Time maters: Exploring the dynamics of bioactive compounds content, bioaccessibility and antioxidant activity during Lupinus angustifolius germination.

Germination is a process that enhances the content of health-promoting secondary metabolites. However, the bioaccessibility of these compounds depends on their stability and solubility throughout the gastrointestinal tract. The study aimed to explore how germination time influences the content and bioaccessibility of γ-aminobutyric acid and polyphenols and antioxidant capacity of lupin (Lupinus angustifolius L.) sprouts during simulated gastrointestinal digestion. Gamma-aminobutyric acid showed a decrease following gastrointestinal digestion (GID) whereas phenolic acids and flavonoids exhibited bioaccessibilities of up to 82.56 and 114.20%, respectively. Although the digestion process affected the profile of phenolic acids and flavonoids, certain isoflavonoids identified in 7-day sprouts (G7) showed resistance to GID. Germination not only favored antioxidant activity but also resulted in germinated samples exhibiting greater antioxidant properties than ungerminated counter parts after GID. Intestinal digests from G7 did not show cytotoxicity in RAW 264.7 macrophages, and notably, they showed an outstanding ability to inhibit the production of reactive oxygen species. This suggests potential benefit in mitigating oxidative stress. These findings contribute to understand the dynamic interplay between bioprocessing and digestion in modulating the bioaccessibility of bioactive compounds in lupin, thereby impacting health.

Proteome reorganization and amino acid metabolism during germination and seedling establishment in Lupinus albus.

During germination plants rely entirely on their seed storage compounds to provide energy and precursors for the synthesis of macromolecular structures until the seedling has emerged from the soil and photosynthesis can be established. Lupin seeds use proteins as their major storage compounds, accounting for up to 40% of the seed dry weight. Lupins are therefore a valuable complement to soy as a source of plant protein for human and animal nutrition. The aim of this study was to elucidate how storage protein metabolism is coordinated with other metabolic processes to meet the requirements of the growing seedling. In a quantitative approach, we analyzed seedling growth, as well as alterations in biomass composition, the proteome, and metabolite profiles during germination and seedling establishment in Lupinus albus. The reallocation of nitrogen resources from seed storage proteins to functional seed proteins was mapped based on a manually curated functional protein annotation database. Although classified as a protein crop, Lupinus albus does not use amino acids as a primary substrate for energy metabolism during germination. However, fatty acid and amino acid metabolism may be integrated at the level of malate synthase to combine stored carbon from lipids and proteins into gluconeogenesis.

Consequences of pollen defense compounds for pollinators and antagonists in a pollen-rewarding plant.

Plants produce an array of defensive compounds with toxic or deterrent effects on insect herbivores. Pollen can contain relatively high concentrations of such defense compounds, but the causes and consequences of this enigmatic phenomenon remain mostly unknown. These compounds could potentially protect pollen against antagonists but could also reduce flower attractiveness to pollinators. We combined field observations of the pollen-rewarding Lupinus argenteus with chemical analysis and laboratory assays to test three hypotheses for the presence of pollen defense compounds: (1) these compounds are the result of spillover from adjacent tissues, (2) they protect against pollen thieves, and (3) they act as antimicrobial compounds. We also tested whether pollen defense compounds affect pollinator behavior. We found a positive relationship between alkaloid concentrations in pollen and petals, supporting the idea that pollen defense compounds partly originate from spillover. However, pollen and petals exhibited quantitatively (but not qualitatively) distinct alkaloid profiles, suggesting that plants can adjust pollen alkaloid composition independently from that of adjacent tissues. We found no relationship between pollen alkaloid concentration and the abundance of pollen thieves in Lupinus flowers. However, pollen alkaloids were negatively associated with bacterial abundance. Finally, plants with more alkaloids in their pollen received more pollinator visits, but these visits were shorter, resulting in no change in the overall number of flowers visited. We propose that pollen defense compounds are partly the result of spillover from other tissues, while they also play an antimicrobial role. The absence of negative effects of these compounds on pollinator visitation likely allows their maintenance in pollen at relatively high concentrations. Taken together, our results suggest that pollen alkaloids affect and are mediated by the interplay of multiple interactions.

Environmental conditions affect the nutritive value and alkaloid profiles of Lupinus forage: Opportunities and threats for sustainable ruminant systems.

The identification of crops that simultaneously contribute to the global protein supply and mitigate the effects of climate change is an urgent matter. Lupins are well adapted to nutrient-poor or contaminated soils, tolerate various abiotic stresses, and present relevant traits for acting as ecosystem engineers. Lupins are best studied for their seeds, but their full foraging potential needs further evaluation. This study evaluated the effects of location and sowing date on forage production, proximate composition, and the detailed mineral and alkaloid profiles of three species of Lupinus (L. albus cv. Estoril, L. angustifolius cv. Tango, and L. luteus cv. Cardiga). Sowing date and location and their interaction with the plant species significantly affected the vast majority of measured parameters, emphasizing the effects of climate and soil conditions on these crops. The relatively high crude protein and in vitro digestibility support the potential of the lupin species studied as sustainable forage protein sources in diets for ruminant animals. The content of individual essential macro and trace elements was below the maximum tolerable levels for cattle and sheep. Lupanine, smipine, and sparteine were the most abundant quinolizidine alkaloids in L. albus cv. Estoril, lupanine, and sparteine in L. angustifolius cv. Tango, and lupinine, gramine, ammodendrine, and sparteine in L. luteus cv. Cardiga. Based on the maximum tolerable levels of total quinolizidine alkaloid intake, the dietary inclusion of forages of L. albus cv. Estoril and L. angustifolius cv. Tango does not pose a risk to the animals, but the high alkaloid content of L. luteus cv. Cardiga may compromise its utilization at high levels in the diet. Overall, the results reveal a high potential for lupins as protein forage sources well adapted to temperate regions and soils with lower fertility, with a relevant impact on livestock sustainability in a climate change era.

Screening of Diverse Lupinus spp. Highlights New Resistances to Sclerotinia sclerotiorum.

Stem rot caused by Sclerotinia sclerotiorum is a serious, and sometimes devastating, disease of lupin (Lupinus spp.). Two hundred and thirty-six lupin accessions from across 12 Lupinus species were screened against the prevalent S. sclerotiorum isolate MBRS-1 (pathotype 76). L. angustifolius accession 21655 and L. albus var. albus accession 20589 showed immune and 'near-immune' responses, respectively. Thirteen accessions of L. angustifolius, three accessions each of L. albus and L. albus var. albus, and a single accession each of L. albus var. graecus, L. mutabilis, L. palaestinus and L. pilosus (totalling ~4%) showed a highly resistant (HR) response. A further 19 accessions of L. angustifolius, two accessions each of L. albus and L. pilosus, and a single accession of L. mutabilis (totalling ~10%) showed a resistant (R) response. The reactions of 16 (15 L. angustifolius, one L. digitatus) of these 236 accessions were also compared with their reactions to a different isolate, WW-3 (pathotype 10). Against this isolate, five L. angustifolius accessions showed a HR response and four showed a R response, and the L. digitatus accession showed a moderate resistance (MR) response. Overall, isolate WW-3 caused significantly (P<0.05) smaller lesions than MBRS-1 across tested accessions in common. In addition, 328 plants in a 'wild' naturalized field population of L. cosentini were screened in situ in the field against isolate MBRS-1. Five (~1.5%) of the 328 plants of wild lupin showed an immune response, 63 (~19%) showed a HR response, and 146 (~45%) showed a R response. We believe this is the first examination of diverse Lupinus spp. germplasm responses to a prevalent pathotype of S. sclerotiorum. Lupin genotypes exhibiting high level resistance to Sclerotinia stem rot identified in this study can now be used as parental lines for crosses in lupin breeding programs and/or directly as improved cultivars to reduce the adverse impact of this disease on lupin crops.

Effective, consistent, and rapid non-contact application methods for seedling basal stem infection by Sclerotinia sclerotiorum.

Sclerotinia sclerotiorum (Lib.) de Bary, an economically devastating soil-borne fungal pathogen known to cause disease across a wide range of plants, produces long-term inoculum called sclerotia that can either germinate carpogenically by ascospores infecting above-ground plant parts or myceliogenically to infect stem base and roots. Typically for research purposes S. sclerotiorum diseases are initiated by direct contact methods, using S. sclerotiorum mycelium agar plugs wrapped around the stem or sclerotia placed directly beneath root mass. However, reproducible non-contact methods leading to basal stem infection are not currently available. Therefore, the objective of this study was to develop effective non-contact protocols that consistently generate basal plant stem infection from S. sclerotiorum in the soil. Using three host plant species (canola, lupin, and lettuce) we determined two methods that reliably produced basal stem infection. The first method, where mycelial agar plugs were positioned just below the soil surface at a distance of 5 mm from each seedling, led to 100% infection in all plants. The second method used pathogen-infested soil by mixing the soil with dry inoculum in the form of a powder prepared from mycelium-colonized organic substrates. Four substrates consistently produced 100% seedling infection at four days after inoculation (DAI); wheat bran, wheat grain, red rice, and hulled millet. In contrast, chia, canary, sesame, and ryegrass seed substrates resulted in less than 50% seedling infection at 10 DAI and infection levels did not progress further. The two soil inoculation methods outlined in this study will enhance future research on the progression of S. sclerotiorum diseases, with the potential to screen disease-resistant host genotypes to basal S. sclerotiorum infection, and in particular to test the effectiveness of soil applications of fungicides or biocontrol agents against S. sclerotiorum basal infection.

New Analytical Approach to Quinolizidine Alkaloids and Their Assumed Biosynthesis Pathways in Lupin Seeds.

Alkaloids play an essential role in protecting plants against herbivores. Humans can also benefit from the pharmacological effects of these compounds. Plants produce an immense variety of structurally different alkaloids, including quinolizidine alkaloids, a group of bi-, tri-, and tetracyclic compounds produced by Lupinus species. Various lupin species produce different alkaloid profiles. To study the composition of quinolizidine alkaloids in lupin seeds, we collected 31 populations of two wild species native to Israel, L. pilosus and L. palaestinus, and analyzed their quinolizidine alkaloid contents. Our goal was to study the alkaloid profiles of these two wild species to better understand the challenges and prospective uses of wild lupins. We compared their profiles with those of other commercial and wild lupin species. To this end, a straightforward method for extracting alkaloids from seeds and determining the quinolizidine alkaloid profile by LC-MS/MS was developed and validated in-house. For the quantification of quinolizidine alkaloids, 15 analytical reference standards were used. We used GC-MS to verify and cross-reference the identity of certain alkaloids for which no analytical standards were available. The results enabled further exploration of quinolizidine alkaloid biosynthesis. We reviewed and re-analyzed the suggested quinolizidine alkaloid biosynthesis pathway, including the relationship between the amino acid precursor l-lysine and the different quinolizidine alkaloids occurring in seeds of lupin species. Revealing alkaloid compositions and highlighting some aspects of their formation pathway are important steps in evaluating the use of wild lupins as a novel legume crop.

Influence of Roasting Temperature on the Detectability of Potentially Allergenic Lupin by SDS-PAGE, ELISAs, LC-MS/MS, and Real-Time PCR.

Seeds of "sweet lupins" have been playing an increasing role in the food industry. Lupin proteins may be used for producing a variety of foods, including pasta, bread, cookies, dairy products, and coffee substitutes. In a small percentage of the population, lupin consumption may elicit allergic reactions, either due to primary sensitization to lupin or due to cross-allergy with other legumes. Thus, lupin has to be declared on commercial food products according to EU food regulations. In this study, we investigated the influence of roasting seeds of the L. angustifolius cultivar "Boregine" on the detectability of lupin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), ELISAs, LC-MS/MS, and real-time PCR. Seeds were roasted by fluidized bed roasting, and samples were drawn at seed surface temperatures ranging from 98 °C to 242 °C. With increasing roasting temperature, the extractability of proteins and DNA decreased. In addition, roasting resulted in lower detectability of lupin proteins by ELISAs and LC-MS/MS and lower detectability of DNA by real-time PCR. Our results suggest reduced allergenicity of roasted lupin seeds used for the production of "lupin coffee"; however, this has to be confirmed in in vivo studies.

Lupin as Ingredient in Durum Wheat Breadmaking: Physicochemical Properties of Flour Blends and Bread Quality.

The popularity of adding pulse flours to baked goods is growing rapidly due to their recognised health benefits. In this study, increasing amounts (3, 7, 10, and 15%) of white lupin flour (Lupinus albus L.) and of protein concentrate from narrow-leaved lupin (Lupinus angustifolius L.) were used as replacements for durum wheat semolina to prepare bread, and their effects on the physicochemical properties of the flour blends, as well as the technological and sensory qualities of bread, were evaluated. The addition of protein concentrate from narrow-leaved lupin and white lupin flour increased the water binding capacity and the leavening rate compared to pure semolina. A farinograph test indicated that the dough development time had a slight but significant tendency to increase with the addition of lupin flour and protein concentrate of narrow-leaved lupin, while had a negative effect on the stability of dough. The alveograph strength decreased (225, 108, and 76 × 10-4 J for dough made with semolina, 15% of protein concentrate from narrow-leaved lupin, and 15% of white lupin flour, respectively), whereas there was an upward trend in the P/L ratio. Compared to re-milled semolina, the samples with lupin flour and protein concentrate from narrow-leaved lupin had low amylase activity, with falling number values ranging from 439 s to 566 s. The addition of the two different lupin flours lowered the specific volumes of the breads (2.85, 2.39, and 1.93 cm3/g for bread made from semolina, from 15% of protein concentrate from narrow-leaved lupin, and from 15% of white lupin flour, respectively) and increased their hardness values (up to 21.34 N in the bread with 15% of protein concentrate from narrow-leaved lupin). The porosity of the loaves was diminished with the addition of the two lupin flours (range of 5-8). The sensory analysis showed that the addition of white lupin flour or protein concentrate from narrow-leaved lupin did not impart any unpleasant flavours or odours to the bread. To conclude, the use of lupin in breadmaking requires adjustments to strengthen the gluten network but does not require a deflavouring process.

Quantitation of Lupinus spp. Quinolizidine Alkaloids by qNMR and Accelerated Debittering with a Resin-Based Protocol.

Quinolizidine alkaloids (QAs) are toxic secondary metabolites of the Lupinus species, the presence of which limits the expansion of lupin beans consumption, despite their high protein content. Evaluation of the level of alkaloids in edible Lupinus species is crucial from a food safety point of view. However, quantitation of QAs is complicated by the fact that not all important alkaloids used for quantitation are commercially available. In this context, we developed a method for the simultaneous quantitation of eight major lupin alkaloids using quantitative NMR spectroscopy (qNMR). Quantitation and analysis were performed in 15 different seed extracts of 11 Lupinus spp. some of which belonged to the same species, with different geographical origins and time of harvest, as well as in all aerial parts of L. pilosus. The mature seeds of L. pilosus were found to be a uniquely rich source of multiflorine. Additionally, we developed a protocol using adsorption or ionic resins for easy, fast, and efficient debittering of the lupine seeds. The protocol was applied to L. albus, leading to a decrease of the time required for alkaloids removal as well as water consumption and to a method for QA isolation from the debittering wastewater.

Liver Antioxidant Capacity and Steatosis in Laying Hens Exposed to Various Quantities of Lupin (Lupinus angustifolius) Seeds in the Diet.

Despite the many beneficial properties of legume plants, their use in diets for poultry is limited by the presence of antinutritional factors. The aim of the study was to determine the activity of DT-diaphorase, ethoxycoumarin O-deethylase, and catalase, and the concentration of malondialdehyde in liver tissue, as well as the activity of SOD and CAT in the serum of Hy-line Brown hens fed a diet supplemented with various doses of Lupinus angustifolius seeds. The results indicate that the use of large amounts of lupin in the diet resulted in an increase in MDA concentration in the liver and the lipid vacuolization of hepatocytes. A significant increase in DTD activity was observed in chickens receiving 15% lupin. Regardless of lupin dose, no increase in SOD activity was observed in chicken serum after 33 days of the experiment. From the 66th day of the experiment, an increase in catalase activity in the serum of laying hens was observed, while low activity of this enzyme was found in the liver. It can be concluded that the short-term use of lupin in the diet of laying hens does not affect the activity of antioxidant enzymes and, therefore, does not affect the oxidative-antioxidant balance of their body.

Flavonoid diversity in bitter and debittered seeds of Andean lupin (Lupinus mutabilis Sweet).

Seeds of ten Andean lupin (Lupinus mutabilis Sweet) ecotypes were collected from different regions of Peru and treated with an aqueous debittering method. Both untreated and treated seeds were analyzed by using LC-MS to investigate flavonoid profiles of different ecotypes and impact of debittering process on these compounds. Thirteen isoflavones (mainly as glycosides of genistein and methoxy-genistein) and eight flavones (glycosylated apigenins and methyl-luteolins) were characterized as the main flavonoids in the seed samples. The untreated lupin seeds contained 187-252 mg/100 g (dry weight) of flavonoids. The main difference among lupin ecotypes was observed in the levels of genistein-malonylhexoside, methoxy-genistein-malonylhexoside, and methyl-luteolin-malonylhexoside. After the debittering treatment, the total flavonoid content in the seeds was decreased to 125-203 mg/100 g dry weight, the aglycones of genistein, methoxy-genistein, and methyl-luteolin being the key distinguishing compounds of ecotypes. The aqueous treatment was effective in degrading flavonoid glycosides and releasing the corresponding aglycones.

Dietary Milk or Isolated Legume Proteins Modulate Intestinal Microbiota Composition in Rats.

Shifts toward increased proteolytic fermentation, such as, for example, in athlete and high-protein weight loss diets, may alter the relative abundance of microbial species in the gut and generate bioactive, potentially deleterious metabolic products. In the current investigation, intestinal (caecal) microbiota composition was studied in rats fed diets differing only in their constituent proteins: milk (casein (CAS), lactalbumin (LA)) or legume (Cicer arietinum, Lupinus angustifolius) protein isolates (chickpea protein isolate (CPI), lupin protein isolate (LI)). ANOSIM and Discriminant Analysis showed significant (p < 0.05) differences at both family and genus levels in both microbiota composition and functionality as a consequence of feeding the different proteins. Differences were also significant (p < 0.05) for predicted functionality parameters as determined by PICRUSt analysis. LA induced a generally healthier microbiota composition than CAS, and higher amounts of Methanobrevibacter spp. and Methanogenic_PWY were found in the LI group. LEfSe analysis of bacterial composition and functional activities revealed a number of groups/functions able to explain the different effects found with milk and legume protein isolates. In conclusion, the mostly beneficial modulation of intestinal microbiota generally found with legume-based diets is likely to be due, at least in part, to their constituent proteins.

Pleistocene diversification of unifoliolate-leaved Lupinus (Leguminosae: Papilionoideae) in Florida.

The importance and prevalence of recent ice-age and post-glacial speciation and species diversification during the Pleistocene across many organismal groups and physiographic settings are well established. However, the extent to which Pleistocene diversification can be attributed to climatic oscillations and their effects on distribution ranges and population structure remains debatable. In this study, we use morphologic, geographic and genetic (RADseq) data to document Pleistocene speciation and intra-specific diversification of the unifoliolate-leaved clade of Florida Lupinus, a small group of species largely restricted to inland and coastal sand ridges across the Florida peninsula and panhandle. Phylogenetic and demographic analyses alongside morphological and geographic evidence suggest that recent speciation and intra-specific divergence within this clade were driven by a combination of non-adaptive allopatric divergence caused by edaphic niche conservatism and opportunities presented by the emergence of new post-glacial sand ridge habitats. These results highlight the central importance of even modest geographic isolation and short periods of allopatric divergence following range expansion in the emergence of new taxa and add to the growing evidence that Pleistocene climatic oscillations may contribute to rapid diversification in a myriad of physiographic settings. Furthermore, our results shed new light on long-standing taxonomic debate surrounding the number of species in the Florida unifoliate Lupinus clade providing support for recognition of five species and a set of intra-specific variants. The important conservation implications for the narrowly restricted, highly endangered species Lupinus aridorum, which we show to be genetically distinct from its sister species Lupinus westianus, are discussed.

The LaCLE35 peptide modifies rootlet density and length in cluster roots of white lupin.

White lupin (lupinus albus L.) forms special bottlebrush-like root structures called cluster roots (CR) when phosphorus is low, to remobilise sparingly soluble phosphates in the soil. The molecular mechanisms that control the CR formation remain unknown. Root development in other plants is regulated by CLE  (CLAVATA3/ EMBRYO SURROUNDING REGION (ESR)-RELATED) peptides, which provide more precise control mechanisms than common phytohormones. This makes these peptides interesting candidates to be involved in CR formation, where fine tuning to environmental factors is required. In this study we present an analysis of CLE peptides in white lupin. The peptides LaCLE35 (RGVHy PSGANPLHN) and LaCLE55 (RRVHy PSCHy PDPLHN) reduced root growth and altered CR in hydroponically cultured white lupins. We demonstrate that rootlet density and rootlet length were locally, but not systemically, impaired by exogenously applied CLE35. The peptide was identified in the xylem sap. The inhibitory effect of CLE35 on root growth was attributed to arrested cell elongation in root tips. Taken together, CLE peptides affect both rootlet density and rootlet length, which are two critical factors for CR formation, and may be involved in fine tuning this peculiar root structure that is present in a few crops and many Proteaceae species, under low phosphorus availability.

Traditional soil fertility management ameliorates climate change impacts on traditional Andean crops within smallholder farming systems.

Global changes, particularly rising temperatures, threaten food security in smallholder mountain communities by impacting the suitability of cultivation areas for many crops. Land-use intensification, associated with agrochemical use and tillage, threatens soil health and overall agroecosystem resilience. In the Andean region, farmers often cultivate crops at multiple elevations. Warming climates have led to a shift in cultivation upslope, but this is not feasible in many areas. Traditional soil fertility management practices together with a focus on traditional (orphan) crops offers promise to cope with rapid climate warming in the region. To understand the impacts of warming and changing nutrient management, we established two side-by-side experiments using the traditional Andean crops Oxalis tuberosa (Oca) and Lupinus mutabilis (Tarwi) at three elevations, each with two fertility treatments (organic and synthetic). Soil and climate data (i.e., temperature and precipitation) were collected throughout the growing season, and crop performance was evaluated through impacts on yield and other growth metrics (e.g., biomass, pest incidence). We used two-way ANOVA to assess the influence of site (elevation) and management type (organic vs. synthetic) on crop performance. Results indicated that warmer climates (i.e., lowest elevation) negatively impact the production and performance of O. tuberosa, but that organic fertilization (sheep manure) can help maintain crop yield and biomass production in warmer conditions relatively to synthetic nutrient inputs. In contrast, L. mutabilis showed accelerated growth in warmer conditions, but grain yield and biomass production were not significantly affected by site and showed no interaction with nutrient management. Our findings highlight that climate warming represents a serious threat to small-scale crop production in the Peruvian Andes and could cause severe declines in the production of locally important crops. Additionally, the continued reliance on traditional crops with organic inputs, instead of synthetic fertilizers, may help support agricultural productivity and resilience under climate change.

Intercropping of Narrow-Leafed Lupin (Lupinus angustifolius L.) and Barley (Hordeum vulgare L.) Affects the Flavonoid Composition of Both Crops.

Barley (Hordeum vulgare L.) is a common cereal crop in agricultural production and is often included in legume-cereal intercropping. Flavonoids, a major class of secondary metabolites found in barley, are involved in plant defense and protection. However, the effect of intercropping on barley flavonoids remains unknown. Herein, an intercropping system involving barley and lupin (Lupinus angustifolius L.) was studied. Intercropping increased the level of luteolin in lupin roots. Lupin-barley intercropping considerably increased genistein, rutin, and apigenin in barley shoots. Genistein and apigenin were also detected in intercropped barley roots and rhizosphere soil. The three flavonoids have been reported as defense compounds, suggesting that lupin triggers a defense response in barley to strengthen its survival ability.

The Beneficial Effects of Inoculation with Selected Nodule-Associated PGPR on White Lupin Are Comparable to Those of Inoculation with Symbiotic Rhizobia.

Nodule endophytes and associated bacteria are non-symbiotic bacteria that colonize legume nodules. They accompany nodulating rhizobia and can form beneficial associations, as some of them are plant growth-promoting rhizobacteria (PGPR) that are able to promote germination and plant growth and increase tolerance to biotic and abiotic stress. White lupin (Lupinus albus) is a legume crop that is gaining relevance as a suitable alternative to soybean as a plant protein source. Eleven nodule-associated bacteria were isolated from white lupin nodules grown in a Tunisian soil. They belonged to the genera Rhizobium, Ensifer, Pseudomonas and Bacillus. Their plant growth-promoting (PGP) and enzymatic activities were tested in vitro. Strains Pseudomonas sp., L1 and L12, displayed most PGP activities tested, and were selected for in planta assays. Inoculation with strains L1 or L12 increased seed germination and had the same positive effects on all plant growth parameters as did inoculation with symbiotic Bradyrhizobium canariense, with no significant differences among treatments. Inoculation with efficient nitrogen-fixing rhizobia must compete with rhizobia present in the soil that sometimes nodulate efficiently but fix nitrogen poorly, leading to a low response to inoculation. In such cases, inoculation with highly effective PGPR might represent a feasible alternative to boost crop productivity.

Lupin as a Source of Bioactive Antioxidant Compounds for Food Products.

Four species of lupin (white lupin, yellow lupin, blue lupin and Andean lupin) are widely cropped thanks to the excellent nutritional composition of their seeds: high protein content (28-48 g/100 g); good lipid content (4.6-13.5 g/100 g, but up to 20.0 g/100 g in Andean lupin), especially unsaturated triacylglycerols; and richness in antioxidant compounds like carotenoids, tocols and phenolics. Particularly relevant is the amount of free phenolics, highly bioaccessible in the small intestine. However, the typical bitter and toxic alkaloids must be eliminated before lupin consumption, hindering its diffusion and affecting its nutritional value. This review summarises the results of recent research in lupin composition for the above-mentioned three classes of antioxidant compounds, both in non-debittered and debittered seeds. Additionally, the influence of technological processes to further increase their nutritional value as well as the effects of food manufacturing on antioxidant content were scrutinised. Lupin has been demonstrated to be an outstanding raw material source, superior to most crops and suitable for manufacturing foods with good antioxidant and nutritional properties. The bioaccessibility of lupin antioxidants after digestion of ready-to-eat products still emerges as a dearth in current research.

Optimization and Characterization of Lupin Protein Isolate Obtained Using Alkaline Solubilization-Isoelectric Precipitation.

The trend in today's society is to increase the intake of vegetable protein instead of animal protein. Therefore, there is a concern to find new sources of alternative protein. In this sense, legumes are the main protein source of vegetable origin. Of all of them, lupins are the ones with higher protein content, although they are currently undervalued as an alternative for human consumption. In this sense, it is vital to characterize and obtain protein isolates from this legume, which satisfies the growing demand. Therefore, in the present work, the procedure for obtaining a lupin (Lupinus luteus) protein isolate (LPI), based on basic solubilization followed by isoelectric precipitation, has been optimized and validated. The optimized LPI, as well as the lupin flour, were subsequently characterized. The chemical composition, physicochemical, as well as the technofunctional properties of the LPI were analyzed. The results show that the proposed procedure had a high yield (23.19 g LPI/100 g flour) and allowed to obtain high-purity protein isolates (87.7 g protein/100 g LPI). The amino acid composition and the chemical scores show high proportions of essential amino acids, being protein deficient only in methionine and valine. Therefore, it can be affirmed that it is a high-quality protein that meets the requirements proposed by the FAO. Regarding the lipid fraction, it is mainly composed of unsaturated fatty acids (C18:1n-9 and C18:2n-6), which is also advisable in order to follow a healthy diet. Finally, LPI showed interesting technofunctional properties (foaming, gelling, emulsifying, water and oil absorption, and solubility), which makes it especially attractive for use in the food industry.