Rapid multi-element characterization of microgreens via total-reflection X-ray fluorescence (TXRF) spectrometry

The Effect of Light Intensity during Cultivation and Postharvest Storage on Mustard and Kale Microgreen Quality

Microgreens are vegetable greens that are harvested early while they are still immature and have just developed cotyledons. One of the disadvantages and a challenge in production is that they exhibit a short shelf life and may be damaged easily. In seeking to prolong the shelf life, some pre- and postharvest interventions have been investigated. Here, kale and mustard microgreens were grown in a controlled-environment walk-in chamber at +21/17 °C, with ~65% relative air humidity, while maintaining the spectral composition of deep red 61%, blue 20%, white 15%, and far red 4% (150, 200, and 250 µmol m-2 s-1 photosynthetic photon flux density (PPFD)). Both microgreens seemed to exhibit specific and species-dependent responses. Higher PPFD during growth and storage in light conditions resulted in increased contents of TPC in both microgreens on D5. Additionally, 150 and 250 PPFD irradiation affected the α-tocopherol content by increasing it during postharvest storage in kale. On D0 150 for kale and 200 PPFD for mustard microgreens, β-carotene content increased. D5 for kale showed insignificant differences, while mustard responded with the highest β-carotene content, under 150 PPFD. Our findings suggest that both microgreens show beneficial outcomes when stored in light compared to dark and that mild photostress is a promising tool for nutritional value improvement and shelf-life prolongation.

Microgreens on the rise: Expanding our horizons from farm to fork

Escalating public health concerns necessitate innovative approaches to food sources. Microgreens, nutrient-rich seedlings of vegetables and herbs, have gained recognition as functional foods. This review explores the evolution of microgreens, cultivation methods, biochemical changes during germination, nutritional content, health benefits, and commercial significance. Comprehensive studies have demonstrated that microgreens have an elevated level of various nutrients. Further, in vitro and in vivo research validated their antioxidant, anticancer, antibacterial, anti-inflammatory, anti-obesity, and antidiabetic properties. Microgreens, termed "desert food," show promise for sustainable food production in climate-vulnerable regions. This paper synthesizes recent research on microgreens, addressing challenges and gaps in understanding their nutritional content and health benefits. It contributes valuable insights for future research, fostering sustainable agriculture and enhancing understanding of microgreens in human health and nutrition.

Determining the Nutrient Content of Hydroponically-Cultivated Microgreens with Immersible Silicon Photonic Sensors: A Preliminary Feasibility Study

Microgreens have gained attention for their exceptional culinary characteristics and high nutritional value. The present study focused on a novel approach for investigating the easy extraction of plant samples and the utilization of immersible silicon photonic sensors to determine, on the spot, the nutrient content of microgreens and their optimum time of harvest. For the first time, it was examined how these novel sensors can capture time-shifting spectra caused by the molecules' dynamic adhesion onto the sensor surface. The experiment involved four types of microgreens (three types of basil and broccoli) grown in a do-it-yourself hydroponic installation. The sensors successfully distinguished between different plant types, showcasing their discriminative capabilities. To determine the optimum harvest time, this study compared the sensor data with results obtained through standard analytical methods. Specifically, the total phenolic content and antioxidant activity of two basil varieties were juxtaposed with the sensor data, and this study concluded that the ideal harvest time for basil microgreens was 14 days after planting. This finding highlights the potential of the immersible silicon photonic sensors for potentially replacing time-consuming analytical techniques. By concentrating on obtaining plant extracts, capturing time-shifting spectra, and assessing sensor reusability, this research paves the way for future advancements in urban farming.

Fire-induced effects on the bioavailability of potentially toxic elements in a polluted agricultural soil: implications for Cr uptake by durum wheat plants

Fire events can modify the distribution and speciation of potentially toxic elements (PTEs) in soil, especially if they are associated to organic matter (OM). In fact, OM can undergo substantial structural modifications at high temperatures, up to the complete mineralization. The present study aims to investigate the changes of PTEs' bioavailability to durum wheat (Triticum durum Desf.) plants after simulating fire events (up to 300 °C and 500 °C) in an agricultural soil polluted by Cr, Zn, Cu, and Pb. The PTEs' uptake and allocation in plant tissues were assessed using the RHIZOtest system. After the fire simulations, no evident risk of accumulation and translocation in plants was observed for Zn, Pb, and Cu. Conversely, a high accumulation in roots and a significant translocation to shoots were observed for Cr, which reached concentrations of 829 mg kg-1 in roots and 52 mg kg-1 in shoots at 500 °C. Additional experimental evidence suggested that Cr was taken up by plants grown on heated soils as Cr(VI). Once acquired by roots, only a small part of Cr (up to 6%) was translocated to shoots where it was likely present as mobile forms, as evidenced by micro X-ray fluorescence (µ-XRF) analyses. Overall, the results obtained provide evidence that the high temperatures occurring during fire events can increase the mobility and bioavailability of certain PTEs transforming apparently safe environments into potentially dangerous sources of pollution. These processes can ultimately affect the human health through the food chain transfer of PTEs or their migration into surface water and groundwater.

TXRF spectral information enhanced by multivariate analysis: A new strategy for food fingerprint

The increased costumers' request of safe and high-quality food products makes food traceability a priority for frauds identification and quality certification. Elemental profiling is one of the strategies used for food traceability, and TXRF spectroscopy is widely used in food analysis even if its potentialities have not been fully investigated. In this work, a new method for food traceability using directly TXRF spectra coupled with multivariate analyses, was tested. Twenty-four different beans' genotypes (Phaseolus vulgaris L.) grown onto two different sites have been studied. After the development of the method for beans' analysis, TXRF spectra were collected and processed with PCA combined with SNV and GLSW filter obtaining a perfect clustering of the seeds according to their geographical origin. Finally, using PLS-DA, beans were correctly classified demonstrating that TXRF spectra can be successfully used as fingerprint for food/seed traceability and that elemental quantification procedure is not necessary to this aim.

X-ray fluorescence spectrometry for environmental analysis: Basic principles, instrumentation, applications and recent trends

In recent years, the conceptual advancement on green analytical chemistry (GAC) has moved in parallel with efforts to incorporate new screening or quantitative low-cost analytical tools to solve analytical problems. In this sense, the role of solid state techniques that allow the non-invasive analysis (or with a minimum sample treatment) of solid samples cannot be neglected. This review describes the basic principles, instrumentation and advances in the application of X-ray fluorescence instrumentation to the environmental sciences research topics, published between 2006 and 2020. Obviously, and because of the enormous number of works that can be found in the literature, it is not possible to exhaustively cover all published articles and the diversity of topics related to the environment in which a solid state technique like XRF has been applied successfully. It is a question of making a compilation of the instrumentation in use, the significant advances in XRF spectrometry and sample treatment strategies to highlight the potential of its implementation for environmental assessment.

Determination of trace elements in placenta by total reflection X-ray fluorescence spectrometry: effects of sampling and sample preparation

Placental elemental composition can serve as an indicator for neonatal health. Medical studies aiming at revealing such cause-and-effect relationships or studies monitoring potential environmental influences consist of large sample series to ensure statistically sufficient data. Several analytical techniques have been used to study trace metals in human placenta. However, most techniques require provision of clear liquid sample solutions and therefore time- and reagent-consuming total digestion of biological tissue is necessary. In total reflection X-ray fluorescence spectrometry (TXRF)-a straightforward multielement analytical technique-in contrast suspensions of minute sample amounts can be analyzed directly. Therefore, herein we report on a valid method to prepare homogenous sample suspensions for sustainable and fast TXRF analysis of large sample series. The optimized method requires only 10 mg of powdered placental tissue and 1 mL nitric acid. Suspensions are readily prepared within 30 min and the found mass fractions of major, minor, and trace elements are in good agreement in comparison to analysis of digests. In addition, possible effects on fixation time and the exact sampling location, i.e., maternal vs. fetal side of the placenta, were studied applying this method. Thereby, significant differences for fetal placenta tissue compared to maternal or intermediate tissue were observed revealing accumulation of trace elements in the fetal side of the placenta. Furthermore, considerable depletion of up to 60% mass fraction with longer fixation duration occurred in particular in fetal placenta tissue. These findings help to understand the large ranges of mass fraction of elements in placenta reported in the literature and at the same time indicate the necessity for more systematic investigation of non-homogenous elements distributed in placenta taking sampling and stabilization methods into account.

The role of emerging micro-scale vegetables in human diet and health benefits-an updated review based on microgreens

Increasing public concern about health has prompted humans to find new sources of food. Microgreens are young and immature plants that have been recently introduced as a new category of vegetables, adapting their production at the micro-scale. In this paper, the chemical compositions including micro-nutrients and some typical phytochemicals of microgreens are summarized. Their edible safety and potential health benefits are also reviewed. Microgreens play an increasingly vital role in health-promoting diets. They are considered good sources of nutritional and bioactive compounds, and show potential in the prevention of malnutrition and chronic diseases. Some strategies in the pre- or post-harvest stages of microgreens can be further applied to obtain better nutritional, functional, and sensorial quality with freshness and extended shelf life. This review provides valuable nutrient data and health information for microgreens, laying a theoretical foundation for people to consume microgreens more wisely, and providing great value for the development of functional products with microgreens.

Antinutritional factors, mineral composition and functional properties of dry fractionated flours as influenced by the type of pulse

Coarse (CF) and Fine (FF) fractions were obtained by dry fractionation (air classification) of raw micronized flour (RM) of kabuli chickpea, green pea, yellow and red lentil. Pea showed the highest phytate content in RM and CF. Stachyose was the main oligosaccharide in lentils, exceeding 50 mg g-1, whereas raffinose (39.9 mg g-1) was abundant in chickpea. Antinutritional factors were significantly enriched in FF, whereas decreased in CF. Total-reflection X-ray fluorescence identified potassium as the main macronutrient in pulses. Ca was highly variable, ranging from 0.92 to 0.28 g kg-1 in pea and yellow lentil, respectively. A significant shift of minerals was observed in FF, but despite the highest phytate content, phytate:Zn ratio of lentils was lower than RM, indicating that Zn was enriched more than phytates. Yellow lentil and pea FF showed a protein content higher than 55 g 100g-1. Dry fractionation significantly affected the physicochemical properties, indicating different potential use of fractions.

Characterization of phytochemicals, minerals and in vitro medicinal activities of bael (Aeglemarmelos L.) pulp and differently dried edible leathers

Aegle marmelos (L.) is a seasonal fruit that contains significant amounts of bioactives like, phenolic acids (gallic acids, 2,3-dihydroxy benzoic acid, chlorogenic acid, p-coumaric acid, vanillic acid), flavonoid (rutin), organic acids (oxalic acid, tartaric acid, malic acid, lactic acid, acetic acid, citric acid, propionic acid, succinic acid, fumaric acid), vitamin C, vitamin B group (thiamine, niacin, pyridoxine, pantothenic acid, biotin, cobalamins, riboflavin), tocopherols (α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol), carotenes (α-carotene, β-carotene, γ-carotene, δ-carotene) and also rich in essential minerals (potassium, calcium, phosphorus, sodium, iron, copper, manganese). This study provides a comprehensive composition analysis (determined using RP-HPLC and Energy Dispersive X-Ray Fluorescence (EDXRF) Spectroscopy). In vitro medicinal activities (antioxidant activity, anti-inflammatory activity, anti-diabetic activity) are quantified for different bael samples. The study also investigates the changes of these bioactive components with freeze, sun, hot air, and microwave drying. The study gives a proper vision to preserve the nutraceutically rich pulp by converting it into fruit leather.

X-ray fluorescence application in food, feed, and agricultural science: a critical review

Recently X-ray fluorescence techniques have been widely used in food and agricultural science areas. Minimal sample preparation, nondestructive analysis, high spatial resolution, and multiple elements measurements within a single sample are among its advantages. In this review, literature of X-ray fluorescence are extensively researched and summarized from food and agricultural science areas focusing on food safety inspection, food nutrition, plant science, soil science, and Ca-related problems in horticultural crops. In addition, the advantages and disadvantages of X-ray fluorescence comparing with traditional analytical techniques of elements are also discussed. The more advanced technology such as developments of detector, scanning system, beamline capability among others would significantly increase future application of X-ray fluorescence techniques. Combination use of XRF with other tools such as chemometrics or data analytics would greatly improve its prediction performance. These further improvements offer exciting perspectives for the application of X-ray fluorescence in the food and agricultural science areas.