Some functional properties of lupin proteins modified by lactic fermentation and extrusion

The aim of this work was to determine modifying effects of lactic fermentation and extrusion processes on functionality of lupin proteins. Protein content, surface hydrophobicity, water absorption capacity (WAC), water solubility index (WSI) and emulsifying properties (EAI, ESI) of protein preparations obtained from lupin seeds (Lupinus luteus, Lupinus albus, Lupinus angustifolius), with various contents of hull, were analyzed. Changes of protein properties were affected by lupin cultivar, hull content and applied processing method. An increase of soluble protein content after controlled lactic fermentation of lupin seeds, and changes of surface protein hydrophobicity, WAC and WSI values after each treatment and significant worsening of protein emulsifying properties were observed. Correlations were found between parameters examined in this study.     

The artificial intelligence-based chemometrical characterisation of genotype/chemotype of Lupinus albus and Lupinus angustifolius permits their identification and potentially their traceability

A chemotyping and genotyping comprehensive approach may be useful for the analytical traceability of food ingredients. The interest for lupin (Lupinus spp.) is developing owing to the high protein percentage as well as the positive technological and nutraceutical properties. The objective was the development of innovative models for discerning between Lupinus albus and Lupinus angustifolius, the most used in human nutrition, by applying multivariate statistical analysis (Principal Component Analysis, PCA) and artificial intelligence (Self Organising Maps, SOMs) onto chemical parameters (proximate composition, alkaloids, tocopherols) or Random Polymorphic DNA fingerprints. The application of PCA to either chemical or genetic data permitted the effective discrimination between the two species, whereas the application of the SOM approach to both data-sets enabled clustering some cultivars. The possibility of discriminating L. albus from L. angustifolius is relevant for lupin traceability: the foreseen fields of application are refined flours or ingredients, where morphological analysis is not applicable.     

Antioxidant capacity and polyphenolic content of high-protein lupin products

In order to produce high protein lupin products, α-galactoside extraction from Lupinus angustifolius cv. Troll and cv. Emir and Lupinus albus cv. Multolupa, and protein isolation from L. albus cv. Multolupa were carried out. Trolox equivalent antioxidant capacity (TEAC), DPPH radical-scavenging activity (DPPH-RSA), peroxyl radical-trapping capacity (PRTC), superoxide dismutase-like activity (SOD-like activity), total phenolic compounds (TPC) and total flavonoids were determined in lupin products. In L. angustifolius cv. Troll, L. angustifolius cv. Emir and L. albus cv. Multolupa α-galactoside-low flours, the TEAC and DPPH-RSA decreased (43%, 38%; 73%, 82%; 77%, 38%, respectively). PRTC decreased in L. angustifolius cv. Troll and L. albus cv. Multolupa α-galactoside-low flours (13% and 98%, respectively), while in those of L. angustifolius cv. Emir, PRTC increased (25%). SOD-like activity and TPC were also affected by α-galactoside extraction and reductions of 30–52% and 38–56%, respectively, were observed. The protein isolate of L. albus cv. Multolupa presented lower TEAC (24%), a similar level of PRTC and twice higher level of DPPH-RSA than did α-galactoside-low Multolupa flour. Moreover, the SOD-like activity of lupin protein isolate was sharply reduced but the TPC content was 24% higher. The technological procedures, α-galactoside extraction and protein isolation, provide high protein lupin products but with lower antioxidant capacity and total phenolic compounds than the raw seeds, although the levels of antioxidant capacity of these lupin products resemble those of cereals.     

Raffinose family oligosaccharides and sucrose contents in 13 Spanish lupin cultivars

The contents of raffinose family oligosaccharides (RFOs) and sucrose in 13 Spanish cultivars of lupin (Lupinus albus, Lupinus luteus and Lupinus angustifolius) were studied, with the aim of selecting those with highest amounts of these oligosaccharides in order to obtain pure RFOs for use as ingredients in functional foods. The levels of sucrose and RFOs (raffinose, stachyose and verbascose) were determined using high perfornnance liquid chromatography (HPLC). There were large variations in the levels of individual RFOs between lupin cultivars. L. albus seeds were characterised by the lowest verbascose content (∼0.4%), L. luteus seeds by the highest contents of stachyose (∼7.4%) and verbascose (∼3.1%) and the lowest of sucrose (∼1.2%),and L. angustifolius seeds by the highest sucrose (∼3.4%) and the lowest stachyose (∼4.6%) contents. Furthermore, there was a wide variation in total α-galactosides between species, with a remarkably high content found in L. luteus (9.5–12.3%) which was about twice that of other lupin cultivars. For this reason, L. luteus seeds are the best choice for obtaining pure RFOs for use as prebiotics in functional foods.     

Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and soya bean

With the objective of promoting the cultivation, usage, and consumption of lupin, in the present study, the chemical and fibre composition of dehulled seeds of seven cultivars of different lupin species (Lupinus angustifolius, Lupinus albus and Lupinus luteus) was determined in comparison to pea (Pisum sativum) and soya bean (Glycine max).     

Effects of bread making methods,lupin variety and gluten powder on the quality of bread enriched with high percentage of lupin flour

Lupin is an economical source of protein, fibre and bioactive compounds, and to obtain these health and nutritional benefits lupin flour has been used in bread production. However, addition of more than 10% lupin flour markedly reduces bread quality mainly due to gluten dilution. The main aim of this research was to retain lupin bread quality enriched with higher percentages of lupin flour (20%) by addition of vital gluten powder (0%, 2%, 3.5% and 5%), investigating the effects of lupin variety (Lupinus albus and L. angustifolius) and two baking systems (rapid and sponge & dough). Impact on bread staling qualities was also determined through texture analysis of samples over a 72-h storage period. Compared to lupin bread with nil gluten addition, significant improvements in loaf volume and crumb texture were observed with addition of gluten powder especially at 5% which increased loaf volume by an average of 20% across lupin sources and baking methods, and crumb softness by 30–50%. Differences were observed between the lupin flour sources. L. angustifolius had a reduced weakening effect when blended with the base flour compared with L. albus. The Sponge & Dough process was found to be more suitable to the inclusion of lupin flour than the rapid process.     

Germination as a process to increase the polyphenol content and antioxidant activity of lupin seeds (Lupinus angustifolius L.)

In this work, the effect of germination of lupin seeds (Lupinus angustifolius L., c.v. Zapatón) on bioactive phenolic compounds as well as on the antioxidant activity was studied. Phenolic compounds were analysed by HPLC-PAD-ESI/MS. The antioxidant activity was determined by spectrophotometry, evaluating the free radical scavenging activity of the samples. Germination produced significant changes in flavonoids and non-flavonoid phenolic compounds. In the analysed samples, isoflavones, flavones and dihydroflavonols in free and conjugated forms were identified. The results obtained indicate that germination modifies the quantitative and qualitative polyphenolic composition of lupin (Lupinus angustifolius L.) seeds during the different days of the process, with a significant increase of flavonoids. An increase in the antioxidant activity was also observed as a consequence of the process. Germination was shown to be a good process to increase the phenolic content of lupin seeds as well as their antioxidant activity.     

The effects of various processing conditions on a protein isolate from Lupinus angustifolius

Lupin protein is a promising ingredient in functional foods because of its purported hypocholesterolaemic and hypotensive activities. In this study a lupin protein isolate from Lupinus angustifolius was thermally and mechanically treated and the effects on its protein profile were determined. As a preliminary step, the main protein components of L. angustifolius were identified, using the canonical proteomic approach, including 2D-separation and mass spectrometry and, whenever necessary, also “de novo peptide sequencing”. Most of the main spots were assigned to the major lupin storage proteins: α-conglutin, β-conglutin, γ-conglutin, and δ-conglutin. The protein degradation induced by the different treatments was studied via differential scanning calorimetry (DSC), 2D-electrophoresis, and mass spectrometry, in order to get the fingerprint of the intact peptides after processing. The results indicate that, even after harsh industrial processing, α-, β- and δ-conglutin are still able to release stable peptides, although they are completely or partially degraded, as shown by the 2D protein profiles and the DSC graphs.     

Fat and fatty acids of white lupin (Lupinus albus L.) in comparison to sesame (Sesamum indicum L.)

The study was undertaken to compare fat and fatty acid profiles in white lupin (Lupinus albus ssp. albus) and sesame (Sesamum indicum L.), representing two different families, Fabaceae and Pedaliaceae. Fat levels were 10.74% and 55.44% in seeds of white lupin and sesame, respectively. The results indicated that oleic, linolenic and arachidic acids in seed fat were higher in white lupin than in sesame cultivars. Oleic acid was the predominant fatty acid in white lupin, whereas linoleic acid was predominant in sesame. Fat content (%) was statistically significantly correlated with linoleic, linolenic and arachidic acids at the genotypic level. The fatty acid composition of white lupin is useful for human consumption. Although oil content of white lupin was lower than that of sesame, white sweet lupin could be improved.     

Interactions between Lupinus angustifolius seeds lipoxygenase and native phenolic compounds in the model system

The aim of this study was to investigate the activity of lipoxygenase extracted from Lupinus angustifolius seeds and its interactions with native lupin polyphenols. The examinated enzyme is active at pH 7.5 causing peroxidation of linoleic acid. The main hydroperoxide produced in the presence of investigated lupin lipoxygenase was 13-hydroperoxy-octadecadienoic acid (13-HPODE t-t). In the presence of the phenolic compounds extracted from L. angustifolius seeds, the changes of lipoxygenase activity were observed. A distinct antioxidant effect of lupin polyphenols observed at their low concentration (0.58???g/ml) was almost completely overcome at higher concentration of phenolic compounds (2.91???g/ml). It comes probably from oxidation of polyphenols in the presence of lupin lipoxygenase. In this mechanism, polyphenol radical formation is possible. The formed radicals decrease the antioxidant efficiency of the phenolic compounds. Eventual phenoxyl radical-mediated peroxidation may be inhibited by the presence of antioxidants able to regenerate flavonoids.     

Effect of instantaneous controlled pressure drop on the phytate content of lupin

Although legumes provide health benefits, they also contain antinutritional factors like phytate. Excessive amounts of phytate in the diet can lead to mineral deficiencies and phytate should be eliminated by processing. During food processing and digestion, phytate can be dephosphorylated to produce degradation products such as myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphates. This paper reports the effect of instantaneous controlled pressure drop (Détente Instantanée Contrôlée, or DIC) treatment on the phytate content of Lupinus albus and Lupinus mutabilis seeds. The results show the potential of the DIC process for the treatment of lupin seeds: phytate content decreased by 16% (L. albus) and 19% (L. mutabilis) after 1 min of DIC treatment and by up to 55% (L. albus) and 60% (L. mutabilis) after a 7 min treatment.     

Germination and Debittering Lupin Seeds Reduce α-Galactoside and Intestinal Carbohydrate Fermentation in Humans

Subjects submitted to untreated and processed test meals of Lupinus albus and Lupinus angustifolius had decreases in breath-hydrogen concentrations (as maximum and cumulative changes), for processed samples compared to untreated samples. Maximum changes (means) in breath-hydrogen decreased from 56.7 and 66.7 Δppm in untreated L. albus and L_- angustifolius, respectively, to 8.4. and 5.9 Δppm in debittered samples (p <0.001). and to 29.6 Δppm in germinated L. albus (p<0.01). Results paralleled the decrease in α-gaiactoside contents of germinated and debittered samples which showed over 90% reduction. Germination and debittering were very effective but debittering was more efficient to decrease fermentation in the human colon.     

Chemical,biological and sensory evaluation of pasta products supplemented with α‐galactoside‐free lupin flours

α‐Galactoside‐free lupin flour has been used to supplement durum wheat semolina flour in order to increase the nutritive value of pasta products. Supplemented pasta products had a shorter cooking time, higher cooking water absorption, cooking loss and protein loss in water than control pasta prepared with only semolina. Sensory evaluation of cooked pastas showed that products supplemented with 80 g kg^?1 of α‐galactoside‐free Lupinus angustifolius var. Emir flour or with 100 g kg^?1 of α‐galactoside‐free Lupinus angustifolius var. Troll flour showed the same acceptability by panellists as the semolina pasta. These levels of supplementation were selected for further studies. The cooked α‐galactoside‐free lupin/semolina pastas showed higher amounts of protein, dietary fibre, calcium, phosphorus, magnesium, zinc and antioxidant capacity than control pasta and a reasonable level of vitamin B₁, vitamin B₂ and vitamin E. Biological assessment of cooked pastas indicated that the true protein digestibility did not change after the fortification of semolina but protein efficiency ratio increased sharply in the pasta supplemented with α‐galactoside‐free lupin flours (2.07 and 1.92 for Emir and Troll lupin varieties, respectively) in comparison with the control pasta (1.11). It is concluded that the α‐galactoside‐free lupin flours are an adequate ingredient to improve the nutritional quality of pasta products without adding flatulent oligosaccharides. Copyright © 2006 Society of Chemical Industry     

Compositional and nutritional evaluation of several lupin seeds

Lupin seeds of different species representing diverse varieties of sweet lupin grown in Poland were investigated. The chemical compositions of lupin isolates and amino acid composition of the proteins, as well as the nutritive values were estimated. No significant differences (P ? 0.05) were observed among lupin isolates in their dry matter, crude fibre or alkaloid contents. The highest protein content (465 ± 11 g/kg d.m.) was found in seeds from lupins belonging to Lupinus luteus (P ? 0.01), while the highest oil content (ca. 115 g/kg d.m.) was found in Lupinus albus (P ? 0.05).     

Development and validation of a sandwich ELISA for the determination of potentially allergenic lupine in food

The paper presents a sandwich enzyme linked immunosorbent assay (ELISA) for the detection of traces of lupine proteins in foods. Anti-lupine antibodies were produced by immunising a rabbit and a hen with a protein extract from white lupine flour. IgY were used as coating and IgG as secondary antibodies. The ELISA detects proteins from white (Lupinus albus) and blue (Lupinus angustifolius) lupine and, with a lower sensitivity, proteins from yellow (Lupinus luteus) lupine. The ELISA does not show any cross-reactivity with 34 plant species potentially used in lupine containing foodstuffs. Accuracy, repeatability, limit of detection (LOD) and limit of quantification (LOQ) were determined by analysing model biscuits and noodles containing from 0 to 10,000 ppm lupine flour. Lupine flour could be detected in the unprocessed doughs as well as in the processed products down to a spiking level of 1 ppm.     

Effect of germination on the protein fraction composition of different lupin seeds

Sweet lupin seeds (Lupinus luteus cv. 4486 and cv. 4492 and Lupinus angustifolius cv. troll and cv. zapaton) were germinated and investigated according to protein composition, nitrogen and amino acid content of Osborne fractions. In raw lupins, globulins (G) comprised the main fraction of lupins, followed by albumins (A) and glutelins+prolamines (Gt + P). Differences in the protein profile of the Osborne fractions were found among species whilst cultivars did not show electrophoretic differences. Amino acid content of protein fractions was also studied and differences among cultivars were found. In general, Glu, Gly, Arg and Ala (as non-essential amino acids, NEAA) and Lys (as essential amino acid, EAA) were predominant in the A fraction, Glu and Arg (NEAA) and Leu and Thr (EAA) were the main ones in the G fraction; while Asp, Glu, Gly and Arg (NEAA) and Leu and Lys (EAA) were the major components of the Gt + P fraction. Germination increased the protein content of L. luteus cv. 4486, L. angustifolius cv. troll and cv. zapaton and caused sharp changes in the protein profile of the Osborne fractions. After germination, the A fraction almost disappeared in the protein profile while G and Gt + P fractions were modified, depending on the lupin species and cultivar.     

Functional lupin seeds (Lupinus albus L. and Lupinus luteus L.) after extraction of α-galactosides

Functional lupin seeds from two different cultivars of white (Lupinus albus L.) and yellow lupin (Lupinus luteus L.) each, were obtained by extraction of α-galactosides. The effect of extraction of α-galactosides from lupin seeds on different nutritional parameters (protein, fat, ash, dietary fibre, starch, sucrose, and vitamins B₁, B₂, E and C) and antinutritional factors (α-galactosides, trypsin inhibitor activity and inositol phosphates) were studied. In lupin seeds, α-galactosides were effectively removed and processed seeds contained very low amounts of flatulence causing factors (∼0.5–1%). Protein, fat and starch contents showed high retention in processed seeds (up to ∼130%). Sucrose and soluble dietary fibre, however, decreased significantly as a result of processing and retentions ranged from 10% to 60%, depending on the variety studied. Vitamins B₁, B₂, E and C were also reduced. Trypsin inhibitor activity was detected only in yellow lupin cultivars and inositol phosphate content was modified slightly after extraction. In summary, the functional lupin seeds, with low contents of α-galactosides, are a product of nutritional importance due to their high protein content, dietary fibre and fat contents as well as acceptable levels of thiamin, riboflavin and vitamin E. They can be incorporated as a proteic source, not only in animal feeding but also in a wide range of foods.     

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 10 mg/100 g 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.     

Semolina supplementation with processed lupin and pigeon pea flours improve protein quality of pasta

The objective of this work was to study the effect of processing (alcoholic extraction, fermentation and germination) on protein quality of lupin (Lupinus angustifolius L. var. Troll and Emir) and pigeon pea (Cajanus cajan L. var. Aroito) flours. Second, the effect of semolina supplementation with the processed legume flours on protein quality of pasta was also evaluated. For protein quality evaluation amino acid composition and chemical score (CS) were determined in raw and processed legume flours as well as cooked semolina pasta supplemented and non-supplemented with processed legumes. Alcoholic extraction did not cause important changes in the amino acid profile of lupin seeds. Certainly, sulphur amino acid content of ethanol extracted lupin flours was reduced but levels remained similar to those usually found in other legumes. However, fermentation and germination of pigeon pea seeds improved some essential amino acids and slight changes in CS indexes were observed. Moreover, semolina supplementation with processed lupin and pigeon pea flours improved protein quality of pasta as a result of higher CS and EAA levels compared to the control cooked semolina pasta. Therefore, ethanol extracted lupin, as well as fermented and germinated pigeon pea seeds are suitable protein sources for formulating new pasta products.