lupinus albus L. (white lupin) were grown in two subcontinental-climate environments and one Mediterranean-climate environment in Italy, to assess the influence of genotypic (G) and genotype×environment (GE) interaction effects on grain yield and grain content of oil, total saturated fatty acids (FAs), polyunsaturated FAs, monounsaturated FAs, and ω-3/ω-6 FA ratio. The variance of genotypic effects was much larger than the GE interaction variance for all variables, except for grain yield, indicating that oil content and FA composition of different varieties can be assessed reliably in just a few test environments. Gas-chromatographic analyses highlighted that linoleic acid and α-linolenic acid were in the range 1.76-4.76mg/g flour (7.79-15.81% of total FAs) and 1.17-3.14mg/g flour (5.40-10.36% of total FAs), respectively. As a consequence, the analysed lupin seeds exhibited a very favourable ω-3/ω-6 FA ratio, ranging from 0.49 to 0.79.

Biodegradation of Chlorsulfuron and Metsulfuron‐Methyl by Aspergillus niger in Laboratory Conditions

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.

The Role of Grain Legumes in the Prevention of Hypercholesterolemia and Hypertension

The seeds of the plants of the Fabaceae, commonly known as “grain legumes” or “pulses,” are major foodstuffs in most countries. In addition, these seeds may also provide some health benefits, in particular in the area of hypercholesterolemia and hypertension prevention. Whereas the hypocholesterolemic activity of soy protein has been well known for decades and was finally supported by the health claim by the U.S. Food and Drug Administration in 1999, similar information on non-soy legumes is scarce. This paper reviews all such available data from animal models and human trials as well as information on the mechanism of action provided by in vitro studies, mainly on cell cultures or assays on specific enzymes. This body of data indicates that a regular consumption of grain legumes may be useful both for the prevention of hypercholesterolemia and hypertension. More investigations are needed, however, for elucidating the mechanism of action and the actual effective components in legumes.

Evaluation of total quinolizidine alkaloids content in lupin flours, lupin-based ingredients, and foods

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.

The microbial degradation of azimsulfuron and its effect on the soil bacterial community

Aims:  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.

Optimization of the Enzymatic Hydrolysis of Lupin (Lupinus) Proteins for Producing ACE-Inhibitory Peptides.

Recently, the enzymatic hydrolysis of Lupinus albus and Lupinus angustifolius proteins with pepsin was showed to produce peptides able to inhibit the angiotensin-converting enzyme (ACE). The objective of the present work was to test different hydrolytic enzymes and to investigate three lupin species (L. albus, L. angustifolius, Lupinus luteus) with the final goal of selecting the best enzyme/species combination for an efficient production of ACE-inhibitory peptide mixtures. Pepsin gave peptides with the best IC50 values (mean value on three species 186 ± 10 μg/mL), followed by pepsin + trypsin (198 ± 16 μg/mL), chymotrypsin (213 ± 83 μg/mL), trypsin (405 ± 54 μg/mL), corolase PP (497 ± 32 μg/mL), umamizyme (865 ± 230 μg/mL), and flavourzyme (922 ± 91 μg/mL). The three species showed similar activity scales, but after pepsin + trypsin and chymotrypsin treatments, L. luteus peptide mixtures resulted to be significantly the most active. This investigation indicates that lupin proteins may be a valuable source of ACE-inhibitory peptides, which may explain the activity observed in experimental and clinical studies and foresee the application of lupin proteins into functional foods or dietary supplements.

Quinolizidine Alkaloids in Seeds of Lupin Genotypes of Different Origins

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.

Updating on the lysinoalanine content of commercial infant formulae and beicost products

Since the safety issue of lysinoalanine (LAL) still remains unresolved, its concentration in infant formulae should be reduced to a minimum. Data collected in the 1980s indicated that LAL is formed in higher amounts in liquid than in powdered formulae. Recently the market of liquid infant formulae is increasing rapidly and there are no new data, so 23 commercial powdered or liquid samples were investigated. In powdered samples, LAL was below the detection limit, whereas liquid adapted formulae contained up to 86 μg/g protein, liquid follow-on formulae up to 390 μg/g protein, and liquid growing milks up to 514 μg/g protein. The concentration of LAL in liquid formulae is considerably lower than in the past; however, the level in a few products remains rather high, especially compared with normal UHT-treated milk. Great differences were observed among products of different companies, which suggests that labelling with the thermal treatment applied would be very advisable. The investigation of some beicost products indicates that LAL is present only in products certainly containing milk proteins. Considering the rather low levels in comparison with liquid infant formulae, the contribution of beicost products to the total LAL daily intake does not seem to be particularly relevant.