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Background and Aims: Wet processed alfalfa-based products can provide high-quality concentrated protein, also contain nutrients and phytochemicals. Agronomic fortification can increase selenium (Se) incorporation into green biomass. For this reason, the aim was to investigate how different forms of Se are incorporated into the green biomass of multiple-harvest alfalfa and how they affect the chemical quality of the processed product candidates. Methods: In this research, alfalfa was enriched with three forms of selenium at different concentrations [selenate (Se(VI)); selenite (Se(IV)); and red elemental Se (Se0)]. The fortified green biomass was fractionated into leaf protein concentrate (LPC), fiber and phytoserum, and changes in selenium content and speciation, protein and phytochemical composition were determined. Results: Total Se content in alfalfa fractions drastically reduced within the four consecutive harvests, particularly for Se(VI) and Se(IV) forms, and significantly varied according to the Se treatments. Selenomethionine (SeMet) was the predominant organic Se species in LPC (35.7–246.0 µg g −1 DW) and fiber (9.0- 47.7 µg g −1 DW) fractions. Se-fortification induced considerable changes in the crude protein of LPC, which varied between 29—45 (m/m)%. Phytochemical composition markedly varied among Se-treatments. Besides several flavonoids, aglycones and glycosyl derivatives, apigenin glucuronide, and apigenin were the most abundant with a concentration up to 170.85 µg g −1 DW. Medicagenic acid concentration was below 1.86 µg g −1 DW in LPC. Conclusions: Se-enhanced alfalfa green biomass could provide functional products, such as LPC, for human and animal consumption with enhanced nutritional value, including Se, protein, and phytochemical contents. [ABSTRACT FROM AUTHOR]

Tolerance of plants towards selenium, a non-essential microelement for higher plants, is a key issue when designing either the indirect (selenium-depletion from highly seleniferous soils) or directed (selenized feed production) enrichment of selenium in forages. Alfalfa (Medicago sativa L.), the well-known forage crop of the Fabaceae family, has been gaining considerable interest due to its application as a green manure, as a cover crop, or in soil remediation by nitrogen fixation. The goal of our study was to assess into which selenocompounds alfalfa plants biotransform the excess selenium uptake from the soil. Selenocompounds (other than selenomethionine and inorganic forms) accumulated in the fiber and the so-called brown juice by-product fractions of processed alfalfa biomass were targeted. Inductively coupled plasma – mass spectrometry assisted multidimensional (strong anion exchange, strong cation exchange, reversed phase) orthogonal chromatographic purification was applied to supply Se-containing fractions in adequately high purity for electrospray high-resolution mass spectrometry (used for the first time for this matrix) analyses. As a total, 30 selenocompounds (with isomers) were described, showing the abundance of the derivatives of selenohexose, selenohomolanthionine, and 2,3-dihydroxypropionic acid. Out of the 30 selenocompounds, 15 could be assigned the elemental composition, and the tentative structure of five compounds including among others deamino-2-oxo-selenohomolanthionine, deamino-hydroxy-selenohomolanthionine, and the dimer of 2,3-dihydroxypropionyl-selenohomocysteine could be presented. The studied fractions arising from the standard alfalfa processing technology contained a wide variety of selenocompounds whose origin can be either the plant's inherent Se metabolism or the processing technology itself. The importance of negative mode data acquisition has been highlighted, as out of the 30 compounds, 16 could be detected exclusively in this electrospray ionization mode. • Tolerance of alfalfa against selenium in selenite-containing soil is described. • 30 selenocompounds detected with multidimensional LC-ICP-MS/ESI-HRMS setups. • Derivatives of selenohomolanthionine and 2,3-dihydroxypropionic acid are assigned. • Selenocompound formerly reported in yeast selenometabolism detected now in alfalfa. • Tentative assignment of 18 selenosugars (with isomers) presented. [ABSTRACT FROM AUTHOR]

ALFALFA is considered as "the Queen of the Forages" due to its high protein content and nutritional value. The production of alfalfa under different stressful environments is a great challenge, representing a serious threat to global food security. To improve the production of alfalfa under stressful conditions, there is a crucial need to understand the response of alfalfa plants to stresses, the mechanisms of tolerance and the management options. Alfalfa is a promising biorefinery crop from which leaf protein concentrates as well as bio-organic fertilizers can be produced. The potential of leaf-derived protein concentrate for human and animal nutrition is huge, yet unexploited. The bio-organic fertilizers derived from alfalfa plants represent a sustainable way to supply the plant with some nutrients. This review article highlights the sustainable use of alfalfa in biorefinery and bio-organic fertilizer production. Moreover, scattered knowledge about its use for production is collected supporting its suitability for improving soil fertility. Last, we discuss the suitability of alfalfa to produce stable yields in the light of changing climate and stressful conditions like salinity. نظرا لقيمته الغذائية وإرتفاع محتواه من البروتين. إن إنتاج البرسيم » ملكة الأعلاف « يعتبر البرسيم الحجازى الحجازى تحت ظروف الإجهادات البيئية المختلفة، والتي تمثل تهديدًا خطيرًا للأمن الغذائي العالمي، تحديًا كبيرًا. ولتحسين إنتاجية البرسيم الحجازى تحت ظروف الإجهاد ، فإن هناك حاجة ماسة لفهم إستجابة نباتات البرسيم الحجازى للإجهاد وآليات التحمل وأساليب الإدارة. البرسيم الحجازى محصول حيوى واعد، فمنه يمكن إنتاج مركزات بروتين الأوراق والأسمدة العضوية الحيوية. إن إمكانات تركيز البروتين المشتق من الأوراق لتغذية الإنسان والحيوان هائلة، ولكنها غير مستغلة. تمثل الأسمدة العضوية الحيوية المشتقة من نباتات البرسيم الحجازى طريقة مستدامة لتزويد النبات ببعض المغذيات. تسلط هذه المقالة المرجعية الضوء على الإستخدام المستدام للبرسيم الحجازى في التكرير الحيوى وإنتاج الأسمدة العضوية الحيوية. علاوة على ذلك، يتم جمع المعلومات المتناثرة حول الإستفادة من إنتاج البرسيم الحجازى ودعم مدى ملاءمته لتحسين خصوبة التربة. أخيرًا، نناقش مدى ملاءمة البرسيم لإنتاج غلات مستقرة في ضوء تغير المناخ وظروف الإجهاد مثل الملوحة. [ABSTRACT FROM AUTHOR]

A pot experiment, under greenhouse conditions, was carried out aiming at investigating the agronomic biofortification of alfalfa (Medicago sativa L.) with Se and monitoring the Se uptake and accumulation dynamics within four consecutive harvests within the same growing season. Two ionic Se forms, i.e., sodium selenate (Se (VI)) and sodium selenite (Se (IV)), were applied once at a rate of 1, 10, and 50 mg kg−1 (added on Se basis), while 10 and 50 mg L−1 of a red elemental Se (red Se0) were used; all Se treatments were added as soil application. Application of Se (VI) at the rate of 50 mg kg−1 was toxic to alfalfa plants. The effect of Se forms on Se accumulation in alfalfa tissues, regardless of the applied Se concentration, follows: Se (VI) > Se (IV) > red Se0. The leaf, in general, possessed higher total Se content than the stem in all the treatments. The accumulation of Se in stem and leaf tissues showed a gradual decline between the harvests, especially for plants treated with either Se (VI) or Se (IV); however, the chemically synthesized red Se0 showed different results. The treatment of 10 mg kg−1 Se (VI) resulted in the highest total Se content in stem (202.5 and 98.0 µg g−1) and leaf (643.4 and 284.5 µg g−1) in the 1st and 2nd harvests, respectively. Similar tendency is reported for the Se (IV)-treated plants. Otherwise, the application of red Se0 resulted in a lower Se uptake; however, less fluctuation in total Se content between the four harvests was noticed compared to the ionic Se forms. The Se forms in stem and leaf of alfalfa extracted by water and subsequently by protease XIV enzyme were measured by strong anion exchange (SAX) HPLC-ICP-MS. The major Se forms in our samples were selenomethionine (SeMet) and Se (VI), while neither selenocysteine (SeCys) nor Se (IV) was detected. In water extract, however, Se (VI) was the major Se form, while SeMet was the predominant form in the enzyme extract. Yet, Se (VI) and SeMet contents declined within the harvests, except in stem of plants treated with 50 mg L−1 red Se0. The highest stem or leaf SeMet yield %, in all harvests, corresponded to the treatment of 50 mg L−1 red Se0. For instance, 63.6% (in stem) and 38.0% (in leaf) were calculated for SeMet yield % in the 4th harvest of plants treated with 50 mg L−1 red Se0. Our results provide information about uptake and accumulation dynamics of different ionic Se forms in case of multiple-harvested alfalfa, which, besides being a good model plant, is an important target plant species in green biorefining. [ABSTRACT FROM AUTHOR]