Microwave-assisted diluted acid digestion for trace elements analysis of edible soybean products

Quantification of essential and potentially toxic elements in paprika (Capsicum annuum L.) varieties by ICP OES and application of PCA and HCA

A closed-block digestion method using diluted HNO3 and detection by inductively coupled plasma optical emission spectrometry (ICP OES) was applied to determine inorganic constituents in different types of paprika (Capsicum annuum L.). The optimized conditions for decomposition were 0.25 g of sample, 2 mL HNO3 (65 % m m-1), 2 mL H2O2 (30 % m m-1), and 4 mL of deionized water at 180 °C for 2 h. The method presented the final digests with low dissolved organic carbon content and residual acid concentration. The limits of quantification ranged from 0.07 (Sr and V) to 21 μg g-1 (Ca). The proposed method was applied to quantify Ba, Ca, Cu, K, Mg, Mn, Na, P, Sr, V, and Zn in 25 paprika samples commercially available in Brazil. The PCA and HCA showed sample dispersion without defined grouping, regardless of the type of paprika, containing a uniformity between their mineral composition.

Microwave-assisted digestion for multi-elemental determination in beans, basil, and mint by ICP OES and flame photometry: An eco-friendly alternative

A microwave-assisted digestion method using diluted HNO3 was proposed for subsequent determination of Ca, Cd, Co, Cu, K, Mg, Mn, Mo, Na, P, Pb, S, V, and Zn in beans, basil, and mint using ICP OES and flame photometry. After applying factorial design, the optimized conditions were an HNO3 concentration of 1 mol L-1, 2.5 mL of H2O2, and a digestion time of 20 min. The method accuracy was assessed using seven reference materials, with statistical agreement between determined and certified values and an RSD of up to 11 %. Linearity was satisfactory (r > 0.999), and limits of quantification ranged from 0.031 mg kg-1 (Mn by ICP OES) to 60 mg kg-1 (K and Na by flame photometry). Applying the method to real samples, the concentrations obtained met the Cd limits established by international regulations. Finally, low agreement was verified between measured concentrations and those reported on food packaging.

Determination of elements in cereals, pseudocereals, and legumes by microwave plasma-atomic emission spectrometry

A novel method for multi-element analysis in cereals, pseudocereals, and legumes was developed for principal (calcium, magnesium, potassium, and phosphorus) and trace (manganese, zinc, iron, copper, and aluminum) element determination using a microwave plasma-atomic emission spectrometer (MP-AES). The method was validated using certified reference analyte values from durum wheat (DUWF-1), corn bran (BRAN-1), quinoa (KINO-1), rice (SRM 1568b), and soy (SRM 3234). Spike recoveries were assessed using field-grown crops that represent staple and minor crops with variable matrix compositions. A closed-vessel microwave-assisted digestion method consisting of 12 mL of deionized water, 2 mL of HNO3, and 2 mL of H2O2 was efficient for the mineralization of all crops. Acceptable measurement agreement was achieved between certified and determined values for all reference materials with recovery ranges from 89 to 120 percent. Plant breeders can use the method to develop and screen crops for improved nutrient density.

An Environmentally Compatible and Less Costly (Greener) Microwave Digestion Method of Bone Samples Using Dilute Nitric Acid for Analysis by ICP-MS

An environmentally compatible and less costly (greener) analytical method for the digestion of bone meal samples using microwave-assisted dilute nitric acid (HNO3) was developed and optimized. The method, employing a mixture of 1 mL concentrated HNO3 and 4 mL of deionized water, offered a comparable performance to the conventional method using 5 mL of concentrated HNO3. The accuracy of the method was validated by using certified reference material NIST 1486 (Bone Meal); percentage recoveries were within ±15% for all eight certified elements. Statistical analysis revealed no significant differences (p > 0.05) in percentage recoveries between the green and conventional methods for all elements except calcium. The greenness of the developed method was evaluated by using the analytical Eco-Scale, achieving a score of 87, categorizing it as an "excellent green analysis" method. This research highlights the potential for adopting greener practices in trace element analysis that reduce the environmental impact and safety risks associated with concentrated acids.

Nanoparticle Effects on Ice Plant Mineral Accumulation under Different Lighting Conditions and Assessment of Hazard Quotients for Human Health

Nanotechnologies can improve plant growth, protect it from pathogens, and enrich it with bioactive and mineral substances. In order to fill the lack of knowledge about the combined environmental effects of lighting and nanoparticles (NPs) on plants, this study is designed to investigate how different HPS and LED lighting combined with CuO and ZnO NPs influence the elemental composition of ice plants (Mesembryanthemum crystallinum L.). Plants were grown in hydroponic systems with LED and HPS lighting at 250 ± 5 μmol m-2 s-1 intensity, sprayed with aqueous suspensions of CuO (40 nm, 30 ppm) and ZnO (35-45 nm, 800 ppm) NPs; their elemental composition was measured using an ICP-OES spectrometer and hazard quotients were calculated. LED lighting combined with the application of ZnO NPs significantly affected Zn accumulation in plant leaves. Cu accumulation was higher when plants were treated with CuO NPs and HPS illumination combined. The calculated hazard quotients showed that the limits are not exceeded when applying our selected concentrations and growth conditions on ice plants. In conclusion, ice plants had a more significant positive effect on the accumulation of macro- and microelements under LED lighting than HPS. NPs had the strongest effect on the increase in their respective microelements.

Green sample preparation of medicinal herbs in closed digester block for elemental determination by ICP OES

This work presents a simple, cost-effective, and environmentally friendly digestion method employing inductively coupled plasma optical emission spectrometry (ICP OES) for the determination of As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, Sr, and Zn in medicinal herbs. A fractional factorial design uses a multivariate strategy to optimize the experimental parameters. At 180 ºC and 120 min of sample digestion, the optimal condition for a closed block digester was achieved with a mixture consisting of 1.38 mL of HNO3 65% m m-1, 1.00 mL of H2O2 30% m m-1, and 2.62 mL of deionized water, using a mass of 0.10 g medicinal herb sample. The optimized procedure resulted in low dissolved organic carbon content and residual acidity concentration. The values of limits of detection (LOD) and of quantification (LOQ) ranging from 0.06 (Cd) to 1.9 (P) mg kg-1 and 0.2 (Cd) to 6.3 mg kg-1 (P), respectively. Accuracy was confirmed through the analysis of three certified reference materials, where agreement ranged from 83 (Sr) to 116% (As) for all analytes. The AGREE metric has confirmed the greenness of the proposed method. Twenty-seven medicinal herbs samples were used to assess the applicability of the developed procedure. Principal component analysis (PCA) was applied to inorganic constituent concentration data to classify the medicinal herbs, an excellent tool for classifying samples.

Trace Elements in Soy-Based Beverages: A Comprehensive Study of Total Content and In Vitro Bioaccessibility

Soy-based beverages are one of the most consumed plant-based beverages, which have been used as a substitute for dairy products. Soy is a source of several nutrients (vitamins, minerals, and phenolic compounds, etc.) and its consumption is usually associated with several benefits, such as the prevention of cardiovascular diseases, cancer, and osteoporosis. However, non-essential trace elements can be found in these beverages. Thus, a comprehensive study concerning trace elements Al, As, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sb, Se, Sn, Sr, and Zn in soy-based beverages was proposed. In vitro digestion allowed to simulate the gastrointestinal juice (bioaccessibility) and the Caco-2 cells culture model was applied for the bioavailability assay. Trace elements measures were performed by inductively coupled plasma optical emission spectrometry (ICP OES). Multivariate analysis classified soy-based beverages according to their soy source (isolate protein, hydrosoluble extract, and beans); Al, Cu, Fe, Mn, Sr, Se, and Zn bioaccessible fractions corresponded to approximately 40%-80% of their total content, and soy-based beverages were found to be a good Fe, Se, and Zn source. However, our results showed risk exposure assessment from daily consumption of one glass of soy-based beverage can contribute to 3.5% and 0.9% of Al Provisional Tolerable Weekly Intake (PTWI) for children and adults, respectively.

Response of Oxidative Stress and Antioxidant System in Pea Plants Exposed to Drought and Boron Nanoparticles

Pea plants are sensitive to water shortages, making them less attractive to farmers. Hoping to reduce the adverse effects of drought on peas and considering the benefits of boron, this study aimed to investigate the impact of boron nanoparticles on the antioxidant system and oxidative stress biomarkers in drought-stressed peas. Experiments were performed in a greenhouse. Pea plants were treated with a suspension of B₂O₃ nanoparticles at 12.5, 25, and 50 ppm concentrations before ten days of water shortage. Drought effects were induced by maintaining 30% substrate moisture. This study investigated the properties of the nanoparticle suspension and different application methods for spraying and watering pea plants. The effects of B₂O₃ nanoparticles and drought were determined on pea growth indicators, oxidative stress biomarkers, and enzymatic and non-enzymatic antioxidants. Spraying with B₂O₃ nanoparticles at 12.5 ppm most effectively stimulated phenol accumulation; FRAP, DPPH, and ABTS antioxidant capacity; and APX, SOD, GPX, and CAT enzyme activity in pea leaves exposed to drought. In addition, B₂O₃ nanoparticles reduced the amount of MDA and H₂O₂ in pea plants grown on a substrate with insufficient moisture. The most substantial positive effect was found on peas affected by drought after spraying them with 12.5 ppm of B₂O₃ nanoparticles. B₂O₃ nanoparticles positively affected the pea height, leaf area, number of nodules, and yield.

Assessing OBT formation and enrichment: ROS signaling is involved in the radiation hormesis induced by tritium exposure in algae

Tritium is the main component of radioactive wastewater from nuclear power plants and can be migrated into organisms to form organically bound tritium (OBT), which may pose a potential risk to aquatic ecosystem. Hence, it is essential to monitor OBT conversion in the presence of tritium exposure. In this study, the effects of pretreatment methods such as digestion on the recovery of tritium were discussed. It was found that microwave digestion pretreatment could improve the recovery of tritium by up to 90 % and allow OBT measurement with a small sample size equivalent to about 60 mg (dry weight). In addition, the efficiency of OBT transformation was different among biological samples, and the radiation hormesis phenomenon was induced by tritium exposure (3.7 × 10⁶ Bq/L) in microalgae Chlorella vulgaris（C. vulgaris）. The tritium exposure may induce radiation hormesis through the reactive oxygen species (ROS) signaling pathway, thus improving the photosynthetic capacity and metabolism level of C. vulgaris. Furthermore, enhancement of photorespiration metabolism and the antioxidation system may be important means for C. vulgaris to balance damage by tritium radiation. This study provides insights for further investigating OBT behavior, and will contribute to understanding the equilibrium damage mechanism of algae exposed to tritium.

Microwave-assisted digestion method using diluted nitric acid and hydrogen peroxide for the determination of major and minor elements in milk samples by ICP-OES and ICP-MS

A novel method for microwave-assisted digestion of milk samples using diluted HNO₃and H₂O₂ with a single reaction chamber was developed for elemental analysis by ICP-based techniques. The optimal conditions for digestion were 0.25 g of sample mass, 6 mL of 0.1 molL^-1HNO₃and 2 mL of 30% H₂O₂ at 250 ℃ and 160 bar. The optimized procedure resulted in low residual carbon content and residual acidity of 260 mgL^-1 and 0.06 mol L^-1, respectively. The limits of detection ranged from 0.286ոg g^-1(Ca) to 82.990ոg g^-1(Fe). In addition, the proposed method was considered an excellent green analysis method with a final score of 87 based on the analytical Eco-Scale. Finally, the method was validated and applied to the determination of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sb, Se, and Zn in milk samples from South Korea.

Concentration of Potentially Toxic Elements in Vegetable Oils and Health Risk Assessment: a Systematic Review and Meta-analysis

The present study evaluates the concentration of potentially toxic elements (PTEs), including Pb, Cd, As, Fe, Zn, Cu, and Ni, in vegetable oils through a meta-analytic approach. The published studies in relation to the concentrations of PTEs in vegetable oils were retrieved from major international databases such as PubMed, Scopus, Web of Science, and Embase followed by meta-analysis. Moreover, the health risk assessment was evaluated using total target hazard quotient (TTHQ) by a Monte Carlo simulation (MCS) model. According to the results of 51 articles included among 958 retrieved studies, the concentrations of the PTEs were as follows: Cd ≈As (0.110 mg/kg) > Pb (0.086 mg/kg) in cottonseed, canola, and olive oil and Fe (12.964 mg/kg) > Zn (1.044 mg/kg) > Ni (0.893 mg/kg) > Cu (0.264 mg/kg) in cottonseed, olive, and soybean for trace elementals, respectively. Based on the continent type, the higher concentration of Cd, As, and Pb was related to PAHO (American region) and AFRO (African region), and the higher concentrations of Fe, Zn, Cu, and Ni were observed in WPRO (Western Pacific Region), EMRO (Eastern Mediterranean Region), and AFRO. On the other hand, non-carcinogenic health risk assessment of the PTEs indicated that there was a different risk pattern in various countries, and the TTHQ level in adult groups was lower than 1. It can be concluded that the consumption of vegetable oils is safe and does not pose risk to the health of consumers.

The Influence of Rootstock and High-Density Planting on Apple cv. Auksis Fruit Quality

Global demand for food is increasing each year, but the area of land suitable for farming is limited. Thus, there is a need to grow not only larger quantities of food but also higher quality food products in the same area. This study aimed to evaluate the influence of rootstock and high-density orchards on cv. Auksis fruit quality. Two rootstocks were selected for this experiment, P 22 super dwarfing and P 60 dwarfing. Apple trees cv. Auksis were planted in the year 2001 in single rows spaced 1.00 m, 0.75 m, and 0.50 m, apart with 3 m between rows. High-density planting and rootstock combination was found to have no significant effect on sugar accumulation and most of the elements in apple fruits. However, super dwarfing P 22 rootstock accumulated significantly higher (up to 45%) content of organic acids and up to 33%-44% lower DPPH free radical scavering activity compared to P 60 dwarfing rootstock. After summarizing the obtained results, apples which accumulated the most antioxidants (according to the activity of phenolic compounds, DPPH^• and ABTS^•), magnesium, and potassium were collected from cv. Auksis apple trees which was grafted on super dwarfing P 22 rootstock and planted at 3 × 0.75 m distances.

Effect of Different Ratios of Blue and Red LED Light on Brassicaceae Microgreens under a Controlled Environment

The consumption of microgreens has increased due to their having higher levels of bioactive compounds and mineral nutrients than mature plants. The lighting conditions during the cultivation of microgreens, if optimally selected, can have a positive effect by further increasing their nutritional value. Thus, our study aimed to determine the changes in mineral nutrients contents of Brassicaceae microgreens depending on different blue–red (B:R) light ratios in light-emitting diode (LED) lighting and to evaluate their growth and nutritional value according to different indexes. Experiments were performed in controlled environment growth chambers at IH LRCAF, 2020. Microgreens of mustard (Brassica juncea ‘Red Lace’) and kale (Brassica napus ‘Red Russian’) were grown hydroponically under different B:R light ratios: 0%B:100%R, 10%B:90%R, 25%B:75%R, 50%B:50%R, 75%B:25%R, and 100%B:0%R. A 220 μmol m⁻² s⁻¹ total photon flux density (TPFD), 18 h photoperiod, 21/17 ± 2 °C temperature and 60% ± 5% relative humidity in the growth chamber were maintained during cultivation. We observed that an increasing percentage of blue light in the LED illumination spectrum during growth was associated with reduced elongation in the microgreens of both species and had a positive effect on the accumulation of mostly macro- and micronutrients. However, different B:R light ratios indicate a species-dependent response to changes in growth parameters such as leaf area, fresh and dry mass, and optical leaf indexes such as for chlorophyll, flavonol, anthocyanin, and carotenoid reflectance.

Multi-element determination in chocolate bars by microwave-induced plasma optical emission spectrometry

Macro- and microelement determination in chocolate bars by microwave-induced plasma optical emission spectrometry (MIP OES) was evaluated after microwave-assisted sample digestion. Optimization of the sample digestion was carried out, and the recommended conditions were obtained at a temperature of 190 °C, with a digestion time of 40 min and in a mixture constituted by 2.3 mL of nitric acid, 1.0 mL of hydrogen peroxide and 4.7 mL of water. The method was applied in the analysis of chocolate bars, and the concentration ranges of the elements determined were (in mg kg^-1): Ca (653-3096); Cr (<0.6-2.8); Cu (<0.16-19.5); Fe (<1.6-227); Mg (147-2775); K (3554-8573); Mn (<0.03-25.2); Na (45.6-1095); Ni (3.2-10.2); P (1111-22594) and Zn (4.8-33.3). The association of the proposed microwave-assisted acid digestion with the MIP OES technique was adequate for multi-element determination in chocolate bars for routine analysis.

Determination of Cl, Br and I in granola: Development of an accurate analytical method using ICP-MS

Microwave-induced combustion (MIC) system for further Cl, Br, and I determination in granola by inductively coupled plasma mass spectrometry (ICP-MS) was proposed. A high sample mass of granola was pressed as pellets and inserted into the proposed MIC system. Water and NH₄OH were evaluated as absorbing solutions. The accuracy was estimated by the analysis of two certified reference materials and also by spike recoveries. Using the optimized conditions (zirconium ball milling, 1 g of granola and 6 mL of 50 mmol L^-1NH₄OH), the agreement with the certified values ranged from 94 to 98% and recoveries higher than 95% were obtained. Low carbon concentration in digests (<25 mg L^-1) was achieved, minimizing interferences by ICP-MS. Blanks were negligible and only diluted solutions were required. The concentration in samples ranged from 322 to 896, 0.618 to 0.980 and < 0.002 to 0.181 µg g^-1 for Cl, Br and I, respectively.

Ilex Paraguariensis exposition to As and Cd in a closed soilless system

The exposition of mate (Ilex Paraguariensis A. St.-Hil.) to As and Cd was investigated in plants derived from young mini-cuttings. Mate plants were cultivated in a closed soilless system, composed of coarse sand as substrate and flood fertirrigation. Plantlets were fertirrigated with nutritive solution and As and Cd solutions were added to the nutritive solution in the final concentration of 8 and 17 mg L^-1 (As) and of 17 and 33 mg L^-1 (Cd) during 14 days. Results show that stem diameter and Dickson quality index (DQI) variables could not be used as a potential indicator of accumulation of As and Cd. The shoot height, number of leaves and chlorophyll index are variables easy and quick to measure and they can be used as parameters to evaluate the stress caused in mate plants cultivation in a closed soilless system. The highest concentration of As and Cd was in roots of plants. Beyond the roots, As and Cd also can be translocated to the leaves achieving high concentrations. In addition, leaves from the treated mate plants were submitted to a hot infusion extraction in order to simulate the traditional beverage and As and Cd were determined in the infusion. Regarding to the infusion procedure, considerable As and Cd amounts were extracted from the leaves leading to conclude that this way of consumption can be an important source of toxic elements for the human diet.

Challenges and trends for halogen determination by inductively coupled plasma mass spectrometry: A review

RATIONALE

In this review, works published in the past 25 years for fluorine, chlorine, bromine, and iodine determination in several matrices by inductively coupled plasma mass spectrometry (ICP-MS) were covered. Usually, the determination of halogens has been performed by ICP-MS using a previous sample preparation step or, more recently, by direct analysis of solid or liquid samples.

METHODS

Methods based on combustion, extraction, pyrohydrolysis, sample dilution in organic or aqueous medium, and wet digestion, among others, are discussed. Moreover, the recent applications of methods based on laser ablation (LA) and electrothermal vaporization (ETV) coupled to ICP-MS are discussed.

RESULTS

The main challenge for methods using sample preparation has been to obtain a final solution compatible with ICP-MS, as well as to overcome problems related to analyte losses and contamination. Interferences due to the presence of dissolved organic compounds in solution, enhancement or suppression of ionization of analytes, and related matrix effects have been of concern when using ICP-MS. For the determination of halogens by ICP-MS using LA and ETV systems, some limitations related to the difficulty of calibration are pointed out, impairing the widespread use of this approach.

CONCLUSIONS

A critical view is presented for further halogen determination by ICP-MS, mainly for matrices considered difficult to digest using conventional protocols.

Response of Mustard Microgreens to Different Wavelengths and Durations of UV-A LEDs

Ultraviolet A (UV-A) light-emitting diodes (LEDs) could serve as an effective tool for improving the content of health-promoting bioactive compounds in plants in controlled-environment agriculture (CEA) systems. The goal of this study was to investigate the effects of UV-A LEDs at different wavelengths (366, 390, and 402 nm) and durations (10 and 16 h) on the growth and phytochemical contents of mustard microgreens (Brassica juncea L. cv. "Red Lion"), when used as supplemental light to the main LED lighting system (with peak wavelengths of 447, 638, 665, and 731 nm). Plants were grown for 10 days under a total photon flux density (TPFD) of 300 µmol m^-2 s^-1 and 16-h light/8-h dark period. Different UV-A wavelengths and irradiance durations had varied effects on mustard microgreens. Supplemental UV-A radiation did not affect biomass accumulation; however, the longest UV-A wavelength (402 nm) increased the leaf area of mustard microgreens, regardless of the duration of irradiance. The concentration of the total phenolic content and α-tocopherol mostly increased under 402-nm UV-A, while that of nitrates increased under 366- and 390-nm UV-A at both radiance durations. The contents of lutein/zeaxanthin and β-carotene increased in response to the shortest UV-A wavelength (366 nm) at 10-h irradiance as well as longer UV-A wavelength (390 nm) at 16 h irradiance. The most positive effect on the accumulation of mineral elements, except iron, was observed under longer UV-A wavelengths at 16-h irradiance. Overall, these results suggest that properly composed UV-A LED parameters in LED lighting systems could improve the nutritional quality of mustard microgreens, without causing any adverse effects on plant growth.

Fe and Zn in vitro bioavailability in relation to antinutritional factors in biofortified beans subjected to different processes

The present work evaluated the effect of different processes in relation to mineral content and its bioavailability, as well as the effect of phytate and oxalate contents in biofortified beans. The following treatments were evaluated: raw beans (RB), cooked and oven-dried soaked beans (BOS), cooked and freeze-dried soaked beans (BFS), cooked and oven-dried beans without soaking (BOWS) and cooked and freeze-dried beans without soaking (BFWS). The mineral contents (mg per 100 g) varied between 3.56 and 5.80 (iron), 20.26 and 89.32 (calcium) and 1.56 and 2.38 (zinc). The oxalate content varied from 3.74 to 10.54 mg per 100 g. The total phytate content ranged from 1803.23 to 2.301 mg per 100 g. Regarding mineral bioavailability in Caco-2 cells, iron retention ranged from 8.89 to 17.85% and uptake was from 12.07 to 13.74 μg. On the other hand, the zinc retention was from 92.27 to 98.6% and uptake ranged from 24.68 to 36.26 μg. The different forms of bean processing can contribute to the mineral profile of this legume, in addition to increasing the bioavailability of some minerals, such as iron and zinc.

Investigation of a rapid infrared heating assisted mineralization of soybean matrices for trace element analysis

A fast sample preparation procedure based on use of infrared (IR) assisted heating for mineralization of soybean derived samples has been developed for their subsequent multielement analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). A cold finger was examined for refluxing of acid vapors to determine its impact on efficiency and economy of digestion. The optimized procedure, based on 1 g subsamples, 8 mL of HNO3 (65% w/w) and exposure of the mixture to a 500 W IR source for 5 min without refluxing, permitted accurate determination of all analytes in NIST SRM 1568b (rice flour). Detection limits using ICP-OES were (µg/kg) 97, 1.0, 39, 185, 0.47 and 1200 for Ca, Cu, Fe, K, Mn and P, respectively, and 18 for Zn by FAAS. The IR-assisted digestion approach provided a low cost, easy to use system having great potential for implementation in routine analysis of trace elements in soybean and similar matrices.

Microwave Pretreatment and Enzymolysis Optimization of the Lotus Seed Protein

Pretreatment with a microwave was conducted before enzymolysis and shown to enhance the enzymolysis, which changed the secondary structure of the lotus seed protein. Under high-power microwave irradiation, sub bonds of the protein were broken, causing disaggregation and unfolding of the secondary structure, namely a decrease in the intermolecular aggregate structure and increase in the random coil structure, making the protein bonds susceptible to papain in the enzymolysis. On the other hand, a response surface methodology (RSM) was launched to investigate the influence of the enzymolysis process variables on the DH (degree of hydrolysis). The statistical analysis revealed that the optimized conditions were a protein substrate concentration of 15 g/L, pH of 5.5, enzymolysis temperature of 57 °C, papain amount of 0.5 g/L, and enzymolysis time of 45 min, for which the predicted value of the DH was 35.64%. The results indicated that a microwave also had better potential for applications in the enzymolysis of foods.

High copper levels in follicular fluid affect follicle development in polycystic ovary syndrome patients: Population-based and in vitro studies

Although the adverse effects of copper overexposure on the liver, kidney, spleen and intestinal organs are well known, information about the impact of copper toxicity on human reproduction is limited. A total of 348 infertile patients were enrolled in our present study, including 89 with polycystic ovary syndrome (PCOS), 145 with fallopian tube obstruction and 114 controls. The follicular fluid concentrations of 22 trace elements were measured by inductively coupled plasma mass spectrometry (ICP-MS). Principal component analysis was used to identify trace element profile alterations in different groups. The mRNA levels of steroidogenesis-related genes were measured by real-time PCR. Our results showed that the trace element profile in follicular fluid was obviously altered in PCOS patients. Copper concentrations were significantly (p < .05) higher in the PCOS group than in the other two groups. Increased copper levels in follicular fluid were associated with a higher number of retrievable oocytes in the PCOS group (B = 1.785, p = .001) but a lower rate of high-quality embryos (B = -6.360, p = .050). Moreover, follicular fluid copper levels were positively correlated with follicular fluid progesterone levels (r = 0.275, p = .010) and testosterone levels (r = 0.250, p = .022). Cultured human granulosa cells overexposed to copper showed significantly (p < .05) increased estradiol secretion and decreased testosterone levels. Real-time quantitative PCR revealed a significant (p < .05) increase in CYP19A1 and HSD3b mRNA expression. Our results indicate that increased copper levels in follicular fluid could affect follicle development in PCOS patients, and the mechanism may be related to copper-induced abnormalities in steroidogenesis.

Nutrient Levels in Brassicaceae Microgreens Increase Under Tailored Light-Emitting Diode Spectra

To increase the nutritional value and levels of essential minerals in vegetable food, microgreens are promising targets. The metabolic processes of microgreens can be managed with different cultivation techniques, which include manipulating the properties of light derived by light-emitting diodes (LEDs). In this study Brassicaceae microgreens (kohlrabi Brassica oleracea var. gongylodes, broccoli Brassica oleracea, and mizuna Brassica rapa var. Japonica) were cultivated under different light spectral quality, and the metabolic changes insoluble sugars (hexoses and sucrose), ascorbic acid, β-carotene, and contents of non-heme iron (Fe) and its connection with magnesium (Mg) or calcium (Ca) levels were monitored. Plants grew under the primary LED light spectrum (the combination of blue light at 447 nm, red at 638 and 665 nm, and far-red at 731 nm) or supplemented with LED green light at 520 nm, yellow at 595 nm, or orange at 622 nm. The photoperiod was 16 h, and a total PPFD of 300 µmol m^-2 s^-1 was maintained. Under supplemental yellow light at 595 nm, the content of soluble carbohydrates increased significantly in mizuna and broccoli. Under all supplemental light components, β-carotene accumulated in mizuna, and ascorbic acid accumulated significantly in kohlrabi. Under supplemental orange light at 622 nm, Fe, Mg, and Ca contents increased significantly in all microgreens. The accumulation of Fe was highly dependent on promoters and inhibitors of Fe absorption, as demonstrated by the very strong positive correlations between Fe and Ca and between Fe and Mg in kohlrabi and broccoli, and the strong negative correlations between Fe and β-carotene and between Fe and soluble carbohydrates in kohlrabi. Thus, the metabolic changes that occurred in treated microgreens led to increases in the contents of essential nutrients. Therefore, selected supplemental LED wavelengths can be used in the cultivation of Brassicaceae microgreens to preserve and increase the contents of specific nutritionally valuable metabolites.

Analysis of children modelling clay (toy) using inductively coupled plasma-based methods

This work proposes the application of a Doehlert design to optimize dilute HNO₃ and H₂O₂ concentrations employed for the digestion of samples of modelling clay for children (used as toy). Inductively coupled plasma-based (ICP) methods were employed to determine 22 inorganic constituents (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Sb, Se, Sr, V and Zn) in children's modelling clay samples. The limits of quantification (LoQ) obtained were between 0.003 mg kg^-1 (Cd, Co and Sb) and 0.54 g kg^-1(Ca) employing ICP-based methods. The accuracy and precision of the methods were evaluated by analysing the certified reference materials (CRMs) oyster tissue (NIST 1566b), rice flour (NIST 1568b), peach leaves (NIST 1547) and tomato leaves (NIST 1573a), along with addition and recovery tests. The children's modelling clay samples presented concentrations of As, Ba, Cd, Cr, Pb, Sb and Se in agreement with the maximum values established by National Institute of Metrology, Quality and Technology (Instituto Nacional de Metrologia, Qualidade e Tecnologia - INMETRO). However, for other elements it were obtained concentrations within the following ranges: Al (0.83 ± 0.12-2.91 ± 0.04 g kg^-1), Ca (16.09 ± 0.20-24.56 ± 1.00 g kg^-1), Cu (< 0.30-30.01 ± 2.11 mg kg^-1), Fe (< 5.3 - 13.21 ± 3.94 mg kg^-1), K (1.31 ± 0.33-33.47 ± 0.75 g kg^-1), Mg (0.90 ± 0.04-1.36 ± 0.05 g kg^-1), Mn (3.32 ± 0.10-121.05 ± 1.88 mg kg^-1), Na (12.07 ± 0.88-36.77 ± 0.50 g kg^-1), Sr (4.23 ± 0.47-22.43 ± 6.95 mg kg^-1), P (1.00 ± 0.13-57.43 ± 0.88 g kg^-1), V (0.25 ± 0.07-1.15 ± 0.19 mg kg^-1), S (3.57 ± 0.77-48.49 ± 1.02 g kg^-1), Zn (< 4.4-11.82 ± 0.49 mg kg^-1), Co (0.020 ± 0.002-0.060 ± 0.020 mg kg^-1) and Ni (< 0.03-1.33 ± 0.46 mg kg^-1). These elements have no minimum and maximum limits established by legislation for children's modelling clay so, a comparison was not possible. The ICP-based methods presented an efficient routine application in the analysis of modelling clay.

Influence of Digestion Procedure and Residual Carbon on Manganese, Copper, and Zinc Determination in Herbal Matrices by Atomic Absorption Spectrometry

Mineralization to the complete oxidation of sample carbon component does not always assure the best analyte recovery. Particular attention should be paid to the presence of silicon in the investigated plant sample and especially in the certified reference material for which Si content is scarcely given by the providers. During mineralization without addition of the hydrofluoric acid, the residual carbon may block silica surfaces and increase availability of an analyte for its spectral determination in the solution. This issue is of particular relevance because standard protocols for digestion of plant matrices often do not support hydrofluoric acid addition. Several procedures recommended for decomposition of herbal plants were applied for the respective certified reference material and examined in detail. Manganese, copper, and zinc contents were analyzed in all samples by the flame atomic absorption spectrometry. Additionally, the residual carbon was determined in all mineralizates. Silicon content was analyzed by the X-ray fluorescence method. The best recoveries were observed for samples characterized by relatively high residual carbon.

"Manganese-induced neurotoxicity: a review of its behavioral consequences and neuroprotective strategies"

Manganese (Mn) is an essential heavy metal. However, Mn’s nutritional aspects are paralleled by its role as a neurotoxicant upon excessive exposure. In this review, we covered recent advances in identifying mechanisms of Mn uptake and its molecular actions in the brain as well as promising neuroprotective strategies. The authors focused on reporting findings regarding Mn transport mechanisms, Mn effects on cholinergic system, behavioral alterations induced by Mn exposure and studies of neuroprotective strategies against Mn intoxication. We report that exposure to Mn may arise from environmental sources, occupational settings, food, total parenteral nutrition (TPN), methcathinone drug abuse or even genetic factors, such as mutation in the transporter SLC30A10. Accumulation of Mn occurs mainly in the basal ganglia and leads to a syndrome called manganism, whose symptoms of cognitive dysfunction and motor impairment resemble Parkinson’s disease (PD). Various neurotransmitter systems may be impaired due to Mn, especially dopaminergic, but also cholinergic and GABAergic. Several proteins have been identified to transport Mn, including divalent metal tranporter-1 (DMT-1), SLC30A10, transferrin and ferroportin and allow its accumulation in the central nervous system. Parallel to identification of Mn neurotoxic properties, neuroprotective strategies have been reported, and these include endogenous antioxidants (for instance, vitamin E), plant extracts (complex mixtures containing polyphenols and non-characterized components), iron chelating agents, precursors of glutathione (GSH), and synthetic compounds that can experimentally afford protection against Mn-induced neurotoxicity.

Chemometric evaluation of trace metals in Prunus persica L. Batech and Malus domestica from Minićevo (Serbia)

The samples of spatial soils and different organs of Prunus persica L. Batech and Malus domestica were analyzed by methods such as inductively coupled plasma optical emission spectroscopy (ICP-OES), Hierarchical Cluster Analysis (HCA), One-way ANOVA, and calculation of biological accumulation factors (BAFs) with the aim of investigating whether these methods may help in the evaluation of trace metals in plants, as well as in the estimation of plant bioaccumulation potentials. ICP-OES provided accurate data on present concentrations of Cu, Zn, Pb, As, Cd, and Ni which showed that most concentrations were in normal ranges, except in some cases for Cu, Zn, and As. HCA illustrated nicely various specifics in the distribution of metals in both investigated systems plant-soil. One-way ANOVA pointed successfully on the existing statistical differences between metal concentrations. Calculated BAFs showed that both plants had very low accumulation rates for all elements; they acted as metal excluders.

The effects of black soybean (Glycine max var.) on chronic cervical pain of sedentary office workers in a northern Chinese population

Chronic cervical pain is a common symptom of sedentary office workers. Black soybean (Glycine max var.) has rich necessary nutrients for the therapy of chronic pain. Thus, it may ease chronic cervical pain. To prove our claim, 260 sedentary office workers with chronic pain were recruited and they consumed the defined diets at breakfast, lunch, and dinner with 1 g, 5 g and 10 g (3 g, 15 g, 30 g daily) cooked black soybean for 24 weeks. Visual analog scale (VAS), neck disability index (NDI) pain scores and short-form 36 (SF-36) health survey questionnaires were applied in the study. The levels of N-methyl-D-aspartate receptors (NMDAR) were measured. The VAS and NDI pain scores reduced and SF-36 scores increased in a 15 or 30 g black soybean daily group compared with a 3 g black soybean daily group after a 24-week therapy (P < 0.05). The 30 g black soybean daily group was better than the 15 g black soybean daily group in relieving chronic cervical pain of sedentary office workers (p < 0.05). The levels of NMDAR were lower in the 15 or 30 black soybean daily group than those in the 3 g black soybean daily group (P < 0.05). Black soybean can ameliorate chronic cervical pain by down-regulating the levels of NMDAR.